Quality improvements of ZnxCdyMg1−x−ySe layers grown on InP substrates by a thin ZnCdSe interfacial layer

The quality of lattice-matched ${\mathrm{Zn}}_x{\mathrm{Cd}}_y{\mathrm{Mg}}_{\text{1−x−y}}\mathrm{Se}$ epitaxial layers grown on (001) InP substrates with a III-V buffer layer has been improved by initially growing a ZnCdSe interfacial layer (50 Å) at low temperature. The widths of double crystal x-ray rocking curves for ${\mathrm{Zn}}_x{\mathrm{Cd}}_y{\mathrm{Mg}}_{\text{1−x−y}}\mathrm{Se}$ epilayers with band gaps as high as 3.05 eV were reduced to about 70 arcsec. The defect density evaluated from etch pit density and plan-view transmission electron microscopy measurements was reduced by two orders of magnitude, to ${10}^6{\text{–10}}^7\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-2}}.$ The photoluminescence band edge emission became more symmetric and slightly narrower. It is proposed that an initial two-dimensional growth mode has been achieved by incorporating such a lattice-matched ZnCdSe layer.