Metal-insulator transition in free-standing VO2/TiO2 microstructures through low-power Joule heating

We investigated voltage bias-driven electronic phase switching from insulating to metallic states in the VO2 thin films having freestanding structures (FSS) and non-freestanding structures (N-FSS). By measuring the electrical power during switching under different thermal conditions, we found that the thermal coupling of the microstructures determined the spatial temperature distribution on the device and strongly affected the efficiency of the insulator-metal switching induced by the Joule effect. The power required for switching in the FSS was two orders lower than that for the N-FSS. This indicates that an appropriate design of the thermal flow is a fundamental issue for developing efficient switching and memristive devices. (C) 2014 The Japan Society of Applied Physics