Molecular beam epitaxial growth of GaAs/AlAs and GaAs/AlGaAs quantum wells on sub-micron-period corrugated substrates

Abstract

We present the results of a study of the growth by molecular beam epitaxy of (Al,Ga)As layers on GaAs sub-micron-period gratings. We study the migration effects of Ga and Al atoms at the patterned substrate surface. The high mobility of Ga atoms leads to the planarization of the V-groove, whereas the low mobility of Al atoms tends to preserve the shape of the grating. This difference in migration of Ga and Al atoms is used to grow disconnected GaAs wires 50–100 Å thick, 1300 Å wide, embedded in AlAs. Another important phenomenon demonstrated here is the enhanced surface migration of Ga atoms inside the V-groove. This effect is evidenced by a reduction of the roughness of GaAs/Al 0.5Ga 0.5As multiple quantum wells grown within the V-groove compared to those grown outside the groove directly after planarization.