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Influence of bath temperatures on physical and electrical properties of potentiostatically deposited Cu2O thin films for heterojunction solar cell applications
摘要： In the present work, the influence of bath temperatures on structural, morphological, vibrational, optical, electrical and photo response properties of the electrochemically deposited cuprous oxide (Cu2O) thin films on fluorine doped tin oxide substrate is extensively investigated with the help of X-ray diffraction (XRD), scanning electron microscopy (SEM), Micro Raman spectroscopy, photo luminescence (PL) spectroscopy, UV–visible spectroscopy, LCR measurement, Keithley 4200 semiconductor characterization system respectively. XRD patterns reveal that the deposited Cu2O films have cubic structure grown along the preferential (111) orientation and the film deposited at 40 °C shows better crystalline nature when compared at 55 and 70 °C. The micro structural properties of films such as crystallite size (D), dislocation density (δ), micro strain (ε) and stacking fault probability (α) were calculated and discussed in detail. SEM displays a well-defined three side pyramid shaped morphology for the film deposited at 40 °C. Micro Raman and PL spectra reveal the film deposited at 40 °C by being better crystalline at a higher acceptor concentration. UV–Visible study shows that the optical energy band gap increases from 2.05 to 2.17 eV with an increase in bath temperature from 40 to 70 °C. The frequency-temperature dependence of impedance analysis shows a higher electrical conductivity for a film deposited at 40 °C compared to other bath temperatures. I-V measurement illustrates a good photoconductivity response for Cu2O thin film deposited at 40 °C compared to films deposited at 55 and 70 °C.
关键词： Micro Raman spectroscopy,X-ray diffraction,Photoconductivity,Cuprous oxide,Pyramid shape
更新于2025-11-19 16:46:39
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Effect of Deposition Potential on Synthesis, Structural, Morphological and Photoconductivity Response of Cu2O Thin Films by Electrodeposition Technique
摘要： The present work describes the effect of deposition potentials on structural, morphological, optical, electrical and photoconductivity responses of cuprous oxide (Cu2O) thin films deposited on fluorine-doped tin oxide glass substrate by employing electrodeposition technique. X-ray diffraction patterns reveal that the deposited films have a cubic structure grown along the preferential (111) growth orientation and crystallinity of the film deposited at ? 0.4 V is improved compared to the films deposited at ? 0.2, ? 0.3 and ? 0.5 V. Scanning electron microscopy displays that surface morphology of Cu2O film has a well-defined three-sided pyramid-shaped grains which are uniformly distributed over the surface of the substrates and are significantly changed as a function of deposition potential. Raman and photoluminescence spectra manifest that the film deposited at ? 0.4 V has a good crystal quality with higher acceptor concentration compared to other films. UV–visible analysis illustrates that the absorption of Cu2O thin film deposited at ? 0.4 V is notably higher compared to other films and the band gap of Cu2O thin films decreases from 2.1 to 2.04 eV with an increase in deposition potential from ? 0.2 to ? 0.5 V. The frequency–temperature dependence of impedance analysis shows that the film deposited at ? 0.4 V has a high conductivity. I–V measurements elucidate that the film deposited at ? 0.4 V exhibits a good photoconductivity response compared to films deposited in other deposition potentials.
关键词： Cu2O thin films,Electrodeposition,I–V measurement,Photoconductivity response
更新于2025-11-19 16:46:39
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Investigations on the quantum chemical studies and physico-chemical properties of an opto-electronic material 1-Allyl-2-Aminopyridine-1-ium bromide
摘要： In the present work, the dual approach of quantum chemical studies and experimental characterizations of the title compound 1-Allyl-2-Aminopyridine-1-ium bromide (1A2APB) were carried out for the first time. The molecular geometry of 1A2APB was optimized by density functional theory (DFT) using B3LYP/6-311++G (d,p) basis set. The optimized geometric structural parameters were compared with the experimental findings and discussed. The dipole moment (μ) and first hyperpolarizability (β) were calculated to predict the NLO behavior. The frontier molecular orbital (FMO), molecular electrostatic potential (MESP), Mulliken atomic charge and thermodynamic properties were investigated to get a better insight of the molecular properties. Stability of the compound arising from hyper-conjugative interactions, intra-molecule re-hybridization and charge delocalization within the molecule were analyzed using NBO analysis. Further, 1A2APB was synthesized and good quality single crystals were grown by slow evaporation technique. Studies such as microanalysis and powder XRD were performed to ascertain material composition and phase respectively. The various characteristic functional groups were identified through FT-IR spectroscopic analyses. The NLO efficiency was measured to be about greater than 5 times that of standard KDP. Thermal behaviors were explored by the simultaneous TG/DTA-DSC thermograms. The UV–Vis–NIR spectral data and fluorescence spectrum were recorded to explore the optical transmission and emission properties respectively. The dielectric properties were evaluated as a function of frequency at various temperatures. The photoconducting nature was analyzed through photoconductivity measurement. The Vicker’s microhardness test was performed at room temperature from which the mechanical stability was analyzed through the classical Meyer’s relation.
关键词： Photoconductivity,Powder XRD analysis,DFT calculations,Organic materials,Non-linear optics,Crystal growth
更新于2025-09-23 15:23:52
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Optical and photoconductive properties of indium sulfide fluoride thin films
摘要： This work reports on transparent semiconducting indium sulfide fluoride (ISF) thin-films exhibiting high sensitivity to ultraviolet radiation. The films were deposited on fused silica and silicon substrates using a radio-frequency plasma-enhanced reactive thermal evaporation system. The deposition was performed evaporating pure indium in SF6 plasma at a substrate temperature of 423 K. Rutherford backscattering measurements were used to determine the chemical composition of the films deposited on silicon substrates. The surface morphology was studied using scanning electron microscopy technique. The film characterization includes electrical, optical, and photoconductivity measurements. The synthesized compound is highly-resistive (~700 MΩ-cm at 300 K) and exhibits an evident semiconducting behavior. The activation energy of 0.88 eV is deduced from the temperature dependence of electrical resistivity. The indirect band energy gap of 2.8 eV is determined from transmittance spectra of the ISF films. The photoconductivity band is centered at 345 nm wavelength. The photoconductivity spectrum also shows the Urbach tail with a characteristic energy of 166 meV. ISF is a promising candidate for a buffer layer in chalcogenide-based solar cells.
关键词： Thin-films,Indium sulfide fluoride,Optical properties,Photoconductivity,Photovoltaics,Amorphous semiconductors
更新于2025-09-23 15:23:52
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Inkjet Printed hybrid light sensors based on Titanium Dioxide and PEDOT:PSS
摘要： We demonstrate photodetectors sensitive to ultraviolet light entirely developed by means of inkjet printing technique and based on titanium dioxide and PEDOT:PSS. Devices have a lateral architecture and are realized on a plastic substrate, thanks to the low thermal budget production process. Pure titania devices behave as standard photodetectors, increasing their conductivity by more than 4 orders of magnitude upon UV light exposure. Bilayers of PEDOT:PSS and titania show an inverted behavior, with a high conductivity in the dark which drops by 7 orders of magnitude upon light exposure: this is likely due to the fast recombination of PEDOT:PSS holes with photogenerated TiO2 electrons. The series connection of pure TiO2 and of PEDOT:PSS/TiO2 bilayer is suggested as the basis for the development of low-power, complementary–like, photosensitive voltage dividers.
关键词： photosensitive voltage divider,inkjet printing,PEDOT:PSS,inverted,UV detector,titanium dioxide,negative photoconductivity,photoresistor
更新于2025-09-23 15:23:52
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - The Effect of H<inf>2</inf>/Ar Plasma Treatment Over Photoconductivity of Sige Nanoparticles Sandwiched Between Silicon Oxide Matrix
摘要： The effect of room temperature hydrogen plasma treatment on the photoconductive properties of the SiO2 matrix containing SiGe nanoparticles is investigated. A considerable increase in photocurrent intensity is observed after plasma treatment. The increase is partly attributed to neutralization of dangling bonds around the nanoparticles and partly to passivation of non-radiative centers and defects in the matrix and at the nanoparticles-matrix interfaces.
关键词： hydrogenation,magnetron sputtering,photoconductivity,HiPIMS,SiGe,SiO2
更新于2025-09-23 15:22:29
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[IEEE 2018 International Semiconductor Conference (CAS) - Sinaia, Romania (2018.10.10-2018.10.12)] 2018 International Semiconductor Conference (CAS) - Enhanced Photoconductivity of SIGE-Trilayer Stack by Retrenching Annealing Conditions
摘要： We studied the effect of short term furnace annealing over the photoconductive properties of tristacked layer i.e. TiO2/(SiGe/TiO2)3. The structure was prepared by depositing alternate layers of TiO2 and SiGe films, using sputtering technique. A direct-current magnetron transmission electron microscopy and grazing incidence spectroscopy was used to analyze the morphology of the structure. Photoconductive properties were studied by measuring photocurrent spectra at different applied voltages and temperatures. Tristack layers were obtained with 5-10 nm SiGe nanocrystals (NCs) by annealing at 600 °C for 5 min. No sign of SiO2 formation was found inside stacked layers. A maximum in the photocurrent spectra was observed at 994 nm at 300 K but it red-shifted gradually to 1045 nm with decrease in temperature to 100 K. This transition in peak maxima is attributed to SiGe NCs, due to lattice vibration and to contribution of non-radiative recombination at low temperatures.
关键词： TiO2,magnetron sputtering,nanocrystals,photoconductivity,SiGe,annealing
更新于2025-09-23 15:22:29
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Shallow and deep trap levels in X-ray irradiated β-Ga2O3: Mg
摘要： The results of the investigation of thermostimulated luminescence (TSL) and photoconductivity (PC) of the X-ray irradiated undoped and Mg2+ doped β-Ga2O3 single crystals are presented. Three low-temperature peaks at 116 K, 147 K and 165 K are observed on the TSL glow curves of undoped crystals. The high-temperature TSL peaks at 354 K and 385 K are dominant in Mg2+ doped crystals. The correlation between doping with Mg2+ ions and the local energy levels of the intrinsic structural defects of β-Ga2O3, which are responsible for the TSL peaks and PC, is established. The nature of TSL peaks and the appropriate photoconductivity excitation bands are discussed.
关键词： Photoconductivity,β-Ga2O3,Single crystal,Activation energy,Trap levels,Thermostimulated luminescence
更新于2025-09-23 15:22:29
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: A first-principles study
摘要： For environmental reasons there is a need for alternative Cd-free buffer materials in Cu(In,Ga)(S,Se)2 (CIGSSe) based thin film solar cells. In this context, β-In2S3 is one candidate material, whose optoelectronic properties can be affected by the presence of impurities. In this study, we investigate the impact of O and Cl impurities on the electronic and optical behavior of β-In2S3 by means of electronic structure calculations within density functional theory using hybrid functionals. We find that β-In2S3 is thermodynamically stable being in contact with both O and Cl reservoirs. Furthermore, we present evidence that O on interstitial sites (Oi) and Cl on 8c In sites (ClIn) cause low-temperature persistent electron photoconductivity. At room temperature, defect levels associated with Cl on S sites (ClS, ClS(cid:2) , and ClS(cid:2)(cid:2) ) get thermally ionized and release free electrons into the system. Thus, the n-type conductivity of the In2S3 buffer layer increases. O impurities on S sites, in contrast, are electrically inert. Hence, we conclude that intentional doping by Cl is a means to improve the properties of β-In2S3 serving as buffer material.
关键词： β-In2S3,hybrid functionals,O and Cl impurities,n-type conductivity,density functional theory,persistent electron photoconductivity,electronic structure calculations
更新于2025-09-23 15:21:21
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Sub-50 picosecond to microsecond carrier transport dynamics in pentacene thin films
摘要： Carrier transport dynamics from sub-50 ps to (cid:2)ls over five temporal decades in pentacene films was studied by transient photoconductivity. The behavior of the temperature independent photocurrent peak suggests that the photogenerated carriers exhibit pre-trapping transport in extended states upon pulsed laser excitation. From 300 ps to (cid:2)30 ns, the carriers thermalize and fall into shallow band tail states, and multiple-trapping and release transport dominates. From (cid:2)30 ns to (cid:2)ls, the weak temperature dependence of power-law photocurrent decay and the linear relation of logarithmic photocurrent with T(cid:3)1/4 suggest a variable range hopping transport in deep trap states.
关键词： transient photoconductivity,carrier transport dynamics,pentacene thin films,multiple-trapping and release transport,variable range hopping transport
更新于2025-09-23 15:21:21