Gas sensing properties of nanosized tin oxide synthesised by mechanochemical processing

Tin oxide thin films have been prepared by mechanochemical processing and spin coating. Separated SnO2 nanoparticles, averaging 24 nm, were produced by mechanochemical processing. The powder consisted primarily of tetragonal SnO2, however, some orthorhombic SnO2 was also found to be present. SnO2 thin films were prepared by spin coating onto alumina transducers, followed by subsequent annealing. XPS analysis concluded the films were essentially stoichiometric with carbon being the main impurity. The average particle size of the SnO2 film was found to be approximately 34 nm. The electrical response of the sensor to O2, over the concentration range 1 ppm to 10%, was measured. The sensor was found to be extremely stable and repeatable, with a response and decay time of approximately 2 min. The response and decay times were found to decrease as the oxygen concentration increased.