TiO2 seed-assisted growth of VO2(M) films and thermochromic performance†
Abstract
This paper reports the TiO2 seed-assisted hydrothermal growth of VO2 films on a quartz substrate. The rutile TiO2 seed layer can promote the oriented growth of VO2(M) at the initial stage of the hydrothermal reaction, and then, the VO2(D) phase further grows on top of the VO2(M) layer. It was found that a pure VO2(M) thin film can grow on the TiO2 seed layer at a temperature as low as 200 °C. A subsequent annealing treatment can transform the VO2(D) phase to the VO2(M) phase. The VO2(M)/TiO2 composite films display thickness-dependent optical and electrical performance, and nearly 55% infrared modulation at 3 μm and 3 orders of magnitude resistance modulation can be realized. Our results demonstrate important progress in growth of VO2(M) thermochromic thin films, which will find potential application in constructing VO2-based switching devices.