Remote hydrogen plasma doping of single crystal ZnO

We demonstrate that remote plasma hydrogenation can increase electron concentrations in ZnO single crystals by more than an order of magnitude. We investigated the effects of this treatment on Hall concentration and mobility as well as on the bound exciton emission peak I-4 for a variety of ZnO single crystals-bulk air annealed, Li doped, and epitaxially grown on sapphire. Hydrogen increases I-4 intensity in conducting samples annealed at 500 and 600 degreesC and partially restores emission in the I-4 range for Li-diffused ZnO. Hydrogenation increases carrier concentration significantly for the semi-insulating Li doped and epitaxial thin film samples. These results indicate a strong link between the incorporation of hydrogen, increased donor-bound exciton PL emission, and increased n-type conductivity. (C) 2004 American Institute of Physics.