INTERFACE CHARACTERIZATION OF HETEROEPITAXIAL ZNSE LAYERS ON GAAS SUBSTRATES BY CATHODOLUMINESCENCE

Cathodoluminescence (CL) spectra of ZnSe layers on GaAs (100) substrates were measured with electron-beam energies from 4 to 40 keV and layer thicknesses from 0.2 to 15-mu-m in order to examine defect-related deep-level emissions from the region near the ZnSe/GaAs heterojunction. Deep-level emissions around 2.2 eV were observed from ZnSe layers thicker than the critical thickness for coherent growth, when the region within 1-mu-m of the heterojunction was excited. No deep-level emissions were detected from coherently grown thin layers irrespective of excitation depth. These results confirm the notion that lattice defects responsible for deep-level emissions are not introduced in coherently grown layers.