NO x gas sensing properties of tungsten oxide thin films synthesized by pulsed laser deposition method

Abstract

Tungsten oxide (WO 3) thin films have been deposited on silicon(1 0 0) and alumina substrates by using a pulsed excimer laser deposition method in oxygen gas. The crystalline structure and crystallographic orientation of the WO 3 films, measured by glancing-angle X-ray diffraction (GXRD) system, suggested that there were distinct peaks of crystalline WO 3(0 0 1), (1 1 1), (2 0 1), (1 2 1), (0 0 2), (1 1 2), and (0 2 2) on the film prepared at P O 2 =10 Pa. The maximum sensitivity of WO 3 film, synthesized at P O 2 =10 Pa for 200 ppm NO x was increased with increasing substrate temperature. The maximum sensitivity for 200 ppm NO and 200 ppm NO 2 were approximately 65 and 170, respectively, at the operating temperature of 400 °C. The substrate temperature results in a notable change in NO x gas sensing properties of WO 3 thin films.