Analysis of interface switching for Nb doped SrTiO3 single crystal device using complex impedance spectroscopy

To analyze the switching mechanism of Nb doped SrTiO3 (Nb:STO) single crystal in a high resistive state (HRS) and low resistive state (LRS), we performed a complex impedance spectroscopy in the frequency domain. We demonstrated the domination of the oxygen vacancies to the resistive switching. Based on the impedance spectroscopy in the HRS and LRS, we concluded that the origin of resistive switching is due to the combination of Schottky junction and a generation of conduction electron from oxygen vacancies. The calculation of activation energies in each resistance state has been performed comparatively, which proposed that a first ionization of oxygen vacancies is responsible for the switching. (C) 2009 Elsevier B.V. All rights reserved.