Size effect on voltage-induced metal-insulator transition in VO$_{2}$ film grown by direct thermal oxidation method

Metal-insulator transition (MIT) in vanadium dioxide (VO$_{2}$) can be induced by diverse stimuli such as temperature, voltage, light and pressure. Voltage induced MIT is of special interest for both scientific understanding and future applications. However, it is still under the debate whether the origin of voltage induced MIT comes from electrical breakdown or Joule heating effect. To figure out this origin, the electrically triggered MIT from the strip-line VO$_{2}$ film devices with dimensions of fixed width (W) of 100 $\mu $m and varied length (L) of 10, 20, 40, and 80 $\mu $m were investigated by temperature and external bias voltage dependent electrical transport, and optical microscopy. It was found that the magnitude of critical electric filed at MIT and its temperature dependence were dependent on the length of the device. In this talk, we will present the size effect on the voltage-induced metal-insulator transition in VO$_{2}$ film grown by direct thermal oxidation method and discuss the origins of voltage driven MIT and its implications.