Investigation on onset voltage and conduction channel temperature in voltage-induced metal-insulator transition of vanadium dioxide

The characteristics of onset voltages and conduction channel temperatures in the metal-insulator transition (MIT) of vanadium dioxide (VO₂) devices are investigated as a function of dimensions and ambient temperature. The MIT onset voltage varies from 18 V to 199 V as the device length increases from 5 to 80 μm at a fixed width of 100 μm. The estimated temperature at local conduction channel increases from 110 to 370 °C, which is higher than the MIT temperature (67 °C) of VO₂. A simple Joule-heating model is employed to explain voltage-induced MIT as well as to estimate temperatures of conduction channel appearing after MIT in various-sized devices. Our findings on VO₂ can be applied to micro- to nano-size tunable heating devices, e.g., microscale scanning thermal cantilevers and gas sensors.