Current-controlled optical modulation in thin VO2 wires
We measured the current-voltage and infrared optical transmission characteristics of thin film VO2 wires over the metal-insulator phase transition. The phase transition had electrical or thermal characteristics depending on the wire geometry and applied current.
Sub-volt broadband hybrid plasmonic-vanadium dioxide switches
The insulator-metal phase transition of a correlated-electron material, vanadium dioxide, is used to demonstrate electrically controlled, compact, broadband, and low voltage plasmonic switches. The devices are micron-scale in length and operate near a wavelength of 1550 nm. The switching bandwidths exceed 100 nm and 400 mV is sufficient to attain extinction ratios in excess of 20 dB. The results illustrate the promise of using phase transition materials for efficient and ultra-compact plasmonic switches and modulators.
Studies on electric triggering of the metal-insulator transition in VO 2 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 (∼340 K). At 77 K, the maximum current jump observed across the E-MIT is nearly 300×. The threshold voltage for E-MIT decreases slightly from ∼2.0 V at 77 K to ∼1.1 V at 300 K across ∼200 nm thick films, which scales weakly over the temperature range of 77–300 K with an activation energy of ∼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 mech...