Structural and optical characterization of InP/GaxIn1−xAsyP1−y quantum wells and interfacial layers

Abstract

Several multiquantum wells of InP/Ga x In 1Ϫx As y P 1Ϫy grown by chemical-beam epitaxy have been studied by high-resolution x-ray diffraction, low-temperature photoluminescence, and Raman scattering to characterize interfacial layers between the barriers and the wells. These interfacial layers are created during the initial stage of growth of the quaternary material as a result of the longer transient for the saturation of the group-III elements flux. The combination of x-ray diffraction and photoluminescence allows a precise determination of the interfacial layer thickness and composition grading and shows that interface roughness is of the order of 1 monolayer. Raman scattering confirms these results and is used to determine values of the sound velocity and of the index of refraction in the quaternary alloy material. ͓S0021-8979͑96͒03419-6͔