Clustering in molecular-beam epitaxial AlxGa1−xAs-GaAs quantum-well heterostructure lasers

Abstract

The effects of alloy clustering in Al_xGa_1−xAs‐GaAs quantum‐well heterostructures (QWH’s) grown by molecular‐beam epitaxy (MBE) are investigated. Both low‐ and high‐level photoluminescence data on three of the best MBE QWH lasers are presented. These data indicate that while clustering in Al_xGa_1−xAs can depend on crystal growth conditions (temperature, stoichiometry, surface chemistry, contamination, etc.), it is to an appreciable extent intrinsic to the alloy. Clustering in Al_xGa_1−xAs can result from the random distribution of Al and Ga atoms regardless of the method of crystal growth. In addition, this work demonstrates cw 300‐K photopumped laser operation of MBE QWH’s, which would not be possible if the distributed and heterointerface defect densities (of unknown amount) were very high.