PROPERTIES OF VAPOR-PHASE EPITAXIAL ZINC SELENIDE CODOPED WITH CADMIUM AND CHLORINE

Zinc selenide epitaxial layers have been grown by ultraviolet-assisted organometallic vapor phase epitaxy (OMVPE) with cadmium and chlorine codoping, using the sources DMSe, DMZn, DMCd, and HCl. Growth was carried out at 400 degrees C with ultraviolet irradiation at an intensity of 4 or 7.5 mW/cm(2). Samples codoped with cadmium showed increased incorporation of chlorine donors relative to control samples having no cadmium codoping. This effect was more pronounced at the lower ultraviolet intensity. The growth rate for the doped films decreased with increasing mole fraction of hydrogen chloride. By the use of cadmium codoping, we have achieved the highest electron concentrations yet reported for hydrogen chloride doping of OMVPE-grown ZnSe. The best results obtained in this study were an electron concentration of 2.4X10(18) cm(-3) and a resistivity of 0.0141 Omega cm (300 K values). We have proposed a model based on the compensation of tetrahedral misfit to explain these results. (C) 1995 American Institute of Physics.