Effect of Si addition on epitaxial growth and gas sensing properties of tungsten oxide films

抄録

WO₃ epitaxial films with the same thickness and in-plane crystal grain size were prepared using pulsed laser deposition with various Si contents in the target to clarify the effect of Si addition to WO₃ on the gas sensing properties. X-ray diffraction measurements indicated that the films grown on the (1102) face of sapphire had a (001) orientation with in-plane epitaxial relationships of [110]WO₃//[0111] or [110]WO₃//[2110]Al₂O₃, regardless of the Si content. Scanning probe microscopy observations revealed that particles with a diameter of several tens of nanometers grow on the surface of the Si-doped WO₃ film. Measurements of the gas response to ethanol and acetone showed superior gas selectivity towards acetone gas at low temperatures, which is due to the catalytic effect of SiO_x particles on the film surface.