Growth of p-type ZnO thin films by (N, Ga) co-doping using DMHy dopant

We investigate p-type doping in ZnO prepared by metal-organic chemical vapour deposition with dimethylhydrazine (DMHy) as the nitrogen dopant source. Results obtained by x-ray photoelectron spectroscopy show that DMHy exhibits a narrow temperature window from 500 to 550 deg C for efficient nitrogen incorporation and that nitrogen doping is critically influenced by growth conditions, e.g. the N/Ga flux ratio in growth. Within an appropriate N/Ga flux ratio range, p-type ZnO can be realized. The effect of the N/Ga flux ratio on the conductivity conversion of ZnO is reported. The extrinsic nitrogen acceptor level is calculated to be about 160 meV from low-temperature photoluminescence spectra.