Theory of line shapes of exciton resonances in semiconductor superlattices

Realistic model calculations on the absorption spectra of semiconductor superlattices are presented. Emphasis is put on the analysis of line shapes of various peak structures arising from discrete excitonic states of one pair of subbands coupled with the excitonic (discrete and continuum) states associated with other pairs of subbands. The angle-dependent valence-band mixing and the final-state interaction effects are properly taken into account via the k-space sampling technique. Our results are in excellent agreement with recent high-resolution photoluminescence excitation spectra for a number of GaAs-Alₓ{Ga}_{1{{-}}x}$As quantum wells and superlattices.