Thermal conductivity of a 300-nm-thick VO2thin film and its temperature dependence across the metal-insulator phase transition (TMIT) were studied using a pulsed light heating thermoreflectance technique. The VO2and Mo/VO2/Mo films with a VO2thickness of 300 nm were prepared on quartz glass substrates: the former was used for the characterization of electrical properties, and the latter was used for the thermal conductivity measurement. The VO2films were deposited by reactive rf magnetron sputtering using a V2O3target and an Ar-O2mixture gas at 645K. The VO2films consisted of single phase VO2as confirmed by X-ray diffraction and electron beam diffraction. With increased temperature, the electrical resistivity of the VO2film decreased abruptly from 6.3 × 10-1to 5.3 × 10-4Ωcm across the TMITof around 325-340K. The thermal conductivity of the VO2film increased from 3.6 to 5.4W m-1K-1across the TMIT. This discontinuity and temperature dependence of thermal conductivity can be explained by the phonon heat conduction and the Wiedemann-Franz law.
ASJC Scopus subject areas
- Physics and Astronomy(all)