Effect of CdCl2 on the photoconductivity of chemically deposited neodymium doped (Cd–Pb)S films

Abstract Effect of CdCl2 on photoconductivity rise and decay, photoconductivity excitation spectra and optical absorption spectra, XRD and SEM studies are presented for different (Cd–Pb)S films. The ratio of photocurrent to dark current (IPC/IDC) of the order of 105 is observed for (Cd0.95–Pb0.05)S films. This value of IPC/IDC improves to 106 for the systems prepared with CdCl2 and to 107 when neodymium nitrate is added. Values of trap depth E, lifetime τ and mobility μ are evaluated from photoconductivity decay. Band gaps are determined from two spectra. Effect of temperature and excitation intensity of radiation are included. SEM studies show cabbage type structure. Diffraction lines in XRD studies are associated to CdS and PbS.