COMPENSATION PROCESSES IN MOLECULAR-BEAM EPITAXIALLY GROWN ZINC SELENIDE DOPED WITH NITROGEN

Recent work has shown that nitrogen produced in a plasma source is a p -type dopant in MBE grown ZnSe with N(a) - N(d) to 1 X 10(18) cm-3, bu t at these concentrations the material is highly compensated. In a pre vious study, we have examined the PL spectra of nitrogen doped materia l grown in our laboratory and have shown that there are two sets of do nor-acceptor pair (DAP) peaks which can be explained by a simple model involving a nitrogen acceptor and two donors. The first donor is a na tive shallow donor and the second is a nitrogen related compensating d onor thought to be a complex of the form V(Se)-Zn-N(Se). Optically det ected magnetic resonance results on samples showing both shallow and d eep DAP luminescence show signals due to the shallow isotropic donors and deep anisotropic donors consistent with our proposed model. Calcul ations of the vacancy concentrations and degree of compensation that s hould be expected in nitrogen doped ZnSe show that at all temperatures and under all growth conditions the material is highly undersaturated with vacancies. The barriers operating to prevent the compensation ar e discussed.