Calculation of the excitonic absorption in parabolic semiconductor quantum-well structures

The absorption for a parabolic quantum well is calculated on the basis of the semiconductor Bloch equations including the full three-dimensional excitonic interaction. Analog parabolic quantum-well structures are compared to structures grown using the “digital alloy technique.” Significant differences are shown to arise in the high-field regime. The excitonic spectra are compared to single-particle spectra and experimental results published by W. Geißelbrecht et al. [Superlattices Microstruct. 23, 93 (1998)]. It is demonstrated that the pronounced broadening of the experimental spectra of structures grown using the “digital alloy technique” can be explained by the influence of interface roughness.