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Publisher: Springer-Verlag (Total: 2574 journals)

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 Applied Physics AJournal Prestige (SJR): 0.481 Citation Impact (citeScore): 2Number of Followers: 10      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0947-8396 - ISSN (Online) 1432-0630 Published by Springer-Verlag  [2574 journals]
• New surface microstructure of mono-si wafer textured using wet chemical
solutions for solar cell (revised paper (2))
• Abstract: Mono-Si textured surface covered with pyramids has been widely used in the solar cell. However, there are few reports of new microstructures instead of pyramids on Mono Si surface. By adding the special additive, we change the anisotropic texturing properties of alkaline solutions to develop a new small tower over Mono Si surface. The surface was evaluated by scanning electron microscopy, minority carrier lifetime instrument and integral reflector. The results show that this new microstructure has the minority carrier lifetime of 9.72 µs, reflectivity of 10.12% within 400–1000 nm, respectively, which are better than that of solar cell based on pyramids structure. By comparing with samples covered with pyramids, it is considered that the new microstructures are suitable for the possible applications of silicon solar cells. In addition, we also found the non-linear relationship between minority carrier lifetime and the tower size.
PubDate: 2019-03-22

• Different methods for removing boron-rich layer and their impacts on the
efficiency of interdigitated back contact solar cells
• Abstract: In this paper, three commonly used methods for boron-rich layer (BRL) (BRL: abbreviation of boron-rich layer, a layer constituted by compound of boron and silicon.) removal and their impacts on the surface passivation and the efficiency of the final interdigitated back contact solar cells are investigated. The method of in-situ oxidation can remove BRL completely, but will cause serious degradation of the bulk lifetime. The method of treatment in boil nitric acid cannot remove BRL completely resulting in a poor passivation quality of the substrate surface. The method of chemical etch treatment (CET) (CET: Abbreviation of chemical etch treatment.) can remove BRL completely and would not cause any degradation of the bulk lifetime. Finally, interdigitated back contact solar cells have been fabricated using the three methods mentioned above for BRL removal and the highest efficiency of 21.17% is achieved with the BRL removed by the method of CET.
PubDate: 2019-03-22

• Characterizations of continuous carbon fiber-reinforced composites for
electromagnetic interference shielding fabricated by 3D printing
• Abstract: With an increase in electromagnetic interference pollution, composites for electromagnetic interference shielding (EMIS) with good shielding performance and friendly processability are widely demanded. Herein, a methodology for preparing composites with controllable shielding effectiveness (SE) is proposed. Carbon fiber (CF)-reinforced polylactic acid composites were fabricated by a 3D printing process, and the SE of the composites was controlled by varying the process parameters. To systematically investigate the feasibility of the methodology, the shielding properties, processability, and mechanical properties of the composites were investigated. The results showed that the SE was controlled in the ranges of 25.1–69.9 dB, 51.1–75.6 dB, and 6.8–78.9 dB by tailoring the number of layers (2–12), hatch spacing (1.6–0.8 mm), and filling angle (90°–0°), respectively. The critical mechanism of the controllability is that the content, spatial distribution, and orientation of CFs can be facilely and digitally controlled during processing. A conformal shell with a SE of 38.5 dB was fabricated to demonstrate superior processability of a complex geometry. The maximum tensile and flexural strengths of the composites were 111.0 and 152.9 MPa, respectively, which were much larger than those of most engineering plastics. Using this methodology, an appropriate SE that is neither excessive nor deficient can be readily realized, which helps to maintain high resource utilization. Complex geometries for EMIS can be rapidly and cheaply obtained without molds, which is difficult for traditional processes. These advantages make the 3D-printed CF-reinforced composites competitive with other EMIS materials and traditional processes.
PubDate: 2019-03-22

• Effect of oxygen concentration on the ferromagnetic transition of La 1.9
Sr 0.1 CoMnO 6 thin films
• Abstract: In this study, the effect of oxygen vacancies on structural and magnetic properties of La1.9Sr0.1CoMnO6 (LSCMO) films deposited on Si (100) substrate was investigated by varying the oxygen partial pressure during film growth, by pulsed laser deposition. The Rietveld refinement manifest the monoclinic phase (with space group P21/n) of the bulk La1.9Sr0.1CoMnO6 sample. A shift in ferromagnetic (FM) phases (Tc) are obtained in both the LSCMO films from that of the bulk La1.9Sr0.1CoMnO6 sample confirmed by a magnetic measurement. The oxygen vacancies, observed through X-ray photoelectron spectroscopy (XPS) measurement, can induce the local vibronic Mn3+–O–Mn3+ superexchange interactions in direct competition with static ferromagnetic Mn4+–O–Mn4+ interactions. In this paper, attempts have been made to tune the magnetic phases by controlling the oxygen vacancies.
PubDate: 2019-03-22

• Sintering behavior of high-concentration Li 2 CO 3 -doped BaTiO 3 ceramics
• Abstract: Li+ ion-doped BaTiO3 (LBT-x, x = 0, 3%, 5%, 7%) ceramics were prepared by the solid-state reaction method, which were analyzed by XRD and EDS. The Ba2TiO4 phase was formed on the surface of sintered LBT-x ceramics with high Li+ concentration (x = 5%, 7%), and tetragonal phase appeared after the removal of Ba2TiO4 surface layer. According to the results from first-principle calculation of 2 × 2 × 2 and 3 × 3 × 3 supercells, Li+ ions can occupy B site of ABO3 perovskite structure. The LBT-x (x = 3%, 5%, 7%) ceramics showed antiferroelectric-like double hysteresis loops which form [LiTi–Vo]− dipoles and pin the domain walls. The piezoelectric constant d33 also decreases due to pinning effect.
PubDate: 2019-03-20

• The precursor solution effect on the synthesis, structure, and optical
properties of the WO 3 –TeO 2 binary compound
• Abstract: In this paper, two synthesis methods of binary compounds of WO3–TeO2 with different precursors solutions including HNO3 (solution A) and HCl (solution B) have been presented. The effect of nitric acid and hydrochloric acid precursors on the structural and optical properties of WO3–TeO2 compounds have been studied. The results of X-ray diffraction showed that in the solution containing HNO3, a large percentage of TeO2 was transformed to Te during the reaction and for solution containing HCl, the two phases of WO3 and TeO2 are observed. The size of the WO3–TeO2 nanoparticles synthesized with the precursor B is smaller than the other one. The images of the field emission scanning electron microscope (FE–SEM) for solution containing HNO3 showed that the morphology of the produced nanoparticles is hexagonal and tetragonal, while solution containing HCl is uniformly polygon monoclinic structure in form of rod. The results of the FT–IR and UV–Vis spectrometry showed that the bonding structure of nanoparticles in solution containing HNO3 is influenced by environmental factors and affects almost on all the vibrational modes of the WO3–TeO2 composition. The energy gap (Eg) for the synthesized samples with the processors A and B were obtained 3.65 eV and 4.02 eV, respectively.
PubDate: 2019-03-20

• Spectroscopic and structural properties of zinc oxide nanosphere as random
laser medium
• Abstract: This work focuses on the preparation and description of zinc oxide nanoparticles (ZnONPs) by hydrothermal method. The ZnONPs here were used as scattering center after mixture with R6G at concentration 10−4 mol/l which was doped by PMMA polymer as a film. The UV–visible (UV–Vis) spectroscopy, photoluminescence spectroscopy (PL), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-rays (EDS) spectroscopy, and transmission electron microscopy (TEM) were performed to characterize the growth, morphology, and optical nature of the samples. Practical results indicate a pure growth of ZnO in the solid case by hydrothermal manufacture technique that can produce high crystallinity and a perfect hexagonal quartzite structure. The average particle sizes were measured to range from 10 to 140 nm. The PL spectrum for pure ZnO as powder appears as maximum peak intensity of ultraviolet region at 385 nm and blue emission band around 472 nm at room temperature (RT), while it is observed that sharp peaks with a linewidth of ~ 10 nm emerge from the emission spectra for the sample at ~ 16 mJ pump energy. It is observed that the peak emission wavelength of the dye ZnONP-doped PMMA as a host (~ 569 nm) is different from that of the bare ZnO nanospheres (~ 385 nm).
PubDate: 2019-03-19

• Superhydrophobic copper surface with mechanical, chemical, and UV
durability along with corrosion resistance and self-cleaning effect
• Abstract: It is the prerequisite of improving the universality, stability, and wear resistance of superhydrophobic materials for the practical applications. A simple and environment-friendly method is developed herein for constructing superhydrophobic copper surface by hydrothermal method. The wettability, surface microstructure, phase structure, and chemical structure of superhydrophobic Cu2S-coated copper surface are examined by contact angle measurement, SEM observation, XRD measurement, FT-IR and EDS analyses. Results show that the superhydrophobic Cu2S-coated copper surface is composed of a large number of Cu2S crystals grafted with long hydrophobic alkyl chains, and which leads to the superhydrophobic copper presenting a rough and hierarchical surface with micro- and nano-scaled binary structure. It is noteworthy that 200 °C of heat treatment has marked influence on the surface microstructure and wettability. Consequently, the mechanical durability of the superhydrophobic copper has been improved greatly upon heat treatment. Just ground on both the hierarchical surface and grafted long hydrophobic alkyl chains as well as heat treatment, the as-prepared superhydrophobic copper surface exhibits not only good mechanical durability and corrosion resistance, but also excellent chemical and UV durability as well as self-cleaning effect. This method provides a novel and simple process to protect the surface of copper. It is believed that such technique may open a new approach to expand the application of copper. Graphical abstract A simple and environment-friendly method is developed for constructing superhydrophobic copper surface by hydrothermal method. Ground on both the hierarchical surface and grafted long hydrophobic alkyl chains as well as heat treatment, the as-prepared superhydrophobic surface exhibits not only good mechanical durability and corrosion resistance, but also excellent chemical and UV durability as well as self-cleaning effect.
PubDate: 2019-03-19

• Design of the high-efficiency transmission-type polarization converter
based on substrate-integrated waveguide (SIW) technology
• Abstract: In this paper, the design of a three-layer linear polarization converter based on substrate-integrated waveguide (SIW) technology is demonstrated. The transmission-type polarization converter with dual frequency polarization conversion characteristics is realized by a square-slot sandwiched by two layers of off-center dipole-slot resonator, and its asymmetric transmission (AT) property can be obtained by rotating the upper and the lower dipole-slot resonator to form an interlaced layout. An excellent polarization conversion ratio (PCR) can be realized by integrating the traditional transmission-type polarization converter with an SIW, and its physical mechanism can be explicated by guided wave field theory. Experimental results are presented and compared with the simulation results, and they demonstrated that ultra-high PCRs of the presented polarization converter are 0.87 and 0.99 for the measurement at the working frequency of 7.34 GHz and the simulation at the working frequency of 7.6 GHz, respectively. The designed polarization converter has greatly expanded the application field of SIW technology.
PubDate: 2019-03-18

• Modeling of triboelectric charge accumulation dynamics at the
metal–insulator interface for variable capacitive structures:
application to triboelectric nanogenerators
• Abstract: This paper presents a dynamic model to study triboelectric charge accumulation in a variable capacitive structure with metal–dielectric interface. The presented model addresses a serious flaw of current published theoretical works related to modeling of triboelectric energy harvesters. Electrostatic analysis of the device in the contact and non-contact modes is performed. Based on the analysis of the non-contact mode, a novel technique is introduced to measure stable parasitic triboelectric charge density on the surface of the dielectric layer. Theoretical analysis for positive and negative charge accumulation is performed separately and key characteristic equations of both cases are extracted. A new measurement technique is developed to assess triboelectric charge build-up on the surface of the dielectric layer by employing a simple bridge rectifier as a test circuit. Based on the measured data, a time-dependent exponential model is suggested for triboelectric charge accumulation on the surface of the dielectric layer. The presented dynamic model is a vital asset in modeling dynamic output of triboelectric nanogenerators (TENG’s). The results show that failure to consider triboelectric charge dynamics in modeling of TENG’s would result in more than 50% error in the simulated output characteristics. Graphical abstract Charge accumulation A new surface charge evaluation technique is introduced. Triboelectric charge accumulation on the surface of dielectrics is calculated and modeled using a simple half-wave rectifier. To get to the model, discrete charge-time points are measured. The dynamic charge model presents an essential asset in simulation of the output performance of TENG’s. positive and negative charge build up is measured.
PubDate: 2019-03-18

• A new type of coherent electromagnetic radiation source based on
interference effect between forward and backward waves in an active
metamaterial slab
• Abstract: In this paper, we shall show first that both reflection and transmission can be significantly amplified when a beam of electromagnetic wave is normally incident into an active (even lossy) metamaterial slab with near-zero-real-part-of-impedance, which is attributed to effect of interference between forward and backward waves in the slab. Then we demonstrate that extended steady electromagnetic waves can be achieved using a double-slab structure, which may be applied to generate coherent electromagnetic wave with very narrow frequency band and very low divergence angle. This work provides feasible scheme to construct a new type of source of coherent electromagnetic radiation based on new physical mechanism.
PubDate: 2019-03-16

• Studying of SiO 2 /capron nanocomposite as a gate dielectric film for
improved threshold voltage
• Abstract: In this study, SiO2 gate dielectric operation was improved using SiO2/capron nanocomposite. SiO2/capron nanocomposite was synthesized by the sol–gel method. The existence of two phases in the nanocomposite structure was revealed using energy dispersive spectroscopy. The formation of hydrogen bonds among SiO2 nanofillers and capron matrix was proved by Fourier transform infrared spectroscopy and thermogravimetric analysis. The fact resulted in the uniform dispersion of SiO2 nanoparticles within capron matrix and the formation of cross-linked network. Pure SiO2, pure capron, SiO2/capron nanocomposite dissolved in benzene alcohol and SiO2/capron nanocomposite dissolved in acid formic as the gate dielectric films were deposited on the p-type Si substrates. Atomic force microscopy showed a significant decrease in the average surface roughness of nanocomposite film (0.02 nm) compared to that of pure SiO2 and pure capron films (18.3 and 7.85 nm, respectively). The operation of deposited films as the gate dielectrics was compared by the current–voltage (I–V) measurements in the metal–insulator–semiconductor structure. Fabricated p-type Si field-effect-transistors demonstrated a great decrease in the leakage currents and the threshold voltages by decreasing the surface roughness of their dielectric films, because the charge transport is strongly associated with trap depth and carrier scattering effects in the semiconductor/dielectric interface. As a result, the threshold voltages were shifted toward downward and reached 1 V for transistor based on SiO2/capron nanocomposite dielectric film.
PubDate: 2019-03-16

• Laser fluence dependence of ripple formation on fused silica by
• Abstract: Laser-induced periodic surface structures (LIPSS, ripples) have attracted great attentions in the fields of surfaces and interfaces, yet their origin still remains puzzling, especially for dielectrics. In this study, a comparative study of the formation of two distinct classes of ripples on fused silica is provided by carefully adjusting the key parameters of laser fluence and pulse number. Two different ablation regimes are identified for LIPSS formation. The threshold fluence of F = 4.07 J/cm2 is defined for the transition from high spatial frequency LIPSS to low spatial frequency LIPSS, which is independent of pulse number. Pulse-to-pulse results show the unique formation processes for each class of LIPSS in different fluence regimes. In the fluence range below the transition threshold (2.54 J/cm2 < F < 4.07 J/cm2), the formation of high spatial frequency LIPSS starts from randomly distributed nanogrooves perpendicularly orientated to E, indicating the excitation of surface-plasmon polaritons as a primary formation mechanism. In the higher fluence regime (F > 4.07 J/cm2), the development of a thin rim surrounding an ablation crater into straight ridges spreading across the crater is observed for the formation of low spatial frequency LIPSS, suggesting a thermal and fluid process involved in the LIPSS formation. The results show that laser fluence plays a key role in controlling the origin of ripples, while pulse number mainly contributes to the subsequent growth of microstructures.
PubDate: 2019-03-16

• Surfactant-free synthesis and experimental analysis of Mn-doped
ZnO–glycerol nanofluids: an ultrasonic and thermal study
• Abstract: A simplistic and environment-friendly approach has been used to prepare surfactant-free Mn-doped ZnO–glycerol nanofluids using high power sonicator. Thermal conductivity of the prepared nanofluids has been measured as a function of temperature and concentration. Maximum thermal conductivity enhancement ~ 32% at 40 °C has been observed with very low nanoparticles loading (2.0 vol% of Mn-doped ZnO-nanoparticles) which is significantly larger than the presently synthesized ZnO–glycerol nanofluids, and that of reported earlier on ZnO-ethylene glycol, and other glycerol-based nanofluids. Our present investigation shows that the thermal conductivity of nanofluids can be increased up to a significant level by changing other physical properties of incorporated nanoparticles than increasing concentration of nanoparticles to a large extent. Various physical phenomena including Brownian motion induced convection effect in conjunction with ballistic diffusion have been proposed for anomalous thermal conductivity enhancement. This may be valuable for various cooling applications and may open avenues for further exploration of efficient heat management with the help of nanosized doped metal oxide suspensions.
PubDate: 2019-03-15

• Combined effects of Mg reducing and Sn doping on the electrical
conductivity of polycrystalline Ca 12 Al 14 O 33 mayenite
• Abstract: Polycrystalline Ca12Al14O33 was prepared by a solid state reaction method. All samples showed the phase of the Ca12Al14O33 by X-ray powder diffraction (XRD). The Mg heat treatment and Sn doping contributions dominated to increase the lattice constant a from 11.909(3) to 12.163(1) Å. Electron excitation energy of all samples were assigned by absorption spectra. The excitation energy between 2.68 and 2.79 eV was found after the Mg heat treatment. Electrical conductivity increased approximately 109 orders of magnitude at room temperature when experiencing Mg heat treatment for 10 h. The highest electrical conductivity obtained from the Ca12Al12.8Sn1.2O33/Mg(10) sample was 7.65 S cm− 1 at 573 K. The low activation energy for electrical conductivity was approximately 0.038 eV as a result of the Mg heat treatment. The influence of the Sn doping excellence supported the increase of the electrical conductivity with the Mg heat treatment process.
PubDate: 2019-03-15

• Enhancement of second harmonic generation in MnF 2 /graphene sandwich
structure
• Abstract: We propose an efficient method for increasing the second harmonic (SH) generation by embedding the graphene (Gr) in SiO2/MnF2/ZnF2 sandwich structure. The external magnetic field is perpendicular to the surface of MnF2/Gr sandwich. Two cases where the Gr layer is put above or below the MnF2 film are compared. For the MnF2/Gr case, the numerical simulation results show that the SH outputs obviously increase one order magnitude compared with the MnF2 sandwich without the Gr layer. In addition, the position and intensity of the SH outputs can be easily controlled by adjusting the external magnetic field strength and gate voltage. However, for the Gr/MnF2 case, the SH outputs rapidly decrease almost near to zero. The electric field distributions show that, in this case, the light intensity in the MnF2 film is further weakened, which causes that SH generations cannot be effectively excited. Besides, the effect of the magnetic field and the Fermi energy on the SH outputs are also studied.
PubDate: 2019-03-15

• Design of nano-sized Pr 3+ –Co 2+ -substituted M-type strontium
hexaferrites for optical sensing and electromagnetic interference (EMI)
shielding in K u band
• Abstract: This research investigates the effect of Pr3+–Co2+ substitution on the structural, optical, and electromagnetic interferrence (EMI) shielding properties of M-type strontium hexagonal ferrites with chemical composition Sr1−xPrxFe12−yCoyO19 (x = 0.0, 0.2, 0.4 and y = 0.00, 0.15, 0.35). The sample was prepared by sol–gel auto-combustion technique, pre-sintered at 400 °C for 4 h and sintered at 950 °C for 5 h. XRD analysis shows that the sample exhibits pure crystalline phase with no presence of impurity such as α-Fe2O3. The presence of three prominent peaks at 434, 543, and 586 cm−1 in FTIR spectra indicates the formation of hexaferrite phase. FESEM micrographs depict nanoparticles with hexagonal plate-like structure of hexaferrites which is vital for microwaves absorption, whereas EDX spectra show the host and substituted ions. The observed band gap was found to decrease with increase in Pr3+–Co2+ concentration. The maximum EMI shielding effectiveness of 27.40 dB at 18 GHz was obtained for the sample S2 which is above the commercial level of 20 dB.
PubDate: 2019-03-15

• Preparation and characterization of perfluorine-SiO 2 nanoparticles and
superhydrophobic fluorosilicone/silica hybrid composite coating
• Abstract: The superhydrophobic fluorosilicone/silica (FS/SiO2) hybrid composite coating was easily fabricated by one-step blending method in this study, whose durable superhydrophobicity could be ensured by fluorosilicone resin (FS) matrix and perfluorine-SiO2 nanoparticles. The prepared perfluorine-SiO2 nanoparticles were detected using FESEM and FT-IR spectra, and the wettability and dispersion effects were studied. The surface morphologies and hydrophobicity of FS/SiO2 coating on glass plates were investigated by AFM and optical contact angle meter, while the adhesion, wear-resistance and chemical regent-resistance for FS/SiO2 superhydrophobic coating were also discussed. At last, the self-cleaning and anti-icing performances of prepared FS/SiO2 superhydrophobic coating were explored. It could be found that the FS coating doped with more than 22% SiO2 would exhibit superhydrophobicity. The water contact angle of the superhydrophobic FS coating could reach 161° and sliding angle 2° in the best condition. The superhydrophobic FS/SiO2 coating possesses relatively satisfied mechanical and chemical stability. Moreover, the prepared superhydrophobic FS/SiO2 hybrid composite coating provided an available selection of protecting surfaces against contamination and icing which validated the practicability.
PubDate: 2019-03-14

• Investigation on physical properties of CdO thin films affected by Tb
doping for optoelectronics
• Abstract: Thin films of Tb-doped CdO were grown on FTO substrates using the sol–gel-spin coater technique. XRD studies confirmed the polycrystalline cubic growth of the films with a (200) preferential orientation. XRD analysis was used to estimate the crystallite sizes, dislocation density, and microstrain values, and found that they are highly dependent on the doping percentage. Homogeneous distributions of the nano-gains were observed from the AFM studies. Energy-dispersive spectroscopy and mapping analyses were used for the uniform elemental composition confirmation. All the films displayed high transmission reaching nearly 80% in the visible spectrum and the effect of Tb doping was very clear by corresponding systematic increase in intensities. The direct band-gap values were estimated from the Tauc plots and are found to be highly tunable based on the doping percentage, which was varying between 2.79 and 2.91 eV. The refractive index and extinction coefficient values are lies between 1.8 and 2.5 and 0.44 to 0.82. The $${\chi ^{(1)}}$$ values are found to be varying between of 0.05 to 0.45 within the range 1–4 eV. This suggests all the linear and nonlinear optical properties of the present samples can be tailored for the various applications by the doping.
PubDate: 2019-03-13

• Correction to: Five non-volatile memristor enigmas solved
• Abstract: The author of the original version of this article makes the following corrections:
PubDate: 2019-03-11

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