Optical properties of imperfect strained-layer InAs/Ga1-xInxSb/AlSb superlattices with infrared applications

We present a microscopic model of the optical properties of several strained-layer InAs/GaSb-based superlattice structures with infrared optoelectronic applications. The requirements, both in technologically motivated and basic physics, for improvements in the theory of the optical properties of disordered, strained-layer systems are identified. Both disordered and perfect structures are modeled, and we analyze in detail their optical spectra, identifying the role played by wave-function confinement in determining spectral features. For those structures with laser applications, we study in detail the effect of ahoy layer disorder on emission line shape at various population inversions. We find that there is a significant change in the linewidth as a result of alloy layer disorder. The optical absorption of a photodetector structure is modeled, and we appraise the potentially degrading effects of Anger recombination processes on its operation. We find good agreement between our predictions and experimental results. This paper presents a set of results in an ongoing research program in which we aim to gain a quantititative understanding of the relationship between microscopic disorder and strain and the optical properties of semiconductor heterostructures.