2006 Volume 47 Issue 8 Pages 1894-1897
The out-of-plane thermal conductivity of sputtered tungsten oxide thin films with thickness of 100 to 300 nm was measured by two omega method based on a new analytical model with consideration of the interfacial thermal resistance between the films and the substrate. The influence of the tungsten oxide structure on the thermal conductivity was studied. The result reveals that the tungsten oxide thin films made with 10% reactive gas of oxygen had a mixed phase of WO2 and WO3, while those made with 100% oxygen were WO3 only. The thermal conductivity of WO3 thin films is 1.63 Wm−1 K−1, and that of WO2/WO3 films is 1.28 Wm−1 K−1. The difference is explained by a higher thermal resistance at the interface of WO2 and WO3 crystals caused by the mismatch of phonon state.