Conductivity of nanocrystalline ZnO(Ga)

Nanocrystalline zinc-oxide powders containing different proportions of gallium, ZnO(Ga), are synthesized by coprecipitation from aqueous solutions followed by annealing at 250$^\circ$C. The dependence of the conductance of the samples on the Ga content is found to be non-monotonous. The temperature dependences of the conductance are studied. The introduction of a low Ga content (0.33–0.50 at%) induces a decrease in the activation energy and the height of the effective potential barrier between nanocrystallites compared to the corresponding parameters of ZnO. Then, as the Ga content is increased, these parameters increase. The data obtained in the study are interpreted within the context of the model of an inhomogeneous semiconductor with large-scale potential fluctuations.