Effect of Duty Cycle on Pulse Electrodeposited Tin Seleno Telluride Semiconductor Thin Film

摘要

Tin seleno telluride thin film was deposited by pulse electrodeposition onto fluorine doped tin oxide coated glass from aqueous solution containing Sn-EDTA, Na_2SeO_3 and TeO_2. The sample was deposited at a potential of -0.40 V vs Ag/AgCl with various duty cycle between 10% to 90% followed by annealing under nitrogen gas at 250°C for 30 minutes. The crystalline structure, morphology and photoresponse of the thin film were analyzed using X-ray diffraction (XRD), scanning electron microscopy and linear sweep photovoltammetry techniques. The XRD pattern shows polycrystalline cubic structure of SnSe_(0.4)Te_(0.6) for film deposited at 50% duty cycle. The domain peak at 2θ=28.82° shows a high intensity and a better photoresponse due to the small crystalline size and better crystallinity. The tin seleno telluride thin film reflects the loose short rod type aggregates at 10% -50% duty cycle and dendritic structure was formed at deposition of 75% and above. The deposited tin seleno telluride is a p-type semicoductor and the band gap was found to be 1.60 eV with direct transition.