Synthesis of ZnO Bicrystals Doped with Co or Mn and Their Electrical Properties

Abstract

Bicrystals of ZnO without intergranular additives were synthesized to elucidate the effect of Co and Mn doping on the varistor properties of ZnO ceramics. Nonlinear current-voltage ( I – V ) characteristics due to the formation of an interfacial barrier were observed in bicrystals doped with Co or Mn, while the nondoped bicrystals exhibited linear I – V relationship. Since the charge transport properties of bulk ZnO crystals were not changed, it is indicated that the energy dispersion and/or density of the interfacial states were changed by the Co and Mn doping.