Role of oxygen vacancies in resistive switching in Pt/Nb-doped SrTiO3

Oxygen vacancies at the metal/oxide interface, driven by an electric field, have been considered responsible for the switching to the low-resistance state. We studied the electrical properties, along with microscopic observations, of the Pt/Nb-doped SrTiO3 (001) single-crystal system. Electron energy loss spectroscopy revealed highly accumulated oxygen vacancies at the interface in the high-resistance state, contrasting to common explanation. Higher resistance state by more oxygen vacancies was further confirmed in Pt/H-2-annealed SrTiO3. These results suggest the presence of an interfacial state which dominantly determined the resistivity by changing the barrier height at the interface. (C) 2014 AIP Publishing LLC.