A new method is described for calculation of the real and imaginary parts of the dielectric function of semiconductors at energies below and above the lowest band gaps, in which the model is based on the Kramers-Kronig transformation and strongly connected with the electronic energy-band structures of the medium. This model reveals distinct structures at energies of the $E_0$, $E_0$+${\Delta }_0$, $E_1$, $E_1$+${\Delta }_1$, and $E_2$ critical points. Analyses are presented for GaP, GaAs, GaSb, InP, InAs, and InSb, and results are in satisfactory agreement with the experimental information over the entire range of energies. The model is able to properly give the optical constants, such as the refractive indices and the absorption coefficients, which are important for a variety of optoelectronic device applications.

• Received 10 November 1986

DOI:https://doi.org/10.1103/PhysRevB.35.7454