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Papers by vasudeva reddy
Conference Papers in Energy, 2013
Indium sulphide (In2S3) is one of the best alternatives for CdS as a buffer layer in CuInGaSe2-ba... more Indium sulphide (In2S3) is one of the best alternatives for CdS as a buffer layer in CuInGaSe2-based thin film heterojunction solar cells. In this work, In2S3 films were prepared by thermal evaporation of In2S3 powder onto glass substrates at different temperatures that vary from 200°C to 300°C. The as-grown films were characterized using appropriate techniques to evaluate the chemical and physical properties. The X-ray diffraction analysis revealed that all the films were polycrystalline in nature with a strong (109) plane as the preferred orientation and consisted of tetragonal and cubic phases. The crystallite size and the lattice parameters are calculated. The scanning electron micrographs indicated smooth surface with fine grains. The optical analysis revealed a high optical transmittance for the layers with a direct optical band gap that varied in the range of 1.8–2.2 eV.
Applied Surface Science
Abstract SnS thin films were prepared by chemical bath deposition using an environmentally friend... more Abstract SnS thin films were prepared by chemical bath deposition using an environmentally friendly and economic complexing agent, tartaric acid (C4H6O6) with different concentrations. X-ray diffraction analysis confirmed that all the deposited films exhibited polycrystalline nature with a predominant plane of (1 1 1) related to an orthorhombic structure. The intensity of the (1 1 1) plane increased with increasing concentration of the complexing agent. Raman spectra of the films showed the characteristic vibrational modes at 94, 160, 191, and 217 cm−1, corresponding to orthorhombic SnS. SEM micrographs showed homogeneous surfaces with the presence of nut-shaped grains. The optical absorption coefficient for the prepared films was >104 cm−1, representing that the deposited films showed high absorption. Electrical studies revealed the p-type conducting nature of the deposited films. The SnS solar cell fabricated with a tartaric acid concentration of 1.2 M showed the highest efficiency of 1.62% with an open-circuit voltage of 0.283 V, a short-circuit current density of 13.9 mA cm−2, and a fill factor of 41.1%.
Atmospheric Environment, 2016
International Journal of Optoelectronic Engineering, 2012
In recent years, zinc cadmium sulphide (Zn x Cd 1-x S) alloy compounds have paid much attention i... more In recent years, zinc cadmium sulphide (Zn x Cd 1-x S) alloy compounds have paid much attention in the fields of opto-electronics, particularly in photovoltaic devices because of its tunable energy gap and the lattice parameters. The energy band gap of Zn x Cd 1-x S is controlled by the change of Zn-composition in order to suit the material properties with that of absorber material in solar cells. In this paper, we report on the effect of Zn-composition on physical properties of Zn x Cd 1-x S thin films deposited on corning glass substrates by solution growth method. The layers were prepared for different 'x' values that vary in the range, 0-1.0 at. %. The as-grown layers were characterized using EDAX, XRD, SEM, and UV-Vis-NIR spectrophotometers. All the layers showed a strong (002) plane as the preferred orientation that exhibited the hexagonal crystal structure. The composition of the layers agrees approximately with that of the elements in the solution. The films showed an average optical transmittance of 72 % at a zinc composition of 0.75 with a band gap of 3.88 eV.
Conference Papers in Energy, 2013
Indium sulphide (In2S3) is one of the best alternatives for CdS as a buffer layer in CuInGaSe2-ba... more Indium sulphide (In2S3) is one of the best alternatives for CdS as a buffer layer in CuInGaSe2-based thin film heterojunction solar cells. In this work, In2S3 films were prepared by thermal evaporation of In2S3 powder onto glass substrates at different temperatures that vary from 200°C to 300°C. The as-grown films were characterized using appropriate techniques to evaluate the chemical and physical properties. The X-ray diffraction analysis revealed that all the films were polycrystalline in nature with a strong (109) plane as the preferred orientation and consisted of tetragonal and cubic phases. The crystallite size and the lattice parameters are calculated. The scanning electron micrographs indicated smooth surface with fine grains. The optical analysis revealed a high optical transmittance for the layers with a direct optical band gap that varied in the range of 1.8–2.2 eV.
Applied Surface Science
Abstract SnS thin films were prepared by chemical bath deposition using an environmentally friend... more Abstract SnS thin films were prepared by chemical bath deposition using an environmentally friendly and economic complexing agent, tartaric acid (C4H6O6) with different concentrations. X-ray diffraction analysis confirmed that all the deposited films exhibited polycrystalline nature with a predominant plane of (1 1 1) related to an orthorhombic structure. The intensity of the (1 1 1) plane increased with increasing concentration of the complexing agent. Raman spectra of the films showed the characteristic vibrational modes at 94, 160, 191, and 217 cm−1, corresponding to orthorhombic SnS. SEM micrographs showed homogeneous surfaces with the presence of nut-shaped grains. The optical absorption coefficient for the prepared films was >104 cm−1, representing that the deposited films showed high absorption. Electrical studies revealed the p-type conducting nature of the deposited films. The SnS solar cell fabricated with a tartaric acid concentration of 1.2 M showed the highest efficiency of 1.62% with an open-circuit voltage of 0.283 V, a short-circuit current density of 13.9 mA cm−2, and a fill factor of 41.1%.
Atmospheric Environment, 2016
International Journal of Optoelectronic Engineering, 2012
In recent years, zinc cadmium sulphide (Zn x Cd 1-x S) alloy compounds have paid much attention i... more In recent years, zinc cadmium sulphide (Zn x Cd 1-x S) alloy compounds have paid much attention in the fields of opto-electronics, particularly in photovoltaic devices because of its tunable energy gap and the lattice parameters. The energy band gap of Zn x Cd 1-x S is controlled by the change of Zn-composition in order to suit the material properties with that of absorber material in solar cells. In this paper, we report on the effect of Zn-composition on physical properties of Zn x Cd 1-x S thin films deposited on corning glass substrates by solution growth method. The layers were prepared for different 'x' values that vary in the range, 0-1.0 at. %. The as-grown layers were characterized using EDAX, XRD, SEM, and UV-Vis-NIR spectrophotometers. All the layers showed a strong (002) plane as the preferred orientation that exhibited the hexagonal crystal structure. The composition of the layers agrees approximately with that of the elements in the solution. The films showed an average optical transmittance of 72 % at a zinc composition of 0.75 with a band gap of 3.88 eV.