Film growth mechanism for electrodeposited copper indium selenide compounds

The Cu2Se–In2Se3 system comprises several copper indium selenide (CIS) compounds with solar-matched bandgaps along with the optimum properties of the CuInSe2 compound. This work investigates electrochemical growth of CIS films under various conditions, initially identified with cyclic voltammetry. The film growth, monitored with X-ray fluorescence analysis, shows excellent composition and thickness uniformity. The results agree with secondary ion mass spectroscopy profiles and X-ray diffraction data, indicating the conversion of initially formed binary phases to homogenous ternary compound. Deposition potential and substrate/electrolyte interface control the film formation mechanism and hence its composition. Electrolyte composition and agitation influence the film thickness. Judicious combination of process parameters is essential to obtain CIS films with optimum properties.

► In-rich copper indium selenide (CIS) compounds offer wide bandgaps.
► Electrodeposition leads to excellent composition and thickness uniformity.
► Initial binary phases convert to homogenous ternary compound.
► Thermodynamic driving force leads to self stabilizing stoichiometries.
► Process parameter control enables optimizing CIS film properties.