Defect studies in strained-layer quantum well heterostructures
The epitaxial growth of mismatched or strained III-V layers was shown to be viable as early as 1960. Osbourn et al suggested that strained layer GaP-GaAs1-xPx superlattices grown by organo-metal1ic vapor phase epitaxy (OMVPE) could be used to fold the Brillouin zone and make indirect-crystal direct. More recently, it has been shown that a strained-layer superlattice can be grown free enough of defects at heterointerfaces to make possible stimulated emission. This has been demonstrated on OMVPE GaAs1-xPx-GaAs (x=0.25) and GaAs-InxGa1-xAs (x=0.2) strained layer superlattices which have been operatedas photopuraped continuous (cw) 300K lasers but which at high excitation levels (> 103Acm-2) prove to be unstable. This paper presents the results of an electron microscope study of the defects produced in a GaAs-InxGa1-xAs strained superlattice as a result of high excitation levels of operation.