Growth of metastable GaAsSb for InP-based type-II emitters

We report on the growth of pseudomorphically strained, metastable GaAs(1-x)Sb(y) (0.22 <= y <= 0.7) films on InP using metal-organic chemical vapor deposition (MOCVD). The temperature-dependence and the influence of the V:III-ratio in the gas phase on the layer growth were investigated. Layer thicknesses, composition, and strain were assessed by high-resolution X-ray diffraction (HRXRD) and spectroscopic ellipsometry. GaAs(1- x)Sb(y) samples with y < 0.6 showed thickness interference fringes in the HRXRD profile, which give evidence of a good crystalline quality and little strain relaxation. The critical layer thickness for the pseudomorphic growth of GaAsSb on InP was determined and compared to predictions based on the theories of People and Bean and Matthews and Blakeslee.