Nitrogen ion behavior on polar surfaces of ZnO single crystals

Nitrogen radicals were irradiated on the (0001) and (0001) surfaces of the ZnO single,crystals, and the stability and the states of N ions on the surfaces were investigated by Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). On the (0001) surface, many N ions replaced the O ions of ZnO during annealing in oxygen gas or vacuum after nitrogen treatment. However, few N ions replaced the O ions of ZnO on the (000 (1) over bar) surface. These results suggest that the nitrogen doping on the (0001) surface is more effective than that on the (000 (1) over bar) surface.