Temperature sensitivity of resistance of VO2 polycrystalline films formed by modified ion beam enhanced deposition

VO2 polycrystalline films were directly prepared from V2O5 powder using modified ion beam enhanced deposition (IBED) method after appropriate annealing. Test results showed that IBED VO2 polycrystalline films have a single orientation, an evident phase transition, a compact structure, and favorable processing properties. The temperature coefficient of resistance (TCR) of the films was up to more than 4%/K, and the IBED VO2 films were firmly adhered to the substrate. The mechanism of the IBED films with higher TCR could be explained as following. The oxygen vacancies and grain boundaries in the films were decreased due to the IBED technology. With a single crystal orientation and dense texture, the conduction activation energy of the IBED VO2 polycrystalline films was closer to that of VO2 single crystal in the semiconductor phase as compared with VOx films formed by other methods. (C) 2004 Published by Elsevier B.V.