Modulation of resistive switching properties of non-stoichiometric WO3−x based asymmetric MIM structure by interface barrier modification

Abstract

The impact of device operation condition and ambient moisture on the interface-type resistive switching (RS) characteristics of a non-stoichiometric polycrystalline tungsten oxide (WO3−x) based metal–insulator–metal device with an Au top electrode and a Pt bottom electrode has been investigated. The device exhibits rectification and stable bipolar RS characteristics without the need for any forming step, where the switching is primarily dominated by the Schottky type Au/WO3−x interface. DC conduction characteristics of the device have been investigated at different temperature, bias stress, and relative humidity conditions. Current conduction through the active layer has been found to be dominated by Schottky emission at low electric field and Poole–Frenkel emission at high electric field. An increase in current and a strong reduction in the rectification characteristic have been observed on subjecting the device to DC bias stress of appropriate polarity as well as increasing ambient moisture. Modification of the Schottky barrier due to defect redistribution when DC bias stress is applied and due to the dipoles induced at the Au/WO3−x interface by water molecules with increasing ambient moisture content have been discussed as a possible mechanism of the observed RS modulation.