Molecular Beam Epitaxial Growth of ZnTe and ZnSe

The electrical and optical properties of ZnTe and ZnSe prepared by molec-ular beam epitaxy have been studied. EPitaxial growth was found to take place at> 250 ~ for ZnTe on GaAs and ZnTe and at> 300 ~ for ZnSe on GaAs; the epitaxial growth ceased at 430 ~,- ~ 470 ~ for ZnTe and at 450 ~, ~ 500~ for ZnSe because of the reevaporation of compound and/or impinging mole-cules. The observed growth rate dependence on substrate temperature and on impinging rate ratio has been explained on the basis of a model in which the number of incorporated and reevaporated molecules are strongly coverage de-pendent. ZnSe on GaAs, and ZnTe on GaAs and ZnTe had good mirror smooth surfaces. ZnTe on InAs and ZnS, however, had a rather rough surface. Ga was found to diffuse, due to a large number of mis.fit defects at GaAs-ZnTe interface, from the GaAs substrate into ZnTe influencing the electrical nd optical properties of grown layers considerably. The resistivities of undoped layers were ~5 f~-cm for ZnTe on ZnTe and,-,104 f~-cm for ZnSe on GaAs. S