GASEOUS NO2 DETECTOR AND DETECTING METHOD

摘要

PURPOSE:To obtain a sensitive film having superior sensitivity and response speed, by using an SnO2 thin film having <= 4 X-ray diffraction intensity ratio of a (110) plane for a (211) plane as the sensitive film. CONSTITUTION:An SnO2 thin film having <= 4 X-ray diffraction intensity ratio of a (110) plane to a (211) plane is used for a sensitive film. Response speed of this gas detector shown by leading edge percentage SA(60) and a tailing edge percentage SD(60) is 85-100% nearly independent to a decrease of an X-ray diffraction intensity ratio I in case of <= 4 ratio I. On the contrary, said speed is slowed down suddenly in case of >= 4 ratio I and is decreased to about 60% nearly independent to an increase of the ratio I. Also, the value of a sensitivity S is about 5-10 nearly independent to the increase of the ration I in case of >= 4 ration I and the sensitivity S is increased corresponding to the decrease of the ratio I in case of <= ratio I. The maximum value of the sensitivity is found at near 240 deg.C operation temperature and the sensitivity becomes zero at >=500 deg.C operation temperature.