Effect of Long Selenization Time on Co Films under a Low Temperature of 300 °C to Synthesize a Nanostructure CoSe2 and Optical Properties

This work investigates a simple and non-toxic method to transform pre-deposited amorphous Co film into CoSe2 films at a fixed, low temperature of 300 °C. Single CoSe2-phase films having good crystallinity were obtained at a selenisation time 24 hours. A nanostructure CoSe2 having two different nano-morphological layers was observed. The CoSe2 films (72 hours) observed a large absorption and a direct band gap.