Saddle-Point Excitons and Fano Resonances in Semiconductor Superlattices

Abstract

Theoretical investigations of optical properties in semiconductor quantum wells and superlattices are presented. In particular, we introduce a line-shape theory for treating excitonic absorption in superlattices. This theoretical method allows one to accurately and efficiently calculate the Green’s function associated with the excitonic Hamiltonian of a realistic superlattice, including the mixing of heavy and light hole states (the valence band mixing) and inter-well tunneling of excitons. Realistic absorption spectra for a number of GaAs-Gal-xAlxAs superlattices were obtained with this method. Interesting features such as the saddle-point excitons and Fano resonances due to the interaction of discrete exciton states with continuum states are discussed. The theoretical predictions are in excellent agreement with available data.KeywordsOscillator StrengthHeavy HoleFano ResonanceExciton StateExciton Binding EnergyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.