Extremely flat interfaces in GaAs/AlGaAs quantum wells with high Al content (0.7) grown on GaAs (411)A substrates by molecular beam epitaxy

Abstract

Effectively atomically flat interfaces over a macroscopic area (200 μm diameter) have been achieved in GaAs/Al 0.7Ga 0.3As quantum wells (QWs) with well widths of 3.6–12 nm grown on (411)A GaAs substrates by molecular beam epitaxy (MBE) for the first time. A single and very narrow photoluminescence peak (FWHM, full width at half maximum, is 6.1 meV) was observed at 717.4 nm for the QW with a well width of 3.6 nm at 4.2 K. The linewidth is comparable to that of growth-interrupted QWs grown on (100)-oriented GaAs substrates by MBE. A 1.5 μm thick Al 0.7Ga 0.3As layer with good surface morphology also could be grown on (411)A GaAs substrates in the entire growth temperature region of 580–700°C, while rough surfaces were observed in Al 0.7Ga 0.3As layers simultaneously grown on (100) GaAs substrates at 640–700°C. These results indicate that the surface of GaAs and Al 0.7Ga 0.3As grown on the (411)A GaAs substrates are extremely flat and stable on the (411)A plane.