High Quality Quantum Wells of InGaP/GaAs Grown by Molecular Beam Epitaxy

Abstract

The materials system AlGaAs/GaAs has been used extensively for synthesis of quantum well (QW) optoelectronic devices. The III-V alloy InGaP provides an alternative to AlGaAs for confinement of GaAs QWs. At the composition for lattice matching to GaAs, In0.48Ga0.52P exhibits a room temperature bandgap of 1.89 eV, somewhat larger than that of Al0.3Ga0.7As, and the In0.48Ga0.52P/GaAs valence band offset (ΔEv) is about 0.3 eV, larger than that of the Al0.3Ga0.52As/GaAs heterojunction. Furthermore, InGaP exhibits a lower concentration of deep levels than AlGaAs, and InGaP does not oxidize as readily as AlGaAs. InGaP/GaAs QWs have been previously reported by Razeghi et al., who used metalorganic chemical vapor deposition to grow wells as narrow as 15Å(1) We report here the growth of InGaP/GaAs QWs by gas-source molecular beam epitaxy (GSMBE). Single QWs as narrow as 6Å and multiple QW superlattices with abrupt interfaces are described.