Studies on electric triggering of the metal-insulator transition in VO2 thin films between 77 K and 300 K

We investigate the electrically triggered metal-insulator transition (E-MIT) in VO2 thin films at temperatures far below the structural phase transition temperature (similar to 340 K). At 77 K, the maximum current jump observed across the E-MIT is nearly 300x. The threshold voltage for E-MIT decreases slightly from similar to 2.0 V at 77 K to similar to 1.1 V at 300 K across similar to 200 nm thick films, which scales weakly over the temperature range of 77-300 K with an activation energy of similar to 5 meV. The phase transition properties are found to be stable after over one thousand scans, indicating reproducible measurements. Analysis of the scaling behavior suggests that the observed weak temperature-dependence of the threshold voltages for E-MIT is smaller than that predicted for a purely current induced Joule heating effect and may include contribution from field effect or carrier injection under applied bias. The results are of potential relevance to the field of phase transition oxide electronics and further understanding of the transition mechanisms. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3619806]