Optimization of Metamorphic InGaAs Quantum Wells on GaAs Grown by Molecular Beam Epitaxy

We investigate the molecular beam epitaxy growth of metamorphic In_xGa_1-xAs materials (x up to 0.5) on GaAs substrates systematically. Optimization of structure design and growth parameters is aimed at obtaining smooth surface and high optical quality. The optimized structures have an average surface roughness of 0.9--1.8nm. It is also proven by PL measurements that the optical properties of high indium content (55%) InGaAs quantum wells are improved apparently by defect reduction technique and by introducing Sb as a surfactant. These provide us new ways for growing device quality metamorphic structures on GaAs substrates with long-wavelength emissions.