Hydrothermal-electrochemical deposition of semiconductor thin films: the case of CuIn(Al)Se_2 compound

摘要

Electrochemical deposition of CuIn(Al)Se_2 thin film from quaternary aqueous solution of Cu, In, Al and Se salts has been carried out at different temperatures (25, 55 and 80 ℃) and it was found that optical properties, crystallinity and phase purity of the as-deposited CuIn(Al) Se_2 films are enhanced at higher temperature. Consequently, electrodeposition of CuIn(Al)Se_2 under hydro-thermal condition at high temperature (120℃) and at different potentials is performed. The characterization of the obtained layers indicates that single phase chalcopyrite film could be deposited by synergism of the electrodeposition and hydrothermal methods at optimized deposition potential (—600 mV). Superior photoconductivity has also been observed in case of electrodeposited layer at 120℃ (hydrothermal condition). More interestingly, post annealing of CIAS thin film prepared by developed procedure at 200 ℃ (ambient atmosphere) results in dense microcrystal-line layer with a photoconductivity 300 times higher than the sample deposited at room temperature.