Luminescence properties of Cd$_{x}$Zn$_{1-x}$O thin films

Thin Cd$_{x}$Zn$_{1-x}$O films with a Cd content in the range from zero to 35 at % are synthesized by pulsed laser deposition. A record-breaking solubility limit of 30 at % of Cd in wurtzite-structured Cd$_{x}$Zn$_{1-x}$O thin films is attained. Apart from the exciton peak, additional peaks associated with an inhomogeneous distribution of Cd in the samples are observed in the low-temperature (10 K) photoluminescence spectra of Cd$_{0.15}$Zn$_{0.85}$O and Cd$_{0.3}$Zn$_{0.7}$O films. An unsteady ($S$-like) temperature dependence of the spectral position of the exciton photoluminescence peak in Cd$_{x}$Zn$_{1-x}$O films is observed. Such a dependence is associated with the effect of the localization of charge carriers.