Modeling the optical properties of AlSb, GaSb, and InSb

Optical constants of AlSb, GaSb, and InSb are modeled in the 1-6 eV spectra l range. We employ an extension of Adachi's model of the optical constants of semiconductors. The model takes into account transitions at E-0, E-0 + D elta(0), E-1, and E-1 + Delta(1) critical points, as well as higher-lying t ransitions which are modeled with three damped harmonic oscillators. We do not consider indirect transitions contribution, since it represents a secon d-order perturbation and its strength should be low. Also, we do not take i nto account excitonic effects at E-1, E-1 + Delta(1) critical points, since we model the room temperature data. In spite of fewer contributions to the dielectric function compared to previous calculations involving Adachi's m odel, our calculations show significantly improved agreement with the exper imental data. This is due to the two main distinguishing features of calcul ations presented here: use of adjustable line broadening instead of the con ventional Lorentzian one, and employment of a global optimization routine f or model parameter determination.