Abstract: High quality Pb_1-xSr_xSe (0≤ x≤0.050) thin films were grown on BaF₂(111) substrates by using molecular beam epitaxy(MBE). Optical and structural properties of the Pb_1-xSr_xSe films were studied using transmission spectrum and high resolution X-ray diffraction (HRXRD). HRXRD patterns indicate that Pb_1-xSr_xSe films has cubic-phase structure, with no SrSe phase separation.
The films orientation is parallel to (111) surface of substrate. The lattice constants of the Pb_1-xSr_xSe films increase with increasing Sr content. The Sr content can be obtained by using Vegard formula. Sharp absorption edges are observed in the transmission spectrum of Pb_1-xSr_xSe films. The fundamental band gap of the Pb_1-xSr_xSe films is attained by simulation. Refractive indexes and absorption coefficients near the fundamental band-gap are obtained by simulation using dielectric function model(DFM).

Key words: Pb_1-xSr_xSe epitaxial films, transmission spectrum, refractive index, absorption coefficient