Indirect probing of defects in unipolar resistive switching NiOx thin films by Ni K-edge resonant inelastic X-ray scattering

Abstract

We present observations of the Ni K-edge resonant inelastic X-ray scattering (RIXS) in NiOx thin films showing unipolar resistive switching (RS). The RIXS spectra of RS NiOx thin films can be described in terms of crystal field (dd) and charge transfer (CT) excitations. We found distorted dd excitations in the films' pristine state before electroforming, and identical excitations for high and low resistance states after electroforming. This suggests that the RS property of NiOx thin film is related to defects in pristine NiOx films, and RS occurs in local nanosized spots too small to be detected by RIXS. (C) 2015 The Japan Society of Applied Physics