Studies on vacuum evaporated PbS1−xSex thin films

Abstract The narrow gap IV–VI semiconductors have been the subject of extensive research owing to their technological importance. The fabrication of devices with alloys of these compounds with detecting and lasing capabilities has been an important recent technological development. The high quality polycrystalline thin films of PbS1−xSex with variable composition (0⩽x⩽1) have been deposited onto ultra clean glass substrates by vacuum evaporation technique. Asdeposited films were annealed in vacuum at 350 K. Structural, electrical and optical properties of PbS1−xSex thin films have been examined. The X-ray diffraction patterns were used to determine the sample quality, crystal structure and lattice parameter of the films. The dc conductivity and activation energy of the films were measured in the temperature range 300–380 K. The absorption coefficient and band gap of the films were determined by absorbance measurements in wavelength range 2500–5000 nm using FTIR spectrophotometer.