Electrodeposition of Cobalt Selenide Thin Films

Cobalt selenide thin films have been prepared onto tin oxide glass substrates by electrodeposition potentiostatically from an aqueous acid bath containing and at . The electrodeposition mechanism was investigated by cyclic voltammetry. The morphological, compositional, structural, and optical properties of the deposited films have been studied using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and optical absorption techniques, respectively. The formation of cobalt selenide was confirmed to proceed via an underpotential deposition mechanism. Se-rich CoSe thin films with compact and homogeneous morphology and hexagonal crystal structure were obtained at a deposition potential of −0.5 V vs saturated calomel electrode. The electrodeposited CoSe film exhibits an optical absorption coefficient of higher than and an optical bandgap of .