MBE growth and characterisation of ZnSe-based II-VI semiconductors

This thesis describes the growth and characterisation of ZnSe-based II-semiconductors by Molecular Beam Epitaxy (MBE). X-ray Interference (XRI) was used to measure the critical thickness of Zn_0_._7Cd_0_._3Se quantum wells (QWs) in ZnSe barriers on GaAs substrates. For 500A barriers the critical thickness was measured as between 70 and 120A. X-ray Topography measurements on ZnSe epilayers grown on GaAs buffer layers gave a critical thickness of between 100 and 110 nm, slightly larger than that of ZnSe epilayers on bare GaAs substrates. The misfit dislocation line density above critical thickness for buffer layer samples is similar to that reported for In_0_._0_6Ga_0_._9_4As layers on GaAs substrates with equal strain. Growth of ZnSe QWs in Zn_0_._5_9Mg_0_._4_1Se layers on parabolically-graded, lattice-matched InGaAs buffer layers resulted in improved Photoluminescence characteristics compared to growth of ZnSe QWs in Zn_0_._6_9Mg_0_._3_1Se layers on GaAs substrates. The lattice constant of zincblende MgS was measured at 5.618 #+-# 0.001A by X-ray Diffraction from a 67nm MgS layer. The growth rate of zincblende MgS was calculated by XRI measurements of thin MgS layers bounded by ZnSe layers. (author)Available from British Library Document Supply Centre-DSC:DXN042553 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo