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Formation of poly-crystalline BaSi2 thin films by pulsed laser deposition for solar cell applications
摘要： A new growth method for BaSi2 thin films by using pulsed laser deposition (PLD) on transparent SiO2 and CaF2 substrates has been developed. X-ray diffraction and Raman spectroscopy revealed the poly-crystalline property of the deposited films. By introducing a thin Si buffer layer on SiO2 substrate, the crystalline quality of BaSi2 thin films were improved. BaSi2 thin films exhibited a Ba/Si ratio very close to 0.5, indicating the good stoichiometry control of PLD growth. The absorption coefficient of the poly-BaSi2 reached 105 cm-1 and its band gap was deduced to be 1.32 eV, which are similar to those grown by molecular beam epitaxy or sputtering. A maximum photoresponsivity of 12.5 mA/W was achieved in the BaSi2 thin film, which implies the potential of PLD-deposited BaSi2 for thin film solar cell applications.
关键词： Thin films,BaSi2,Solar energy materials,Pulsed laser deposition
更新于2025-09-11 14:15:04
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Structural, optical and electrical studies of DC-RF magnetron co-sputtered Cu, In & Ag doped SnS thin films for photovoltaic applications
摘要： This work reports the tuning of optical and electrical properties of SnS through the incorporation of Cu, In and Ag atom without altering its chemical and crystal structural properties, using DC-RF magnetron co-sputtering technique with an in-situ substrate temperature of 400 °C. Doping is increased up to ~10% by varying the DC sputtering voltage as evident from EDAX analysis. Morphological studies show the variation in surface morphology, particle size and surface roughness due to the incorporation of dopant cation into SnS lattice sites. Film with optimized doping of ~5% resulted the substitutional doping of dopant cations (Cu2+, In3+ and Ag2+) into SnS lattice sites which resulted an improved absorption coefficient and hall carrier concentration with a decrease in band gap and electrical resistivity. Hall measurement studies of Cu 4.8% doped SnS film shows the p-type conductivity with lowest electrical resistivity of 90 Ω cm and improved carrier concentration of 1017 cm?3.
关键词： SnS thin films,Optical energy band gap,Co-sputtering,Electrical resistivity,Phase formation
更新于2025-09-11 14:15:04
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Effect of Qamma Irradiation on Optoelectronic Properties of Two Barrier Structures of Nano Crystalline Silicon Solar Cells
摘要： The possibilities of applying the technology of plasma-chemical deposition of films of a-Si1-xGex: H (x=0 ÷ 1), undoped and doped with PH3 and B2H6, for use in a pin-structure solar cells. The optical, electrical and photoelectric properties, as determined by the amount of hydrogen of the film. We found that the property of the film strongly depends on the composition and level of hydrogenation. The number of hydrogen atoms in the films was varied by changing the composition of the gas mixture and measured the infrared absorption films a-Si:H and a-Ge:H.
关键词： Coefficient of carrier collection,Method double-barrier structure analysis,Silicon thin films,Photocurrent photogeneration
更新于2025-09-11 14:15:04
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Core/shell-structured TiO2/PbS photoanodes for high-performance CsPbBr3 perovskite solar cells
摘要： PbS colloidal quantum dots (CQDs) were used as sensitizers to modify the mesoporous TiO2 (m-TiO2) layer/CsPbBr3 perovskite interface in solar cells by controlling the various spin-coating cycles on the surface of m-TiO2. The visible light absorption of m-TiO2 was enhanced because of the PbS CQDs. The prominent power conversion efficiency (PCE) of 5.04% for the core/shell-structured TiO2/PbS photoanode was higher than that of the pristine device (2.45%). This investigation provides a basis for the effect of CQD sensitization of the functional interfaces on the performance of perovskite solar cells (PSCs) under ambient conditions.
关键词： Thin films,Deposition,Composite materials,Interface
更新于2025-09-11 14:15:04
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Femtosecond-laser-ablation induced transformations in the structure and surface properties of diamond-like nanocomposite films
摘要： Femtosecond laser ablation processing is applied for surface modification and micropatterning of diamond-like nanocomposite (DLN) films (a-C:H:Si:O films). Using a visible femtosecond laser (wavelength 515 nm, pulse duration 320 fs), microgroove patterns have been fabricated on the DLN films, aimed at further studies of their properties. The studies were focused on (i) structural transformations in the surface layers using Raman spectroscopy and transmission electron microscopy (TEM), (ii) wettability of laser-patterned films, and (iii) nano/microscale friction properties of laser-patterned DLN films using lateral force microscopy. Raman spectroscopy and TEM data showed characteristic features of the surface graphitization during ultrashort-pulse ablation. High resolution TEM study of the microgrooves revealed the formation of cubic SiC nanocrystals (4–8 nm size) on the laser-ablated surface. The water contact angle measurements showed anisotropic wetting behavior of the grooved surfaces (the contact angle was different in the directions parallel and perpendicular to microgrooves), depending on the groove depth (aspect ratio). Lateral force microscopy examination (with micro-sized Si tips) showed that the laser-patterned regions exhibited low friction properties compared to the original surface. The obtained results demonstrate that femtosecond laser processing is an effective technique to generate new properties of hard DLN coatings at the micro and macroscale.
关键词： Diamond-like nanocomposite films,Femtosecond laser ablation,Micropatterning,SiC nanocrystals,Graphitization,Wettability
更新于2025-09-11 14:15:04
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Boron Nitride Nanotubes in Nanomedicine || Boron nitride nanotube films: preparation, properties, and implications for biology?applications
摘要： Boron nitride nanotubes (BNNTs) share the same structure as carbon nanotubes (CNTs), but have boron and nitrogen atoms sitting close to each other. Some properties of BNNTs are similar to their carbon counterparts, such as mechanical strength, thermal conductivity, and wettability. However, there are also many differences between them. BNNTs are insulators with a wide bandgap of about 6 eV, which is not sensitive to their diameter and chirality. Compared to CNTs, BNNTs are more thermally stable in air and, therefore, better candidates as fillers in metal/ceramic composites, field emitters, and thermal management materials at high temperatures. BNNTs show strong light emission at ～227 nm in the deep ultraviolet (DUV) region and are useful in optoelectronic, medical, data storage, and lithography applications. Isotopic 10BNNTs not only exhibit greatly improved thermal conductivity superior to that of CNTs, but also provide radiation shielding. Due to the electric polarization, BNNTs are piezoelectric and suitable for electromechanical devices on the nanoscale.
关键词： biology applications,Boron nitride nanotubes,properties,BNNT films,preparation
更新于2025-09-11 14:15:04
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Structural studies of thin Mg films
摘要： In the present work variable energy positron annihilation spectroscopy (VEPAS) was employed for investigation of defects in Mg films. VEPAS characterization was combined with scanning electron microscopy and X-ray diffraction in order to determine grain size and texture respectively. The aim of this study was to examine the effect of deposition temperature and various substrates on structure and defects in Mg films prepared by RF magnetron sputtering. SEM observations revealed that films deposited on sapphire (0001) substrate exhibit always smaller grains than films deposited on amorphous fused silica and silicon (100) substrates, which have comparable grain size. Defect studies by VEPAS showed that positrons in Mg films studied are trapped at misfit dislocations and at vacancy-like defects in grain boundaries. Moreover, the films deposited on a substrate heated at 300?C exhibited lower concentration of defects and larger grain size compared to the films deposited at room temperature. Subsequent annealing at 300?C for 1 h of the films deposited at room temperature causes a slight decrease of defect density due to coarsening of grains.
关键词： SEM,Mg films,VEPAS,grain size,defects,XRD
更新于2025-09-11 14:15:04
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Thin Films with Checkerboard-Ordered Oxygen Vacancies and Low Magnetic Damping
摘要： The possibility of affecting the magnetic properties of a material by dielectric means, and vice versa, remains an attractive perspective for modern electronics and spintronics. Here, we report on epitaxial Bi(Fe0.5Mn0.5)O3 thin films with exceptionally low Gilbert damping and magnetoelectric coupling above room temperature (< 400 K). The ferromagnetic order, not observed in bulk, has been detected with a total magnetization of 0.44 μB/formula units with low Gilbert damping parameter (0.0034), both at room temperature. Additionally, a previously overlooked check-board ordering of oxygen vacancies is observed, providing insights on the magnetic and dielectric origin of the multifunctional properties of the films. Finally, intrinsic magnetodielectric behavior is observed as revealed by the variation of dielectric permittivity well above room temperature. These findings show the possibility of electric-field-controlled magnetic properties, in low Gilbert-damping-based spintronic devices, using single-phase multiferroic materials.
关键词： magnetodielectric,Gilbert damping,thin films,Bi(Fe0.5Mn0.5)O3,magnetoelectric coupling
更新于2025-09-11 14:15:04
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Influence of oxygen vacancy on the response properties of TiO2 ultraviolet detector
摘要： In this paper, the effect of sputtering distance between target and substrate (DTS) on the structural, morphological and optical properties of TiO2 films were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that crystallite size and surface morphology were strongly dependent on DTS. The X-ray photoelectron spectroscopy (XPS) results showed that obvious three peaks including C1S, Ti2p and O1s could be clearly observed and binding energy was 285, 458 and 531 eV, respectively. For each sample, four peaks at about 386, 462, 527 and 595 nm in photoluminescence (PL) spectrum were observed and produced by intrinsic recombination, F center, F+ center and electrons transferred from 3d Ti3+ states to the deep levels OH?, respectively. Finally, photoresponse properties of UV detector based on TiO2 films were further analyzed and TiO2 UV detector prepared by DTS of 80 mm showed a high responsivity of 2.02 ×10-4 A/W and photosensitivity of 32.25, also, exhibited a fast response with a rise time (τr) of 0.98 s and fall time (τf) of 3.14 s.
关键词： UV detector,oxygen vacancy,TiO2 thin films,X-ray photoelectron spectroscopy
更新于2025-09-11 14:15:04
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Influence of cadmium precursor concentrations on the structural, optical and electrochemical impedance properties of CdZnS thin films
摘要： Thin films of cadmium zinc sulfide (CdZnS) were deposited on microscopic glass substrates using the chemical bath deposition method and the effects of the Cd precursor concentrations on the morphological, structural and optical properties of the films were studied. The surface morphology as revealed by scanning electron microscope showed closely packed nano particles randomly spread on the surface of the glass substrates. The x-ray diffraction studies showed that the thin films were polycrystalline and the crystallite size decreased with increase in the concentration of the Cd precursor. While the optical absorbance decreased, the bandgap energy increased as the concentration of the cadmium source increased. Electrochemical studies were performed by cyclic voltammetry analysis and impedance measurements at low frequency ranges. Simulation model on the impedance model was carried out to obtain a more quantitative analysis of the data. The ternary CdZnS thin film developed in this work could be useful as window layer in solar cell fabrication.
关键词： electrochemical impedance properties,optical properties,chemical bath deposition,structural properties,CdZnS thin films,cadmium precursor concentrations
更新于2025-09-11 14:15:04