Improved interface abruptness in pseudomorphic InGaAs/AlGaAs quantum wellswith (411) A superflat interfaces grown by molecular beam epitaxy

Improved interface abruptness was achieved in pseudomorphic InxGa1-xAs/Al0. 34Ga0.66As quantum wells (QWs) (x similar or equal to 0.2) with extremely f lat interfaces over a wafer-size area [(411)A superflat interfaces] grown o n (411)A GaAs substrates by decreasing the substrate temperature T-s under a low V/III ratio during molecular beam epitaxy (MBE). Significant redshift s of low-temperature (12 K) photoluminescence (PL) peaks were observed for the (411)A and simultaneously grown (100) QWs with decreasing T-s because o f the improved interface abruptness resulting from suppressed surface segre gation of In atoms during MBE. Full widths at half maximum (FWHMs) of the P L peaks from the (411)A QWs grown at T-s = 450-540 degreesC under the low V /III [As-4/(Ga+In)] pressure ratio of 10 showed almost no dependence on T-s and were 20%-30% smaller than the best PL FWHMs of the corresponding (100) QWs of this study, indicating that the (411)A InGaAs/AlGaAs superflat inte rfaces can be successfully formed even for the low T-s of 450 degreesC. (C) 2001 American Vacuum Society.