Recovery of (411)A Superflat Interfaces in GaAs/Al0.3Ga0.7As Quantum Wells Grown on (411)A GaAs Substrate by Molecular Beam Epitaxy

Abstract

The recovery of (411)A superflat interfaces in a GaAs/Al0.3Ga0.7As quantum well (QW) grown on a (411)A GaAs substrate by molecular beam epitaxy (MBE) has been investigated. The (411)A superflat interfaces can be realized only under a low V/III ratio (V/III = 7) and the flatness of the interfaces degrades under a condition of a high V/III ratio (V/III = 14). When the V/III ratio was changed during MBE growth of a lower Al0.3Ga0.7As barrier layer from 14 to 7 at only 2 nm below the lower (GaAs-on-AlGaAs) interface of the QW with a well width of 1.8 nm, the linewidth of the photoluminescence peak from the QW became as small as that of a 1.8 nm GaAs/Al0.3Ga0.7As QW with (411)A superflat interfaces. This result indicates that if only a 2-nm-thick Al0.3Ga0.7As layer were grown with V/III = 7 on the rough surface of an Al0.3Ga0.7As layer formed with V/III = 14, the (411)A superflat surface would be formed. This technique could be useful in fabricating GaAs/Al0.3Ga0.7As resonant tunneling diodes with (411)A superflat interfaces, which have good n-type GaAs contact layers obtained with V/III ≥14 on the (411)A GaAs substrate.