Features of photoconductivity and luminescence of CdS thin films and Cd$_{1-x}$Zn$_x$S solid solutions under laser excitation

The features of photoconductivity and luminescence of CdS thin films and Cd$_{1-x}$Zn$_x$S solid solutions obtained by chemical pulverization with subsequent pyrolysis under laser excitation have been studied experimentally. Pulsed liquid (473–547 nm) and nitrogen (337 nm) lasers were used as a radiation source. An experimental study was made of the photoconductivity and photoluminescence spectra of Cd$_{1-x}$Zn$_x$S thin films depending on the composition $x$ at different excitation intensities and the relaxation curves of nonequilibrium photoconductivity. It is shown that the observed features in the photoconductivity and photoluminescence spectra of Cd$_{1-x}$Zn$_x$S thin films are due to direct band-to-band transitions. Amplification of light is observed at high intensities of optical excitation in thin CdS films.