Electronic and thermal effects in the insulator-metal phase transition in VO2 nano-gap junctions

Abstract

By controlling the thermal transport of VO2 nano-gap junctions using device geometry, contact material, and applied voltage waveforms, the electronically induced insulator-metal phase transition is investigated in the adiabatic heating and transient carrier injection regimes. With a gradual ramping of an applied voltage on a microsecond time scale, the transition electric field threshold can be directly reduced by the Joule heating. With an abrupt applied voltage, the transition threshold is initiated by carriers injected within the first tens of nanoseconds, but the complete insulator-metal phase transition is limited by thermal redistribution times to hundreds of nanoseconds.