Composition Tuning of Single Step Electrodeposited CuInSe2 Thin Films Using Sodium Dodecyl Sulfate as Additive

Abstract

CuInSe2 (CISe) thin films were electrodeposited on FTO substrates by single step deposition technique from an aqueous solution containing CuCl2, InCl3, HSeO3− ions and citric acid-sodium dodecyl sulfate (SDS) as the pH adjuster and additive, respectively. The effect of SDS concentration on the structural, composition, morphology and photo-electrochemical properties was characterized by SEM/EDAX, XRD, Raman and electrochemical (PEC) studies. The linear sweep voltammetry (LSV) and electrochemical impedance (EIS) results revealed that the addition of SDS limits the Cu-Se incubation time and enhances the diffusion controlled process which is considered to be the origin of the compositional and morphological tuning nature of the SDS in CISe deposition. The structural, compositional and PEC analysis revealed that for SDS concentration less the critical micelle concentration has almost no effect in controlling the Cu2Se secondary phase. The samples deposited in the presence of SDS (> 8 mM) exhibited better PEC properties due to the reduced Cu2Se phase. Further, the Mott–Schottky analysis of all the as-deposited thin films exhibited p-type conductivity.