DOPING OF ZINC-SELENIDE-TELLURIDE

We investigate the doping behavior of ZnSe/ZnTe short period superlattices. p-type doping is achieved with a dc nitrogen plasma source, n-type doping with chlorine from a ZnCl2 Knudsen source. Even a small Te content has a strong positive effect on p doping: Doping levels in the upper 10(19) cm-3 range are achieved, and ohmic contacts can be obtained even for low carrier concentrations. The data are in excellent agreement with a theory based on the amphoteric native defect model. The opposite is valid for n doping: At Te concentrations above 20% electron concentrations are below 10(16) cm-3. As a possible way to get both good n- and p-type doping at the same lattice constant we propose the use of the quaternary compound Zn(1 - y)Mg(y)Se(1 - x)Te(x).