Microscopic theory of scattering in imperfect strained antimonide-based heterostructures

A microscopic theory to provide quantitative predictions of scattering cross sections and carrier lifetimes in imperfect strained layer superlattices is developed. Strain-dependent empirical pseudopotentials are formulated to obtain the electronic wave functions with the results of scattering theory employed to extract the dynamical information. The theory is applied to a number of imperfect ${\mathrm{Ga}}_x{\mathrm{In}}_{1-x}\mathrm{S}\mathrm{b}/\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}$ superlattices, containing isovalent substitutional anion defects, both isolated and in interface islands. Key factors governing the lifetime are identified, including defect atom type, location and lattice relaxation, and the detailed size and shape of the interface islands. Multiple scattering processes are shown to become significant for larger interface islands. Typical elastic scattering lifetimes for isolated antimony defects of $1.6\mu \mathrm{s}$ are predicted, dropping to 0.4 ns for islands containing approximately 50 defect ions.