ROLE OF CADMIUM IN ENHANCING OPTICAL-PROPERTIES AND CHLORINE DOPING OF PHOTO-ASSISTED OMVPE-GROWN ZNSE

The influence of cadmium doping in enhancing: (i) near-band edge (NBE) to deep-level emissions (DLE) photoluminescence intensity ratio, and (ii) chlorine incorporation in HCl doped ZnSe films, has been studied. The epitaxial ZnSe was grown using low-temperature photo-assisted org anometallic vapor phase epitaxy (OMVPE) using DMSe, DMZn, and DMCd alk yl sources. More intense near band-edge emission is observed when the growth temperature is reduced from 400 to 360 degrees C. The deep-leve l emissions show a threshold-like dependence on UV light intensity for a given temperature. Cadmium doping is found to improve the NBE/DLE p hotoluminescence intensity ratio, and this improvement is more pronoun ced at higher growth temperature. Properties of n-type ZnSe films co-d oped with cadmium and chlorine, using HCl and DMCd as dopant sources h ave also been investigated. Samples co-doped with Cd showed higher ele ctron concentrations and this effect was more pronounced at lower UV i ntensities. By the use of Cd co-doping, we have achieved the highest e lectron concentrations (2.4 x 10(18) cm(-3)) yet reported for HCl dopi ng of OMVPE-grown ZnSe.