STRONG ENHANCEMENT OF THE OPTICAL AND ELECTRICAL-PROPERTIES, AND SPONTANEOUS FORMATION OF AN ORDERED SUPERLATTICE IN (111)B ALGAAS

Abstract

Strong enhancement in the luminescence intensity is observed in Al0.22Ga0.78As epitaxial layers grown on misoriented (111)B GaAs as compared to those simultaneously grown on (100) GaAs. For a 1 degrees misorientation the luminescence intensity is almost 10 to 1000 times that of the (100) layers, depending on the growth temperature. Room temperature electron mobility for 3 degrees misoriented (111)B Al0.18Ga0.82As is 19% higher than that for side-by-side grown (100). The strong luminescence associated with a large red shift of 90 meV and the 19% mobility enhancement are related to the long range composition ordering in (111)B AlGaAs, which is observed by cross-sectional transmission electron microscopy in a 280 Angstrom Al0.4GaAs quantum well heterostructure with Al0.7GaAs barriers grown on (111)B GaAs substrates.