Investigation on copper doped CdSe thin films for photodetector applications

Abstract

Cu doped CdSe thin films of thickness 300 ± 20 nm were grown on glass substrates by thermal co-evaporation technique with high purity CdSe and Cu2Se powders as source materials. Different spectroscopic analysis technique was adopted to study the impact of Cu incorporation on the properties of the CdSe films. As Cu concentrations increased in the system, XRD peak position and optical absorption edge have shifted systematically. The formation of Cu acceptor levels and occurrence of radiative transitions from defect levels to valence band were confirmed by photoluminescence. The chemical state and crystal phase of deposited films were investigated by Raman analysis. XPS spectra showed a minor quantity of oxygen present in the doped films. Hall measurement revealed that Cu dopant altered the majority carrier type from n to p. The prepared films are photosensitive materials, and sample with 15 at% Cu showed good photoresponse and is suitable for photodetector applications.