Energy Levels of Direct Excitons in Semiconductors with Degenerate Bands

Abstract

A new method to investigate the direct-exciton spectrum in semiconductors with degenerate bands is described. This method, which sloves the effective-mass Hamiltonian using symmetry arguments and second-order perturbation theory, gives a general and accurate description of exciton states in semiconductors. Direct excitons in group-IV elements, III-V compounds, and II-VI compounds are investigated. For Ge and GaAs, the binding energy is in excellent agreement with previous calculations. For all other substances, our treatment represents the first theoretical investigation. The results are in satisfactory agreement with available experimental data.