Abstract

Various phases of VO₂ have been observed since the discover of Mott transition, and these phases can be modulated by manipulation of various stimuli. In this study, we employed external strain to drive the phase change in single VO₂ nanobeam, and two types strain-sensitive devices were fabricated utilizing different phase transition mechanisms. The first one is based on the insulating phase transition of M₁ and M₂, and the competition mechanism between the insulating phases was observed by in-situ confocal Raman microscopy and the ratio of M₁/M₂ in nanobeam can be well controlled by external strain. This principle was utilized for assembling high performance strain sensor with quick and reversible response and the high gauge factor (~347). Another device is based on the insulating-metallic phase transition of VO₂ nanobeam that benefited from its typical strong correlation characteristic. Combining self-heating and external strain these two environmental stimuli, the insulating and metallic phase of VO₂ nanobeam can be switched through coupling the bias voltage and applied strain, which was used for high-performance electro-mechanical switch fabrication. The switch is very fast and stable, more importantly, we achieved the single-domain transition, thus allowing the device with four orders of magnitude change in resistance.

© 2013 Optical Society of America