Entity

Time filter

Source Type


Yadav A.A.,Thin Film Physics Laboratory
Journal of Alloys and Compounds | Year: 2012

Undoped and Fe doped CdSe thin films have been deposited onto the amorphous and fluorine doped tin oxide coated glass substrates by spray pyrolysis. The Fe doping concentration has been optimized by photoelectrochemical (PEC) characterization technique. The structural, surface morphological, compositional, optical and electrical properties of undoped and Fe doped CdSe thin films have been studied. X-ray diffraction study reveals that the as deposited CdSe films possess hexagonal crystal structure with preferential orientation along (1 0 0) plane. AFM analysis shows uniform deposition of the film over the entire substrate surface with minimum surface roughness of 7.90 nm. Direct allowed type of transition with band gap decreasing from 1.74 to 1.65 eV with Fe doping has been observed. The activation energy of the films has been found to be in the range of 0.14-0.19 eV at low temperature and 0.27-0.44 eV at high temperature. Semi-conducting behavior has been observed from resistivity measurements. The thermoelectric power measurements reveal that the films are of n type. © 2012 Elsevier B.V. All rights reserved.


Yadav A.A.,Thin Film Physics Laboratory
Journal of Materials Science: Materials in Electronics | Year: 2014

Thin films of copper selenide were deposited onto amorphous glass substrates at various substrate temperatures by computerized spray pyrolysis technique. The as deposited copper selenide thin films were used to study a wide range of characteristics including structural, surface morphological, optical and electrical, Hall Effect and thermo-electrical properties. X-ray diffraction study reveals that the films are polycrystalline in nature with hexagonal (mineral klockmannite) crystal structure irrespective of the substrate temperature. The crystalline size is found to be in the range of 23-28 nm. The SEM study reveals that the grains are uniform with uneven spherically shaped and spread over the entire surface of the substrates. EDAX analysis confirmed the nearly stoichiometric deposition of the film at 350 C. The direct band gap values are found to be in the range 2.29-2.36 eV depending on the substrate temperature. The Hall Effect study reveals that the films exhibit p-type conductivity. The values of carrier concentration and mobility for the film are found to be 5.02 × 1017 cm-3 and 5.19 × 10-3 cm2 V-1 s-1; respectively for film deposited at 350 C. © 2014 Springer Science+Business Media New York.


Yadav A.A.,Thin Film Physics Laboratory
Journal of Materials Science: Materials in Electronics | Year: 2014

Thin films of copper selenide have been deposited by spraying a mixture of aqueous solutions (0.50 M) of copper chloride hydrate (CuCl2· 2H2O) and selenourea [H2NC(Se)NH2] on preheated fluorine doped tin oxide coated glass substrates at various substrate temperatures. The cell configurations copper selenide/0.5 M K2SO 4/C are used for studying the capacitance-voltage (C-V) characteristics in the dark, current-voltage (I-V) characteristics in dark and under illumination, photovoltaic power output and spectral response characteristics of the as deposited films. Photoelectrochemical study records that as deposited copper selenide thin films are of p-type. The spectral response characteristics of the films at room temperature show a prominent, sharp peak at 550 nm. The measured values of efficiency (η) and fill factor (FF) are found to be 0.99 % and 0.51 respectively for film deposited at 350 °C. © 2014 Springer Science+Business Media New York.


Yadav A.A.,Thin Film Physics Laboratory | Masumdar E.U.,Thin Film Physics Laboratory
Electrochimica Acta | Year: 2011

Polycrystalline undoped and indium-doped CdS 0.2Se 0.8 thin films were deposited on FTO-coated glass substrates by spray pyrolysis. The cell configurations CdS 0.2Se 0.8/1 M (Na 2S + S + NaOH)/C and In:CdS 0.2Se 0.8/1 M (Na 2S + S + NaOH)/C were used to study a wide range of photoelectrochemical characteristics including capacitance-voltage in the dark, current-voltage characteristics in the dark and under illumination, photovoltaic power output and spectral response and to perform electrochemical impedance spectroscopy studies. The study reveals that the films exhibit n-type conductivity. Various PEC parameters such as the junction ideality factor under illumination, series and shunt resistances, fill factor and efficiency have been estimated for the PEC cells formed with CdS 0.2Se 0.8 and indium-doped CdS 0.2Se 0.8 thin films. The efficiency and fill factor of these PEC cells are found to be improved from 0.79% and 0.46 to 2.12% and 0.49, respectively, with indium doping in CdS 0.2Se 0.8 thin films. Electrochemical impedance spectroscopy studies show that doping of indium into CdS 0.2Se 0.8 thin film improves the performance of resulting PEC cells. © 2011 Elsevier Ltd. All rights reserved.


Yadav A.A.,Thin Film Physics Laboratory
Journal of Alloys and Compounds | Year: 2013

The Fe-incorporated CdSe films are deposited on FTO-coated glass substrates by computerized spray pyrolysis technique. The Fe concentration is optimized by using photoelectrochemical (PEC) technique. The cell configurations CdSe/1 M (Na2S + S + NaOH)/C and Fe:CdSe/1 M (Na2S + S + NaOH)/C are used to study a wide range of photoelectrochemical characteristics including capacitance-voltage characteristics in dark, current-voltage characteristics in the dark and under illumination, photovoltaic power output and spectral response and to perform electrochemical impedance spectroscopy studies. The study reveals that the films exhibit n-type conductivity. Various parameters such as the junction ideality factor under illumination, series and shunt resistances, fill factor and efficiency are estimated for the PEC cell formed with CdSe and Fe-incorporated CdSe thin films. Band edges of Fe incorporated CdSe thin films are located. The best result obtained for conversion efficiency is 1.48% at 0.30 mol% Fe, which is three times more than the one reported for pure CdSe (0.50%) material. The value of fill factor is found to be improved from 0.44 to 0.63 with Fe incorporating in CdSe thin films. Electrochemical impedance spectroscopy studies show that incorporating of Fe into CdSe thin film improves the performance of resulting PEC cells. The utility of this work is in improving in efficiency of the PEC solar cell. © 2012 Elsevier B.V. All rights reserved.

Discover hidden collaborations