Comparison of structural and optical properties in strained GaInAsP MQW structures grown by MOVPE and MOMBE

The growth parameter dependence of the transition from 2D to 3D growth of G aInAsP multiple quantum well (MQW) structures up to epsilon(B) = 0.5% tensi le-strained barriers was examined. Identical MQW structures with epsilon(W) = 1% compressively strained wells were grown by metal organic vapor-phase epitaxy (MOVPE) and metal organic molecular beam epitaxy (MOMBE) and charac terized by photoluminescence (PL), X-ray diffraction and transmission elect ron microscopy. Increasing the tensile barrier strain resulted in deteriora ted optical and crystalline properties beyond a critical strain limit, whic h depends on growth temperature. The deterioration originates from lateral layer thickness and strain modulations. Their density, amplitude and thus t heir effect on the optical MQW properties are different for both growth met hods. High-quality MOMBE-grown MQW structures up to epsilon(W) = 2% compres sive well strain and epsilon(B) = 0.5-1% tensile barrier strain could be ac hieved by inserting thin intermediate layers at each internal interface. Th e composition of these intermediate layers has a significant effect on MQW material properties. (C) 2000 Elsevier Science B.V. All rights reserved.