Porous WO_3 from anodized sputtered tungsten thin films for NO_2 detection

摘要

In this paper, porous WO_3 films were prepared by anodic oxidation of metallic tungsten (W) films deposited on alumina substrates. The structural and morphological properties of the porous WO_3 films were investigated using field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). A large number of cracks appeared on the surface of films after anodization, which makes the films porous. The porous WO_3 sensors achieved their maximum response values to NO_2 at a low operating temperature of 150 ℃. The porous WO_3 sensors showed high response values, great stability and fast response-recovery characteristics to different concentration of NO2 gas due to the high specific surface area and special structural and morphological properties.