Chemical bath deposition of nanocrystaline CdS and CdPbS layers and investigation of their photoconductivity

Abstract

ABSTRACTThe investigation of photoconductive properties of chemical bath deposited (CBD) cadmium sulphide (CdS) layers was the main objective of this work. For completeness, the CdS layers were characterized using X-ray diffraction, scanning electron microscopy, optical absorption, DC electrical conductivity, photoconductivity measurements. It has been found that the CdS layers grown are hexagonal with (002) preferential orientation. The n-type CdS materials show 100–200 nm clusters consisting of 10–20 nm size crystallites. The optical band gap is 2.42-2.52 eV, which shows a red-shift to 2.34 eV upon heat treatment. The effect of Cu doping and co-deposition of CdS with PbS were also investigated. Dark conductivity was increased after heat treatment of pure CdS layers, and decreased in case of Cu doped samples. Photoconductive response time of Cu doped CdS and Cd(Pb)S samples were smaller than the response time of pure CdS samples.