Investigation on I-V characteristics of current induced metal insulator transition in VO2 device

Abstract

The I-V characteristics of two terminal planar VO2 film devices are investigated as the devices undergo the current induced metal insulator transition (I-MIT). The I-MIT occured when the device resistivity reached ∼7 Ωcm, where metallic grains formed initial conductive current path within insulating matrix. The transition time needed for the I-MIT increased with increasing external resistance, REXT, connected to the device in series, i.e. ∼390 μs (REXT = 5 kΩ) to ∼1400 μs (REXT = 20 kΩ). The transition time is closely related to the RC time delay from capacitance discharge of the VO2 device. During the I-MIT, the amount of discharge current was estimated as large as ∼100 mA, which was larger than the current just before the I-MIT. After the I-MIT, the current density decreased from 1.1 × 106 A/cm2 to 6.5 × 105 A/cm2, suggesting a large temperature changes up to ∼300 °C.