Paper Contents
Abstract
Abstract- Cadmium sulfide thin films have been synthesized by spray pyrolysis method on glass substrates. The synthesized thin films are characterized by different characterization techniques such as XRD, SEM, EDAX and UV-Vis-IR spectroscopy. The XRD analysis shows that films are polycrystalline in nature with hexagonal structure and no preferential orientation. The XRD analysis confirms grain sizes close to nano regime. Surface morphology of samples is studied by SEM which also shows grain sizes around 150 nm. Compositional analysis from EDAX data shows that the films synthesized have slight deviation from stoichiometry and are cadmium rich. Optical studies revealed the direct band gap nature of CdS. It has 2.4 eV band gap value. CdS is one of the important semiconducting materials used in hetero-junction thin film solar cells such as CdSCdTe, CdSCuInSe2, CdSCuInGaS2. Keywords- CdS thin films, XRD, SEM, EDAX and UV Vis-IR spectroscopy. 1. Introduction- Extensively studied and technologically incorporated Cadmuim Sulfide (CdS), is an important semiconductor material used in polycrystalline thin film solar cells. The n-type semiconducting nature and wide band gap has made it the common window layer in many hetero-junction solar cells such as CdSCdTe, CdSCuInSe2, CdSCuInAlSe2 (CIAS), CdSCuInGaSe2 (CIGSe), CdSCuInGaS2 (CIGS), CdSCu2ZnSnS4. 1 Among these CIGS and CdTe based modules are in production lines by companies like First Solar, Global Solar, Shell Solar etc. 1 . This material has direct band gap with value of 2.4 eV and excellent stability in electrolytes. CdS has attracted as an electrode to be used in Photo-Electrochemical solar cells (PEC)-the next generation solar cells mimicked from dye sensitized solar cells (DSSC). CdS thin films are prepared by many deposition techniques such as Chemical Bath Deposition (CBD), Electro-deposition, Sputtering and Spray pyrolysis etc. 2-5. Among these different methods, spray pyrolysis is a simple and inexpensive technique with easy doping. Although CBD is used in thin film PV industry, reports on CBD showed secondary phases such as Cd(OH)2 and CdO which results into deterioration.1, 6-8. CdS films deposited by spray pyrolysis method do not show such phases but they do exhibit non stoichiometry with either cubic or hexagonal or mixed structures.9 This work reports the synthesis of CdS thin films by spray pyrolysis method and the results obtained from structural, morphological, compositional and optical characterizations have been discussed.
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Copyright © 2023 Mr.INGALE V D. This is an open access article distributed under the Creative Commons Attribution License.
