Super-Flat Interfaces in Pseudomorphic In_xGa_1-xAs/Al_0.28Ga_0.72As Quantum Wells with High In Content (x = 0.15) Grown on (411)A GaAs Substrates by Molecular Beam Epitaxy

Abstract

Pseudomorphic In x Ga 1- x As/Al 0.28 Ga 0.72 As ( x = 0.085–0.15) quantum wells (QWs) with well widths of 1.2, 2.4, 3.6, 4.8, 7.2 and 12 nm have been grown on (411)A and (100) GaAs substrates at a temperature ( T s ) of 520°C by molecular beam epitaxy (MBE). The interface flatness of the QWs was characterized by photoluminescence (PL) at 4.2 K. PL linewidths of the narrow (411)A QWs ( L w = 2.4 nm) with x = 0.085 and 0.15 were 7.3 meV which is approximately 30–40% smaller than those of the (100) QWs, indicating that extremely flat interfaces over a macroscopic area [(411)A super-flat interfaces] have been realized in the pseudomorphic In x Ga 1- x As/Al 0.28 Ga 0.72 As QWs (up to x = 0.15) grown on the (411)A GaAs substrates, similar to lattice-matched GaAs/Al x Ga 1- x As QWs grown on (411)A GaAs substrate previously reported.