Modulating memristive performance of hexagonal WO3 nanowire by water-oxidized hydrogen ion implantation

Abstract

In a two-terminal Au/hexagonal WO3 nanowire/Au device, ions drifting or carriers self-trapping under external electrical field will modulate the Schottky barriers between the nanowire and electrodes, and then result in memristive effect. When there are water molecules adsorbed on the surface of WO3 nanowire, hydrogen ions will generate near the positively-charged electrode and transport in the condensed water film, which will enhance the memristive performance characterized by analogic resistive switching remarkably. When the bias voltage is swept repeatedly under high relative humidity level, hydrogen ions will accumulate on the surface and then implant into the lattice of the WO3 nanowire, which leads to a transition from semiconducting WO3 nanowire to metallic HxWO3 nanowire. This insulator-metal transition can be realized more easily after enough electron-hole pairs being excited by laser illumination. The concentration of hydrogen ions in HxWO3 nanowire will decrease when the device is exposed to oxygen atmosphere or the bias voltage is swept in atmosphere with low relative humidity. By modulating the concentration of hydrogen ions, conductive hydrogen tungsten bronze filament might form or rupture near electrodes when the polarity of applied voltage changes, which will endow the device with memristive performance characterized by digital resistive switching.

Recent Developments and Perspectives for Memristive Devices Based on Metal Oxide Nanowires

“…The drift of oxygen vacancies was considered responsible for memristive properties with hysteretic I – V characteristics also in hexagonal WO 3 NWs, as observed by He et al Moreover, it was shown that resistive switching properties of WO 3 NWs can be influenced by water molecule adsorption . It is worth noticing that new features of resistive switching can be observed in Na x WO 3 (sodium tungsten bronze) NWs as observed in a later work by Lei et al, where the switching was proposed to be controlled by the migration of Na + ions along the NW and can be thus attributed to a metallization memory effect.…”

“…[168,169] It is worth noticing that new features of resistive switching can be observed in Na x WO 3 (sodium tungsten bronze) NWs as observed in a later work by Lei et al, [170] where the switching was proposed to be controlled by the migration of Na + ions along the NW and can be thus attributed to a metallization memory effect. [168,169] It is worth noticing that new features of resistive switching can be observed in Na x WO 3 (sodium tungsten bronze) NWs as observed in a later work by Lei et al, [170] where the switching was proposed to be controlled by the migration of Na + ions along the NW and can be thus attributed to a metallization memory effect.…”

Thermal Water Splitting on the WO3 Surface: Experimental Proof

“…8 Although it is usually assumed that the memristive properties of WO 3 is induced by the migration of oxygen vacancies, Zhou et al hypothesize purely based on I-V curves that the enhancement is a result of H + ions stemming from oxidized water drifting on the surface of a WO 3 nanowire via the Grotthuss mechanism. 8 Despite the vast amount of research done on WO 3 across the many application fields, the reactions between the surface and the atmosphere are still poorly understood. Specifically, despite its omnipresence in applications, the interaction between humidity and the WO 3 surface remains unclear.…”

Quantifying Capacitive‐Like and Battery‐Like Charge Storage Contributions Using Single‐Nanoparticle Electro‐optical Imaging

“…The OD onset could occur at more negative potentials for those particles with a significant contact resistance. Another possible explanation is that varying amounts of structural or surface adsorbed water in these nanorods influences the Li‐ion binding energetics at the WO 3 /electrolyte interface, and diffusion behavior within the nanorod bulk …”