Role of deposition time on structural, optical and electrical properties of In-rich Cu–In–S spinel films grown by electrodeposition technique

Abstract

CuIn5S8 spinel films were grown at different deposition times onto (ITO)-coated glass substrates using a one-step electrodeposition route of In-rich Cu–In–S system. A contribution to the knowledge of thickness (or deposition time) dependence of structural, morphological, optical, and electrical properties of CuIn5S8 thin film is reported. According to these studies, when the deposition time is extended beyond 10min, X-ray diffraction pattern has indicated a growth mode along the (311) plane which is consistent with the CuIn5S8 cubic spinel structure. XRD peaks broaden and shift depending on film thicknesses which are presumably due to strain and size effect. From AFM analysis, nucleus density, size, roughness, as well as film thickness have increased with increasing deposition time from 1 to 30min. Through optical measurements, both values of transmittance and band gap have decreased respectively from approximately (∼77%) to (∼40%) and from 2.75eV to 1.53eV with the increase of deposition time. The film deposited at 15min shows a minimum electrical resistivity of about 3.12×10−3Ωcm. It is also reported that by controlling the electrodeposition time, n-type or p-type conductivity of CuIn5S8 could be adjusted.