Electronic and optical properties of perfect and imperfect 2 to 6 superlattices

The calculation of the electronic and optical properties of mercury telluride-cadmium telluride, HgTe-CdTe, superlattices are presented. An empirical pseudopotential method is employed, which fully accounts for the (large differences in) microscopic potentials and relativistic corrections. We consider superlattices in which the interfaces between the constituent materials are spatially abrupt, the model usually invoked in the literature. We also consider the effect of superlattices with microscopically imperfect interface geometry. These are the first calculations in which such a realistic model is considered. The effect of removing this bulk like translational symmetry at the interfaces is investigated and new states localized at the interfaces are discussed. Experimental data are discussed (transport and photoluminescence results) which may provide evidence for the results found by our calculations. The possibilities and scope of structures available via band structure engineering with II-VI materials is considered. Calculations performed on mercury telluride-zinc cadmium telluride, HgTe-ZnCdTe structures are presented which are examples of how the HgTe-CdTe structures may be engineered. The structures discussed are compared to the equivalent HgTe-CdTe structures. The design of a superlattice comprising of HgCdTe-CdTe is discussed in the context of the enhancement of optical non-linearities. How the HgTe-CdTe superlattice may be tailored to suite the requirements of the mechanism to provide such enhancements is shown.