OPTICAL AND X-RAY-ANALYSIS OF ZNSXSE1-X/ZNSE SUPERLATTICES GROWN ON GAAS BY METALORGANIC VAPOR-PHASE EPITAXY

X-ray diffractometry, Raman backscattering and photoluminescence were applied to characterize ZnSxSe1-x/ZnSe superlattices, grown on GaAs(100) by metalorganic vapour phase epitaxy (MOVPE). As sulphur precursor materials diethylsulphide (DES) and H2S were compared. Furthermore, we investigated the influence of different kind of buffer layers, the effect of increasing the number of periods and the consequences of stabilization during growth interruptions. Superlattices with a high crystal quality and very regular periodicity were obtained for 120-period structures, grown with DES as precursor, without intentional buffer layer. They show very narrow folded acoustical phonons in the Raman spectrum and their X-ray diffraction pattern contains not only sharp satellite peaks, whose fine structure reveals monolayer fluctuations, but also fringes which are due to interference from the entire stack.