P-TYPE NITROGEN-DOPED ZNSE EPILAYERS BY IONIZED CLUSTER BEAM EPITAXY

At a low temperature of 250 degrees C, p-type nitrogen doped ZnSe epit axial layers with a resistivity as low as 0.008 Omega . cm were grown by means of the ionized cluster beam (ICB) epitaxy technique using N-2 as dopant source. The ICB epitaxy enabled a growth rate of p-type ZnS e as high as 1-1.5 nm/s, and the nitrogen atom doping concentration ca n be controlled up to 10(20) cm(-3) as was estimated by X-ray photoele ctron spectroscopy (XPS) analysis. The structural perfection of the ep itaxial layers was characterized by X-ray diffraction (XRD) and reflec tion high energy electron diffraction (RHEED). The ZnSe lattice consta nt, as measured by XRD, decreased as the N concentration increased. We attribute this lattice expantion to some nitrogen atoms located at in terstitial sites.