Development of CdSe thin films for application in electronic devices
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Thin films of cadmium selenide (CdSe) have been deposited on fluorine-doped tin oxide (FTO)-coated glass using potentiostatic electrodeposition method. The suitable range of deposition potentials for the formation of stoichiometric layer of CdSe was established using cyclic voltammograms. The films have been characterised using X-ray diffraction (XRD), Raman spectroscopy, optical absorption, scanning electron microscopy, atomic force microscopy and photo-electrochemical (PEC) cell techniques. XRD results show that the deposited films are polycrystalline in nature having hexagonal structure with preferred orientation along (002) plane. PEC study reveals that the films have n-type electrical conductivity. The optical bandgap of the film have been estimated to be 2.00 and 1.80 eV for as-deposited and heat-treated layers respectively when grown at a cathodic potential of 1,972 mV. The electronic quality of the electrodeposited CdSe layers was also tested using the device structure glass/FTO/n-CdSe/Au which produced Schottky diodes with rectification factor of 102.9, reverse saturation current of ~372 nA and threshold voltage of ~0.15 V. The potential barrier observed for Au/n-CdSe interface is >1.10 eV.
KeywordsSeO2 Thin Film Solar Cell Thin Film Material Cadmium Selenide CdSe Thin Film
The authors would like to acknowledge Stuart Creasey of MERI, Sheffield Hallam University, UK and Leon Bowen of Physics Department, Durham University, UK for carrying out SEM measurements. Margarita Dergecheva of Inst. of Organic Catalysis and Electrochemistry, Almaty, Kazakhstan is also thanked for carrying out AFM measurements. The contributions made by Paul Bingham, Fijay Fauzi, Hussein I. Salim, Azlian AbdulManaf and Mohammad Madugu are greatly appreciated. The principal author wishes to thank the Commonwealth Scholarship Commission and Sheffield Hallam University for financial support to undertake this research. The Federal University of Technology, Akure, Nigeria is also acknowledged for their support.