In 0.18 Ga 0.82 As/GaAs 1−y P y quantum wells grown on (n11)A GaAs substrates by molecular beam epitaxy

Abstract

We have investigated the influence of V(As4+P2)/III(Ga) pressure ratio on interface flatness of In0.18Ga0.82As/GaAs1−yPy (2.9 nm/20 nm) single quantum wells (SQWs) (y=0.18–0.32) grown on (100)- and (n11)A-oriented GaAs substrates (n=3, 4, and 5) by molecular beam epitaxy. With decreasing V(As4+P2)/III(Ga) pressure ratio from 8 to 4, full width at half maximum (FWHM) of 11 K photoluminescence (PL) peak of the (411)A SQW was dramatically reduced to 7.8 meV, while those of the (311)A and (100) SQWs increased from their best FWHM (7.3 and 6.8 meV). This is different from those in the other SQWs. The best values of FWHM of the (311)A and (411)A SQWs were as small as those of the (100) In0.18Ga0.82As/GaAs1−yPy and In0.17Ga0.83As/Al0.3Ga0.7As QWs. The highest PL intensity was observed for the (411)A SQW grown under V(As4+P2)/III(Ga)=4. The (311)A SQWs grown under V(As4+P2)/III(Ga)=4 to 8 have 60%–70% smaller PL intensity than the (411)A SQW, but they have much higher PL intensity than the (100) and (511)A SQWs. This implies that the (311)A and (411)A In0.18Ga0.82As/GaAs1−yPy QWs have a good optical quality.