Gate-Tunable Thermal Metal–Insulator Transition in VO₂ Monolithically Integrated into a WSe₂ Field-Effect Transistor

Abstract

Vanadium dioxide (VO2) shows promise as a building block of switching and sensing devices because it undergoes an abrupt metal–insulator transition (MIT) near room temperature, where the electrical resistivity changes by orders of magnitude. A challenge for versatile applications of VO2 is to control the MIT by gating in the field-effect device geometry. Here, we demonstrate a gate-tunable abrupt switching device based on a VO2 microwire that is monolithically integrated with a two-dimensional (2D) tungsten diselenide (WSe2) semiconductor by van der Waals stacking. We fabricated the WSe2 transistor using the VO2 wire as the drain contact, titanium as the source contact, and hexagonal boron nitride as the gate dielectric. The WSe2 transistor was observed to show ambipolar transport, with higher conductivity in the electron branch. The electron current increases continuously with gate voltage below the critical temperature of the MIT of VO2. Near the critical temperature, the current shows an abrupt and discontinuous jump at a given gate voltage, indicating that the MIT in the contacting VO2 is thermally induced by gate-mediated self-heating. Our results have paved the way for the development of VO2-based gate-tunable devices by the van der Waals stacking of 2D semiconductors, with great potential for electronic and photonic applications.

A Vanadium Dioxide‐PMMA Composite For Microwave Radiation Switching

“…undergo significant changes as a result of MIT. This compound with outstanding switchable properties found its application for elaboration of thermochromic materials, [22][23][24][25] actuators, [26][27][28] photodetectors, [29][30][31] field-effect transistors, [32,33] memory devices, [34] etc. Among all possible applications, microwave radiation switching through phase transition in VO 2 attracts considerable attention.…”

Femtojoule‐Power‐Consuming Synaptic Memtransistor Based on Mott Transition of Multiphasic Vanadium Oxides

“…Notably, studies on the integration of VO 2 into various electronic devices, such as resistors, [ 19 ] resistive random access memory selectors, [ 20 ] and transistors, [ 21 ] have been reported. These studies demonstrate the unique functions of VO 2 ‐implemented devices, for example, the transition between non‐volatile and volatile memory effects; [ 22 ] abrupt subthreshold swing in metal‐oxide‐semiconductor field‐effect transistors; [ 23 ] and the fast response to various stimuli such as heat, bias, and light. [ 24,25 ] However, the practical application of Mott memory devices by using transition metal oxides, including VO 2 , requires further innovations to overcome several technical issues, such as difficulties associated with the deposition of single VO 2 phase thin films, reliable Mott transition of multiphasic VO x , and importantly, heat generation during device operation since it can adequate to destabilize VO 2 .…”

Abruptly-Switching MoS₂-Channel Atomic-Threshold-Switching Field-Effect Transistor With AgTi/HfO₂-Based Threshold Switching Device

“…A 2D phase-FET with vanadium dioxide (VO 2 ) was proposed. However, the VO 2 -based 2D phase-FET has problems, e.g., high off-state leakage current, and high drive voltage [17], [18]. This is because the connected/integrated VO 2 -based TS device has a low off-state resistance (R off ∼ 10 6 ) and a high threshold voltage (V T ).…”