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  Subjects -> PHYSICS (Total: 749 journals)
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    - NUCLEAR PHYSICS (44 journals)
    - OPTICS (87 journals)
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PHYSICS (545 journals)            First | 1 2 3 4 5 6 | Last

Pattern Recognition in Physics     Open Access   (Followers: 1)
Pergamon Materials Series     Full-text available via subscription  
Phase Transitions and Critical Phenomena     Full-text available via subscription   (Followers: 1)
Philosophical Magazine     Hybrid Journal   (Followers: 2)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences     Full-text available via subscription   (Followers: 5)
Philosophy and Foundations of Physics     Full-text available via subscription  
Physica B: Condensed Matter     Hybrid Journal   (Followers: 5)
physica status solidi (a)     Hybrid Journal   (Followers: 1)
physica status solidi (b)     Hybrid Journal   (Followers: 1)
physica status solidi (c)     Hybrid Journal   (Followers: 1)
Physica Status Solidi - Rapid Research Letters     Hybrid Journal   (Followers: 1)
Physical Communication     Hybrid Journal  
Physical Review C     Full-text available via subscription   (Followers: 17)
Physical Review Special Topics - Physics Education Research     Open Access   (Followers: 6)
Physical Review X     Open Access   (Followers: 4)
Physical Sciences Data     Full-text available via subscription   (Followers: 1)
Physics - spotlighting exceptional research     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B     Full-text available via subscription   (Followers: 2)
Physics and Chemistry of Liquids: An International Journal     Hybrid Journal  
Physics and Chemistry of the Earth, Parts A/B/C     Hybrid Journal   (Followers: 3)
Physics and Materials Chemistry     Open Access  
Physics Essays     Full-text available via subscription  
Physics in Medicine & Biology     Full-text available via subscription   (Followers: 8)
Physics in Perspective     Hybrid Journal   (Followers: 1)
Physics International     Open Access   (Followers: 2)
Physics Letters A     Hybrid Journal   (Followers: 10)
Physics Letters B     Open Access   (Followers: 3)
Physics of Fluids     Hybrid Journal   (Followers: 24)
Physics of Life Reviews     Hybrid Journal   (Followers: 1)
Physics of Plasmas     Hybrid Journal   (Followers: 6)
Physics of the Dark Universe     Open Access  
Physics of the Solid State     Hybrid Journal   (Followers: 3)
Physics of Wave Phenomena     Hybrid Journal   (Followers: 1)
Physics Procedia     Partially Free   (Followers: 1)
Physics Reports     Full-text available via subscription   (Followers: 2)
Physics Research International     Open Access   (Followers: 1)
Physics Today     Hybrid Journal   (Followers: 19)
Physics World     Full-text available via subscription   (Followers: 3)
Physics-Uspekhi     Full-text available via subscription  
Physik in unserer Zeit     Hybrid Journal  
Physik Journal     Hybrid Journal  
Plasma Physics and Controlled Fusion     Hybrid Journal   (Followers: 2)
Plasma Physics Reports     Hybrid Journal   (Followers: 2)
Pramana     Open Access   (Followers: 9)
Preview     Hybrid Journal  
Proceedings of the National Academy of Sciences     Full-text available via subscription   (Followers: 452)
Proceedings of the National Academy of Sciences, India Section A     Hybrid Journal   (Followers: 3)
Progress in Materials Science     Hybrid Journal   (Followers: 18)
Progress in Planning     Hybrid Journal   (Followers: 1)
Progress of Theoretical and Experimental Physics     Open Access  
Quantum Electronics     Full-text available via subscription   (Followers: 2)
Quantum Measurements and Quantum Metrology     Open Access  
Quarterly Journal of Mechanics and Applied Mathematics     Hybrid Journal   (Followers: 3)
Radiation Effects and Defects in Solids     Hybrid Journal   (Followers: 1)
Radiation Measurements     Hybrid Journal   (Followers: 2)
Radiation Physics and Chemistry     Hybrid Journal   (Followers: 1)
Radiation Protection Dosimetry     Hybrid Journal   (Followers: 2)
Radiation Research     Full-text available via subscription   (Followers: 2)
Radio Science     Full-text available via subscription   (Followers: 3)
Radiological Physics and Technology     Hybrid Journal   (Followers: 1)
Reflets de la physique     Full-text available via subscription  
Reports on Mathematical Physics     Full-text available via subscription  
Reports on Progress in Physics     Full-text available via subscription   (Followers: 2)
Research & Reviews : Journal of Physics     Full-text available via subscription  
Research in Drama Education     Hybrid Journal   (Followers: 9)
Research Journal of Physics     Open Access  
Results in Physics     Open Access   (Followers: 1)
Reviews in Mathematical Physics     Hybrid Journal  
Reviews of Accelerator Science and Technology     Hybrid Journal  
Reviews of Geophysics     Full-text available via subscription   (Followers: 19)
Reviews of Modern Physics     Full-text available via subscription   (Followers: 17)
Revista Colombiana de Física     Open Access  
Revista Mexicana de Astronomía y Astrofísica     Open Access  
Revista Mexicana de Física     Open Access  
Revista mexicana de física E     Open Access  
Rheologica Acta     Hybrid Journal   (Followers: 3)
Russian Journal of Mathematical Physics     Hybrid Journal  
Russian Journal of Nondestructive Testing     Hybrid Journal   (Followers: 1)
Russian Physics Journal     Hybrid Journal  
Samuel Beckett Today/Aujourd'hui     Full-text available via subscription   (Followers: 2)
Science and Technology of Nuclear Installations     Open Access   (Followers: 1)
Science China : Physics, Mechanics & Astronomy     Full-text available via subscription   (Followers: 1)
Science Foundation in China     Full-text available via subscription   (Followers: 2)
Scientific Journal of Physical Science     Open Access  
Scientific Reports     Open Access   (Followers: 11)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 16)
Sensor Letters     Full-text available via subscription   (Followers: 1)
Sensors and Actuators A: Physical     Hybrid Journal   (Followers: 31)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 3)
Shock and Vibration     Hybrid Journal   (Followers: 7)
Shock Waves     Hybrid Journal   (Followers: 4)
Small     Hybrid Journal   (Followers: 8)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 20)
Solid State Physics     Full-text available via subscription  
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 1)
South African Journal for Research in Sport, Physical Education and Recreation     Full-text available via subscription   (Followers: 4)
Space Research Journal     Open Access   (Followers: 2)
Space Weather     Full-text available via subscription   (Followers: 3)
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy     Hybrid Journal   (Followers: 7)
Spectrochimica Acta Part B: Atomic Spectroscopy     Hybrid Journal   (Followers: 4)

  First | 1 2 3 4 5 6 | Last

Journal Cover physica status solidi (c)
   [3 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1862-6351 - ISSN (Online) 1610-1642
     Published by John Wiley and Sons Homepage  [1604 journals]   [SJR: 0.397]   [H-I: 27]
  • Preparation and characterization of doped and undoped nanoporous carbon
           for heavy metal removal from aqueous solution
    • Authors: Imed Ghiloufi; Lassaad El Mir
      Pages: n/a - n/a
      Abstract: Nanoporous composites based on pyrogallol and formaldehyde (PF) reached by metallic nickel nanoparticles have been prepared using sol‐gel method to obtain PF/Ni adsorbent materials. The obtained samples were subjected of heat treatment under inert atmosphere at different pyrolysis temperatures during two hours. The X‐ray diffraction analysis (XRD) shows that PF sample were composed by amorphous material while PF/Ni XRD spectra exhibited the presence of metal nickel characteristic lines. The transmission electron microscopy (TEM) images indicate that PF sample was formed by homogenous material, and metallic nickel nanoparticles sized around 30 nm were dispersed in the PF/Ni nanocomposite. These materials were used to study the effect of pyrolysis temperatures on the uptake of Cr, Ni, Cd and Co from aqueous solution. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:22.550571-05:
      DOI: 10.1002/pssc.201400017
       
  • Investigation of AlGaInP heterostructures under gamma‐irradiation in
           the field of restructuring defect structure
    • Authors: Alexander Gradoboev; Ksenia Orlova
      Pages: n/a - n/a
      Abstract: The given paper presents the results of studying the resistance of AlGaInP heterostructures with multiple quantum wells to 60Co gamma‐quantum irradiation. The research was completed for light emitting diodes (λ = 630 nm). The irradiation was completed under the passive powering mode without the imposition of the electric field while the level of exposure was characterized by the absorbed dose. It has been established that the emission power reduction has three stages. At the first stage the radiation power reduces due to radiation‐induced transformation of the initial structure defects, at the second stage – due to the introduction of radiation defects, in the extreme case the second stage transforms into the third stage (low electron injection mode). On the boundary between the first and the second stages transient processes are observed – restoration of emission power against its general reduction. The authors identify the heterostructures for which a pronounced effect of small doses is observed – restoration of emission power due to radiation‐induced relaxation of mechanical stresses without formation additional structural defects. The given process precedes the first stage of emission power reduction under gamma quantum irradiation. Besides, the authors identify the heterostructures which demonstrate two additional transient processes at the first stage. The researchers also establish the relations allowing describing the emission power change at the given stages. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:21.200279-05:
      DOI: 10.1002/pssc.201400072
       
  • Magnetic resonance in ion‐beam synthesized Fe3Si films (computer
           simulation)
    • Authors: N. A. Balakirev; V. A. Zhikharev
      Pages: n/a - n/a
      Abstract: High dose Fe+ ion implantation into Si assisted by an external magnetic field parallel to silicon surface results in the formation of thin granular film with pronounced uniaxial magnetic anisotropy in the film plane. It was suggested that the anisotropy is caused by the growth of elongated clusters of magnetic silicide Fe3Si. In the present work, the features of magnetic resonance spectra for two‐dimensional array of elongated clusters are numerically studied. Absorption spectra reveal anisotropy when observed in the magnetic field lying in the film plane. In magnetic field perpendicular to the film the dipole‐dipole interaction between the clusters results in a bimodal resonance signal at low level of the film filling. The dipolar field distribution over the (400x400) lattice for several values of the lattice filling is computer simulated. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:20.182638-05:
      DOI: 10.1002/pssc.201400083
       
  • Effect of 2.5 MeV proton irradiation on the critical parameters of
           composite HTS tapes
    • Authors: Landysh Antonova; Timofey Demikhov, Alexey Troitskii, Alexander Didyk, Alexander Kobzev, Alexander Yurasov, Sergey Samoilenkov, Galina Mikhailova
      Pages: n/a - n/a
      Abstract: In this paper we study the radiation resistance of high temperature superconductor (HTS) tapes based on GdBCO produced by SuperOx‐Japan Company to proton irradiation with an energy of 2.5 MeV in the fluence range from 6.1×1014 p/cm2 to 1×1017 p/cm2. The dependences of critical parameters on radiation fluencies were investigated. Strong influence of radiation on critical current is revealed at T=77 K in the self‐field of the sample. The change of the critical temperature dependence is not so significant. The critical current increase after proton irradiation was not revealed at the experiment conditions (at T = 77 K). The Van de Graaff accelerator in Dubna was used for the iradiation. Measurements of Tc and Ic of the samples were carried out by the DC resistive method. A radiation resistance threshold Φ = 6×1015 p/cm2 was determined. This means that the critical current does not drop by more than 20% of the initial value. The current decreases by more than an order of magnitude at Φ = 6×1016 p/cm2 and 77 K without external magnetic field. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:19.659513-05:
      DOI: 10.1002/pssc.201400104
       
  • Ion beam synthesis of embedded III‐As nanocrystals in silicon
           substrate
    • Authors: Rim Khelifi; Mathieu Frégnaux, Yann Le Gall, Dominique Muller, Guy Schmerber, Daniel Mathiot
      Pages: n/a - n/a
      Abstract: Our goal is to use the versatility of ion beam synthesis to grow nanocrystals of InxGa1‐xAs alloys embedded in a silicon substrate. We study, first, the annealing conditions necessary to grow well defined InAs and GaAs binary nanocrystals. High dose of As, Ga and In is implanted, respectively, at 130, 130 and 180 keV to have overlapping as‐implanted profiles. The nanocrystals growth is then achieved by rapid thermal annealing at various temperatures between 650 and 800 °C for 1 min under an argon gas flow. Rutherford backscattering spectroscopy profiles show that no significant impurity out‐diffusion occurs below 800 °C for both systems. In and As thermal redistributions lead to superposed profiles. Raman spectroscopy measurements prove that InAs nanocrystals are formed above 650 °C, while 800 °C annealing is necessary to obtain GaAs nanocrystals and show that these thermal budgets are enough to fully recrystallize the implanted layer. Grazing incidence X‐ray diffraction patterns exhibit clearly InAs and GaAs related peaks. These results prove that GaAs and InAs nanocrystals can be grown in a common temperature range (700‐800 °C), opening the route to the growth of ternary InxGa1‐xAs alloys in the same conditions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:18.297695-05:
      DOI: 10.1002/pssc.201400107
       
  • Contribution of iron silicide nanoparticles to the magnetic behavior of
           annealed Fe‐implanted 6H‐SiC
    • Authors: M. L. Diallo; A. Fnidiki, M. Viret, M. Drouet, D. Eyidi, A. Declémy
      Pages: n/a - n/a
      Abstract: The Fe‐implanted SiC is an interesting system in the DMS field although ion implantation induces strong microstructural defects needing post‐implantation treatments for recovery. These post‐implantation treatments often induce the formation of parasitic magnetic secondary phases. In this work, using XRD, SEM, TEM, CEMS and SQUID it is shown that post‐annealing of Fe‐implanted 6H‐SiC at 380°C with a few 1016Fe+ ions/cm2 at 900°C/60min, 1000°C/85min and 1300°C/4min enhanced the ferromagnetic ordering which can be partially explained by the formation of iron rich superparamagnetic nanoparticles. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:17.51796-05:0
      DOI: 10.1002/pssc.201400114
       
  • Photoluminescence properties of lamellar nano‐composites obtained by
           Cd intercalation of GaSe and GaSe:Eu single crystals
    • Authors: Dumitru Untila; Valeriu Cantser, Mihail Caraman, Igor Evtodiev, Liviu Leontie, Liliana Dmitroglo
      Pages: n/a - n/a
      Abstract: In this work surface morphology, composition and photoluminescence at 293 K and 78 K, of composite obtained by intercalation of GaSe and GaSe:Eu (0.49 at.% and 1.00 at.%) single crystal lamellas with Cd from vapor phase at 753 K and 830 K are investigated. As‐obtained composite consists of CdSe and microstructured GaSe single crystallites. Photoluminescence spectrum of GaSe:Eu single crystal lamellas is composed of Eu3+ emission band 5D0 → 7F1, 5D0 → 7F2 and 5D1 → 7F3 transitions) and indirect exciton line in GaSe crystallites. Emission spectrum of single crystalline GaSe–CdSe composite, at 78 K and 293 K, consists of donor‐acceptor band in GaSe microcrystallites and emission band of CdSe crystallites. Composite derived from the intercalation of GaSe:Eu (0.49 at.%) single crystals with Cd exhibits strong visible luminescence. Its quasi‐continuous photoluminescence spectrum is produced by superposition of luminescent emissions of CdSe nano‐ and microparticles, and microstructured GaSe. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:16.088233-05:
      DOI: 10.1002/pssc.201400127
       
  • Raman microscopy as a defect microprobe for hydrogen bonding
           characterization in materials used in fusion applications
    • Authors: Cédric Pardanaud; Younès Addab, Céline Martin, Pascale Roubin, Bernard Pegourié, Martin Oberkofler, Martin Köppen, Timo Dittmar, Christian Linsmeier
      Pages: n/a - n/a
      Abstract: We present the Raman microscopy ability to detect and characterize the way hydrogen is bonded with elements that will be used for ITER's plasma facing components. For this purpose we first use hydrogenated amorphous carbon samples, formed subsequently to plasma‐wall interactions (hydrogen implantation, erosion, deposition...) occurring inside tokamaks, to demonstrate how this technique can be used to retrieve useful information. We pay attention in identifying which spectroscopic parameters are sensitive to the local structure (sp3/sp2) and which gives information on the hydrogen content using isothermal and linear temperature ramp studies on reference samples produced by plasma enhanced chemical vapor deposition. We then focus on the possibility to use this fast, non‐destructive and non‐contact technique to characterize the influence of hydrogen isotope implantation in few nanometers of graphite and beryllium as C is still used in the JT‐60 tokamak and Be is used in JET and will be used as plasma‐facing component in the future reactor ITER. We also pay attention on implantation in tungsten oxide which may be formed accidently in the machine. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:15.463186-05:
      DOI: 10.1002/pssc.201400141
       
  • Ion‐induced degradation of phase stability and hardness of TiZrSiN
           nanocomposite thin films
    • Authors: V. V. Uglov; G. Abadias, S. N. Dub, G. N. Tolmachova, S. V. Zlotski, A. Michel, I. A. Saladukhin, S. S. Leshkevich, P. I. Gaiduk, V. Jasulaitene
      Pages: n/a - n/a
      Abstract: The effects of ion irradiation (180 keV Xe2+, doses 1×1016 cm–2 and 5×1016 cm–2) on the structure, phase composition and hardness of thin (300 nm) nanocomposite (Ti,Zr)1‐xSixNy films deposited by magnetron sputtering (silicon concentration x≤0.22) were studied. It was found that the increase in Si content results in the transformation of structure from nanocrystalline (x ≤ 0.07, grain size about 18 nm) to nanocomposite (0.07 ≤ x ≤ 0.11, grain size about 8 nm) and then to amorphous (x ≥ 0.18) state. Nanocomposite films consist of two‐phase: crystalline cubic (Ti,Zr)N grains (∼ 8 nm size) surrounded by a thin amorphous a ‐TiSiN layer. Ion irradiation with Xe ions triggers the crystallization of (Ti,Zr)N‐rich grains for amorphous films (x≥0.18). It was found that irradiation leads to a decrease in nanoindentation hardness, due to the accumulation of Xe ion in the film, as well as the elemental redistribution of solid solution constituents in the area of collisions cascades. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:13.959331-05:
      DOI: 10.1002/pssc.201400142
       
  • Kinetic Monte Carlo simulation of nanostructural evolution under
           post‐irradiation annealing in dilute FeMnNi
    • Authors: M. Chiapetto; C. S. Becquart, C. Domain, L. Malerba
      Pages: n/a - n/a
      Abstract: Post‐irradiation annealing experiments are often used to obtain clearer information on the nature of defects produced by irradiation. However, their interpretation is not always straightforward without the support of physical models. We apply here a physically‐based set of parameters for object kinetic Monte Carlo (OKMC) simulations of the nanostructural evolution of FeMnNi alloys under irradiation to the simulation of their post‐irradiation isochronal annealing, from 290 to 600 °C. The model adopts a “grey alloy” scheme, i.e. the solute atoms are not introduced explicitly, only their effect on the properties of point‐defect clusters is. Namely, it is assumed that both vacancy and SIA clusters are significantly slowed down by the solutes. The slowing down increases with size until the clusters become immobile. Specifically, the slowing down of SIA clusters by Mn and Ni can be justified in terms of the interaction between these atoms and crowdions in Fe. The results of the model compare quantitatively well with post‐irradiation isochronal annealing experimental data, providing clear insight into the mechanisms that determine the disappearance or re‐arrangement of defects as functions of annealing time and temperature. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:13.214493-05:
      DOI: 10.1002/pssc.201400143
       
  • Study on optical properties and γ‐ray irradiation resistance of
           heavy metal oxide tellurite glasses
    • Authors: Yongtao Zhou; Stefania Baccaro, Alessia Cemmi, Yunxia Yang, Guorong Chen
      Pages: n/a - n/a
      Abstract: Optical properties and irradiation resistance of heavy metal oxide tellurite glasses in the TeO2‐PbO‐Bi2O3‐B2O3 system doped with different ions are investigated. The results indicate that the matrix glass has a moderate UV cut‐off edges at about 386 nm wavelength. The UV cut‐off positions are obviously shifted to red by the addition of Ce4+. The introduction of Cr3+, Ce4+ and Ni2+ into the matrix glass exerts positive influences on irradiation resistance of glasses and cerium plays the most pronounced role. Such phenomena are mainly attributed to the variable valences of these cations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:11.935369-05:
      DOI: 10.1002/pssc.201400148
       
  • The inelastic thermal spike model applied to metal/insulator interfaces
    • Authors: A. Chettah; H. Amekura, R. Baeker, H. Kucal, Y. Takeda, M. Matsuda, A. Iwase
      Pages: n/a - n/a
      Abstract: Recently, inter‐diffusion induced by 200 MeV Xe ion irradiation in metal‐insulator interfaces (Bi/Al2O3and Au/Al2O3) was investigated experimentally via in‐situ RBS measurements using 16 MeV C ions. In this work, the experimental results were tried to be explained by the inelastic thermal spike model (ITSM). Although these results explained qualitatively the inter‐diffusion, the experimentally observed diffusion length (∼800 nm) at a fluence value of 7 x 1013cm‐2was much larger than the estimated maximum value within the ITSM (∼80 nm). It was found that the Bi concentration profiles measured via in‐situ RBS could not be fitted by simple diffusional ones. We suggested that the main responsible of the huge atomic diffusion exhibited by Bi in Al2O3could be the directional motion of Bi atoms in molten Al2O3triggered off by the pressure due to liquid‐vapor phase transition of Bi near the interface. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:11.231224-05:
      DOI: 10.1002/pssc.201400149
       
  • Modification and reduction of defects in thin gate dielectric of MIS
           devices by injection‐thermal and irradiation treatments
    • Authors: Vladimir V. Andreev; Gennady G. Bondarenko, Vladimir M. Maslovsky, Alexander A. Stolyarov, Dmitry V. Andreev
      Pages: n/a - n/a
      Abstract: The effect of high‐field injection‐thermal and irradiation treatments on the MIS structures reliability and defect reduction in the nanoscale gate dielectric has been investigated. Injection‐thermal treatment (ITT) of MIS structures consisted of high‐field electron injection into gate dielectric with the charge of defined value and subsequent parameter stabilization of MIS structures by means of thermal annealing. The MIS structures have been studied using novel techniques of multilevel current stress. Our study shows that the ITT can improve reliability of MIS structures (increase of charge‐to‐breakdown value) and identify defective structures. The ITT provides structural modification of SiO2 and Si–SiO2 interfaces. It has been shown that the ITT at elevated temperatures can reduce the reliability of MIS devices. Performing ITT at high temperatures leads to decrease of charge‐to‐breakdown average value in MIS structures. It has been demonstrated that irradiation treatment allows to reduce density of defects in thermal SiO2 films, SiO2 films doped with phosphorus, oxynitride films and as a result to increase reliability of MIS devices. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:09.449695-05:
      DOI: 10.1002/pssc.201400151
       
  • Thermodynamic analysis of defect formation in BiFeO3
    • Authors: T. Tchelidze; T. Gagnidze, A. Shengelaya
      Pages: n/a - n/a
      Abstract: In this paper the thermodynamic analysis of equilibrium concentration of defects for the system BiFeO3(solid)‐O2 (gas) is carried out. The analysis is performed by the Kroger method of quasi‐chemical equations. The concentration of defects and free carriers vs. oxygen partial pressure in surrounding atmosphere at definite temperature are obtained. The calculations were carried out for 3 nm BiFeO3 nanowires too. When the defects ionization energies and material band gap are increased in nanowires, the picture of defects thermodynamics is changed. In 3 nm nanowire the area of self‐compensation is significantly broadened. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-29T05:10:08.322224-05:
      DOI: 10.1002/pssc.201400153
       
  • Low temperature hydrogenated microcrystalline silicon‐carbon alloys
           deposited by RF‐PECVD
    • Authors: Sofia Gaiaschi; Marie‐Estelle Gueunier‐Farret, Erik V. Johnson
      Pages: n/a - n/a
      Abstract: Two sets of hydrogenated microcrystalline silicon carbon alloys were deposited by standard radio frequency (RF) plasma enhanced chemical vapor deposition at a substrate temperature of 175 °C. The effect of the methane flow rate and of the RF‐power were investigated. Samples were deposited from a silane and methane gas mixture, highly diluted in hydrogen. The increase in methane flow rates leads to a decrease of the crystalline volume fraction and an increase in carbon incorporation. On the other hand, decreasing the RF‐power shifts the microcrystalline‐to‐amorphous transition at higher methane flow rates. Moreover, for similar amount of carbon incorporated, the decrease in RF‐power leads to materials showing higher crystalline volume fraction and average grains sizes. Both ion bombardment energy and carbon incorporation contributes to the microstructural properties of the deposited alloys. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:57.60578-05:0
      DOI: 10.1002/pssc.201400034
       
  • Nanoscale electrical characterization of graphene contacts to AlGaN/GaN
           heterostructures
    • Authors: Gabriele Fisichella; Giuseppe Greco, Salvatore Di Franco, Fabrizio Roccaforte, Sebastiano Ravesi, Filippo Giannazzo
      Pages: n/a - n/a
      Abstract: In this paper, we describe a highly reproducible method to transfer graphene (Gr) grown on copper by chemical vapour deposition to the surface of AlGaN/GaN heterostructures and we report a nanoscale electrical characterization of current transport at Gr contact to AlGaN. This latter investigation has been carried out using local current‐voltage measurements by conductive atomic force microscopy (CAFM), performed both on the Gr‐coated and bare AlGaN surface (reference). These analyses provide information on the lateral uniformity of the Schottky barrier height (SBH) between Gr and AlGaN. Gr contacts to AlGaN exhibit much more uniform and significantly lower SBH (∼0.4 eV) than common metals, such as gold, with SBH∼0.96 eV. These results can be useful for future applications in high frequency transistors based on AlGaN/GAN heterostructures and Gr. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:56.325426-05:
      DOI: 10.1002/pssc.201400078
       
  • Thermodynamic study of the ternary system
           gallium‐arsenic‐bismuth
    • Authors: N. Elayech; H. Fitouri, Y. Essouda, A. Rebey, B. El Jani
      Pages: n/a - n/a
      Abstract: Binary thermodynamic data, successfully used for phase diagram calculations of binary system Ga‐As, Ga‐Bi and As‐Bi were used for prediction of phase equilibria in ternary Ga‐As‐Bi system. The parameters for the thermodynamic models of the constituent binary systems and those for the Ga‐As‐Bi system are optimized in this study using data on phase equilibria and data on the different alloys available in the literature and calculated in the present work. The implications of the phase data for solution epitaxy are discussed. The liquidus surface and isothermal section were calculated. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:54.653667-05:
      DOI: 10.1002/pssc.201400147
       
  • Optical properties of plasmonic nanoparticles distributed in size
           determined from a modified Maxwell‐Garnett‐Mie theory
    • Authors: Y. Battie; A. Resano‐Garcia, N. Chaoui, A. En Naciri
      Pages: n/a - n/a
      Abstract: The optical properties of spherical gold and silver nanoparticles distributed in size are investigated through a new effective medium theory. It is about the modified Maxwell‐Garnett‐Mie theory (MMGM) that takes into account the intrinsic confinement, dynamic effects and the nanoparticle radius distribution. In the case of monodispersed nanoparticles with a radius in the 1 nm‐25 nm range, MMGM is equivalent to the Mie theory. Compared to the conventional effective medium theory, we demonstrate that MGMM gives better description of the measured extinction spectra of colloidal gold and silver solutions. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:53.365108-05:
      DOI: 10.1002/pssc.201400190
       
  • Monte Carlo study of the early growth stages of 3C‐SiC on
           misoriented <11‐20> and <1‐100> 6H‐SiC
           substrates: role of step‐island interaction
    • Authors: M. Camarda; A. La Magna, F. La Via
      Pages: n/a - n/a
      Abstract: In this paper, we use three‐dimensional kinetic Monte Carlo simulations on superlattices to study the hetero‐polytypical growth of cubic silicon carbide polytype (3C‐SiC) on hexagonal 6H‐SiC step‐bunched substrates with miscuts towards the and directions. We find that the preferential 3C conversion observed on misoriented substrates could be due to a different step‐to‐island interaction which enhances island stability and expansion in this specific direction. For this reason 3‐4 degrees off step‐bunched 6H substrates with miscut towards the direction should be the best choice for the stable and reproducible hetero‐polytypical growth of high quality cubic epitaxial films. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:52.000426-05:
      DOI: 10.1002/pssc.201400197
       
  • Green light‐emitting CdTe nanocrystals: synthesis and optical
           characterizations
    • Authors: Luciana Algieri; Roberta Rosato, Maria Elena Mosca, Maria Lucia Protopapa, Anna Grazia Scalone, Francesca Di Benedetto, Luigi Bucci, Leander Tapfer
      Pages: n/a - n/a
      Abstract: In this work, we report on the synthesis of CdTe nanocrystals (NCs) by using of two different saturated long‐chain capping ligands, oleic (OA) and myristic acids (MA), and investigate their influence on the nanocrystals optical properties. The main goal of our study is to identify the ligand that allows slowing down the growth rate of the NCs after nucleation, in order to obtain small enough nanocrystals emitting in the blue‐green part of the optical spectrum. Our results show clearly that oleic acid allows a good control on the CdTe NCs growth, finally leading to a fine‐tuning of the NCs size‐dependent emission from the green to the yellow part of the spectrum. Instead, a faster reaction kinetics, which arises in a lower possibility to produce small NCs emitting in the green part of the spectrum, was noticed using myristic acid. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:50.640015-05:
      DOI: 10.1002/pssc.201400203
       
  • Electroluminescence of germanium LEDs on silicon: Influence of antimony
           doping
    • Authors: Bernhard Schwartz; André Klossek, Martin Kittler, Michael Oehme, Erich Kasper, Jörg Schulze
      Pages: n/a - n/a
      Abstract: Antimony‐doped Ge‐LEDs were subjected to electroluminescence studies at temperatures about 300 K and 80 K. The LEDs were grown on Si substrates by MBE. The thickness of the active layer was 300 nm. For the p+nn+‐LEDs the Sb concentrations were 1 × 1018, 1 × 1019, 3 × 1019, 4 × 1019, 7 × 1019 or 1 × 1020 cm–3, respectively. As reference a p+in+‐LED without intentional doping in the active layer was used. The investigated specimen exhibited dominance of the direct transition line at about 0.8 eV. Moreover, luminescence indirect transition was observed. In general, the spectra reveal higher EL intensities at room temperature as compared to 80 K. With decreasing temperature the direct peak was blue shifted. The highest EL intensity was found for the LED with Sb concentration of 3 × 1019 cm–3. With increasing Sb doping a red‐shift of the direct peak was observed, caused by band gap narrowing. In addition, a simulated curve of the direct transition was compared with our samples and fits well with the measured spectra. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-10-10T08:20:49.145608-05:
      DOI: 10.1002/pssc.201400056
       
  • Silicon film deposition on crystalline, sintered and powder substrates
           using an inline optical processing CVD system
    • Authors: André Augusto; Filipe Serra, António Vallêra, João M. Serra
      Pages: n/a - n/a
      Abstract: An inline optical CVD process operating at low temperature (10 mm/min) inside the furnace. Solid silicon substrates were laser textured to reduce the reflectivity, leveraging the growth rates. Laser patterning has a strong influence in the growth rate, reaching values up to 9 µm/min. Using pressed silicon powder substrates, growth rates increase dramatically to 40‐90 µm/min. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-30T14:40:28.076031-05:
      DOI: 10.1002/pssc.201400126
       
  • Properties of electrodeposited germanium thin films
    • Authors: Yasutaka Uchida; Tomoko Funayama, Yoshiaki Kogure, Kazuyoshi Ueno
      Pages: n/a - n/a
      Abstract: In this paper, the results of Ge film deposited by electroplating method was studied and showed the possibility of making a NIRS sensor by the Ge film. Cu/Ti double layer structure could use the cathode electrode on the glass substrate during the GeCl4 electroplating. The deposition rate of electroplating Ge film was 100 nm/h, however, that rate was improved to 570 nm/h by introducing a spacer between Cu thin film and extraction electrode and Ar gas bubbling. The oxygen content of as‐deposited film was about 10%, however, this value reduced to lower than 1% by using the Ar bubbling. The deposited film was amorphous and its optical band gap was 0.73 eV. 200 nm‐thick Ge film was formed on flexible substrate by electroplating method. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-30T14:40:27.001746-05:
      DOI: 10.1002/pssc.201400094
       
  • Effect of total gas pressure in sputtered hydrogenated amorphous silicon
    • Authors: Abdelkrim Fedala; Aghilas Dad, Moussa Khefiani‐Guellil, Sonia Tata, Claude Simon, Tayeb Mohammed‐Brahim
      Pages: n/a - n/a
      Abstract: Hydrogenated amorphous silicon (a‐Si:H) thin films are prepared using DC magnetron sputtering method at a substrate temperature of 200 °C using a plasma of argon and hydrogen gas mixture. The effects of the total gas pressure (TGP) during the deposition on structural, optical and electrical properties of the films are investigated. A decrease of the polyhydride bonding groups concentration (SiHn) is observed in FTIR spectra when the TGP increases. The optical gap remains constant. With increasing TGP the dark and photoconductivity increase, the defect density of states determined from constant photocurrent method (CPM) decreases, and the quantum efficiency mobility lifetime product (ημτ) is enhanced by a factor of more than fifty. Thus, the structural and electrical properties are enhanced by only increasing the TGP. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-30T14:40:25.827951-05:
      DOI: 10.1002/pssc.201400070
       
  • Structural and photoconductivity properties of silicon carbon thin films
    • Authors: U. Coscia; G. Ambrosone, D. K. Basa, V. Rigato, S. Binetti
      Pages: n/a - n/a
      Abstract: Nanostructured films composed of silicon crystallites dispersed in an hydrogenated amorphous silicon carbon matrix have been deposited by plasma enhanced chemical vapour deposition from silane‐methane mixtures diluted in hydrogen by varying the rf power. Compositional, structural, optical and photoconductivity properties of the films have been investigated. The increase in rf power in the 40‐80 W range enhances the incorporation of carbon and hydrogen in the amorphous matrix and decreases the volume fraction and size of the silicon crystallites leading to an enlargement of the optical band gap from 2.07 to 2.20 eV. Steady state photoconductivity measurements, performed under monochromatic radiations in the visible range, have demonstrated the occurrence of monomolecular recombination kinetics in the samples under illumination and that the mobility‐lifetime product of the free electrons as a function of the optical gap decreases from 1.9 × 10–7 to 2.5 × 10–9 cm2V–1 as in the case of device quality films deposited by silane‐methane mixtures diluted in hydrogen. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-30T14:40:24.646207-05:
      DOI: 10.1002/pssc.201400063
       
  • Analysis of the reduction of tensile stress by post‐growth annealing
           methods in multicrystalline silicon wafers produced by the RST process
    • Authors: O. Martínez; A. Tejero, E. Tupin, M. A. González, J. Jiménez, C. Belouet, C. Baillis
      Pages: n/a - n/a
      Abstract: In this work, we analyze the residual stress, in both as‐grown and post‐growth annealed silicon ribbon on a sacrificial carbon template, by the simulation of the thermo‐mechanical behavior of the cooling ribbon using the Abaqus software, and the measurement of stress on the free silicon surface by µ‐Raman spectroscopy. The results of the simulations gave limits within which flat ribbons could be obtained for a combination of silicon thickness, ribbon width and pull rate. Stress relaxation by off‐line thermal treatments is used to optimize a post‐growth annealing furnace in line with the ribbon growth system. The fragile behavior of the ribbon during laser cutting can be considerably reduced by a short relaxation of the ribbon at medium temperatures around 850 °C, which were observed to give the best behavior in terms of residual tensile stress relaxation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-30T14:40:22.957361-05:
      DOI: 10.1002/pssc.201400047
       
  • Oxygen gettering in low‐energy arsenic or antimony ion implanted
           Cz‐silicon
    • Authors: O. Oberemok; V. Kladko, V. Litovchenko, B. Romanyuk, V. Popov, V. Melnik, J. Vanhellemont
      Pages: n/a - n/a
      Abstract: Low energy As or Sb ion implantation followed by furnace annealing was used to create ultra shallow junctions. It was found that a significant amount of oxygen was redistributed from the Si bulk to the As implanted layer leading even to an increase of the screening oxide film thickness. Using a marker layer created by implantation of 18O ions, it was confirmed that a large number of interstitial oxygen atoms are transferred from the bulk of the Si wafer to the wafer surface during implanted As activation annealing. Estimation of the O diffusivity in Si during the 950 °C activation anneal, yields a value of about 10–10 cm2 /s which is more than an order of magnitude larger than the literature value which is close to 7 × 10–12 cm2/s. In the case of Sb implantation, the oxygen gettering effect is much reduced. This difference in oxygen behavior can be attributed to the influence of mechanical stress in the near surface highly doped layer. The configuration of the mechanical stress field is different for the cases of As and Sb implantation, with tensile stress dominating for the latter. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:20.912161-05:
      DOI: 10.1002/pssc.201431562
       
  • Room temperature kerfless silicon thin foils obtained via a stress
           inducing epoxy layer
    • Authors: João Serra; Pierre Bellanger, Pierre O. Bouchard, Marc Bernacki
      Pages: n/a - n/a
      Abstract: We present 5 × 5 cm2 SLIM‐cut foils obtained by cooling form curing temperatures of 150 °C to room temperature using an epoxy stress inducing layer. Numerical simulations were performed to help the definition of an optimum geometry and we demonstrate the capability to obtain several thin foils from the same substrate. The evolution of minority carrier lifetime upon successive exfoliation of the same substrate is presented. Measured lifetimes in these silicon foils increase after etching suggesting that recombination centers are present close to the foil surface. Effective lifetimes of 50 microseconds were obtained in 120 µm thick foils, corresponding to diffusion length much larger than the foil thickness. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:18.426638-05:
      DOI: 10.1002/pssc.201400105
       
  • An amazing semiconductor choice for high‐frequency FET:
           H‐terminated polycrystalline diamond film prepared by DC arc jet CVD
           
    • Authors: C. M. Li; J. L. Liu, L. X. Chen, J. J. Wei, L. F. Hei, J. J. Wang, Z. H. Feng, H. Guo3
      Pages: n/a - n/a
      Abstract: With the development of information and communication technology, conventional semiconductors such as Si and GaAs cannot satisfy the requirement of high‐frequency and high‐power electronic devices. By contrast, diamond film has been considered to be a potential material alternative due to the highest Johnson and Keyse figures of merit. In this paper, H‐terminated polycrystalline diamond films with different quality were prepared by DC arc jet CVD through adjusting the deposition conditions. The conductive behaviour of p‐type channel on H‐terminated diamond surface was compared and analyzed based on the N‐related impurity and spontaneous polarization model. After that, MESFETs (metal‐semi‐conductor field effect transistor) were fabricated on H‐terminated diamond and the radio frequency (RF) performance was evaluated. The cut off frequency (fT) of 11 GHz and the maximum oscillation frequency (fmax) of 18.5 GHz for MESFET in our situation were obtained. It was found that equivalent circuit elements were lower or comparable with the reported values for the FETs with the highest fT and fmax except the gate capacitance, which indicates that the carrier mobility should be improved further for high‐frequency devices application. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:16.294012-05:
      DOI: 10.1002/pssc.201400076
       
  • Processing‐induced near‐interfacial thermal donor generation
           in (100)Si/Si‐oxycarbide insulator structures revealed by electron
           spin resonance
    • Authors: S. Iacovo; A. Stesmans, S. Nguyen, V. V. Afanas'ev
      Pages: n/a - n/a
      Abstract: Low temperature electron spin resonance (ESR) study of Cz‐(100)Si/insulator structures with organosilicate films of low dielectric constant κ grown at 300 °C using plasma‐enhanced chemical vapor deposition (PECVD) reveals, after subjection to UV‐irradiation assisted thermal curing at 430 °C to remove organics, the observation of the NL8 ESR spectrum. This indicates the generation in the c‐Si substrate of singly ionized thermal double donor (TDD) defects with a core contained of oxygen atoms. The generation is found to be highly non uniform, which is concluded to be the result of interfacial stress acting as the major driving component in the enhancement of TDD formation during thermal treatment. This suggests substantial stress being involved with PECVD organosilicate low‐κ glasses. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:14.279615-05:
      DOI: 10.1002/pssc.201400064
       
  • Properties of a‐SiGe:H thin films: correlation between
           photosensitivity density of states
    • Authors: Lamia Laidoudi; Abdelkrim Fedala, Abla Rahal
      Pages: n/a - n/a
      Abstract: Thin films of hydrogenated amorphous silicon germanium (a‐Si1‐xGex:H) alloy are prepared using DC magnetron sputtering method, at a substrate temperature of 150 °C. Silicon and germanium are co‐pulverized. All our films are deposited in the same preparation conditions except for those having a germanium content from 27% to 40%. Structural, optical and electrical properties are systematically studied from IR absorption, optical transmission and electrical measurements. Hydrogen content is determined by integrating the wagging mode infrared absorption. The increase of the Ge content from 27% to 40% is responsible for a decrease in optical bandgap of 1.59 to 1.43 eV and a reduction of the total content of hydrogen bonds in both Si‐H and Ge‐H configurations. A good correlation is observed between the reduction of the optical gap and the increase of one order of magnitude of the dark conductivity. The white light sensitivity shows a significant degradation due to germanium incorporation in the silicon matrix. Therefore, this degradation increases with germanium content. The density of states (DOS) located at the Fermi level g(EF) is estimated from the analysis of capacitance‐frequency measurements on Au/a‐Si1‐xGex:H/c‐Si(N+) Schottky structure, in zero bias condition. In our layers, the turn on condition which permits to measure the complete response of the deep states, for 1 kHz frequency, occurs at a relatively high temperature (over 75 °C). The measured density of states increases from 3x1016 cm‐3 eV‐1 to 3x1018 cm‐3 eV‐1 when the germanium content increases. This can highlight the narrow correlation between sensitivity degradation and density of states augmentation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:12.440977-05:
      DOI: 10.1002/pssc.201400059
       
  • Effect of nitrogen mole fraction on hydrogenated amorphous silicon nitride
           deposited by DC magnetron sputtering: transition between metallic and
           reactive sputtering
    • Authors: Kamel Mokeddem; Mohamed Kechouane
      Pages: n/a - n/a
      Abstract: The hydrogenated amorphous silicon nitride thin films are deposited by DC magnetron sputtering in argon, molecular hydrogen and nitrogen plasma mixture. The films are deposited at 150 °C and at 130 W sputtering power with wide range of nitrogen mole fraction. The plasma is characterized by the target voltage measurement. The samples are characterized by the optical transmission measurements and the physicochemical structure is studied by the FTIR absorption spectroscopy. When the nitrogen mole fraction increases from 0.075 to 0.24 the target voltage decrease from 413 to 325 V and increases suddenly to 450 V when nitrogen mole fraction increases to 0.69. The decrease of target voltage may be due to the transition from metallic to reactive sputtering process and its increase can be explained by the implantation of reactive ions in the target. Sputtering rate and refractive index decrease respectively from 8.33 to 1.73 Å/sec and from 2.52 to 1.68 with nitrogen mole fraction. The value of refractive index at critical nitrogen mole fraction is about 1.8. When the nitrogen mole fraction increases the frequency related to Si‐H band, on FTIR spectrum, shift from 2097 cm‐1 to reach 2209 cm‐1 at the critical nitrogen mole fraction. Thereafter it varies sharply to 2190 cm‐1 and remains constant. A sudden change is observed on the sputtering rate, on the intensity of the band attributed to the stretching vibration of N‐H and Si‐H bonds. From these results we believe that the stoichiometric composition is reached at the critical nitrogen mole fraction and beyond this the deposited films are rich of nitrogen and hydrogen. This is consistent with the explanation given of the variation of the target voltage. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:10.419148-05:
      DOI: 10.1002/pssc.201400058
       
  • Non‐contact high precision alternative to Hg‐probe for dopant
           profiling in SiC
    • Authors: Andor Czett; Csaba Buday, Sasha Savtchouk, Dmitriy Marinskiy
      Pages: n/a - n/a
      Abstract: The silicon carbide industry has been expanding in the recent years, producing a search for SiC non‐contact electrical characterization methods capable of replacing the commonly used Hg‐probe technique. In this work we present doping metrology based on the corona‐Kelvin method, which was originally developed and used for silicon IC dielectric and interface characterization. The method employs corona discharge in air to deposit precise doses of charge on the SiC surface. The corresponding depletion voltage is then measured with a Kelvin probe enabling non‐contact determination of the static charge‐voltage and capacitance‐voltage characteristics. The approach incorporates three novel elements: 1. corona charging of SiC to high depletion voltage with constant surface potential method; 2. the derivative charge‐voltage measurements for d(1/C2)/dV analysis and doping profiling; 3. surface charge neutralization with appropriate SiC illumination for repeated measurements. We demonstrate excellent repeatability and accuracy of the novel approach for n and p‐type SiC doping measurements in a range from 1014cm‐3 to mid 1018cm‐3 and excellent correlation with results obtained with mercury‐probe C‐V. Using multi‐layer epitaxial SiC structures, we further demonstrate the effectiveness of novel non‐contact depth profiling. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-17T14:10:07.925429-05:
      DOI: 10.1002/pssc.201400057
       
  • Silicon nanowires: synthesis, optical properties and applications
    • Authors: Cristiano D'Andrea; Maria José Lo Faro, Paolo Musumeci, Barbara Fazio, Fabio Iacona, Giorgia Franzò, Pietro Gucciardi, Cirino Vasi, Francesco Priolo, Alessia Irrera
      Pages: n/a - n/a
      Abstract: Group‐IV semiconductor nanowires (NWs) are attracting the interest of a wide scientific community as building blocks for a wide range of future nanoscaled devices. We used metal‐assisted chemical etching of Si substrates to synthesize Si NWs with different length and nanometer‐size diameter. NWs obtained by this technique have exactly the same structure and doping of the substrate and present quantum confinement effects. Photoluminescence (PL) emission at room temperature from Si NWs is reported. We observed an increasing behaviour of the PL intensity as a function of the NWs length. The fabrication of light emitting devices based on Si NWs, showing electroluminescence emission at room temperature under low voltage excitation, is also reported. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-12T05:10:13.275103-05:
      DOI: 10.1002/pssc.201400052
       
  • Ion beam analysis of Heusler alloy Fe3Si epitaxially grown on Si(111)
    • Authors: Yoshihito Maeda; Yuki Kawakubo, Yuya Noguchi, Kazumasa Narumi, Seiji Sakai
      Pages: n/a - n/a
      Abstract: We have investigated atomic ordering of Heusler alloy Fe3Si(111) epitaxially grown on Si(111) by using ion beam analysis. The total atomic displacement along Si directions was deduced from the minimum yield χmin and the critical angle Ψ1/2 for channeling. The total displacement consists of both one‐dimensional thermal vibrations computed by the Debye theory and static displacements due to imperfections, lattice mismatch, thermal expansion etc. The atomic displacement increased as the annealing temperature increased from 373 to 573 K. We found that this static displacement came from a difference in thermal expansion between the Fe3Si film and Si substrates at the anneal temperature and was quenched into room temperature as a remnant displacement. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-12T05:10:12.417819-05:
      DOI: 10.1002/pssc.201400027
       
  • First principles analysis of atomic configurations of group IV elements in
           Ge crystal for solar cells
    • Authors: Ryo Matsutani; Koji Sueoka, Eiji Kamiyama
      Pages: n/a - n/a
      Abstract: We focused on group IV semiconductors, i.e., Ge (Si), containing C, Si (C, Ge), and/or Sn atoms as alternative candidates for poly‐Si crystals to achieve higher engineering efficiency in solar cells in this research. The main target of this study was to obtain basic data on atomic configurations, such as bond strain and stable sites for substituted C, Si, and Sn atoms in Ge and for C, Ge, and Sn atoms in Si crystals through first principles analysis. We found that ((C, Si)/C) atoms with smaller covalent radii than (Ge/Si) formed tensile local strain along zigzag bonds in the direction while (Sn/(Ge, Sn)) atoms with larger covalent radii than (Ge/Si) formed compressive local strain. Another important result was that local strains except for zigzag bonds had opposite signs to strains along zigzag bonds. The main results to summarize stable configurations of substitutional IV elements were: (1) C and Sn (Si) atoms were stable at positions next to one another, while Si and Sn atoms were stable at mostly separated positions in Ge crystals. (2) C (Ge) and Sn atoms were stable at positions next to one another, while C and Ge atoms were stable at mostly separated positions in Si crystals. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-12T05:10:11.555634-05:
      DOI: 10.1002/pssc.201400029
       
  • Influence of copper contamination on the illuminated forward and dark
           reverse current‐voltage characteristics of multicrystalline
           p‐type silicon solar cells
    • Authors: Tleuzhan Turmagambetov; Sébastien Dubois, Jean‐Paul Garandet, Benoit Martel, Nicolas Enjalbert, Jordi Veirman, Etienne Pihan
      Pages: n/a - n/a
      Abstract: We studied the influence of copper (Cu) on the performances of conventional photovoltaic (PV) solar cells by growing two multicrystalline (mc) boron‐doped silicon (Si) ingots from ultra‐pure feedstocks, one of these feedstocks being deliberately contaminated with 90 ppm wt of Cu. Industrial‐like solar cells were fabricated and the associated external gettering and hydrogenation effects were studied. An originality of our approach consisted in evaluating the forward but also reverse current‐voltage (I‐V) characteristics of the fabricated cells. Furthermore we assessed the stability under illumination of the PV parameters as Cu is known to be responsible for light‐induced degradations (LID) of the carrier lifetime. On the one hand we unexpectedly showed that the PV conversion efficiency (η) was not affected by the initially large Cu concentrations. We demonstrated that it was due to the complementary actions of the external gettering effect developed by the phosphorus‐diffusion and the bulk hydrogenation. The Cu‐addition slightly enhanced the pn junction hard breakdown, however the extracted junction breakdown voltages fulfilled the common industrial requirements for this parameter. On the other hand we highlighted significant decreases under illumination of the PV performances for the Cu‐contaminated solar cells fabricated from wafers coming from the upper part of the ingot (i.e., samples with the highest Cu concentration). These decreases could be explained by the previously proposed mechanisms in the literature, which argue that the excess charge carriers could reduce the electrostatic repulsion between interstitial Cu ions and Cu precipitates, this effect enhancing the Cu precipitation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-12T05:10:10.418578-05:
      DOI: 10.1002/pssc.201400036
       
  • Quantitative analysis of carbon impurity concentration in silicon
           epitaxial layers by luminescence activation using carbon ion implantation
           and electron irradiation
    • Authors: Satoko Nakagawa; Kazuhiko Kashima
      Pages: n/a - n/a
      Abstract: The calibration curve for the carbon concentration in silicon epitaxial layers was obtained by photo‐luminescence spectroscopy after carbon ion implantation and electron irradiation. Low carbon concentrations on the order of 1014 atoms/cm3 affected properties such as the on‐resistance and carrier lifetime of insulated gate bipolar transistors (IGBTs). We focused on carbon impurities because interstitial carbon can form complexes, such as complexes of interstitial and substitutional carbon (Ci‐Cs) and of interstitial carbon and oxygen (Ci‐Oi), which produce deep levels in the energy band gap. To verify the effects of carbon impurities separately from those of oxygen impurities, oxygen‐free silicon epitaxial layers were studied. The carbon concentration in silicon epitaxial wafers was evaluated quantitatively by using our calibration curve. Carbon ion implantation and photoluminescence spectrum measurements were performed to obtain the slope of the calibration curve. In addition, secondary ion mass spectrometry measurement gave absolute carbon concentration against photo‐luminescence intensity for fixing the calibration curve. The calibration curve was used to determine the carbon concentration for each IGBT. Carbon impurity concentrations as low as 1014 atoms/cm3 in silicon epitaxial layers lowered device performance. Therefore, decreasing the carbon impurity concentration is essential for improving the performance of advanced IGBTs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-12T05:10:09.410256-05:
      DOI: 10.1002/pssc.201400046
       
  • Outdoor characterization of amorphous silicon based photovoltaic modules
           with different structures
    • Authors: Thomas Mambrini; Anne Migan‐Dubois, Christophe Longeaud, Mustapha Elyaakoubi
      Pages: n/a - n/a
      Abstract: Three different amorphous silicon structures of PV modules were analyzed in outdoor condition during one month. The Staebler‐Wronski effect (or light induced degradation effect) is well known for the amorphous technology and depends strongly on the manufacturing process and its structure. Due to this effect, the amorphous PV modules loose performances compared to their initial characteristics. The behaviour, during and after the aging of different amorphous silicon PV module, is investigated and a new amorphous structure, less sensitive to the Staebler‐Wronski effect and with a better response under real conditions of use is exposed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-09-12T05:10:08.507824-05:
      DOI: 10.1002/pssc.201400048
       
  • Cover Picture: Phys. Status Solidi C 9–10/2014
    • Pages: n/a - n/a
      Abstract: Extended X‐ray absorption fine structure (EXAFS) can provide perhaps the most extensive information on the local atomic structure, as well as on the lattice dynamics, for a broad class of materials. However, conventional methods of EXAFS data treatment are often limited to the nearest coordination shells of the absorbing atom due to the difficulties in accurate accounting for multiple‐scattering effects. Besides, it is often difficult to resolve non‐equivalent groups of atoms in a single coordination shell due to strong correlation between struc‐tural parameters. In the study of the EXAFS data for wurtzite‐type bulk ZnO by J. Timoshenko, A. Anspoks, A. Kalinko, and A. Kuzmin (see pp. 1472–1475), these problems are overcome by applying two different simulation‐based methods: classical Molecular Dynamics (MD) and a novel Evolutionary Algorithm (EA) approach. The important part of the EA method is the employment of Morlet wavelet transform to represent the available EXAFS data in real and reciprocal space simultaneously, and hence to benefit from much more information being available for the analysis (wavelet image of the Zn K‐edge EXAFS spectrum and a part of ZnO structure are shown on the cover). Such combined approach allowed to separate the contributions of thermal disorder and the effect of noncentrosymmetric zinc oxide structure, being responsible for its piezoelectrical and pyroelectrical properties, and also to test the accuracy of several available force–field models, which are commonly used in MD simulations of bulk and nanosized ZnO.
      PubDate: 2014-09-10T09:52:16.776932-05:
      DOI: 10.1002/pssc.201470057
       
  • Issue Information: Phys. Status Solidi C 9–10/2014
    • Pages: n/a - n/a
      PubDate: 2014-09-10T09:52:12.043946-05:
      DOI: 10.1002/pssc.201470058
       
  • Multi‐frequency electron spin resonance study of inherent Si
           dangling bond defects at the thermal (211)Si/SiO2 interface
    • Authors: S. Iacovo; A. Stesmans
      Pages: n/a - n/a
      Abstract: Multifrequency low temperature electron spin resonance (ESR) studies were carried out to atomically assess inherent point defects at the thermal ‘higher index' (211)Si/SiO2 interface. This reveals, as dominant imperfections, Pb‐type centers (generic entity Si3≡Si•, the dot representing an unpaired sp3‐like hybrid) occurring in densities of ∼1 × 1013 cm–2 for oxidation temperatures ∼400 °C. On the basis of the pertinent ESR characteristics, the inherent basic defect is typified as the Pb0(211) variant, resembling closely the Pb0 center in standard (100)Si/SiO2. At the higher index (211)Si/SiO2 interface, these defects predominantly pertain to defected Si atoms located at (111)‐face terraces. Combination of angular and frequency (ν) dependent studies show the Pb0(211) peak‐to‐peak line width ΔBpp to be composed of a residual width (ν→0) of 2.2 ± 0.1 G, to which dipolar broadening contributes an essential part, and a substantial inhomogeneous broadening component due to g distribution, predominantly in g⊥, induced by non‐uniform interface strain –also similar to the Pb0(100) properties. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:40:13.233383-05:
      DOI: 10.1002/pssc.201400071
       
  • Sol–gel deposited phosphorus and boron doped thin silica films for
           diffused n+p and n+pp+ structures
    • Authors: Armel Duvalier Pene; Bouchaib Hartiti, Laurent Bitjoka, Phillippe Thevenin, Cesar Kapseu
      Pages: n/a - n/a
      Abstract: The realization of a silicon solar cell emitter is a critical and very important step in photovoltaic technology. Indeed, the surface concentration of boron (B) or phosphorus (P) and junction depth determines the photovoltaic conversion efficiency of silicon solar cells. Several techniques are used for the realization of emitters n+p and n+pp+ among which the vapor diffusion, ionic implantation and diffusion from solid sources are the most common. This work will be devoted to the realization of emitters made by diffusion of P or B from solid doping sources developed by the sol–gel method associated to spin coating on monocrystalline and polycrystalline silicon wafers. The doping solutions were prepared by sol–gel method using methyltriethoxysilane “MTEOS” or tetramethoxysilane “TEOS” and H4PO3 or H3BO3 as precursors. The n+ junction was realized by emulsion of phosphoric acid in isopropanol while the p+ junction was obtained by emulsion of boric acid H3BO3 in isopropanol or by diffusion of aluminium at high temperatures. Our samples were annealed at temperatures ranging from 850 to 1000 °C in a classical furnace under Nitrogen atmosphere. The four point technique has been used to study the electrical properties of n+p and n+pp++ structures. The results of measurements showed values of the sheet resistance Rs comparable to those of literature and confirm the diffusion of phosphorus and boron from liquid and solid sources prepared by sol–gel method. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:40:12.172213-05:
      DOI: 10.1002/pssc.201400060
       
  • Temperature dependent switching behaviour of nickel silicided undoped
           silicon nanowire devices
    • Authors: Jürgen Beister; Andre Wachowiak, André Heinzig, Jens Trommer, Thomas Mikolajick, Walter M. Weber
      Pages: n/a - n/a
      Abstract: In this work, we investigate the temperature dependence of electrical switching properties of back‐gated, undoped Si‐nanowire field‐effect transistors with Ni‐silicided source/drain contacts. A simple, phenomenological model illustrates the leading order temperature dependence of the source‐drain current, which originates predominantly from charge carrier injection by tunneling through the Schottky junction. Drain current versus gate voltage measurements have been performed for various temperatures and several drain voltages on a single nanowire device. The temperature dependence of the drain‐source current for specific gate and drain voltages is analysed within the framework of voltage dependent effective barrier heights. As a result, the temperature dependence of the tunnelling current is not only important for the sub‐threshold region, but also plays a significant role in the transistor “on‐state”. In addition, the effective barrier heights for electrons and holes tend towards the natural Schottky barriers of the NiSi2‐Si interface, if the applied external fields generate the case of flat band condition at the injection Schottky barrier, i.e. in the deep “off‐state” region. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:40:10.98697-05:0
      DOI: 10.1002/pssc.201400055
       
  • Band engineering and absorption spectra in compressively strained
           Ge0.92Sn0.08/Ge (001) double quantum well for infrared photodetection
    • Authors: N. Yahyaoui; N. Sfina, J.‐L. Lazzari, A. Bournel, M. Said
      Pages: n/a - n/a
      Abstract: We report a theoretical investigation of strained Ge1−xSnx/Ge (001)‐oriented quantum wells as a bulding block in active region of infrared photodetector. The electronic band parameters, gaps, discontinuities and effective masses for heterointerfaces between compressively strained Ge1−xSnx and relaxed Ge have beencomputed at room temperature. From this preliminary and mendatory work, we conclude that pseudomorphic Ge1−xSnx alloys become direct band gap semiconductors at a Sn‐fraction of 15.3%, e.g. a lattice mismatch as high as 2.3%. Due to achievable critical layer thickness and mainly solid solubility limit, a type‐I compressively strained Ge/Ge0.92Sn0.08/Ge (double) quantum well is studied by solving Schrödinger equation without and applied bias voltage. A strong absorption coefficient (> 1×104 cm−1) and a Stark shift of the direct transition between 2.01 μm and 2.25 μm at large external fields (40kV/cm) are attractive characteristics for the design of infrared photodetectors (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:40:09.615156-05:
      DOI: 10.1002/pssc.201400054
       
  • Electrically detected magnetic resonance study on defects in Si
           pn‐junctions created by proton implantation
    • Authors: Gernot Gruber; Stefan Kirnstoetter, Peter Hadley, Markus Koch, Thomas Aichinger, Holger Schulze, Werner Schustereder
      Pages: n/a - n/a
      Abstract: The present study focuses on electrically detected magnetic resonance (EDMR) investigations of proton implanted silicon. The samples were prepared on n‐type silicon wafers highly doped diffused boron (B) p‐region, forming a pn‐junction. A large additional n‐type doping was introduced by proton (H+) implantation. We compare samples with implantation doses up to 1015 H+/cm–2 and investigate the effects of anneals at 350 °C. We observe different types of defects in the differently prepared samples. One doublet with 118.5 G HF splitting and a g ‐value of 2.0095(4) is only observed in the samples implanted with the highest dose and is assigned to hydrogen. The structure of the other observed defects remains unidentified and can only tentatively be assigned to hydrogen. More extensive measurements would have to be performed to get a better picture. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:40:08.136114-05:
      DOI: 10.1002/pssc.201400053
       
  • High dose proton implantations into silicon: a combined EBIC, SRP and TEM
           study
    • Authors: Stefan Kirnstoetter; Martin Faccinelli, Christian Gspan, Werner Grogger, Moriz Jelinek, Werner Schustereder, Johannes G. Laven, Hans‐Joachim Schulze, Peter Hadley
      Pages: n/a - n/a
      Abstract: Proton (H+) implantations are used in power semiconductor devices to introduce recombination centers (Hazdra et al., Microelectron. J. 32(5), 449–456 (2001)) or to form hydrogen related donor complexes (Zohta et al., Jpn. J. Appl. Phys. 10, 532–533 (1991)). Proton implantations are also used in the 'smart cut' process to generate defects that can be used to cleave thin wafers (Romani and Evans, Nucl. Instrum. Methods Phys. Res. B 44, 313–317 (1990)). However, the implantation damage resulting from H+implantations is not completely understood. In this study, protons with energies from 400 keV up to 4 MeV and doses up to 1016 H+/cm² were implanted into highly ohmic boron doped m:Cz silicon (100). Electron Beam Induced Current (EBIC) measurements were performed to locally determine the minority charge carrier diffusion length. The diffusion length decreases with increasing implantation dose and incorporated damage. Spreading Resistance Profiling (SRP) measurements were performed to analyze the charge carrier concentration profiles for different annealing procedures. The electrical activation and growth of the defect complexes varies strongly with the annealing parameters. Transmission Electron Microscopy measurements were made to investigate the microscopic structures formed by the high dose implantation processes. Due to the high local damage density resulting from low energy and high dose H+ implants, platelet structures are formed. During high‐energy high‐dose H+implantations, the implanted hydrogen generates strain in the crystal lattice resulting in changes in the distances between atomic planes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:40:06.968116-05:
      DOI: 10.1002/pssc.201400051
       
  • Depletion of superjunction power MOSFETs visualized by electron beam
           induced current and voltage contrast measurements
    • Authors: Stefan Kirnstoetter; Martin Faccinelli, Moriz Jelinek, Werner Schustereder, Johannes G. Laven, Hans‐Joachim Schulze, Peter Hadley
      Pages: n/a - n/a
      Abstract: Electron Beam Induced Current (EBIC) measurements were used to produce cross sectional images of superjunction power transistors. These images show how the depletion width expands under reverse bias. Superjunctions are alternating p‐ and n‐type doped vertical columns placed between drain and source in a power transistor (Deboy et al., in: Proc. IEDM, 983–685 (1998); Lorenz et al., in: Proc. PCIM Europe, 250–258 (1998)). These columns allow a higher substrate doping of the drift region, resulting in a lower on‐state resistance while still maintaining a high breakdown voltage. When the device is reverse biased, the space charge region of the superjunction should expand symmetrically due to the homogeneous doping (in the n and p region) until the complete device depletes. The depletion process was also visualized using voltage contrast (VC) measurements. Here the secondary electron signal was detected when the device was reverse biased. We show that EBIC and VC measurements can provide valuable input for process tuning and process simulations, enabling the use of smaller dimensions and higher doping levels
      PubDate: 2014-08-08T04:30:06.467238-05:
      DOI: 10.1002/pssc.201400050
       
  • An EBIC and SRP study on thermal donors in proton implanted p‐type
           magnetic Czochralski silicon
    • Authors: Martin Faccinelli; Stefan Kirnstoetter, Werner Schustereder, Johannes G. Laven, Peter Hadley
      Pages: n/a - n/a
      Abstract: The concentration of defects in silicon can be changed by ion implantations and thermal annealing steps. Some of the defects incorporated during these processes form complexes which can act as donors or acceptors and their concentration can even overcome the initial doping concentration of the material, and hence, cause an inversion of the doping type. One way to introduce defects and also to catalyse the formation of defect complexes is by proton implantation. For our project, a high resistivity p‐type magnetic Czochralski (m:Cz) grown silicon wafer was implanted with 4 MeV protons at an implantation dose of 2 ×1014 cm–2. The wafer was broken into pieces and these pieces were annealed at different temperatures resulting in different concentrations of defect complexes. The defects were investigated in the proton implanted region and in the substrate region beyond the penetration depth of the protons (where only the heat treatment caused a change in the defect concentrations). The local doping type and the relative change of the minority carrier diffusion length were measured using Electron Beam Induced Current (EBIC). Furthermore, resistivity profiles were measured using Spreading Resistance Profiling (SRP). The results show several changes of the doping type, the minority carrier diffusion length and the resistivity profile. In addition to donor complexes already reported in the literature, the formation of additional high temperature donor complexes has been observed. The data shows that the presence of hydrogen in silicon has a far higher influence on the changes of the electrical properties of the material at annealing temperatures between 400 °C and 510 °C than at higher annealing temperatures. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:30:05.270823-05:
      DOI: 10.1002/pssc.201400045
       
  • Electron beam silicon purification
    • Authors: Anatoly Kravtsov; Alexey Kravtsov
      Pages: n/a - n/a
      Abstract: Purification of heavily doped electronic grade silicon by evaporation of N‐type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150‐300 kg) and yield solar grade silicon. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:23:33.625363-05:
      DOI: 10.1002/pssc.201400031
       
  • Determination of the single crystal Ge Young’s modulus between room
           temperature and melting temperature using the impulse excitation technique
           
    • Authors: Akhilesh K. Swarnakar; Omer Van der Biest, Jan Van Humbeeck, Jan Vanhellemont
      Pages: n/a - n/a
      Abstract: In the present study, the vibrational properties of single crystal Ge samples are studied between room and melt‐ing temperature using the impulse excitation technique (IET). From the IET measurements, the temperature dependent Young's moduli Eijk of single crystal Ge are extracted in the (100), (110) and (111) crystallographic directions in inert atmosphere. The results show an anomalous softening of an elastic constant around 890 °C temperature during the measure‐ment. The Young's moduli values between 88 to 132 GPa are obtained close to the melting temperature, depending on the crystallographic direction. Empiric expressions are derived for the temperature dependence of E(100), E(110) and E(111). (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-08-08T04:20:05.544496-05:
      DOI: 10.1002/pssc.201400011
       
  • Photoluminescence properties of Ce3+ ions in Ce‐doped SiO1.5 thin
           films containing Si nanocrystals
    • Authors: J. Weimmerskirch‐Aubatin; M. Stoffel, X. Devaux, A. Bouché, M. Vergnat, H. Rinnert
      Pages: n/a - n/a
      Abstract: We investigate the luminescence properties of Ce3+ ions in Ce‐doped SiO1.5 thin films containing Si nanocrystals (Si‐ncs) by means of steady‐state photoluminescence (PL), time‐resolved PL and PL excitation spectroscopy. Strong Ce‐related blue luminescence is observed with the naked eye at room temperature. The Ce‐related lumines‐cence is found to ncrease with the Ce content in the films while simultaneously, the Si‐nc‐related luminescence decreases. Moreover, the decay time of the Si‐nc related luminescence decreases for increasing Ce concentrations thus suggesting a possible indirect excitation of the Ce3+ ions via Si‐ncs. However, PL excitation measurements show that Ce3+ ions are mainly directly excited with only a negligible influence of the Si‐ncs. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:14.445674-05:
      DOI: 10.1002/pssc.201400042
       
  • Tuning optical a‐SiC/a‐Si active filters by UV bias light in
           the visible and infrared spectral ranges
    • Authors: M. Vieira; M. A. Vieira, I. Rodrigues, V. Silva, P. Louro
      Pages: n/a - n/a
      Abstract: Visible range to telecom band spectral translation is accomplished using an amorphous SiC pi'n/pin wavelength selector under appropriate front and back optical light bias. Results show that background intensity works as selectors in the infrared region, shifting the sensor sensitivity. Low intensities select the near‐infrared range while high intensities select the visible part according to its wavelength. Here, the optical gain is very high in the infrared/red range, decreases in the green range, stays close to one in the blue region and strongly decreases in the near‐UV range. The transfer characteristics effects due to changes in steady state light intensity and wavelength backgrounds are presented. The relationship between the optical inputs and the output signal is established. A capacitive optoelectronic model is presented and tested using the experimental results. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:13.125023-05:
      DOI: 10.1002/pssc.201400020
       
  • Comparison between experimental and simulated strain profiles in Ge
           channels with embedded source/drain stressors
    • Authors: R. Bühler; G. Eneman, P. Favia, H. Bender, B. Vincent, A. Hikavyy, R. Loo, J. A. Martino, C. Claeys, E. Simoen, N. Collaert, A. Thean
      Pages: n/a - n/a
      Abstract: Two planar Ge‐based MOSFET structures were analysed for n‐ and p‐type transistors with tensile and compressive strain implemented in the channel direction using source/drain stressors. Strain profiles measured by nano‐beam diffraction (NBD) have been compared with Sentaurus process simulations. The TCAD simulations were tuned with the actual process using NBD measurements, resulting in a more realistic simulation and, therefore, a more reliable interpretation is now possible. dark‐field scanning transmission electron microscopy images added to the strain profiles returned interesting results about the Ge virtual substrate condition and how it disturbs the NBD readings due to the presence of extended defects in strain relaxed Ge buffer layers. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:12.035703-05:
      DOI: 10.1002/pssc.201400021
       
  • Mediation effect of sub‐monolayer carbon on interfacial mixing in Ge
           growth on Si(100)
    • Authors: Yuhki Itoh; Ryo Hayase, Shinji Hatakeyama, Tomoyuki Kawashima, Katsuyoshi Washio
      Pages: n/a - n/a
      Abstract: The mediation effect of carbon (C) on interfacial mixing in Ge growth was studied using C‐covered Si surface (Ge/C/Si) and C over thin Ge buffer layer (Ge/C/Ge/Si) systems. The samples were prepared by solid‐source molecular beam epitaxy system with electron beam gun for C sublimation and K‐cell for Ge evaporation. The interdiffusion at the interface and deterioration in crystallinity of Ge layer was evaluated by Raman spectroscopy and X‐ray diffraction, respectively. In the case of Ge/C/Si system, the interdiffusion of Si and Ge atoms was suppressed by more than 0.3 monolayer (ML)‐C depositions while crystallinity of Ge layer was deteriorates by the formation of Si‐C at the Si surface and the incorporation of C atoms in Ge layer. In the case of Ge/C/Ge/Si system, the crystallinity of Ge layer was maintained even at C coverage of a few MLs, however, the amount of C to suppress the Ge/Si interdiffusion was more than 3 ML. From the correlation between Ge crystallinity and surface roughness, Ge/C/Ge/Si structure is considered to be more effective to take advantage of C mediation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:11.101235-05:
      DOI: 10.1002/pssc.201400032
       
  • Viability of the use of an a‐SiC:H multilayer device in a domestic
           VLC application
    • Authors: P. Louro; V. Silva, M. A. Vieira, M. Vieira
      Pages: n/a - n/a
      Abstract: In this paper the viability of an integrated wavelength optical filter and photodetector for visible light communication (VLC) is discussed. The proposed application uses indoor warm light lamps lighting accomplished by ultra‐bright light‐emitting diodes (LEDs) pulsed at frequencies higher than the ones perceived by the human eye. The system was analyzed at two different wavelengths in the visible spectrum (430 nm and 626 nm) with variable optical intensities. The signals were transmitted into free space and measured using a multilayered photodetector based on a‐SiC:H/a‐Si:H. The detector works as an optical filter with controlled wavelength sensitivity through the use of optical bias. The output photocurrent was measured for different optical intensities of the transmitted optical signal and the extent of each signal was tested. The influence of environmental fluorescent lighting was also analysed in order to test the strength of the system. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:10.256382-05:
      DOI: 10.1002/pssc.201400035
       
  • Enhancement of IR photoluminescence of β‐FeSi2 nanocrystals by
           Cu‐doping and study of its mechanism
    • Authors: Yoshihito Maeda; Takahide Tatsumi, Yuki Kawakubo, Yuya Noguchi, Hiroyuki Kobayashi, Kazumasa Narumi, Seiji Sakai
      Pages: n/a - n/a
      Abstract: We have investigated the IR photoluminescence (PL) behavior of Cu‐doped β‐FeSi2 nanocrystals (β‐NCs) embedded in Si layers. The diffusion rate of Cu atom was controlled by annealing. The most appropriate condition brought the largest intensities of both the intrinsic A band emission at 0.803 eV by 214% and the acceptor related C band emission at ∼0.75 eV by 582% in comparison with those of non‐doped β‐NCs. Rutherford backscattering spectrometry (RBS) revealed increase of Cu atoms in the Si layer with β‐NCs with increasing the anneal duration. The C band enhancement surely is originated from increase of a density of state at acceptor levels relating to increase of Cu in β‐lattice. Photocarrier injection PL measurements (PCI‐PL) reveal that the enhancement of the A band emission may be attributed to a controlled migration process of holes with a repeated trap process due to Cu‐doping into the Si phase. This dynamic condition leads to an increase of valence band offset at the β‐NCs/Si heterointerfaces where the migration of holes from the β‐NCs to Si is prevented, so that a radiative recombination rate can be enhanced. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:09.416628-05:
      DOI: 10.1002/pssc.201400039
       
  • Raman analysis of gold catalyst vapor liquid solid germanium nanowires
    • Authors: M. Israel; A. Moreac, R. Rogel, J. P. Landesman, L. Pichon
      Pages: n/a - n/a
      Abstract: Germanium nanowires (GeNWs) were synthesized in a low pressure chemical vapor deposition reactor (LPCVD) using a vapor‐liquid‐solid process (VLS). In this work, the focus is put on the characterization of these GeNWs using scanning electron microscopy (SEM) combined with Raman spectroscopy. In particular, NWs with conical shape grown at a moderate temperature (320 °C) were investigated in terms of the intensity measured for the Ge‐related Raman line. The two main observations, discussed in this paper, are the anomalous magnitude of this line, as compared to measurements under the same conditions on a Ge(100) substrate, and the oscillations observed when the Raman line intensity is measured while scanning the laser beam along the axis of the conical shaped NWs, from the tip to the bottom. These effects are discussed involving the fact that optical modes appear in such NWs (both for the incident and Raman scattered light) when conditions on the diameter, the laser excitation wavelength, and substrate (on which the NWs are transferred after growth) are fulfilled. Taking into account these specific optical modes, the effects observed can be explained. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-25T05:10:08.278128-05:
      DOI: 10.1002/pssc.201400041
       
  • Electronic structureof amorphous ZnO films
    • Authors: Dieter Schmeißer; Jörg Haeberle, Pedro Barquinha, Diana Gaspar, Luís Pereira, Rodrigo Martins, Elvira Fortunato
      Pages: n/a - n/a
      Abstract: We use resonant photoemission spectroscopy (resPES) to study the electronic properties of amorphous ZnO (a‐ZnO) layers. We report on the core levels, the valence band (VB) PES data, and the X‐ray absorption (XAS) data which we use for the conduction band (CB) density of states. From these results we are able to derive the partial density of states (pDOS) of O2p and Zn4s4p states in the VB and CB, respectively as well as a band scheme. At the O1s resonance we observe a band of localized defect states which is located between the Fermi energy and the CBM. At the Zn2p edge the XAS data indicate that localized Zn4s4p states are involved in the DOS starting already at the Fermi energy. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-24T06:10:08.545943-05:
      DOI: 10.1002/pssc.201400010
       
  • High temperature electrical conductivity in hydrothermally grown ZnO
    • Authors: K. Lott; T. Nirk, L. Türn, S. Shinkarenko, A. Öpik, E. Kortunova, P. Shvanskiy, E. Gorokhova, A. Vishnjakov
      Pages: n/a - n/a
      Abstract: Results of measurements of high temperature electrical conductivity (HTEC) in undoped hydrothermally grown ZnO single crystal are presented. HTEC measurements were made under the Zn component vapor pressure (up to 1 atm) and in the temperature range from 873 K to 1273 K. Reliable thermodynamic equilibrium in the ZnO crystal for HTEC measurements of isotherms and isobars was obtained at the temperatures higher than 873 K. Surprisingly slow chemical diffusion prolonged the high temperature measurement cycles continuously for several weeks. In our experiments the absolute value of HTEC in undoped hydrothermally grown ZnO was several orders of magnitude higher than HTEC in undoped ZnS. Slopes of HTEC isotherms varied with component vapor pressure and changed in the range from 0.2 to 0.4. For HTEC isobar in the temperature range from 1173 K to 1273 K it was found activation energy value 0.3‐0.4 eV at zinc vapour pressure 0.092 atm. Defect model for explanation of this high temperature experiment is discussed in connection with impurities. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-07-24T06:10:07.34355-05:0
      DOI: 10.1002/pssc.201400009
       
  • Effect of iron on the dielectric properties of silicate glasses prepared
           by sol‐gel
    • Authors: S. A. Salehizadeh; M. P. F. Graça, M. A. Valente
      Pages: n/a - n/a
      Abstract: The sol‐gel method is a very flexible route for producing sieving matrix such as SiO2 with pore radii in nanoscale region to embed oxide particles like Fe2O3. In this work, iron oxide nanoparticles embedded in a SiO2 glassy matrix prepared by the sol‐gel method have been investigated as a function of Fe/Si ratio. Different composition of dried gels with 1, 2, 10 and 20 mol% of Fe2O3 in the SiO2 matrix were heat‐treated (HT) in air, at temperatures from 400 ºC up to 1400 °C. The structure and morphology of the obtained glasses and glass‐ceramics were studied by X‐ray powder diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM). Impedance spectroscopy measurements and magnetic characterization were performed as function of temperature and the results are related with the microstructure. The X‐ray diffraction patterns showed that increasing the amount of Fe2O3 oxide promotes the formation of crystalline phases, in particular silicate phases. The increase of the heat‐treatment temperature has a similar behavior. The electrical and dielectric properties were related with these structural modifications and with the sample morphology. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-26T06:10:21.942599-05:
      DOI: 10.1002/pssc.201400015
       
  • Annealing related changes in near‐edge absorption and structural
           properties of Al‐doped ZnO thin films
    • Authors: S. Schönau; F. Ruske, S. Neubert, B. Rech
      Pages: n/a - n/a
      Abstract: In order to clarify the origin of the previously reported reduction of sub‐band gap absorption of sputtered ZnO:Al films upon thermal annealing and raising deposition temperature, structural characterization using Ra‐man spectroscopy was carried out on various films. Correlation of the Urbach energy to the FWHM of the E(high)2 mode was found. Oxygen addition to the film growth did not result in changes of the Urbach energy, despite pronounced changes of the electrical properties. The results suggest that extended defects, rather than intrinsic point defects, give rise to the sub‐band gap absorption. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-26T06:10:21.028944-05:
      DOI: 10.1002/pssc.201400002
       
  • Kinetic parameters of Cd1‐x‐yMnxZnyTe alloys melting and
           crystallization processes
    • Authors: V. Kopach; O. Kopach, P. Fochuk, L. Shcherbak, A. Bolotnikov, R. B. James
      Pages: n/a - n/a
      Abstract: The knowledge about parameters of melting and crystallization processes is required for controlled growth of ternary or quaternary single crystals from the melts. The differential thermal analysis method was used for investigation of the melting and crystallization kinetic parameters of Cd1‐x‐yMnxZnyTe alloys (x = 0.05–0.25, y = 0.05, 0.10). Two different ways of sample thermal processing allow us to study the supercooling‐superheating dependencies and the volume fraction of quasi‐solid phase (clusters) depending on the melt holding temperature and time. “Negative” supercooling of Cd1‐x‐yMnxZnyTe melts was observed when superheating of the melts don't exceed 20 K after their melting start. The su‐ percooling values of Cd1‐x‐yMnxZnyTe melts decreased with increasing x (i.e. Mn content). The change of the melts holding time from 10 to 60 min has no effect on the supercooling values. Volume fraction of Cd1‐x‐yMnxZnyTe alloys clusters existing in the melt decreased with the holding temperature increasing. Full homogenization occurred only after of Cd0.95‐xMnxZn0.05Te melts superheating higher than 1385 K, below this temperature melts exist in semiliquid state. The volume fraction of the quasi‐solid phase is smaller if the melt was heated at 10 K/min than after heating at 5 K/min to the same temperature. Melting temperature of Cd0.95‐xMnxZn0.05Te alloys decreased with Mn content increasing. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-26T06:10:20.120683-05:
      DOI: 10.1002/pssc.201300660
       
  • Modeling and multifractal analysis of radiation defect evolution in solids
    • Authors: Kazbek Baktybekov; Aliya Baratova
      Pages: n/a - n/a
      Abstract: The results of modeling of radiation defects formation and evolution on the surface and in the volume of a crystal are presented in this paper. Statistical properties are calculated for the investigated system. It is revealed that defect structure is a multifractal and system entropy decreases, while observing self‐organization of the physical system. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-20T07:23:11.964285-05:
      DOI: 10.1002/pssc.201400005
       
  • Influence of annealing on the properties of (Cd,Mn)Te crystals
    • Authors: M. Witkowska‐Baran; D. M. Kochanowska, A. Mycielski, R. Jakieła, A. Wittlin, W. Knoff, A. Suchocki, P. Nowakowski, K. Korona
      Pages: n/a - n/a
      Abstract: Semi‐insulating (Cd,Mn)Te crystals are believed to be suitable to successfully replace the commonly used (Cd,Zn)Te and CdTe crystals as a material for manufacturing large‐area X‐ and γ‐ray detectors. The purpose of the studies was to elaborate the technology of the (Cd,Mn)Te crystal plates with high resistivity, uniform in the whole volume of the plate. The article presents a method of annealing of the monocrystalline (Cd,Mn)Te crystal plates, giving the desired, repeatable results. The semi‐insulating (Cd,Mn)Te crystals, doped (for compensation) mainly by vanadium, but sometimes by Cl, In, or Cl and V, were grown by the Bridgman method, and the monocrystalline plates were cut. Subsequently the plates were annealed in Cd vapour. The resistivity of the plates was around 109 Ωcm, and the μτ‐product was about 10‐4 ‐10‐3 cm2/V. Mapping of the resistivity was performed on both the as‐grown crystals and the annealed crystal plates. The resistivity of the as‐grown crystals was in the range of 105‐106 Ωcm and inhomogeneous. After annealing the resistivity increased up to 109 Ωcm and better homogeneity could be seen. Annealing in the saturated Cd vapour influenced tellurium inclusions/precipitates. It was studied by IR transmission microscopy. For the as‐grown samples the density of Te inclusions (>1 µm) was ≈ 4×105 cm‐3, but for the annealed samples it was ≈ 104 cm‐3. The low‐temperature photoluminescence (PL) measurements indicated significantly lowered concentrations of acceptors after annealing. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-14T05:20:08.412358-05:
      DOI: 10.1002/pssc.201300746
       
  • Photoluminescence study of γ‐irradiation effect on the defect
           structure in Ge‐doped CdTe single crystals
    • Authors: Iu. Nasieka; L. Rashkovetskyi, M. Boyko, V. Strelchuk, Z. Tsybrii, B. Danilchenko, L. Shcherbak
      Pages: n/a - n/a
      Abstract: An effect of γ‐irradiation in the dose range 10‐500 kGy on the defect structure of Ge‐doped CdTe single crystals (CdTe:Ge) was investigated via the method of low‐temperature photoluminescence. It was obtained that γ‐irradiation in mentioned above dose range leads to the substantial decreasing of intensities of excitonic emission bands – D0X, A0X, VDX and increase in the intensities of impurity‐related emission bands – eA1,eA2, DA. It was shown that such changes in the luminescence can be explained by radiation‐stimulated redistribution of luminescence centers between recombination channels. The latter includes vacancy‐type defects filling by Ge dopant atoms which leads to the improving of the crystalline perfection of irradiated CdTe:Ge crystals. Mentioned material quality increasing was confirmed analysing the electron‐LO‐phonon coupling in irradiated crystals which was characterized via the Huang‐Rhys factor for corresponding luminescence bands. For the verification of the assumption about radiation‐stimulated compensation of native defects the resonant Raman measurements also were carried out. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-14T05:10:19.789265-05:
      DOI: 10.1002/pssc.201300571
       
  • Raman investigation on thin and thick CdTe films obtained by close spaced
           vacuum sublimation technique
    • Authors: D. Nam; H. Cheong, A. S. Opanasyuk, P. V. Koval, V. V. Kosyak, P. M. Fochuk
      Pages: n/a - n/a
      Abstract: The CdTe thin and thick films were obtained by the close spaced vacuum sublimation technique on a glass substrate under the following growth conditions: the evaporator temperature was 620 °C; and the substrate temperature was varied in the range from 250 °C to 550 °C. High purity CdTe powder was used as a charge for evaporation. The Raman spectra were measured using TRIAX 320 and TRIAX 550 spectrometers at room temperature. The 488‐nm line and 514.5‐nm line of an Ar+ laser and a 785‐nm diode laser were used as excitation sources. The signal was collected by the liquid nitrogen cooled charge‐coupled‐device (CCD) detector. A number of intense Raman peaks at 140, 167, 190, 271, 332 and 493 cm‐1 were observed and were interpreted as TO (140 cm‐1), 1LO (167 cm‐1), 2LO (332 cm‐1), 3LO (493 cm‐1) phonon modes and plasmon‐phonon mode (190 cm‐1). The presence of several phonon replicas in the Raman spectra confirms high crystal quality of the samples. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-14T05:10:18.985556-05:
      DOI: 10.1002/pssc.201300577
       
  • Self‐compensation limited conductivity of Cl‐doped CdTe
           crystals
    • Authors: O. L. Maslyanchuk; L. A. Kosyachenko, S. V. Melnychuk, P. M. Fochuk, T. Aoki
      Pages: n/a - n/a
      Abstract: The conductivity of semi‐insulating Cl‐doped CdTe crystals produced by Acrorad Co. Ltd. with a resistivity ρ = (3‐6)×109 Ω·cm (300 K) was investigated. It is shown that the Fermi level in the band gap is located below the Fermi level in intrinsic CdTe which indicates the hole conductivity of the material. The concentration of holes in the studied crystals is determined to be 2‐3 orders of magnitude higher than the concentration of electrons. The statistics of electrons and holes in a semi‐insulating semiconductor containing self‐compensation complexes (centers) is considered bearing in mind that the effect of background impurities and defects in heavily Cl‐doped CdTe crystal is strongly reduced. A method for determining the ionization energy and the compensation degree of deep donors contained in the complexes was applied. It is shown that virtually intrinsic conductivity of the studied CdTe crystals is provided by the donors with ionization energy 0.68‐0.69 eV, whose level is located at 0.05‐0.06 eV above the middle of the band gap. Due to strong compensation, the Fermi level turns out below the middle of the band gap. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-14T05:10:18.072856-05:
      DOI: 10.1002/pssc.201300694
       
  • Studies of the surface regions of (Cd,Mn)Te crystals
    • Authors: Dominika Kochanowska; Marcin Rasiński, Marta Witkowska‐Baran, Małgorzata Lewandowska, Andrzej Mycielski
      Pages: n/a - n/a
      Abstract: The growth process conditions affect quality of the crys­tal. Structural defects such as grains, twin boundaries and precipitates are formed during the crystal growth. The defects (especially‐inclusions) at the surface can be investigated in a microscale by the scanning electron microscopy (SEM). It is shown in the article that a well known etchant, usually used for visual inspection of the quality of the CdTe‐related crystals, can be applied to the preparation of the (Cd,Mn)Te surface for SEM investigations. Samples, cut from different parts of a (Cd,Mn)Te crystal, were ground, mechano‐chemically polished, and treated by the special etchant (to indicate polarity and to reveal twinning). After that treatment the defects (grain and twin boundaries, tellurium inclusions) at the surface became much more accessible for both SEM and visual investigations. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-14T05:10:17.056833-05:
      DOI: 10.1002/pssc.201300711
       
  • LEDs based on p‐type ZnO nanowires synthesized by electrochemical
           deposition method
    • Authors: V. Kapustianyk; B. Turko, I. Luzinov, V. Rudyk, V. Tsybulskyi, S. Malynych, Yu. Rudyk, M. Savchak
      Pages: n/a - n/a
      Abstract: The data concerning the light‐emitting diodes based on ZnO homojunction with ITO/n ‐ZnO/p ‐ZnO+photoresist/Au/Ti and ITO/n ‐ZnO/p ‐ZnO+pho‐toresist+PEDOT:PSS/Au/Ti structures are reported. The p ‐ZnO nanowires were grown by electrochemical deposition method. It is suggested that the p ‐type conductivity first of all is connected with the zinc vacancies VZn. The clear rectifying behavior was observed on the current‐voltage curve of the ZnO p ‐n homojunction. The broad electroluminescence (EL) emission bands in the blue, green and red regions lead to observation of the white light by a naked eye under forward bias. The intrinsic defects such as Zni, VZn, Vo and Oi would be responsible for occurrence of these bands. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-07T06:30:10.579816-05:
      DOI: 10.1002/pssc.201300671
       
  • Structural, electrical and optical properties of zinc‐iridium oxide
           thin films deposited by DC reactive magnetron sputtering
    • Authors: Martins Zubkins; Roberts Kalendarev, Jevgenijs Gabrusenoks, Kaspars Vilnis, Andris Azens, Juris Purans
      Pages: n/a - n/a
      Abstract: ZnO‐IrO2 thin films were deposited on glass by DC reactive magnetron sputtering at room tem‐perature. Structural, electrical and optical properties were investigated as a function of iridium atomic concentra‐tion in the films. XRD data shows that ZnO‐IrO2 thin films are X‐ray amorphous and Raman spectrum resembles the spectrum of IrO2, without any distinct features of wurtzite ZnO structure. The lowest film resistivity and the highest transmittance achieved in the present study were 1.4 × 10‐3 Ωcm and 33% at 550 nm, respectively. However, resistivity and transmittance are inversely related to the iridium concentration in the films.
      PubDate: 2014-05-07T06:23:11.504355-05:
      DOI: 10.1002/pssc.201300653
       
  • Influence of annealing in Zn vapor on the luminescence of MgZnO ceramics
    • Authors: I. Markevich; T. Stara, O. Kolomys, A. S. Romanyuk, V. Strelchuk
      Pages: n/a - n/a
      Abstract: ZnO‐based compounds that exhibit a number of strongly overlapping emission bands in visible spectral region are promising materials for white‐light emitters with continuous emission spectrum. Defect‐related emission in doped with different impurities ZnO, however, spreads from green to red spectral region, so its shift toward shorter wavelengths is required. We supposed that this problem can be solved due to broadening of ZnO band gap by alloying ZnO with MgO. The enhancement of visible emission brightness is also an important problem. In this work, MgxZn1‐xO ceramics with x =0 and x=0.2 were sintered both in air and Zn vapor at 950 oC. Emission and Raman scattering spectra were measured at 300 K using 325 nm line of He‐Cd laser as excitation source. In samples sintered in air, bright UV emission and weak visible one took place, adding MgO to ZnO resulting in blue‐shift of the latter. Sintering in Zn vapor was found to weaken UV emission and to increase drastically the brightness of visible one especially in blue‐green spectral region. As a result, bright blue radiation was observed from MgZnO ceramics under excitation by considerably week UV light. Obtained effects were accounted for by the shift of “green” centers energetic level with respect to involved band edge as a result of band‐gap broadening and by the increase of this center density due to annealing in Zn vapor. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-07T06:23:10.54456-05:0
      DOI: 10.1002/pssc.201300647
       
  • Influence of doping precursor on band gap and morphologies of
           sol‐gel deposited ZnMgO thin films
    • Authors: Amanpal Singh; Sonia Saini, Dinesh Kumar, P. K. Khanna, Mukesh Kumar, B. Prasad
      Pages: n/a - n/a
      Abstract: Zn1–xMgxO thin films were deposited by sol–gel route on p–type Si (100) and quartz substrates. It is ob‐served that the incorporation of Mg and morphological features of the sol–gel derived Zn1–xMgxO thin films extremely depend upon the selection of doping (Mg) precursor salts. Investigation of different doping precursors such as magnesium acetate, magne‐sium chloride and magnesium nitrate have been carried out. Zn1–xMgxO (x = 0.15) thin films deposited us‐ing each doping source were annealed at 300, 500, 700 and 900 °C in the presence of oxygen for one hour. The results showed that the magnesium nitrate required lower annealing temperature and provided good quality of films, However traces of N were observed in the films. The surface morphology and microstructure of the depos‐ited thin films were analyzed by atomic force microscopy. The crystallite dimension, shape and the growth rate were found to be significantly affected by dopant precursors. The chemical compositions were determined by elemen‐tal dispersive spectra. The band gap modulation is stud‐ied by varying the magnesium content from x = 0.00 to 0.40 for each type of salt for Mg doping. The Zn1–xMgxO films deposited using magnesium chloride exhib‐ited poor band gap modulation and lower quality of mi‐crostructure. The films deposited using magnesium ace‐tate exhibited minimum defects, good crystallinity and higher band gap modulation. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-07T06:20:21.788418-05:
      DOI: 10.1002/pssc.201300593
       
  • Optical and structural properties of Al2O3/ZnO nanolaminates deposited by
           ALD method
    • Authors: Adib Abou Chaaya; Roman Viter, Ieva Baleviciute, Mikhael Bechelany, Arunas Ramanavicius, Donats Erts, Valentyn Smyntyna, Philipe Miele
      Pages: n/a - n/a
      Abstract: We report on the investigation of optical and structural properties of Al2O3/ZnO nanolaminates. The nanolaminates were deposited on Si and glass substrates by Atomic layer deposition method. Structural properties of nanolaminates were studied by SEM, GIXRD, and AFM. Optical characterization was performed by transmittance and photoluminescence spectroscopy. Complex analysis of monolayer properties was done by ellipsometry. Optical constants for Al2O3 and ZnO monolayer were calculated.
      PubDate: 2014-05-07T06:20:20.87946-05:0
      DOI: 10.1002/pssc.201300607
       
  • Local structure and dynamics of wurtzite‐type ZnO from
           simulation‐based EXAFS analysis
    • Authors: Janis Timoshenko; Andris Anspoks, Aleksandr Kalinko, Alexei Kuzmin
      Pages: n/a - n/a
      Abstract: Conventional methods of EXAFS data analysis are often limited to the nearest coordination shells of the absorbing atom due to the difficulties in accurate accounting for the so‐called multiple‐scattering effects. Besides, it is often difficult to resolve the non‐equivalent groups of atoms in a single coordination shell due to strong correlation between structural parameters. In this study we overcome these problems by applying two different simulation‐based methods, i.e., classical molecular dynamics (MD) and reverse Monte with evolutionary algorithm (EA), to the analysis of the Zn K‐edge EXAFS data for wurtzite‐type bulk ZnO. The RMC/EA‐EXAFS method allowed us to separate the contributions of thermal disorder and the effect of noncentrosymmetric zinc oxide structure, being responsible for its piezoelectrical and pyroelectrical properties. The MD‐EXAFS method allowed us to test the accuracy of several available force‐field models, which are commonly used in the MD simulations of ZnO nanostructures.
      PubDate: 2014-05-07T06:20:20.0518-05:00
      DOI: 10.1002/pssc.201300615
       
  • Optical and electrical studies of transparent conductive AZO and ITO
           sputtered thin films for CIGS photovoltaics
    • Authors: R. A. Mereu; S. Marchionna, A. Le Donne, L. Ciontea, S. Binetti, M. Acciarri
      Pages: n/a - n/a
      Abstract: Due to the many advantages of aluminum doped zinc oxide (AZO) as an alternative to indium tin oxide (ITO), the optical and electrical properties of AZO thin films deposited on large substrates by D.C. pulsed magnetron sputtering have been investigated in view of future industrial applications. In order to evaluate the effectiveness of AZO thin films as transparent conductive oxide (TCO), their properties have been compared with those of standard ITO grown with the same technique. The effect of the thickness on the optical properties revealed higher transmittance values for AZO (T>86 %) than for ITO (T>83 %) films. The best resistivity values obtained for AZO were about 9.7×10–4 Ωcm versus 5.09×10–4 Ωcm measured for ITO films. Moreover, it was observed that the film resistivity is significantly influenced by the working pressure in the case of AZO films while the ITO resistivity appears almost unaffected. Finally, since both the optical and electrical properties are influenced by the film thickness, it was crucial to determine the proper AZO thickness in order to obtain the optimum of electrical and optical properties for the photovoltaic applications. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-07T06:20:19.187917-05:
      DOI: 10.1002/pssc.201300631
       
  • Concentration determination and activation of rare earth dopants in zinc
           oxide thin films
    • Authors: A. Ziani; A. Tempez, C. Frilay, C. Davesnne, C. Labbé, Ph. Marie, S. Legendre, X. Portier
      Pages: n/a - n/a
      Abstract: In this paper, we will present the development of rare‐earth (RE) doped zinc oxide (ZnO) films for white light emitting diodes (LED). We will present the structural changes of these films as well as their optical properties and associated photoluminescence before and after rapid thermal treatments. We will report depth profile results from plasma profiling time of flight mass spectrometry (PP‐TOFMS) giving the distributions and concentrations of the different elements in the films. We will correlate depth profile and luminescence data to understand the RE emission mechanisms in ZnO matrix. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-07T06:20:18.382059-05:
      DOI: 10.1002/pssc.201300636
       
  • Influence of deposition parameters on ZnO and ZnO:Al thin films
    • Authors: Nilufer Evcimen Duygulu; Alp Osman Kodolbas, Ahmet Ekerim
      Pages: n/a - n/a
      Abstract: Zinc oxide (ZnO) and 2% aluminium doped ZnO (ZnO:Al) thin films were deposited on glass by using r.f. magnetron sputtering without intentional heating. The r.f. power was varied in the range of 150 W to 175 W and process gas (argon) pressure was changed from 0.20 Pa to 0.60 Pa in small variation ranges to identify the influence of sputtering parameters. Achieved results were analysed with the help of XRD, AFM, SEM, HRTEM, four point probe, optical transmittance measurement techniques. According to the results, 165 W was selected as optimum r.f. power value, while 0.20 Pa for ZnO and 0.30 Pa for ZnO:Al thin films were determined as argon gas pressure values. All the thin films were oriented with the crystallographic c‐(002) axis perpendicular to the substrate surface. Moreover, at this deposition values; the resistivity was measured as around 10‐3Ω.cm, while the deposition rate showed variations. The optical transmittance of ZnO:Al was obtained (85%) higher than ZnO (75%) thin film. The optical band gap was changed from 3.45 eV to 4.2 eV. Surface roughness (RMS) values were obtained as 5.44 nm for ZnO and as 2.36 nm for ZnO:Al. (© WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-07T06:20:17.60807-05:0
      DOI: 10.1002/pssc.201300640
       
  • UV detector based on zinc oxide nanorods obtained by the hydrothermal
           method
    • Authors: Bartlomiej S. Witkowski; Lukasz Wachnicki, Sylwia Gieraltowska, Piotr Sybilski, Krzysztof Kopalko, Marcin Stachowicz, Marek Godlewski
      Pages: n/a - n/a
      Abstract: Properties of UV detector based on ZnO nanorods, grown by a hydrothermal method, are discussed. The innovative growth technology was used to produce ZnO nanorods. It is characterized by a much higher growth rate, than reported (till now) in the literature, and a very low costs (both of technology and materials). Importantly, ZnO nanorods grown by this method are free from oxygen vacancies. Despite the fact that detector proposed by us is not based on a single nanorod, but on a whole array of nanorods, it is very sensitive. The detector shows sensitivity of 20 mW/m2 (2 µW/cm2) upon UV illumination. Due to a high energy band gap of zinc oxide and a high purity of the obtained nanorods visible light is not detected. The resistivity/current changes are proportional to illumination intensity, i.e., detector response scales with the intensity of UV light. The observed changes of the detector resistivity relate to surface reactions generated upon an illumination. Importantly, detector does not need annealing or cleaning to reset to an initial state.(© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:15.381857-05:
      DOI: 10.1002/pssc.201300761
       
  • Electrical characterization of organic (amorphous) electronic materials
    • Authors: Peter Stallinga
      Pages: n/a - n/a
      Abstract: Organic electronic materials, or amorphous electronic materials in general, have relatively low conductivity and this limits their application to the low‐frequency electronics market. To describe electronic conduction in these materials it is common to use percolation [1] or (variable range) hopping theory [2] (the two being equivalent). This is an inheritance from the earlier research in organic materials that were invariably insulators, where conduction was a perturbation – movement of charge was a rare event. Summarizing in this paper our work on organic electronic materials, it is shown that for electronic materials, instead, it is better to revert to classical semiconductor theories, like band theory [3]. If we include a large density of traps in the energy system, all observed phenomena are easily explained. This includes 1. strong temperature dependent charge‐carrier mobility, 2. field‐dependent mobility, 3. anomalous transient behavior. Moreover, it is consistent with observations in many types of devices, ranging from two‐terminal devices such as diodes to three‐terminal devices such as thin‐film transistors [4]. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:14.237667-05:
      DOI: 10.1002/pssc.201300508
       
  • Formation of ordered array of core/shell ZnS/Ge/ZnS nanostructures by
           thermal evaporation method
    • Authors: A. Beltiukov; R. Valeev, E. Romanov, V. Mukhgalin
      Pages: n/a - n/a
      Abstract: This paper reports the results of studies of ZnS/Ge/ZnS nanostructures, obtained by high vacuum thermal deposition of ZnS and Ge powders into porous anodic aluminium oxide (AAO) with different diameters of pores. Scanning electron microscopy (SEM) investigations reveal two types of nanostructures having the form of rings (sample with diameter of pores 70 nm) and rods (samples with diameter of pores 80 and 110 nm). It is also shown that the other porosity parameters such as interporous distances affect the formation of a particular type of nanostructures. X‐ray and electron diffraction study show two phases, ZnS and Ge. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:13.138862-05:
      DOI: 10.1002/pssc.201300623
       
  • Seasonal variation of performance in concentrator photovoltaic system
    • Authors: Kei Nomura; Yasuyuki Ota, Takashi Minemoto, Kensuke Nishioka
      Pages: n/a - n/a
      Abstract: Concentrator Photovoltaic (CPV) system was installed in the University of Miyazaki, Japan. The system's output parameters and meteorological condition experienced by the system i.e. incident irradiance, incident spectrum distribution, and cell temperature were recorded. A statistical analysis method was proposed so that the influences of spectrum distribution variations and cell temperature on the output performance of the system can be observed separately. It was found that the performance of the CPV system significantly depended on the variation of the incident solar spectrum distribution rather than cell temperature. Using this method, the performance of CPV system was analysed throughout the seasons. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:11.940701-05:
      DOI: 10.1002/pssc.201300629
       
  • The study of large semiconducting boron doped single crystal diamond
           sectorial structure
    • Authors: A. Chepugov; S. Ivakhnenko, V. Garashchenko
      Pages: n/a - n/a
      Abstract: The sectorial structure of semiconductor single‐crystal diamond grown at high pressure and temperature was considered. Influence of crystal structure on shape of IR‐absorption maps and photoluminescence glow were studied. The distribution of boron impurity and its concentration in the areas which belonging to different growth sectors were measured. The analysis of the effect of the conditions of type IIb crystal growth at HPHT on their structure was performed, conditions for getting the most homogeneous samples were defined. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:10.973538-05:
      DOI: 10.1002/pssc.201300633
       
  • Swift Xe ion irradiation effect on structure and vibrational properties of
           undoped and Cd‐doped ZnO films
    • Authors: Denys Myroniuk; Ivan Shtepliuk, George Lashkarev, Vasyl Lazorenko, Vladimir Skuratov, Izabella Timofeeva, Artem Romaniuk, Viktor Strelchuk, Oleksandr Kolomys
      Pages: n/a - n/a
      Abstract: The undoped and Cd‐doped (0.4, 0.5 at. %) ZnO films deposited by radiofrequency magnetron sputtering have been irradiated by 167 MeV Xe26+ ions with energy to a fluence 3×1012 ions/cm2. The structure and vibrational properties of as‐grown and irradiated samples were studied using X‐ray diffraction and Raman spectroscopy techniques. It was found that Cd‐doped ZnO films in comparison with undoped films demonstrate an improvement of crystal structure due to increased size of X‐ray coherent scattering regions, relaxation of strain between grains in the films and reduction of modes which relates to defects in ZnO crystal lattice. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:10.08855-05:0
      DOI: 10.1002/pssc.201300641
       
  • Towards X‐ray in‐situ visualization of ammonothermal crystal
           growth of nitrides
    • Authors: Saskia Schimmel; Ulrike Künecke, Hasan Baser, Thomas G. Steigerwald, Benjamin Hertweck, Nicolas S. A. Alt, Eberhard Schlücker, Wilhelm Schwieger, Peter Wellmann
      Pages: n/a - n/a
      Abstract: In‐situ X‐ray visualization of hydrothermal growth of silicalite‐1 is applied as an intermediate step for developing X‐ray in‐situ visualization techniques for ammonothermal growth of nitride materials. In‐situ X‐ray imaging of silicalite‐1 crystals grown by the bulk material dissolution technique (Shimizu and Hamada, Angew. Chem., Int. Ed. 38, 2725 (1999) [1]) is demonstrated using a stainless steel autoclave equipped with ceramic aluminium oxide windows. Processes in the reaction medium such as local density changes are also visualized. The transferability of the technique to ammonothermal growth of nitrides is evaluated. Furthermore, the applicability of windowless autoclaves for X‐ray in‐situ monitoring of ammonothermal crystal growth of nitrides is investigated. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:09.220193-05:
      DOI: 10.1002/pssc.201300656
       
  • Structural, electrical and optical properties of CuGaTe2 absorber for
           thin‐film solar cells
    • Authors: Ammar Messous; Abdesselam Bouloufa, Kamal Djessas, Idris Bouchama
      Pages: n/a - n/a
      Abstract: Near‐stoichiometry composition CuGaTe2 (CGT) thin films prepared by close‐spaced vapour transport (CSVT) with copper excess in the source has been investigated and was confirmed by energy dispersive spectroscopy. The influence of temperature substrate on structural properties of CGT was studied, with the optimal substrate temperature at 480 °C. Morphological and structural analyses allowed identifying the type of crystallites. Crystalline phases of the films were examined using X‐ray diffraction. A strong (112) orientation perpendicular to substrate plane was observed and additional reflections planes were also detected. The electrical resistivity was determined using the four probe method and lies in the 0.127‐0.271 Ω cm range. The direct bandgap is about 1.7 eV and resistivity showed a low value. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-05-02T06:10:08.368508-05:
      DOI: 10.1002/pssc.201300657
       
  • Electrical resistivity and its thermal coefficient of TiW alloy thin films
           prepared by two different sputtering systems
    • Authors: Yutaka Sakurai; Yuya Takeda, Shinji Ikeda, Yoshinori Sakamoto
      Pages: n/a - n/a
      Abstract: Electrical resistivity and its thermal coefficient (TCR) of TiW alloy thin films which were prepared by using two different sputtering systems have been investigated. System A is a DC‐magnetron sputtering system equipped with a single composite‐target that allows the contents controllable by an external field of solenoid as reported in previous papers (Sakurai and Takeda, Abstract of E‐MRS 2005 Fall Meeting [1] and Sakurai et al., Solid State Phenom. 154, 175 (2009) [2]). The system A prepared specimens with the range of 21.6 to 36.6 at% of W‐contents. The TCR varies from minus to plus at 32 at % of W‐content. On the other hand, System B is a RF‐magnetron sputtering system equipped with multi‐targets and multi‐sputtering‐sources. The system B covered the whole binary composition ranges by controlling power ratio for two independent sputtering sources. The resistivity characteristics show a parabolic curve with the maximum value on Ti‐rich contents. The TCR decreases at the contents that shows the maximum resistivity, but the TCR is always plus and does not cross zero. Difference of the properties by using the two systems will be discussed. In the system A, the background is exhausted by an oil diffusion pump and the pressure is higher (lower vacuum degree) than the background in the system B with a turbo molecular pump. This suggests that zero TCR would be achieved by introducing the controlled impurities (O2 or N2) into the binary alloy films. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:23:08.833515-05:
      DOI: 10.1002/pssc.201300621
       
  • Nanostructured Y‐doped ZrO2 powder: peculiarities of light emission
           under electron beam excitation
    • Authors: N. Korsunska; V. Papusha, O. Kolomys, V. Strelchuk, A. Kuchuk, V. Kladko, Yu. Bacherikov, T. Konstantinova, L. Khomenkova
      Pages: n/a - n/a
      Abstract: Present work deals with the study of luminescence and structural properties of Y‐doped ZrO2 nanopowders sintered by co‐precipitation of Zr and Y nitrates. The structural and light emitting properties were controlled by X‐ray diffraction, transmission electron microscopy, Raman scattering, photo‐ (PL) and cathodoluminescence (CL) methods. Generally, room temperature PL spectra showed several bands in UV‐orange range, whose shapes depend on the excitation light wavelength. Along with this, CL spectra demonstrate additional “red” emission, which intensity exceeds that of other CL bands. At lower temperatures, preferable enhancement of “red” CL band, its narrowing and peak position shift to the longer wavelengths were found. This behavior testifies to the non‐elementary nature of “red” CL band. Its nature and mechanism of its excitation are discussed. It is supposed that some impurities (such as Fe and/or Zn) or complex defects, containing oxygen vacancies and these impurities, are responsible for “red” emission appeared under electron beam excitation only. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:23:07.869618-05:
      DOI: 10.1002/pssc.201300597
       
  • Enhanced dielectric properties of nitrogen doped epitaxial Gd2O3 thin
           films on Si
    • Authors: Ayan Roy Chaudhuri; A. Fissel, H. Jörg Osten
      Pages: n/a - n/a
      Abstract: The impact of nitrogen doping on the growth electronic band structure and electrical properties of epitaxial Gd2O3 thin films on Si (111) has been investigated. Epitaxial layers of Gd2O3:N were grown on p‐type Si (111) substrates by solid source molecular beam epitaxy technique using molecular N2O as the nitridation agent. Substitutional nitrogen incorporation into the dielectric layer was confirmed by secondary ion mass spectroscopy and X‐ray photoelectron spectroscopy measurements. Significant reduction of the leakage current density and disappearance of capacitance‐voltage hysteresis in the Gd2O3:N layers indicate that nitrogen doping in Gd2O3 successfully eliminates the adverse effects of the oxygen vacancy induced defects in the oxide layer. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:23:07.01246-05:0
      DOI: 10.1002/pssc.201300596
       
  • Influence of solar radiation on the performance of organic solar cell
    • Authors: Abla Guechi; Mohamed Chegaar, Abdelali Merabet
      Pages: n/a - n/a
      Abstract: The electrical current generated by the solar cells is very sensitive to the incident spectral distribution and intensity. This distribution varies greatly during the day due to changes in the sun's position or weather conditions. This work investigates the feasibility of using a solar spectral radiation model SMARTS2 to estimate the global solar irradiance and assess the influence of solar spectrum on the conversion efficiency of the organic thin film solar cells (PBDTTT) (poly[4,8‐bis‐substituted‐benzo[1,2‐b:4,5‐b0]dithiophene‐2,6‐diyl‐alt‐4‐substituted‐ thieno[3, 4‐b]thiophene‐ 2,6‐diyl])). The variation of the common performance indicators such as short circuit current, fill factor, open circuit voltage, and efficiency are shown and discussed for each month. The results show that the variations in the solar spectrum affect the different materials to different extent. The maximum efficiency is obtained in the summer months; however the lower efficiency is obtained during winter. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:23:06.103212-05:
      DOI: 10.1002/pssc.201300594
       
  • Growth of Fe nanocrystals on LaAlO3 (001) and epitaxial relationship
           determination by RHEED and XPS
    • Authors: Mohamed Zanouni; Emmanuel Denys, Mickael Derivaz, Didier Dentel, Mustapha Diani, Chiraz Ben Azzouz, Jean‐Luc Bischoff
      Pages: n/a - n/a
      Abstract: Non‐volatiles flash memories embedding nanocrystals are promising devices. These memories are made of semiconducting or metallic nanostructures inserted in an insulating matrix. SiO2, traditionally used as an insulator, is gradually replaced by high‐dielectric materials called “high‐k” oxides, to reduce leakage currents. In this context, we used a crystalline lanthanum aluminate (LaAlO3) oxide. The magnetic properties of nanoparticles of Fe can increase the storage capacity in the memories compared to the semiconductor nanostructures as Si or Ge. Memories combining these two materials require complex monolithic structures such as “LaAlO3/Fe/LaAlO3/Si(001)”. In this context we have studied the initial growth of Fe on a solid substrate of LaAlO3 (001). Fe deposits were performed by molecular beam epitaxy (MBE) at different substrate temperatures. Chemical and structural properties were investigated by X‐ray photoelectron spectroscopy (XPS) and reflection high‐energy electron diffraction (RHEED). The temperature dependence study indicates that the growth of Fe on LaAlO3 is epitaxial with a single epitaxial relationship in a tight temperature window around 500 °C. The plane (001) of Fe is parallel with the LaAlO3(001) surface, but the iron unit cell is rotated of 45° around the growth direction compared with the substrate one (Fe // LaAlO3). This configuration minimizes the elastic strain of the Fe which grow with the Volmer‐Weber mode. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:20:13.451936-05:
      DOI: 10.1002/pssc.201300566
       
  • New approach to the growth of SiO2 nanowires using Sn catalyst on Si
           substrate
    • Authors: Alexandr Zamchiy; Evgeniy Baranov, Sergey Khmel
      Pages: n/a - n/a
      Abstract: Silica nanowires were synthesized from mixture monosilane with hydrogen by gas‐jet electron beam plasma chemical vapor deposition method for the first time. The synthesis was carried out on silicon substrate with up to micrometer‐sized particles of Sn catalyst. SEM observations show that this method provides different morphology of the nanowires and catalyst. Oriented arrays of silica nanowires bunches (microropes) were synthesized in the area corresponding to the mixture jet axis. Cocoons‐like, bamboo‐like, and jellyfish‐like morphology was observed in the area corresponding to periphery of the jet. Probably there was realised vapor‐liquid‐solid (VLS) growth mechanism, where multiple nanowires grow simultaneously from the surface of one catalyst drop. The growth rate of the microropes is about 25 nm/s at synthesis temperature 330 °C. Possible growth model has been suggested in order to explain the results. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:20:12.355306-05:
      DOI: 10.1002/pssc.201300574
       
  • A comparative analysis of infrared luminescence spectra of ZnSe:Yb,
           ZnSe:Gd, and ZnSe:Cr crystals
    • Authors: Gleb Colibaba; Evghenii Goncearenco, Dmitrii Nedeoglo, Natalia Nedeoglo
      Pages: n/a - n/a
      Abstract: Photoluminescent and optical properties of ZnSe crystals doped with Yb and Gd rare‐earth elements (REEs) and Cr impurity are investigated in infrared (IR) spectral range. The influence of stoichiometric deviation on photoluminescence (PL) spectra of the crystals is investigated and the structure of complex IR PL bands is analysed. The good coincidence between the IR PL spectra of the samples doped with Yb, Gd, and Cr is shown. Correlation between the component parts of the bands at 1 and 2 µm is found and possibility to control the composition of IR PL spectra by enrichment of the samples with Zn or Se is discussed. The model that explains the formation of associative centres based on the REEs and background Cu impurity fixed in the nodes of crystal lattice with tetrahedral symmetry, which are responsible for IR PL bands, is proposed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:20:11.549179-05:
      DOI: 10.1002/pssc.201300587
       
  • Obtaining of II‐VI compound substrates with controlled electrical
           parameters and prospects of their application for nanoporous structures
    • Authors: Gleb Colibaba; Evghenii Goncearenco, Dmitrii Nedeoglo, Natalia Nedeoglo, Eduard Monaico, Ion Tiginyanu
      Pages: n/a - n/a
      Abstract: Substrates of II‐VI semiconductor compounds may be widely used in fabrication of nanoporous matrices (NM), which give the possibility to obtain nanowires and nanotubes of various materials with good application prospects in various fields. The easiest and cost‐effective method to obtain nanoporous matrices is electrochemical etching (ECE), which, however, depends on conductive properties of the substrates. The conditions of growing homogeneous ZnSe, ZnS, ZnSSe, ZnO, and ZnCdS single crystals by physical and chemical vapour transport methods are discussed. Based on the results of investigation of electrical, optical, and photoluminescence properties of the samples with various doping levels, the prospect of examined technology for manufacturing the substrates of these compounds with large area and controlled n‐type electrical conductivity varied up to 20, 0.3, 0.3, 9, and 30 Ω–1cm–1, respectively, is estimated. Possible utilization of these substrates for preparation of NM by ECE is analyzed. The results of nanostructuring using various electrolytes are shown. The prospect of using ZnSe and ZnCdS compounds for manufacturing nanopore arrays with diameter down to 30 nm and nanopo‐rous structures with a specific morphology on ZnO substrates is demonstrated. Technological limitations for fabrication of the similar structures on the basis of ZnS and ZnSSe substrates are also analyzed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2014-04-29T02:20:10.619365-05:
      DOI: 10.1002/pssc.201300590
       
  • Contents: Phys. Status Solidi C 9–10/2014
    • Pages: 1383 - 1387
      PubDate: 2014-09-10T09:52:14.664381-05:
      DOI: 10.1002/pssc.201470059
       
  • Novel materials for electronic, optoelectronic, photovoltaic, and energy
           saving applications
    • Authors: M. Godlewski; A. J. Zakrzewski
      Pages: 1388 - 1388
      Abstract: The Symposium F: “Novel materials for electronic, optoelectronic, photovoltaic and energy saving applications” of the 2013 E‐MRS Fall Meeting (held in Warsaw, Poland, on 16–20 September 2013) was organized to cover many important aspects of basic and applied research of novel materials for present and future industrial applications. Particular emphasis was given to new technological and application concepts concerning both bulk crystals and various quantum structures of reduced dimensionality, like quantum wells and quantum dots (nanoparticles). The presented results on application‐oriented materials were mostly focused on light emitting structures, light detectors, solar cells and materials for spintronics. Special attention was given to the technological aspects and challenges: growth techniques, defect control and structure optimization, doping procedures, optical properties and degradation processes. Relevant experimental techniques and crystal growth procedures were also discussed. Experimental results were compared with theoretical calculations giving deeper insight into many problems of modern materials science. Over 100 researchers from all over the world participated in this symposium, giving in all 15 invited lectures, 38 contributed talks and 70 poster presentations.
      PubDate: 2014-09-10T09:52:12.330793-05:
      DOI: 10.1002/pssc.201470060
       
  • ZnO – Materials Science from Research to Electronic Applications
    • Authors: George Lashkarev; Vitalii Karpyna
      Pages: 1459 - 1459
      Abstract: The following section contains invited and contri‐ buted papers presented at Symposium K “ZnO – Material science from research to electronic applications” of EMRS Fall Meeting held in Warsaw, Poland, September 16–20, 2013. The symposium was organized by the principal organizer George Lashkarev (Institute for Problems of Material Science, Ukraine) and four co‐organizers: Robert Triboulet (CNRS/GEMAC, Univ. of Versailles, France), Robert Kudra‐wiec (Institute of Physics, Wrocław University of Technology, Poland), Serhii Trushkin (Institute of Physics PAS, Poland) and Rositza Yakimova (Department of Physics, Chemistry and Biology (IFM), Sweden). Symposium K gathered 82 participants from 28 countries with 10 invited talks, 25 oral presentations and 42 posters. The symposium was focused on the fundamental understanding of growth processes of ZnO films and structures, the role of point defects and impurities, electrical and optical properties and priority applications of ZnO in electronics and optoelectronics. The main idea of Symposium K was to narrow the evident gap between the research groundwork on ZnO and its possible industrial introduction. We consider this symposium as the next turn in the direction of wide applications of ZnO in the future. We take this opportunity to thank the colleagues who acted as scientific committee members and program committee members as well as the presenters who submitted a manuscript for publication and referees who ensured the scientific quality of the proceedings.
      PubDate: 2014-09-10T09:52:16.334482-05:
      DOI: 10.1002/pssc.201470061
       
  • CdTe and Cd‐rich Ternary Tellurides
    • Authors: Robert Triboulet
      Pages: 1509 - 1509
      Abstract: The E‐MRS Symposium entitled “CdTe and Cd‐rich ternary tellurides: Growth and characterization, physics of defects and impurities, surfaces and applications” was organized in Warsaw (16–20 September 2013), three years after the meeting dedicated to the “Smart growth” of CdTe and Cd‐rich ternary tellurides which was held in the framework of the 2010 E‐MRS Fall Meeting. It covered the most prominent, modern and fundamental aspects of research on these materials as well as their applications in fields such as nuclear detectors and photovoltaic cells. While CdTe‐based nanostructures are displaying a spectacular boom and are at the forefront of CdTe research, as illustrated by several hundreds of papers devoted to them in the recent literature, a significant activity is nevertheless still dedicated to bulk CdTe and associated Cd‐rich ternary tellurides, mainly CdZnTe and CdMnTe. The principal focus areas are in the fields of physics of macro‐defects, point‐defects and impurities in as‐grown and annealed crystals; surfaces and interfaces; refinement of the growth and characterization of crystals and devices; appli‐ cations dealing mainly with photovoltaic cells for which mass production has begun, and X‐ray and γ‐ray detectors, which are under development with material quality widely recognized as the key remaining issue. These topics were emphasized during the symposium and the different issues associated with them are identified and discussed. A few manuscripts only were submitted for publication in the proceedings, according to a recent deplorable and unfortunate fashion. The present proceedings are then constituted of a very limited number of contributions in which we hope the readers will nevertheless find a great interest.
      PubDate: 2014-09-10T09:52:17.35873-05:0
      DOI: 10.1002/pssc.201470062
       
  • Numerical analysis of light elements transport in a unidirectional
           solidification furnace
    • Authors: Koichi Kakimoto; Bing Gao, Satoshi Nakano
      Pages: n/a - n/a
      Abstract: Quantitative study of light elements such as carbon and oxygen in multi‐crystalline silicon for solar cells is required to grow crystals with high quality. The transport of both carbon and oxygen is one of the critical issues to increase efficiency of solar cells made of silicon materials. Concentrations of carbon and oxygen in a furnace affect each others, therefore it is important to control mass transfer of carbon and oxygen in a furnace. Numerical calculation with a chemical reaction between carbon and oxygen was carried out to study how both light impurities are incorporated into crystals through the melt and gas during solidification process. The effects of flow rate and pressure on the impurities were examined. An increase in the flow rate can reduce both carbon and oxygen impurities in the crystal, though the reduction of carbon is more obvious. An increase in gas pressure can also obviously reduce the oxygen impurity but has only a small effect on the carbon impurity (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2010-11-15T04:22:05.648279-05:
      DOI: 10.1002/pssc.200900117
       
 
 
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