Molecular-beam epitaxy growth and nitrogen doping of hexagonal ZnSe and ZnCdSe/ZnSe quantum well structures on hexagonal ZnMgSSe bulk substrates

Hexagonal ZnMgSSe bulk substrates have been synthesized as attractive alternatives for the homoepitaxial growth of II-VI device structures. Hexagonal ZnSe epilayers and ZnCdSe/ZnSe quantum well structures were grown on these substrates by molecular-beam epitaxy. The cross-sectional transmission electron microscopy image shows that the ZnSe epilayer replicated the hexagonal structure of the substrate. The 6 K photoluminescence (PL) spectra of the hexagonal ZnSe layers show strong impurity-bound-exciton emissions at about 2.796 eV. No Y-line (defect-related emission) is observed in the spectra suggesting good substrate preparation and growth conditions. The 77 K PL spectra of hexagonal quantum well structures show dominant emission from the ZnCdSe well layer. Double-crystal x-ray rocking curves indicate that the ZnSe epitaxial layers and the substrates are near lattice matched. Doping of hexagonal ZnSe with nitrogen was performed. Photoluminescence spectra suggest th;tt these samples exhibit donor-acceptor-pair emission with typical characteristics of heavily doped (compensated) samples. (C) 2000 American Vacuum Society.