Growth and characterization of semiconducting Pb1−xMgxS thin films prepared by hot-wall epitaxy

We have investigated the fabrication of Pb 1− x Mg x S thin films on BaF 2 substrates by using hot-wall epitaxy. Mg concentration x and its deviations from stoichiometry in the Pb 1 −x Mg x S thin films were controlled by monitoring the growth conditions. We found a widened solubility range of Mg in the Pb 1 −x Mg x S thin film as compared to the same range obtained for bulk growth. The values of the energy band gap of the films increased with increasing x . The relation between the energy band gap E g and the composition x of the Pb 1 −x Mg x S thin films follows the expression E g =0.417+1.111 x −0.861 x 2 ( x ⩽0.12). The information obtained here will be useful for future preparation of Pb 1− x Mg x S 1− y Se y or Pb 1− x (Mg 1− y Sr y ) x S quaternary films for fabrication of mid-infrared lasers.