Band gaps, effective masses and refractive indices of PbSrSe thin films: Key properties for mid-infrared optoelectronic device applications

Abstract

Key properties of PbSrSe thin films grown by molecular beam epitaxy have been studied for mid-infrared optoelectronic device applications. Detailed knowledge of the material parameters for the device design is required. The material parameters considered are: temperature-dependent band gaps, composition (or band gap)-dependent effective masses, and energy-dependent refractive indices. The study has been carried out by a combination of temperature-dependent photoluminescence and absorption measurements with the theoretical models on PbSrSe thin films of Sr compositions of as high as 0.276. The derived empirical equations for band gaps, effective masses, and refractive indices have been employed successfully in PbSe/Pb0.934Sr0.066Se multiple quantum well mid-infrared laser systems, for studying the band offsets and subband behavior. We have shown that the derived material parameters clearly promise of being applied to other PbSrSe thin films and PbSe/PbSrSe heterostructure systems for their optoelectronic applications.