Cyclic Voltammetry Investigation of the Mechanism of CuInSe_2 and CuIn(Al)Se_2 Electrodeposition from Aqueous Solution

Electrodeposition of CuInSe_2 (CIS) and CuInAlSe_2 (CIAS) from aqueous solution is systematically investigated by cyclic voltammetry implemented at different scan rates. It is shown that electrodeposited CIS and CIAS layers are formed on the substrate through electrochemical- chemical interactions of the reduced species on the substrate. The results confirm that the induced electrodeposition is the main mechanism of incorporating Aluminum and Indium in the deposited layer. Effect of electrodeposition potential on composition of the prepared film is also studied which confirms that at potential of -0.7 V, composition close to CIAS solar cells desired stoichiometry is obtained. X-ray Diffraction Analysis (XRD) also indicates that in potential range of -0.7-0.8 V almost the single phase of chalcopyrite is deposited while additional binary selenide phases are formed at more positive potentials and the metallic indium phase is formed at negative potentials.