NO2 Gas Sensor Using ITO Thin Films Prepared by Electron Shower and Magnetron Sputtering

The sensitivity of the ITO films prepared by electron shower increased exponentially with concentration of NO₂, and the sensitivity was 130 at 500 ppm NO₂. The sensitivity increased with decreasing the film thickness below 40nm. The sensitivity was highest at 250°C and the reproducibility was excellent. The sensitivity and the critical thickness of a film prepared by sputtering were lower than that prepared by electron shower. The surface roughness of the film prepared by electron shower was ten times higher, which affected the sensitivity.