Modeling of temperature-dependent resistance in micro- and nanopolycrystalline VO2 thin films with random resistor networks

Micro- and nanopolycrystalline VO2 thin films with hysteretic first-order metal-insulator transition were fabricated by the reactive ion-beam sputtering method. The phase transition temperatures of the micro- and nanopolycrystalline films are at 68 and 45 °C, respectively. Using the random-resistor-network model, the characteristics of hysteretic resistance versus temperature are simulated for these films. The modeling results are checked against the experimental measurements. There is satisfactory agreement between the calculated resistance-temperature trajectories and the measured major hysteresis loops for both micro- and nanopolycrystalline films over the whole temperature range from the low-temperature semiconductor behavior to the high-temperature metallic state, which gives strong support to the present approach.