MICROSTRUCTURE AND NO2 SENSING PROPERTIES OF FE2O3 THIN-FILMS

W-doped Fe2O3 films have been fabricated on polycrystalline alumina su bstrates by the RF magnetron sputtering method, and effects of anneali ng temperature on the NO2 sensing properties have been examined. The c rystal structure of the obtained film changed from Fe3O4 to alpha-Fe2O 3 after annealing at temperatures of 500 to 700-degrees-C in air. An i ncrease in the annealing temperature increased the particle size, resu lting in a decrease in the NO2-gas sensitivity. These results suggest that the NO2 sensitivity of W-doped Fe2 O3 film depends on the particl e size.