Native defects and Pr dopant around grain boundaries in Pr-doped and undoped ZnO bicrystals were investigated by electron energy loss spectroscopy, with especial regard to the relationship with current–voltage characteristics. The Pr-doped bicrystal exhibited a non-linear current–voltage characteristic, whereas the undoped bicrystal exhibited an ohmic characteristic. In the Pr-doped bicrystal, Pr was found to be present within 8nm of the grain boundary. Electron energy-loss spectroscopic investigations of native defects, combined with first-principles calculations, indicated the presence of Zn vacancies in the vicinity of the Pr-doped grain boundary. The formation of Zn vacancies was considered to be at the origin of the non-linear current–voltage characteristic.

Identification of Native Defects around Grain Boundary in Pr-Doped ZnO Bicrystal using Electron Energy Loss Spectroscopy and First-Principles Calculations. Y.Sato, T.Mizoguchi, F.Oba, M.Yodogawa, T.Yamamoto, Y.Ikuhara: Applied Physics Letters, 2004, 84[26], 5311-3