Epitaxial and bulk ZnSe of good structural perfection have been grown by vapor-phase techniques. Epitaxial undoped ZnSe layers were grown by metal-organic chemical vapor deposition (MOCVD) on GaAs {100} substrates in a horizontal-flow quartz reactor chamber. Conventional pyrolytic growth at 450°C was used, with diethyl zinc (DEZn) and diethyl selenium (DESe) reactants transported in hydrogen carrier gas.

Layers with smooth surface morphology and very good crystal structure were obtained, with no evidence of gas-phase pre-reaction. Sharp electron channeling patterns produced in the scanning electron microscope (SEM) indicated that {100}-oriented ZnSe layers were grown on (100) GaAs surfaces, as expected. X-ray rocking-curve analysis with a silicon four-crystal monochrom-ator gave full-width at half-maximum (FWHM) line widths of 165 to 180 arc-sec for layers 2.5 to 3.0 μm thick, better than values for MOCVD-grown ZnSe/GaAs reported to date in the literature known to us. Cathodoluminescence (CL) imaging in the SEM showed significant defect substructure in the layers, probably due to lattice-misfit dislocations in the interface region. Bright blue CL emission from the layers was observed in the SEM at both 77K and room temperature, indicating the dominance of radiative recombination in the material.

Bulk ZnSe crystals were grown using a physical vapor transport technique. The crystals, a few millimeters on a side, had fully developed crystal facets, predominantly {110(-oriented. X-ray rocking-curve analysis gave FWHM values of about 19 arc-sec, indicating excellent structural perfection.