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  Subjects -> ENGINEERING (Total: 2268 journals)
    - CHEMICAL ENGINEERING (190 journals)
    - CIVIL ENGINEERING (183 journals)
    - ELECTRICAL ENGINEERING (103 journals)
    - ENGINEERING (1201 journals)
    - ENGINEERING MECHANICS AND MATERIALS (380 journals)
    - HYDRAULIC ENGINEERING (55 journals)
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ENGINEERING (1201 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 17)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 247)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 17)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 10)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 29)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 38)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 31)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 17)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 16)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 1)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 7)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 5)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 10)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 25)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 43)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 7)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 8)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 22)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 26)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 266)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 188)
Composites Part B : Engineering     Hybrid Journal   (Followers: 280)
Composites Science and Technology     Hybrid Journal   (Followers: 183)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 14)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 7)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 28)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 10)
Computing and Visualization in Science     Hybrid Journal   (Followers: 5)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 30)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 7)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 42)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)
CTheory     Open Access  

        1 2 3 4 5 6 7 | Last

Journal Cover Current Applied Physics
  [SJR: 0.716]   [H-I: 55]   [4 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 1567-1739
   Published by Elsevier Homepage  [3048 journals]
  • Roughness influence on the sheet resistance of the PEDOT:PSS printed on
           paper
    • Abstract: Publication date: Available online 14 November 2017
      Source:Current Applied Physics
      Author(s): Rogério M. Morais, Maykel S. Klem, Maíza S. Ozório, Tiago C. Gomes, Neri Alves
      The use of paper as a platform to manufacture organic electronic devices, electronic paper, has expanding potential for many applications because of several properties offered. In this work, we show a study of PEDOT:PSS printed by inkjet on bond paper, vegetal paper and sheets of PET. The relation between the surface density of the deposited material, morphology and resistivity was investigated for samples printed with a commercial Hewlett-Packard(HP)® printer and Microsoft Word® software. The amount of material deposited, i.e. surface density, was controlled using the print number in the same position and changing the gray scale used in the image formation. Changing the surface density of printed PEDOT:PSS, it is possible to produce a continuous film permeating the papers fibers. Sheet resistances obtained, when 7.0 mg cm−2 of PEDOT:PSS were deposited on the surfaces, were: (a) 413.2 kΩ/Sq for bond paper, (b) 5.6 kΩ/Sq for vegetable paper and (c) 2.3 kΩ/Sq for PET. The exponential dependence of sheet resistance with the surface density of printed material allows us to evaluate the strong influence of substrate roughness on PEDOT:PSS conductivity and to predict, for each one, conditions to minimize it.

      PubDate: 2017-11-16T14:47:52Z
       
  • High efficiency screen-printed n-type silicon solar cell using
           co-diffusion of APCVD boron emitter and POCl3 back surface field
    • Abstract: Publication date: Available online 14 November 2017
      Source:Current Applied Physics
      Author(s): Kyungsun Ryu, Keeya Madani, Ajeet Rohatgi, Young-Woo Ok
      We present the fabrication and analysis of Passivated Emitter and Rear Totally Diffused (PERT) solar cells on n-type silicon using a co-diffusion process. In a single high temperature step, a BSG/SiOx stack deposited by APCVD and a POCl3 back surface field diffuse into the wafer to form the boron doped emitter and phosphorus doped back surface field. The SiOx layer on top of BSG acts as a masking layer to prevent cross-doping of phosphorus as well as a blocking layer for boron out-diffusion. This resulted in an initial sheet resistance of 76 Ω/□ with good uniformity and a final p+ emitter sheet resistance of 97 Ω/□ after boron rich layer removal. Additionally, bulk lifetime was investigated before and after the high temperature step that resulted in an increase from 1.2 ms to 1.5 ms due to a POCl3 gettering effect. A peak cell efficiency of 20.3% was achieved and each recombination component in terms of saturation current density was calculated and analyzed to understand the cell for further efficiency enhancement.

      PubDate: 2017-11-16T14:47:52Z
       
  • Elucidating iron doping induced n-to p-characteristics of Strontium
           titanate based ethanol sensors
    • Abstract: Publication date: Available online 14 November 2017
      Source:Current Applied Physics
      Author(s): Neha Sarin, Monu Mishra, Govind Gupta, Ivan P. Parkin, Vandna Luthra
      A series of pure and iron doped strontium titanate, (SrFexTi1-xO3; x = 0, 0.1 and 0.2) powders were synthesized, characterized and used to fabricate ethanol sensors for low concentration. X-Ray Diffraction (XRD) technique was used to confirm the single phase formation. Microstructural properties of the powders were investigated using scanning electron microscopy (SEM). Electrical conductivity of all the samples at room temperature (RT) was measured. Sensors were optimized for best responsiveness by varying the operating temperature from 350 °C to 500 °C.The sensor with doping x = 0.2 exhibited best sensing response at 400 °C for ethanol gas. The undoped sensor demonstrated a decrease in resistance on exposure to ethanol gas whereas Fe-doped sensors showed increase in resistance. The doping induced changeover from n to p behavior in the sensing response on doping has been investigated and corroborated with an observed shift in the Fermi level position by X-ray photoelectron spectroscopy (XPS). The disparity in gas sensing response clearly demonstrates inter-connection of multiple influencing factors such as electrical conductivity, morphology, porosity and change in chemical composition on doping. The sensors were exposed to ethanol, nitrogen dioxide, carbon monoxide, butane gases at concentration between 5 ppm and 50 ppm. The sensor exhibited much reduced relative response to all gases other than ethanol which can be utilized for wide range of applications.

      PubDate: 2017-11-16T14:47:52Z
       
  • Effects of heating rate on the magneto-optical properties of
           bismuth-substituted yttrium iron garnet films prepared via modified
           metal-organic decomposition
    • Abstract: Publication date: Available online 14 November 2017
      Source:Current Applied Physics
      Author(s): Viet Dongquoc, Rambabu Kuchi, Phuoc Cao Van, Soon-Gil Yoon, Jong-Ryul Jeong
      This work investigated the effects of heating rate and annealing on the magneto-optical properties of bismuth-substituted yttrium iron garnet (Bi-YIG) thin films on glass and (111)-oriented single-crystalline gadolinium gallium garnet (GGG) substrates fabricated by metal-organic decomposition (MOD). We modified the MOD method by eliminating the pre-annealing process. We performed annealing at various temperatures to determine the optimal temperature for obtaining the Bi-YIG phase. We then annealed at the optimized temperature using various heating rates. The optimal conditions were annealing for 1 h at 750 °C at a heating rate of 30 °C/min on GGG to obtain highly crystallized fine grains. The Faraday rotation for this film was about –10.5°/μm. The optimized heating rate enhanced the magneto-optical properties due to improved crystallinity and saturated magnetization. The Bi-YIG thin films prepared by this prescribed MOD method exhibited excellent magneto-optical performance and are potential candidates for applications in optical devices.

      PubDate: 2017-11-16T14:47:52Z
       
  • Micromagnetic study of domain wall depinning driven by nanosecond current
           pulse in notched Permalloy nanowires
    • Abstract: Publication date: Available online 10 November 2017
      Source:Current Applied Physics
      Author(s): Dede Djuhana, Candra Kurniawan, Dong-Hyun Kim
      The complete understanding of domain wall (DW) dynamics is important in the design of future spintronic devices. The characteristics of faster time-scale and lower current amplitude to move DW along nanowire are crucial in fabrication upgrade. In this study, we have investigated depinning behavior of magnetic domain wall triggered by nanosecond current pulse in notched Permalloy nanowires by means of micromagnetic simulation. We introduced double-triangular notch as the constrictions in the nanowire. The non-adiabaticity of the spin-transfer-torque is considered in simulation by varying the non-adiabatic constant (β) value. We observed that the depinning current density (J d) was not significantly affected by β for notch size (s) < 50 nm. Interestingly, we found that the depinning time (t d) for β ≥ 0.04 was slightly constant for all the cases with s > 70 nm, where the DW structure was kept to be a transverse structure during the depinning process. The broadly applicable depinning behavior is considered to contribute to the development of high-speed memory storage devices based on magnetic domain wall.

      PubDate: 2017-11-16T14:47:52Z
       
  • Fabrication and applications of ultraflexible nanostructures using
           dielectric heating-assisted nanoimprint on PVC films
    • Abstract: Publication date: Available online 7 November 2017
      Source:Current Applied Physics
      Author(s): Tsung-Yeh Wu, Po-Cheng Tsai, Shu-Cheng Lo, Yi-Ru Li, Kuang-Li Lee, Sen-Yeu Yang, Pei-Kuen Wei
      We developed dielectric heating-assisted nanoimprint method for rapid fabrication of ultraflexible nanostructures. Using spin-coating polyvinyl-chloride (PVC) film on the glass slide, the dielectric heating on PVC film helped the pattern transfer from the mold to PVC film in few seconds. Various kinds of nanostructures were successfully made on PVC films with about 20-μm thickness. We demonstrated the applications of ultraflexible metallic nanostructures for bending measurement using surface plasmon resonance (SPR) and surface enhanced Raman scattering (SERS) on the curved surfaces. For measuring bending angles using SPR on capped nanowire arrays, the minimum detection angle was 2.4 × 10−3 degree under 0.02 nm wavelength resolution. For SERS measurement, the nanorod arrays on a curved substrate can increase SERS signals for two times as compared to planar SERS substrate.

      PubDate: 2017-11-08T14:24:58Z
       
  • Facilitating epitaxial growth of ZnO films on patterned GaN layers: A
           solution-concentration-induced successive lateral growth mechanism
    • Abstract: Publication date: Available online 7 November 2017
      Source:Current Applied Physics
      Author(s): Rong-Ming Ko, Yan-Ru Lin, Ching-Yi Chen, Pai-Feng Tseng, Shui-Jinn Wang
      The hydrothermal epitaxy of ZnO films on a patterned GaN layer with a honeycomb etching hole array is demonstrated. Through m-planes of the GaN layer exposed on the vertical walls of the etching holes, highly crystalline ZnO films via multiple lateral growth stages can be realized. It is found that higher concentrations of zinc nitrate hexahydrate (ZNH) and hexamethylenetetramine (HMT) in hydrothermal solution yield a larger number of ZnO molecules to speed up ZnO growth during the initial stage of hydrothermal growth, also create secondary crystals and initialize further lateral growth stages to bridge neighboring ZnO prisms after smooth surfaces formed on the m-plane of a ZnO prism. A successive lateral growth mechanism that strongly depends on ZNH and HMT concentrations in the hydrothermal solution is proposed and discussed.
      Graphical abstract image

      PubDate: 2017-11-08T14:24:58Z
       
  • DFT study of the adsorption of 2, 3, 7, 8-tetrachlorodibenzofuran (TCDF)
           on vacancy-defected graphene doped with Mn and Fe
    • Abstract: Publication date: Available online 2 November 2017
      Source:Current Applied Physics
      Author(s): Qingxiao Zhou, Yongliang Yong, Weiwei Ju, Xiangying Su, Xiaohong Li, Chaoyang Wang, Zhibing Fu
      Dioxins are highly toxic to humans and environment, and developing the effective methods to control and detect the organic pollutant is particular important. Here we performed a density functional theory (DFT) study on the adsorption of 2, 3, 7, 8-tetrachlorodibenzofuran (TCDF) molecules on the modified graphene substrates. The results indicated that the introducing of vacancy-defect and dopants (Mn and Fe) significantly improves the sensitivity toward TCDF molecules. The impurity played a crucial role for interacting with TCDF molecules. Furthermore, the adsorption of TCDF induced band-gap open in defected graphene substrates, which could be seen as electric signal to detect TCDF pollutant. The present study is expected to be useful to explore effective materials to detect and remove dioxin pollutants based on graphene.

      PubDate: 2017-11-08T14:24:58Z
       
  • Geometrical thickness of titania photoanode as an influential parameter in
           controlling the photovoltaic performance of CdS Quantum Dot Sensitized
           Solar cells
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): M.B. Rajendra Prasad, Parvin S. Tamboli, Ravi V. Ingle, Kiran D. Diwate, Prashant K. Baviskar, B.R. Sankpal, K.C. Mohite, Sandesh R. Jadkar, Habib M. Pathan
      Geometrical thickness of photoelectrode is one of the important design considerations that can substantially improve the device performance in Quantum Dot Sensitized Solar cells. The present work deals with the influence of the Photoanode (PA) thickness on the photovoltaic performance of these excitonic solar cells. Optical, morphological and electrochemical properties of these films are studied using UV–Visible spectroscopy, Scanning electron microscopy and Cyclic Voltammetry. Sandwich solar cells assembled using these PAs are further characterized using Electrochemical Impedance Spectroscopy and Chronoamperometry to investigate the electron transfer processes occurring at the sensitized photoelectrode/Electrolyte interface. These cells are then evaluated for their photovoltaic performance using J-V characteristics. The results obtained are explained qualitatively invoking the thickness dependent parameters like Light harvesting efficiency and Electron transfer yield to establish the effect of PA thickness on the solar cell performance.

      PubDate: 2017-11-01T14:12:56Z
       
  • Effect of a TiN alkali diffusion barrier layer on the physical properties
           of Mo back electrodes for CIGS solar cell applications
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Weimin Li, Xia Yan, Armin G. Aberle, Selvaraj Venkataraj
      Cu(In,Ga)Se2 thin-film solar cells have attracted strong interest in the photovoltaic community due to their high efficiency and demonstrated industrial relevance. As the most commonly used back electrode for CIGS solar cells, molybdenum (Mo) is typically deposited on soda-lime glass substrates by magnetron sputtering. During the high-temperature CIGS absorber formation process step, alkali (Na) atoms diffuse from the soda-lime glass substrate into the CIGS absorber via the Mo contact, a process that is known to improve the cell efficiency. However, Na diffusion from soda-lime glass sheets is an uncontrolled process, which adds to batch-to-batch variations due to fluctuations in the glass quality and process parameters such as the CIGS formation temperature. Hence, a diffusion barrier layer between the glass substrate and the Mo back electrode is required to prevent this uncontrolled impurity diffusion. In this study, a TiN diffusion barrier layer is deposited by reactive magnetron sputtering of a metallic Ti target, using various N2 flow conditions. It is observed that the adhesion, microstructure, and morphology of the Mo films get significantly improved by the introduction of a TiN barrier layer, which in turn leads to better cell efficiencies. Hence, the TiN/Mo bilayer design developed in this work seems to be a good choice for enhancing the efficiency of CIGS solar cells.

      PubDate: 2017-11-01T14:12:56Z
       
  • A theoretical study of the structural and electronic properties of trans
           and cis structures of chlorprothixene as a nano-drug
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Samaneh Bagheri Novir
      Geometrical structure, electronic and optical properties, electronic absorption spectra, thermodynamic properties, natural charge distribution, MEP analysis, and charge transfer analysis of trans and cis structures of chlorprothixene drug have been investigated with DFT and TDDFT methods. The results of the computations show that the calculated quantum quantities of the cis isomer of chlorprothixene are in agreement with the activity of cis-chlorprothixene as a drug. Cis structure of chlorprothixene has slightly better absorption properties than the trans structure on the basis of TDDFT calculations. The NLO quantities of the cis structure are higher than the trans structure, and the chemical hardness of the cis isomer, is smaller than the trans isomer which specifies that the reactivity and charge transfer of the cis structure of chlorprothixene is higher than the trans structure. The MEP maps of both conformations of chlorprothixene show that the top of the N atom and the around of the S and Cl atoms of the molecule are proper regions for electrophilic reactions. The calculated thermodynamic parameters illustrate that these parameters are improving with increasing temperature because of the enhancement of molecular vibrational intensities with temperature.
      Graphical abstract image

      PubDate: 2017-11-01T14:12:56Z
       
  • Two-dimensional porous polyphthalocyanine (PPc) as an efficient
           gas-separation membrane for ammonia synthesis
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Zhaoran Wang, Huilong Dong, Xiaohui Yu, Yujin Ji, Tingjun Hou, Youyong Li
      Porous monolayer materials have been proven potential for gas separation and purification, because of their natural pathways of controllable sizes and well-ordered distribution. In this work, a novel material, two-dimensional (2D) porous polyphthalocyanine (PPc) is investigated by density functional theory (DFT) simulations for separating NH3 from H2 and N2 during ammonia synthesis process. Based on the calculated diffusion barriers through transition state search, we demonstrate that 2D PPc is able to offer high selectivity (107) of (H2, N2)/NH3 at room temperature. Further molecular dynamics (MD) simulation also indicates that the 2D PPc can effectively separate NH3 from H2 and N2. Thus the 2D PPc is promising for the practical applications of synthetic ammonia process.

      PubDate: 2017-11-01T14:12:56Z
       
  • Electrical and optical properties of core-shell InAs-InAsyP1-y nanowires
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Chan Ho Choi, Hee Dae Kim, Rochelle Lee, Jae Cheol Shin, Doo Gun Kim, Jong Su Kim
      Although III-V semiconductor nanowires are attractive building blocks for future nanoscale optoelectronic applications, their optical and electrical properties are unsatisfactory compared to those of the bulk materials. In particular, the large surface-to-volume ratio of a nanowire system leads to a high density of states along its surface, acting as an efficient non-radiative recombination center. Growing a higher bandgap material on the nanowire surface (i.e., core-shell structure) reduces the carrier recombination loss because the shell layer spatially separates charge carriers in the core region from the surface states. Nevertheless, a large difference in the crystal lattice parameters between the core and shell layer can generate misfit dislocations at the heterointerface, providing new carrier scattering centers. Here, InAs-InAs0.75P0.25 and InAs-InP core-shell structured nanowires were grown and their electrical and optical properties were compared with those of bare InAs nanowires. The electron mobility is highest for the InAs-InAs0.75P0.25 nanowires while the strongest photoluminescence intensity is achieved from InAs-InP nanowires. This suggests that the misfit dislocations along the heterointerface of the nanowire need to be considered for applications of electrical devices.

      PubDate: 2017-10-14T00:28:11Z
       
  • Electronic structure and optical properties for blue
           phosphorene/graphene-like GaN van der Waals heterostructures
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Jingjing Guo, Zhongpo Zhou, Tianxing Wang, Zhansheng Lu, Zongxian Yang, Chang Liu
      In this paper, first-principle calculations based on density functional theory are carried out to explore the interface properties of the blue phosphorene/graphene-like GaN van der Waals heterostructures. The edge positions for valence and conduction band of blue phosphorene and graphene-like GaN nanosheets change with the Fermi energy level and form the type-II heterostructure. The internal electric field facilitates the separation of electron−hole pairs and restrained the carrier recombination in the blue phosphorene/graphene-like GaN interfaces.
      Graphical abstract image

      PubDate: 2017-10-10T02:18:45Z
       
  • Ex-situ atomic force microscopy on the growth mode of SrRuO3 epitaxial
           thin film
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Bora Kim, Sang A Lee, Daehee Seol, Woo Seok Choi, Yunseok Kim
      The functional properties of devices based on perovskite oxides depend strongly on the growth modes that dramatically affect surface morphology and microstructure of the hetero-structured thin films. To achieve atomically flat surface morphology, which is usually a necessity for the high quality devices, understanding of the growth mechanism of heteroepitaxial thin film is indispensable. In this study, we explore heteroepitaxial growth kinetics of the SrRuO3 using intermittent growth scheme of pulsed laser epitaxy and ex-situ atomic force microscopy. Two significant variations in surface roughness during deposition of the first unit cell layer were observed from atomic force microscopy indicating the possible formation of the half unit cell of the SrRuO3 before the complete formation of the first unit cell. In addition, layer-by-layer growth mode dominated during the first two unit cell layer deposition of the SrRuO3 thin film. Our observation provides underlying growth mechanism of the heteroepitaxial SrRuO3 thin film on the SrTiO3 substrate during the initial growth of the thin film.

      PubDate: 2017-10-10T02:18:45Z
       
  • Simple active-layer patterning of solution-processed a-IGZO thin-film
           transistors using selective wetting method
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Seungwoon Lee, Jaewook Jeong
      In this paper, we report a selective-patterning method of active layers for the fabrication of solution-based amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO TFTs). Using simple stamping of a reusable poly(dimethylsiloxane) (PDMS) substrate onto a SiOX/Si substrate, the surface of SiOx/Si was easily changed to the hydrophobic state because the PDMS substrate contains a large amount of methyl ligands. By combining oxygen plasma treatments through a shadow mask, the active layer was self-defined through selective coating of the a-IGZO solution owing to the difference of the wetting properties. The electrical performance of the resulting TFTs was comparable with that of TFTs fabricated with the conventional method. Because the proposed method is very simple and the PDMS substrate is reusable compared to other selective-wetting methods that use self-aligned monolayers, it is expected to be applicable to the fabrication of low-cost and large-area electronic applications.

      PubDate: 2017-10-10T02:18:45Z
       
  • Effect of adding a polymer and varying device size on the resistive
           switching characteristics of perovskite nanocubes heterojunction
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Young Jin Yang, Muhammad Muqeet Rehman, Ghayas Uddin Siddiqui, Kyoung Hoan Na, Kyung Hyun Choi
      Emerging resistive switching devices are believed to play a vital role in realizing ultra-dense nanocrossbar arrays for the next generation mass storage memory. This work reports the resistive switching effect in organic-inorganic hybrid nanocomposite of perovskite oxide zinc stannite nanocubes (ZnSnO3 NCs) and a polymer Poly(methyl methacrylate) (PMMA). The functional layer was sandwiched between indium tin oxide (ITO) and silver (Ag) electrodes on a flexible PET substrate. The obtained electrical results clearly exhibited that the addition of PMMA in ZnSnO3 NCs enhanced electrical endurance (500 biasing cycles), retention time (∼104 s), switching ratio (∼103) and repeatability of our memory device. Moreover the effect of device size on the resistive switching characteristics of this hybrid nanocomposite is also explored by varying the diameter of top electrode. The whole device fabrication except bottom layer was done through all printed technology such as electrohydrodynamic atomization (EHDA) and inkjet reciprocating head. The developed memory device displayed characteristic bipolar, nonvolatile and rewritable memory behavior at a low operating voltage. The obtained results of chemical, structural, electrical and surface morphology are added to completely understand the impact of adding a polymer on the switching characteristics of perovskite NCs.

      PubDate: 2017-10-10T02:18:45Z
       
  • Facile hydrothermal synthesis of Eu3+-activated NaYF4 nanocrystals and
           their Judd-Ofelt analysis, photoluminescence and cathodoluminescence
           properties
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Peng Du, Jae Su Yu
      The Eu3+-activated NaYF4 nanocrystals were synthesized via a facile hydrothermal technique. The resultant compounds were characterized by X-ray diffraction pattern, transmission electron microscope images and photoluminescence (PL)/cathodoluminescence (CL) spectra. Under near-ultraviolet light excitation, the characteristic emissions of Eu3+ ions were detected in the prepared nanocrystals and the red emission at 615 nm originating from the 5D0 → 7F2 transition dominated in the emission spectrum. The luminescent spectrum revealed that the Eu3+ ions populated the low symmetry sites in NaYF4 lattices. Furthermore, a theoretical calculation based on the Judd-Ofelt theory was performed to evaluate the intensity parameters to further explore the local structure environment surrounding Eu3+ ions in NaYF4 lattices. The temperature-dependent PL emission spectra were recorded to study the thermal stability of the resultant nanocrystals and the activation energy was determined to be 0.149 eV. Ultimately, the CL properties of the final products as a function of accelerating voltage and filament current were investigated. These results revealed that the synthesized nanocrystals are a promising candidate for white light-emitting diodes and field emission displays as red-emitting phosphors.

      PubDate: 2017-10-02T01:27:08Z
       
  • Timoshenko beam model for vibrational analysis of double-walled carbon
           nanotubes bridged on substrate
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Jingnong Jiang, Lifeng Wang
      This paper proposes a continuum three-segment double Timoshenko beam (TSDTB) model to investigate free vibration of double-walled carbon nanotubes (DWCNTs) bridged on a silicon channel. Accurate explicit formulas of the van der Waals (vdW) interactions between each tube as well as between the tubes and a substrate are derived for a better prediction of the vibrational behaviors of the DWCNTs. An analytical modified Fourier series method (MFSM) is developed for the vibrational analysis of the TSDTB model. Numerical results show the good convergence characteristics and accuracy of the MSFM. The overlapped lengths between DWCNTs and the substrate at both ends have almost no effects on the lower natural frequencies of the TSDTB model when the overlapped lengths are long enough. Moreover, the natural frequencies of the TSDTB model are much less than of those of one-segment double Timoshenko beam (OSDTB) model with clamped supported boundary condition, whereas the TSDTB model can be equivalent to the simply supported OSDTB model under certain condition. In addition, the effects of vdW interaction coefficients on the vibrational behaviors of the DWCNTs are also revealed. The obtained results in this work should be greatly helpful in the design and application of CNTs-based nanomechanical resonators.

      PubDate: 2017-10-02T01:27:08Z
       
  • Electrical properties of polycrystalline and single crystalline nickel
           layer capped ZnO nanowires
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Devika Mudusu, Koteeswara Reddy Nandanapalli, Sreekantha Reddy Dugasani, Jang Won Kang, Sung Ha Park, Charles W. Tu
      This article reports the electrical characteristics of pristine, polycrystalline and single crystalline nickel (Ni) layer capped zinc oxide (ZnO) nanowires. Core/shell ZnO/Ni nanostructures were developed using chemical vapor deposition and e-beam evaporation, and the structures were annealed at different temperatures. Field effect transistor (FET) devices were fabricated using photolithography and investigated their characteristics at room temperature. All FET devices exhibited depletion-mode characteristics with n-type conductivity. However, single-crystalline Ni shelled ZnO nanowires based FET devices showed a high on/off ratio and transconductance, as compared to other devices. The overall measurements show that though the ZnO nanowires capped with Ni layer, their electrical properties remain same as pristine ZnO nanowires.
      Graphical abstract image

      PubDate: 2017-10-02T01:27:08Z
       
  • One-pot hydrothermal preparation of BiOBr/BiPO4 with improved
           photocatalytic performance originated from remarkably enhanced separation
           of electron-hole pairs
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Jiufu Chen, Shengtian Huang, Junbo Zhong, Jianzhang Li, Wei Hu, Xia Yin, Ran Duan
      In this paper, to further promote the photocatalytic performance of BiPO4, BiOBr was employed to couple with BiPO4. Rod-like BiOBr/BiPO4 composites with improved photocatalytic performance were facilely constructed by one-pot hydrothermal method. The composites were characterized by Brunauer -Emmett-Teller (BET) method, X-ray diffraction patterns (XRD), UV–Vis diffuse reflectance spectra (DRS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), surface photovoltage spectroscopy (SPS) and electron spin-resonance (ESR) spectroscopy. The photocatalytic performance of the samples towards degradation of rhodamine B (RhB) and phenol aqueous solution was evaluated under the simulated sunlight irradiation. The SPS results reveal that the separation of photogenerated electron-hole pairs has been promoted due to the formation of heterojuctions. The ESR measurements demonstrate that OH and h+ are involved in the photocatalytic reaction. The photocatalytic evaluation display that the sample with molar ratio of Br−/PO4 3− = 0.4% holds the highest activity. The results further substantially exhibit that coupling BiPO4 with BiOBr can remarkably boost the photocatalytic performance of BiPO4, benefiting from significantly enhanced separation of photoinduced charge pairs. Based on all the observations, a Z-scheme separation and transfer scheme of the photo-induced charge pairs of BiOBr/BiPO4 was proposed.
      Graphical abstract image

      PubDate: 2017-10-02T01:27:08Z
       
  • Green synthesis of seaweed surfactant based CdO-ZnO nanoparticles for
           better thermal and photocatalytic activity
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): S. Rajaboopathi, S. Thambidurai
      Green synthesis of seaweed-macro algae based cadmium oxide-zinc oxide (SCZ) nanoparticles was prepared by the simple chemical precipitation method. The functional group characteristics and crystalline properties of the nanoparticles were analyzed by Fourier transform infra-red spectroscopy and X-ray diffraction analysis. The optical band gap energy of SCZ nanoparticles showed in lower value (3.11 eV), these can be due to the incorporation of seaweed (SW) and cadmium oxide (CdO). Small fiber like seaweed constituent was entangled over the CdO-ZnO nanoparticles, these were confirmed with High resolution scanning electron microscope and Field emission gun-transmission electron microscope analysis. The particle size of SCZ nanoparticles was obtained in the range of 20–50 nm. Thermal characteristics of SCZ nanoparticles have higher stability than SW and SW-ZnO. The photo catalytic degradation performance of SCZ nanoparticles was significantly improved and their efficiency was achieved to 99.57, 95.2 and 94.3%, under sunlight, visible light and UV light irradiation using RB198 dye molecules, respectively. The higher percentage of RB198 dyes degraded within 15 min interval under sunlight irradiation. In addition, their photo degradation characteristics of nanoparticles were further tested to pollutants of phenol solution. These results indicate that the surfactant based CdO-ZnO nanoparticles could be employed as an efficient photo catalyst for the degradation of industrial effluents.
      Graphical abstract image

      PubDate: 2017-09-25T00:51:58Z
       
  • Pushing the limits of lithium bis(oxalate)borate/acetonitrile using
           1-ethyl-3-methylimidazolium tetrafluoroborate for supercapacitors
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Louis Hamenu, Alfred Madzvamuse, Mengyang Hu, Latifatu Mohammed, Chris Yeajoon Bon, Sang Jun Kim, Won Il Cho, Jongwook Park, Jang Myoun Ko
      Supercapacitors provide us with enormous power output for energy storage. Their energy output however still remains quite low compared to other energy storage materials like the batteries. This paper reports a highly stable liquid electrolyte which is composed of mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate(EMIBF4) ionic liquid with highly stable lithium bis(oxalate)borate LiBOB/acetonitrile(ACN). The electrolytes display remarkable supercapacitive performance at a high voltage of 3 V. The electrochemical impedance spectroscopy shows that EMIBF4 helps to reduce the bulk resistance and charge transfer resistance across the electrode surfaces by facilitating high ionic diffusions across the electrode/electrolyte interface. The high stability and high ionic conductivity of the electrolytes reflected in the good cycling performance tests at 2.8 V with a maximum delivery capacitance of 19.5Fg-1 after 1000cycles at a high scan rate of 200 mVs-1.

      PubDate: 2017-09-25T00:51:58Z
       
  • Fluid heating in a nano-scale Poiseuille flow: A non-equilibrium molecular
           dynamics study
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Fahim Faraji, Ali Rajabpour
      In this paper we develop a non-equilibrium molecular dynamics computer simulation to study the fluid heating in a nano scale Poiseuille flow system and discuss the effects of the fluid-wall interaction strength and wall temperature on the fluid heating. We calculate the fluid temperature distribution, as well as the heat flux from the fluid towards the walls and the interfacial thermal resistance and discuss the variations of the fluid heating caused by the viscous and surface frictions as the fluid-wall interaction strength and wall temperature vary. It is found that as the fluid-wall interactions strengthen, the fluid heating diminishes. In weak interactions, the heat flux from the fluid to the wall is almost independent of the wall temperature while the interfacial thermal resistance decreases with increased wall temperature and the surface friction is the major contribution to the fluid heating; in contrast, in large interactions, both the heat flux and thermal resistance increase with increased wall temperature and the viscous friction is the major contribution to the fluid heating.

      PubDate: 2017-09-25T00:51:58Z
       
  • 2D printed graphene conductive layers with high carrier mobility
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Evgenyi Yakimchuk, Regina Soots, Igor Kotin, Irina Antonova
      The comparison of different suspensions, obtained from the same material source subjected to electrochemical exfoliation and to analogous auxiliary treatments, but in different solutions, allowed choosing the most effective approach to obtaining graphene suspensions. It was found for the layers with a thickness of 10–20 nm printed from a water-based suspension that the sheet resistance was 5–10 kΩ/□, and the carrier mobility was equal to 30–40 cm2/V·s. The most important parameter determining the mobility of carriers in the films obtained from suspensions is found to be the flake thickness. The carrier mobility strongly decreased from ∼100 to 0.05 cm2/V·s when the flake thickness changed from one monolayer to few monolayers (up to ∼ 4–5 nm). This effect is most likely associated with the quality of the connection between the flakes. Only monolayer - bilayer flakes are capable of forming real connections in the film due to van-der-Waals forces.
      Graphical abstract image

      PubDate: 2017-09-25T00:51:58Z
       
  • Trap states analysis in AlGaN/AlN/GaN and InAlN/AlN/GaN high electron
           mobility transistors
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): S. Latrach, E. Frayssinet, N. Defrance, S. Chenot, Y. Cordier, C. Gaquière, H. Maaref
      The paper deals with trap effects in InAlN/AlN/GaN and AlGaN/AlN/GaN high electron mobility transistor structures using frequency dependent conductance and High-Low frequency capacitance analysis. We performed a comparative study on electrical characteristics of electron devices. Capacitance-voltage characteristics revealed hysteresis with a voltage shift that was attributed to the accumulation of charges at the InAlN/AlN and AlGaN/AlN heterointerfaces. Using a simple extraction method, a rather low density of trapped charges is evaluated. On the other hand, bias and frequency dependent measurements are carried out in the vicinity of threshold voltage to determine the interface trap density Dit, trap time constant τit and trap state energy position ET. It is found that device with InAlN barrier exhibits high trap state densities in the range of 1012 -1014 cm−2eV−1, approximately one order of magnitude larger than with AlGaN barrier.

      PubDate: 2017-09-19T02:37:14Z
       
  • Enhanced thermoelectric performance of n-type bismuth selenide doped with
           nickel
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Chiranjit Kulsi, Kajari Kargupta, Saibal Ganguly, Dipali Banerjee
      Bismuth selenide (Bi2Se3) and transition metal (nickel) doped (5 and 7.5 mol %) Bi2Se3 have been prepared by solvothermal approach for investigation of thermoelectric properties of the materials. The morphological characterization reveals plate and flake like structures for undoped and doped samples respectively. There is a decrease in lattice constant, computed from Rietveld refinement data and crystallite size, found using Debye-Scherrer equation for doped samples. Doping by nickel increases the electrical conductivity and reduces both thermo power and thermal conductivity of the materials than pure Bi2Se3. Reduction in thermal conductivity of the doped samples by 42%, results in an increase in figure of merit (ZT) of nickel doped (5%) materials by one order of magnitude (0.02–0.22) compared to pure Bi2Se3.
      Graphical abstract image

      PubDate: 2017-09-19T02:37:14Z
       
  • Enhanced quantum confinement in tensile-strained silicon nanocrystals
           embedded in silicon nitride
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Chang-Hee Cho, Jang-Won Kang, Il-Kyu Park, Seong-Ju Park
      Here, we report that the tensile strain in silicon nanocrystals embedded in silicon nitride significantly changes the size-dependent evolution of the conduction and valence energy levels, compared with strain-free silicon nanocrystals. Using capacitance spectroscopy, the quantum-confined energy shifts in the conduction and valence levels were identified as ΔE C (eV) = 11.7/d 2 , and ΔE V (eV) = −4.5/d 2 , where d is the mean diameter of the silicon nanocrystals in nanometers. These findings indicated that the tensile strain in the silicon nanocrystals significantly increased the quantum confinement, by a factor of 3.3 in the conduction levels, and by a factor of 1.8 in the valence levels.

      PubDate: 2017-09-19T02:37:14Z
       
  • Magnetic domain wall motion across a step of Dzyaloshinskii-Moriya
           interaction
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Ik-Sun Hong, Seo-Won Lee, Kyung-Jin Lee
      Magnetic domain wall motion is numerically studied in a nanowire with a Dzyaloshinskii-Moriya interaction (DMI) step at which DMI varies in real space. The spatially modulated DMI results in the formation of asymmetric domain wall energy landscape across the step, which affects the domain wall motion significantly. Utilizing this DMI step, we propose a domain wall memory device where the switching of up- and down-state is induced by a spin-orbit spin-transfer torque (SOT)-driven domain wall motion. This domain wall memory device is expected to have a high switching efficiency.

      PubDate: 2017-09-12T02:09:35Z
       
  • Effect of beryllium doping and vacancy in band structure, magnetic and
           optical properties of free standing germanene
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Namrata Dhar, Debnarayan Jana
      Ab initio calculations of electronic, magnetic and optical properties of defected (beryllium (Be) doped or void induced) buckled free standing (FS) germanene have been explored. Concentrations of doping as well as vacancy (keeping a fixed low amount of Be) are increased thoroughly, in order to study the modifications of different physical properties critically. Our study reveals that, incorporation of doping and void destroy Dirac cone in band structure of germanene. Finite bandgap for the requirement of field effect transistor (FET) applications is obtained in case of semiconducting configuration with 15.62% doping concentration. Magnetism is also induced for doping of Be with high concentration only, which is supported from projected density of states (PDOS) and charge density analysis. Anisotropic effects are prominent in optical properties like dielectric functions, absorption spectra, reflectivity and its modulation and conductivity. Static real part of dielectric constant increases linearly with increase in doping concentration but decreases with increase in vacancy concentration considering parallel polarization of electro-magnetic (EM) wave. Predicted computational results of plasma frequencies are in well agreement with expected analytical data. Peak corresponding to maximum intensity of electron energy loss spectra (EELS) appears at the position of plasma frequency in case of every structure. We expect, this study may help for better understanding of next generation germanene based nano-technology.

      PubDate: 2017-09-12T02:09:35Z
       
  • Effects of Fe insertion in CoFeB in the middle electrode on the properties
           of MgO double-barrier magnetic tunnel junctions
    • Abstract: Publication date: December 2017
      Source:Current Applied Physics, Volume 17, Issue 12
      Author(s): Jongill Hong, Sangho Lee
      We successfully improved the tunnel magnetoresistance ratio (TMR) of an MgO/CoFeB/MgO-based double-barrier magnetic tunnel junction (DMTJ) by inserting ultra-thin Fe into a CoFeB middle electrode. The Fe played as an absorber of B diffused out of the CoFeB and thereby facilitated the crystallization of the CoFeB at the interface. Changes in resistivity of the middle electrode with Fe insertion calculated by the modified current-in-plane tunneling method suggested that they can be explained by the formation of Fe borides, which is ascribed to the fact that Fe indeed promoted the diffusion of B by providing places for the B diffusion. As a result, Fe insertion improved the (001) texture of the middle electrode and thereby increased the TMR of the junction due to enhanced coherent tunneling. However, when inserted Fe was thick, the tunnel properties of DMTJs were degraded because of the absence of strong (001) texture of MgO. Materials and their thickness for a middle electrode are key parameters to successful application of DMTJs for spin devices.

      PubDate: 2017-09-07T02:09:22Z
       
  • Enhanced output power of InGaAs/GaAs infrared light-emitting diode with
           GaxIn1-xP tensile strain barrier
    • Abstract: Publication date: Available online 3 September 2017
      Source:Current Applied Physics
      Author(s): Hyung-Joo Lee, In-Kyu Jang, Won-Chan An, Lee Ku Kwac, Hong-Gun Kim, Joon Seop Kwak
      Various GaxIn1-xP strain barriers were evaluated for their ability to compensate for the strain of lattice mismatched InGaAs/GaAs MQWs structures. A GaxIn1-xP (χ = 0.53) tensile strain barrier, which was inserted between the n-confinement and InGaAs/GaAs multi-quantum well (MQW) active region, was effective in reducing the compressive strain caused by In0.07GaAs in multiple quantum wells (MQWs). Importantly, a remarkably enhanced PL intensity was obtained by retuning the strain of In0.07GaAs QWs based on a Ga0.53InP tensile strain barrier. A fabricated IR-LED chip, having retuned In0.08GaAs/GaAs MQWs with a Ga0.53InP tensile strain barrier, yielded double the light output power of the IR-LED chip without a Ga0.53InP strain barrier. This suggests that the use of a Ga0.53InP tensile strain barrier is essential for compensating for the compressive strain of lattice-mismatched InGaAs/GaAs MQWs with a 940 nm emitting wavelength, followed by the improved output power of the IR-LED chips.

      PubDate: 2017-09-07T02:09:22Z
       
  • Investigation of carbon monoxide adsorption onto sumanene (C21H12)
           decorated with Li+ ions toward its elimination
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Adel Reisi-Vanani, Marziyeh Safipoor
      One of the important techniques to attract gaseous pollutant is placement of metals or their cations on carbon-based materials. In this study, Li+ ions were applied in order to promote adsorption of CO gas on sumanene bowl-shaped nanostructure. The results of theoretical calculations at MP2/6-311+G(d,p)//B3LYP/6-31G(d) level showed that the binding energy (BE) for chemisorption of Li+ ions on sumanene in convex faces is higher than concave one and decreases with the number of Li+ from one to three. It is observed that above Li+ ions or between them in bridge form at inner surface of Li+-sumanene configurations are the most appropriate sites for CO trapping. The CO-Li+-sumanene systems possessed the higher BE than CO-sumanene systems. Natural population analysis (NPA) and natural bond orbital (NBO) analysis obviously revealed that charge distribution in sumanene is affected by lithium ions and not by CO molecules. Besides, density of state (DOS) curves specified that the energy gap in Li+-sumanene reduced considerably after CO attraction. Consequently, decorated sumanene by Li+ ions is appropriate sorbent for removal CO contaminant from environment.

      PubDate: 2017-09-01T01:48:57Z
       
  • Pressure and molecular-weight dependences of elastic properties of
           polystyrene polymers studied by Brillouin spectroscopy
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Byoung Wan Lee, Min-Seok Jeong, Jong Sun Choi, Jaehoon Park, Young Ho Ko, Kwang Joo Kim, Jae-Hyeon Ko
      Pressure and molecular-weight dependences of acoustic mode behaviors of polystyrene polymeric material were investigated by using Brillouin spectroscopy. The longitudinal, the transverse and the bulk sound velocities were measured over a wide pressure range from ambient pressure to more than 10 GPa for five polystyrene polymers whose molecular weight ranging from 3700 to 979200. The longitudinal and the bulk sound velocities displayed nearly the same pressure dependence for all polystyrenes indicating that the effective free volume is very similar in five polystyrene polymers despite the huge change in the molecular weight. The Poisson's ratio slightly increased with decreasing molecular weight.

      PubDate: 2017-09-01T01:48:57Z
       
  • Flexible transparent electrodes made of core-shell-structured carbon/metal
           hybrid nanofiber mesh films fabricated via electrospinning and
           electroplating
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Jin Woo Huh, Hwan-Jin Jeon, Chi Won Ahn
      The development of practical flexible transparent electrodes is one of the major core technology fields for future nanoscale optoelectronics. Despite the many efforts to replace the indium tin oxide (ITO) electrode, preparing practical alternatives that satisfy the essential requirements of flexible transparent electrodes remains a challenge. In this work, core-shell-structured carbon/metal hybrid mesh (CS-CMHM) films, comprised of a metal layer coated onto conductive carbon nanofiber network structures, were fabricated using electrospinning and electroplating and demonstrated potential for use as flexible transparent electrodes. In contrast to previously described techniques that use conventional polymer fibers as sacrificial structures, the conductive carbon nanofibers used in the current technique that we developed provided bi-functionality: they formed conductive core channels and artificial supports of the metal structures. The CS-CMHM films displayed superior optoelectrical, mechanical, and thermal properties: they transmitted ∼91% of visible light, showed a low sheet resistance of ∼2.7 Ω/sq, and displayed excellent mechanical stability even after 10000 cycles of bending the films to a radius of 5 mm; also, applying a voltage of only 3 V to a transparent heater based on CS-CMHM films resulted in the temperature of the film surface increasing very rapidly in the first 20 s, and soon thereafter reaching ∼280 °C. Based on these results, we believe that the use of CS-CMHM films and the process we developed to fabricate them open up great opportunities for high-performance flexible transparent electronics.
      Graphical abstract image

      PubDate: 2017-09-01T01:48:57Z
       
  • Structural stability and electrical characteristic of DNA lattices doped
           with lanthanide ions
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Sreekantha Reddy Dugasani, Bramaramba Gnapareddy, Jang Ah Kim, Sanghyun Yoo, Taehyun Hwang, Taesung Kim, Sung Ha Park
      The main aim of doping DNA lattices with lanthanide ions (Ln-DNA complex) is to change the physical functionalities for specific target applications such as electronics and biophotonics. Ln–DNA complexes based on a double-crossover DNA building block were fabricated on glass using a substrate-assisted growth method. We demonstrated the structural stability of Ln–DNA complexes as a function of Ln ion concentration by the atomic force microscopy. The Ln ion doping in DNA lattices was examined using a chemical reduction process, and the electrical characteristics of Ln–DNA complexes were tested using a semiconductor parameter analyzer. The structural phase transition of DNA lattices from the crystalline to amorphous phases occurred at a certain critical concentration of each Ln ion. Ln ions in DNA lattices are known to be intercalated between the base pairs and bound with phosphate backbones. When DNA lattices are properly doped with Ln ions, Ln–DNA complexes revealed the complete deformation with chemical reduction process by ascorbic acid. The current increased up to a critical Ln ion concentration and then decreased with further increasing Ln ions. Ln–DNA complexes will be useful in electronics and photonics because of their unique physical characteristics.

      PubDate: 2017-09-01T01:48:57Z
       
  • Surface chemistry modification in ITO films induced by Sn2+ ionic state
           variation
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Jiwoong Kim, Dooyong Lee, Sehwan Song, Sam Yeon Cho, Jong-Seong Bae, Wanyeon Kim, BuHyun Youn, Yangdo Kim, Jeong-Soo Lee, Sang Don Bu, Sungkyun Park
      In this study, the surface-chemistry-dependent hydrophobicity and antibacterial properties of ITO films were examined. After annealing of the films, their surface root-mean-square roughness increased and remained the same regardless of the annealing environment. However, depending on the annealing environment (O2, N2, Ar, or vacuum), the contact angle increased with increasing Sn2+ contents in the films. Furthermore, the antibacterial effect of the annealed films decreased regardless of the annealing environment. The depth-dependent chemical state determined by X-ray photoelectron spectroscopy showed an increase in the Sn content at the surfaces of all films. In particular, the as-grown film exhibited the highest Sn content at the surface and also the strongest antibacterial effect.

      PubDate: 2017-09-01T01:48:57Z
       
  • Electrosynthesized poly(1,5-diaminonaphthalene)/polypyrrole nanowires
           bilayer as an immunosensor platform for breast cancer biomarker CA 15-3
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Vân-Anh Nguyen, Huy L. Nguyen, Dzung T. Nguyen, Quan P. Do, Lam D. Tran
      In this paper, an electrosynthesized bilayer film of polypyrrole nanowire and poly(1,5diaminonaphthalene) on a disposable screen-printing carbon ink electrode is presented. The inner polypyrrole nanowire layer had a large surface-to-volume ratio and high conductivity in the neutral medium, whereas the outer layer of poly(1,5diaminonaphthalene) had functional amino groups on the polymer chains. The combination of polypyrrole nanowire and poly(1,5diaminonaphthalene) showed a promising material for electrochemical biosensing. Here we reported an electrochemical immunosensor based on this approach for the purpose of detecting breast cancer biomarkers. The bilayer could enhance the surface coverage of antibody anti-CA 15-3 and consequently improve the sensitivity and stability of the immunosensors. The magnetic beads were used as carriers of labeled antibody anti-CA15-3 and HRP (horseradish peroxidase) in order to achieve an amplification of the signal. Under optimized conditions, the linear range of the immunoassay was 0.05–20 U mL−1 with a detection limit of 0.02 U mL−1 CA 15-3 antigen.

      PubDate: 2017-09-01T01:48:57Z
       
  • Synthesis of pure and biocompatible gold nanoparticles using laser
           ablation method for SERS and photothermal applications
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): M. Vinod, Ramapurath S. Jayasree, K.G. Gopchandran
      In the recent past, gold nanoparticles synthesized using pulsed laser ablation in biocompatible mediums has attracted scientific and technological interest. In this work, it is found that the gold nanoparticles prepared using laser ablation of gold target in water is inherently non-toxic. These particles have shown that they are photothermally active when excited with 532 nm laser line, in conjunction with the plasmon band. The surface charge of these nanoparticles is found to be negative. The X-ray photoelectron spectroscopy measurements indicated the possibility of partial oxidation of the surfaces of these gold nanoparticles and electron micrographs indicated that the surfaces of these particles are relatively smooth. Raman measurements made with crystal violet as probe molecules using these nanoparticles as substrates and Raman spectra from L929 cells after incubation with these gold nanoparticles have shown that they can enhance the scattered Raman signal.
      Graphical abstract image

      PubDate: 2017-09-01T01:48:57Z
       
  • Influence of FeSe doping on superconducting properties of MgB2 by hybrid
           microwave method
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Cheng Cheng, Zhenjie Feng, Qing Li, Xu Wang, Chuan Yu, Hao Chu, Ya Yang, Changqin Liu, Yiming Cao, Zhe Li, Jingzhe Chen, Chao Jing, Shixun Cao, Jincang Zhang
      The effect of FeSe doping on the physical properties of MgB2 is studied. Bulk samples of the FeSe doped MgB2 with weight ratio x ( F e S e : M g B 2 ) = 0 % , 3 % , 7 % a n d 10 % were prepared by hybrid microwave method. It is proved that FeSe is not stable together with MgB2. Fe2+ enters into MgB2 lattice, some Mg2+ and Se2− are combined into the new impurity compound MgSe. The superconducting transition temperature (T c ) slightly decreased with increasing doping content of FeSe from R-T and M-T curves, which results from the substitution of Mg2+ by Fe2+ in the MgB2 lattice. The J c increase slightly with the FeSe doping content increasing from 3 wt % to 10 wt %, which results from the increasing MgSe impurity pinning centers.

      PubDate: 2017-09-01T01:48:57Z
       
  • Investigation on I-V characteristics of current induced metal insulator
           transition in VO2 device
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Gi Yong Lee, Howon Kim, Bongjin Simon Mun, Changwoo Park, Honglyoul Ju
      The I-V characteristics of two terminal planar VO2 film devices are investigated as the devices undergo the current induced metal insulator transition (I-MIT). The I-MIT occured when the device resistivity reached ∼7  Ωcm , where metallic grains formed initial conductive current path within insulating matrix. The transition time needed for the I-MIT increased with increasing external resistance, REXT, connected to the device in series, i.e. ∼390 μs (REXT = 5 kΩ) to ∼1400 μs (REXT = 20 kΩ). The transition time is closely related to the RC time delay from capacitance discharge of the VO2 device. During the I-MIT, the amount of discharge current was estimated as large as ∼100 mA, which was larger than the current just before the I-MIT. After the I-MIT, the current density decreased from 1.1 × 106 A/cm2 to 6.5 × 105 A/cm2, suggesting a large temperature changes up to ∼300 °C.

      PubDate: 2017-09-01T01:48:57Z
       
  • Degradation of fill factor in P3HT:PCBM based organic solar cells
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Vinamrita Singh
      In this paper, the degradation of fill factor with time of organic bulk heterojunction solar cells has been investigated up to 312 h. The experimental data of P3HT:PCBM solar cells has been analyzed theoretically to determine the parameters which affect the FF. The existing empirical formula has been applied to degradation data, and it was found to deviate drastically as the cell degrades, indicating that the correct behavior of solar cell is not imitated using the current FF formula. In view of the discrepancy, the expression for fill factor has been modified taking into account the material and device properties, which directly influence the working of a solar cell. All the values can be determined experimentally. The results of the modified expression gives better theoretical fit of FF with time. The results highlight the parameters which should be targeted in order to overcome the short lifetime of organic solar cells.

      PubDate: 2017-09-01T01:48:57Z
       
  • Observation of spin dependent electrochemical potentials at room
           temperature in a quantum well structure
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Youn Ho Park, Hyun-jun Kim, Joonyeon Chang, Hyun Cheol Koo
      Spin transport with a strong Rashba spin splitting is observed in a semiconductor channel. Using the current injection into the side of the quantum well, the potentiometric signal and the spin-torque-induced magnetization change are simultaneously detected. In this geometry, the spin current is directly injected from the ferromagnetic electrode into the quantum well channel and the electrochemical potential is monitored by the detection ferromagnet. For the side injection instead of vertical injection, the milling of the top cladding layer is not necessary, so the efficient spin transport and the undamaged Rashba spin splitting can be realized. The ferromagnetic detector senses the Rashba-effect-induced electrochemical potential shift brought by the charge current and this potentiometric signal is also modified by the magnetization rotation induced by the spin current. The large potential changes of 1.03 Ω and 0.96 Ω are observed at 1.8 K and 300 K, respectively.

      PubDate: 2017-09-01T01:48:57Z
       
  • Comparative study for electrical transport characteristics of
           self-assembled monolayers formed by benzenethiol, cyclohexanethiol, and
           adamantanethiol
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Junwoo Kim, Hyunhak Jeong, Sicheon Seong, Mingi Kim, Dongku Kim, Wang-Taek Hwang, Yeonsik Jang, Barbara Yuri Choi, Jeongmin Koo, Seung Bum Park, Jaegeun Noh, Takhee Lee
      We investigated the effect of molecular backbone structure on the electrical transport properties of self-assembled monolayer (SAM)-based molecular devices which were made with using three different molecules; benzenethiol (denoted as BT), cyclohexanethiol (CHT), and adamantanethiol (ADT). These molecules have similar ring-shaped backbone structures but different molecular orbital systems. The molecular devices were fabricated as a vertical metal-SAM-molecule structure by a conventional optical lithography-based microscale via-hole technique with employing PEDOT:PSS (poly(3,4-ethylenedioxythiophene)) stabilized with poly(4-styrenesulfonic acid) interlayer, which leads to a high device yield. We found that the current density of BT molecular devices was one order higher than that of CHT and ADT molecular devices due to the different molecular orbital systems. Also, we observed that the current densities of CHT and ADT devices were slightly different according to the statistical analysis because of the different structural uniformity of SAMs.

      PubDate: 2017-09-01T01:48:57Z
       
  • Tunnel magnetoresistance of homocatenated silicon and germanium clusters
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Yukihito Matsuura
      The spin-polarized transport characteristics of homocatenated clusters of group 14 elements have been studied using the non-equilibrium Green's function formalism. Compared with the carbon cluster, silicon and germanium clusters with extended σ-conjugation had a high tunnel magnetoresistance (TMR) ratio at a low bias voltage. This phenomenon was caused by the low energy level of the LUMO from σ-conjugation extended throughout the whole molecule and by the spin polarization of the sulfur located between the σ-conjugated system and the ferromagnetic electrode.
      Graphical abstract image

      PubDate: 2017-09-01T01:48:57Z
       
  • Rectifying electronic transport and the role of Fowler-Nordheim tunneling
           in Ag/PVDF/Au capacitor structures
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): K. Pramod, R.B. Gangineni
      The electron transport through β phase dominant Polyvinylidene fluoride (PVDF) thin films in its intrinsic form is investigated and reports the stable rectification up to ±30 V in Ag/PVDF/Au capacitor structures. A practical resistance ratio of ∼40 between −1 V and 1 V and a maximum ratio of ∼77 at −24 V and 24 V exhibits its potential usage in selector devices. Furthermore, the nonpolar electronic transport is analysed with Schottky, Space Charge Limited Current (SCLC), Poole-Frenkel (PF) and Fowler-Nordheim (FN) tunneling mechanisms with respect to electrode, thickness and temperature variations.

      PubDate: 2017-09-01T01:48:57Z
       
  • A novel orange-red emitting Ba2Ca(BO3)2:Sm3+ phosphor to fill the amber
           gap in LEDs: Synthesis, structural and luminescence characterizations
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): M. Manhas, Vinay Kumar, Vivek K. Singh, J. Sharma, Ram Prakash, Vishal Sharma, A.K. Bedyal, H.C. Swart
      The present paper reports on the structural and luminescent properties of un-doped and Sm3+ doped Ba2Ca(BO3)2 phosphors synthesized by the conventional solid state method. For structural characterizations, the X-ray diffraction, FTIR spectroscopy and Rietveld refinement method were used. The FTIR spectrum was composed of basic BO3 and BO4 structural units of borates. The Sm3+ doped phosphors under 402 nm (6H5/2 → 4L13/2) excitation, showed an orange red emission corresponding to the 601 nm (4G5/2 → 6H7/2) transition of the Sm3+ ion. An increase in the PL emission intensity was observed up to 2 mol % with the increase in Sm3+ ions concentration. The critical distance between the Sm3+– Sm3+ ions were found to be 24.36 Å. Moreover, the phosphors decaytime and optical bandgap at different concentration of Sm3+ ion also have been discussed in details. All the results show that Ba2Ca(BO3)2:Sm3+ phosphor may be used with a near ultraviolet (n-UV) chip to fill the amber gap in light emitting diodes (LEDs).
      Graphical abstract image

      PubDate: 2017-07-28T02:01:53Z
       
  • Structure, electronic properties and electronic excitation analyses of
           Si60Si60 dimer and Si59AlSi59P complex
    • Abstract: Publication date: November 2017
      Source:Current Applied Physics, Volume 17, Issue 11
      Author(s): Ambrish Kumar Srivastava, Sarvesh Kumar Pandey, Neeraj Misra
      The electronic properties of nanoclusters, such as Si60 cage, are remarkably changed by substitution of heteroatom such as Al or P. How do such impure Si60 cages behave when brought together to form a complex? To address this, we have performed DFT and TD-DFT based calculations on Si60 Si60 dimer and Si59AlSi59P complex. We have explored various electronic properties of Si59AlSi59P complex and compared with those of Si60 Si60 dimer. We notice that the bonding along with binding energies of cages in the complex is slightly different than that of dimer. The higher dipole moment and smaller energy gap of the complex compared to dimer suggest its increased polarity and conductivity. The density-of-state curves reveal that the frontier orbitals of the complex are slightly shifted relative to dimer such that their energy gap is decreased. The electronic excitation analyses suggest that the electronic transition in Si59AlSi59P complex takes place via charge transfer (CT) mode, and the strength of this CT interaction is much larger than that of Si60 Si60 dimer. This is confirmed by larger oscillator strength, larger distance between the centroid of hole and electron as well as larger Δr index value. We believe that these findings might be useful in the application of Si-nanoclusters in the field of molecular electronics and nanoelectronics.
      Graphical abstract image

      PubDate: 2017-07-28T02:01:53Z
       
 
 
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