REFLECTIVITY ANALYSIS OF ZNS LAYERS GROWN ON GAAS AND SI SUBSTRATES BY METAL-ORGANIC VAPOR-PHASE EPITAXY

We have grown high-purity ZnS layers by metal organic vapour-phase epi taxy onto (100) GaAs and (111) Si substrates using triethylamine dimet hylzinc. As is usually reported, the morphology and the crystalline qu ality assessed by the optical Nomarski microscope and by double x-ray diffraction are similar on both substrates. However, we demonstrate fo r the first time, using reflectivity experiments along with a theoreti cal fit, that the crystalline quality of the sample deposited onto Si substrates is much poorer. This observation is interpreted in terms of antiphase defects related to the lack of polarity of the Si substrate .