Highly sensitive NO2 gas sensor fabricated with RF induction plasma deposition method

For the development of highly sensitive NO2 gas sensor, SnO2-based film was prepared using radio-frequency (RF) induction plasma deposition (IPD) method. It is first shown that the IPD process is possible to fabricate a gas sensitive film consisting of nanostructured particles supported by rather large particles by controlling several processing parameters of plasma deposition. The effect of processing parameters and annealing temperatures on the physical properties of SnO2 thin films was examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) method. The sensor films were used to detect NO2 gas at a concentration range from 20 to 200 parts-per-billion (ppb), and the results show that the gas sensors have achieved high sensitivity at extremely low NO2 concentration down to 20 ppb with the response and recovery time less than several minutes. (C) 2003 Elsevier B.V. All rights reserved.