Unipolar resistive switching in insulating niobium oxide film and probing electroforming induced metallic components

Abstract

We have observed unipolar-type resistance switching in an ultrathin niobium oxide film. An analysis of the temperature dependence of the resistance switching transport revealed that low-resistance state showed a type of electrical conduction typically observed in metals. The modification in chemical binding states of the film in different resistance states was studied using x-ray photoelectron spectroscopy. The analysis of XPS showed that metallic suboxides NbO delta (delta << 2), decomposed from some of Nb2O5 and NbO2 components of the film, were created after electroforming process, suggesting that the metallic suboxides are constituting elements of metallic channels in the low resistance state.