TIGHT-BINDING STUDY OF OPTICAL-PROPERTIES IN SHORT-PERIOD IN0.53GA0.47AS INP SUPERLATTICES/

We present theoretical calculations of the imaginary part of the diele ctric function, epsilon(2)(omega), of In0.53Ga0.47As/InP superlattices (SL's). An empirical tight-binding (TB) description of electronic sta tes, including spin-orbit effects, is employed. We demonstrate that th e absorption spectra of the constituent bulk materials can be reproduc ed very well with an appropriate choice of values for optical matrix e lements between TB basis functions. These parameters then yield the ab sorption spectra of SL's. We have calculated epsilon(2)(omega) for ult rathin (In0.53Ga0.47As)(n)/(InP)(n) SL's with n=2 and 4. The computed epsilon(2) of SL's shows features similar to those found in the spectr a of bulk constituents with some discernible effects due to confinemen t and SL periodicity.