Understanding the Charge Transport Mechanism in VRS and BRS States of Transition Metal Oxide Nanoelectronic Memristor Devices

This report presents the charge transport mechanisms in the virgin resistance state (VRS) and breakdown resistance state (BRS) of transition metal oxide memristor devices with tungsten (W) electrodes. The devices behaved as reconfigurable diodes up to ±3.2 V in VRS without the need of any intentional electroforming. The mechanism of conduction in VRS was observed to be governed by tunneling at low temperatures and Frenkel-Poole (F-P) conduction at high temperatures. The BRS was achieved by applying sweep voltages above ±3.2 V after which the device failed to reset. The mechanism of charge transport in BRS was governed by ohmic conduction through defect-assisted localized conduction channels. The barrier height for F-P conduction in VRS and activation energy of defects for ohmic conduction in BRS were experimentally measured.