Role of substitution of sulfur atoms by oxygen atoms on optical characteristics of lead sulfide semiconductor

Abstract

PbS1–xOx (x = 0, 0.05, 0.1, 0.15, 0.2) samples were prepared using the solid-state reaction method at low temperature. Rietveld refinement was performed, and the obtained structural and microstructural parameters for all PbS1–xOx samples. The occupancy of diffused oxygen ions at Wyckoff position 4b (½½½) is increased on the expense of sulfur, which is consistent with the results obtained by the energy-dispersive X-ray spectroscopy (EDS) analysis. The samples surface morphology of the prepared samples was probed by field emission scanning electron microscopy (FESEM) images. Fourier-transform infrared spectroscopy (FTIR) spectra were measured for the sample to examine the chemical composition and find out the effect of decreasing sulfur (x). The effect of sulfur deficiency in PbS1–xOx system on the linear and nonlinear optical parameters was explored using the UV diffused reflectance technique. The refractive index of each sample exhibited a normal dispersion. The values of Eg for PbS1–xOx samples (x = 0, 0.05, 0.1, 0.15, 0.2) are 0.84, 0.79, 0.83, 0.81 and 0.72 eV, respectively. The photoluminescence excitation and emission spectra for all samples were measured. The origin of different emitted colors was also studied.