To improve sensing properties of WO3 thin film gas sensor on NO2 at room temperature

the WO3 thin films are sputtered on Al2O3 by DC facing target magnetron sputtering

the samples is rapidly thermal treated in the mixture gas of N2∶ O2=4∶ 1

and at different temperature of 500

600 ℃and 700 ℃.The morphology of all the three samples are investigated by scanning electron microscope（SEM）

the crystallization structure is characterized by X-ray diffraction（XRD）.The NO2 sensing measurement experiments are taken under the LED light at the room temperature.The result shows that the sample after rapidly thermal treated at 600 ℃ performs best

with the sensitivity of about 100 and has good response and recovery property.LED is easy to integrate with IC

and has low energy consumption

simple

and practical.