The Meyer–Neldel Rule in Conduction Mechanism of the Electrospun ZnO Nanofibers

Abstract

An analytical model describing the conductivity of ZnO nano¯bers depending on the grains size is proposed. The research is based on the thermal dc electrical measurements of a single electrospun ZnO nano¯ber calcined at di®erent temperatures. In the our previous research, we showed that electrical conduction of ZnO nano¯bers is mainly thermally activated. The activation energy of conductivity was strongly dependent on the grain size, which in turn depended on the calcination temperature. This could be due to migration of a point defect in the grain of ZnO and could change the carrier concentration. Our recent studies have shown that ZnO nano¯bers behavior is consistent with the Meyer-Neldel rule. This indicates an exponential energy distribution of deep level traps in the material. Based on the theoretical assumptions and experimental data, the improved model of conductivity in a single ZnO nano¯ber calcined at di®erent temperatures was proposed.