The role played by Pr-doping in double Schottky barrier formation at single grain boundaries was investigated by using a combination of current-voltage measurements, atomic-resolution Z-contrast scanning transmission electron microscopy and first-principles calculations. Although Pr segregated to the specific atomic site along boundaries, it was found not to be the direct cause of non-linear current-voltage properties. Under suitable annealing conditions, Pr instead enhanced the formation of acceptor-type native defects that were essential for the creation of double Schottky barriers in ZnO.

Role of Pr Segregation in Acceptor-State Formation at ZnO Grain Boundaries. Y.Sato, J.P.Buban, T.Mizoguchi, N.Shibata, M.Yodogawa, T.Yamamoto, Y.Ikuhara: Physical Review Letters, 2006, 97[10], 106802 (3pp)