Thin films of CuxZn1−xS nanocomposite with varying copper content (x = 0.3, 0.5, and 0.7) were successfully synthesized by the pulsed laser deposition (PLD) technique from their fabricated powders by the precipitation method for optoelectronic applications. The impact of Cu content on the film’s structural, morphological, optical, and electrical characteristics was investigated. Elemental composition analyses indicated that thin CZS films consisted only of their constituent elements and were free of any noted impurities. XRD patterns demonstrated that all as-grown thin films were polycrystalline in nature and adopted various planes and phases of CuS and ZnS binary compounds. Increasing the Cu content caused a more pronounced CuS phase while, at the same time, suppressing the ZnS phase. This alteration also resulted in an increase in crystallite size and a decrease in crystal defects. AFM images showed that Cu content had a significant effect on the surface topography of the films. Optical results pointed to a red shift at the film absorption edge, indicating a drop in the direct energy band gap with the rise in Cu content. The optical constants, such as the extinction coefficient, dielectric constant, and refractive index, were also determined. Hall effect measurements suggested that increasing the Cu content in the as-deposited thin films resulted in enhanced electrical conductivity and hole concentration. The electrical characteristics of fabricated Al/p-CZS/n-Si/Al heterostructures (HSs) showed photosensing properties. The photosensing parameters, such as photosensitivity, photoresponsivity, and resistance-based sensitivity, were calculated as a function of Cu content under an illumination of 40 mW/cm2. CZS-based photosensor with heterojunction (HJ) interface exhibited a maximum photosensitivity of 6.6 at a reverse bias of 0.75 V.
Mohammed et al. (2026) studied this question.