Influence of the Composition of the Gas Medium in Reactive Ion-Beam Sputtering on the Electrical Properties of Nitrogen-Doped ZnO Films

The influence of the composition of the gas medium in reactive ion-beam sputtering on the electrical properties of nitrogen-doped ZnO films was studied. It was found that, in the temperature range of 300-500 K, the electron transport in the experimental films occurs via variable-range hopping over localized states near the Fermi level. The parameters of ZnO were estimated according to the Mott model. It was established that the density g(EF) of localized states at the Fermi level is maximum in sputtering in a nitrogen medium and increases with increasing partial nitrogen pressure. For films deposited in a nitrogen–oxygen mixture, the density of states is lower, indicating the competing influence of oxygen and nitrogen on the formation of the defect structure.