Model calculation of the optical properties of semiconductor quantum wells

A simple model system is solved exactly to gain insight on electron-hole interaction effects on the optical properties of semiconductor quantum wells and superlattices. An $N$-layer film of a simple cubic two-band semiconductor with a contact electron-hole interaction is considered, and the optical absorption function is calculated exactly by Green's-function techniques. The electron-hole interaction introduces peaked structures at subband thresholds in qualitative agreement with experiment. The transition from three-dimensional behavior (for large $N$) to two-dimensional behavior (for $N\ensuremath{\sim}1$) is also investigated.