Absorption, stimulated emission, and clustering in AlAs-AlxGa1−xAs-GaAs superlattices

Publisher Website
Google Scholar
Abstract
Absorption and photoluminescence data are presented on two AlAs‐AlxGa1−xAs‐GaAs superlattices (SL’s) grown by metalorganic chemical vapor deposition (MO‐CVD). One SL is an 80‐period all‐binary structure with AlAs barriers and GaAs wells. The other SL consists of 121 periods of AlxGa1−xAs (x∼0.5) barriers and GaAs wells. The effects of clustering in the alloy‐barrier SL lead to a spectral shift to lower energy that can be characterized by an effective well size L′z larger than the intended well size of Lz ∼80 Å. Absorption data and low‐level photoluminescence data on both SL’s correspond closely to the calculated confined‐particle transitions. At high excitation levels, however, stimulated emission, including cw 300‐K laser operation, occurs ∼h/ωLO below the lowest (n = 1) confined‐particle transitions.