Field-effect modulation of conductance in VO2 nanobeam transistors with HfO2 as the gate dielectric

TL;DR

This study demonstrates gate voltage-induced conductance changes in VO2 nanobeam transistors with HfO2 dielectric, revealing hysteresis and memory effects related to the insulator-metal transition.

Contribution

It reports the first observation of field-effect modulation and hysteresis in VO2 nanobeam transistors using HfO2 as the gate dielectric.

Findings

Conductance change of ~6% induced by gate voltage in insulating phase

Hysteresis loop area increases with slower gate sweep rates

Presence of phase lag indicating a memory effect in the system

Abstract

We study field-effect transistors realized from VO2 nanobeams with HfO2 as the gate dielectric. When heated up from low to high temperatures, VO2 undergoes an insulator-to-metal transition. We observe a change in conductance (~ 6 percent) of our devices induced by gate voltage when the system is in the insulating phase. The response is reversible and hysteretic, and the area of hysteresis loop becomes larger as the rate of gate sweep is slowed down. A phase lag exists between the response of the conductance and the gate voltage. This indicates the existence of a memory of the system and we discuss its possible origins.