Low temperature NO2 sensing performance of nano-structured SnO2 thin films

摘要

SnO2 thin films were prepared by spray pyrolysis technique. Aqueous solution (0.05M) of SnCl2·2H2O in deionized water was chosen as the starting solution for the preparation of thin films. The aerosol produced by nozzle was sprayed on glass substrate heated at 250 oC. The sensing performance of the films was tested for various gases such as LPG, hydrogen, ethanol, carbon dioxide, ammonia, nitrogen dioxide, nitrogen monoxide and sulphurdioxide. The sensor (30 min) showed high gas response (S = 1165 at 150 oC) on exposure of 100 ppm of NO2 and high selectivity against other gases. Its response time was short (4 s) and recovery was also fast (9 s). To understand reasons behind this uncommon gas-sensing performance of the films, their structural and microstructural properties were studied using X-ray diffraction, electron microscopy (FE-SEM and TEM) respectively. Elemental composition was studied using energy dispersive of X-rays (EDAX). The results are discussed and interpreted.