Sensitivity control of SnO2 by morphology of thin film

Gas sensing properties of SnO2 thin films with different microstructures fabricated by RF magnetron sputtering method were investigated over the temperature range 623–773 K, using the same concentration of H2 or CH4 containing dry air as test gases. The SnO2 thin film with dense structure gave much larger conductivity change in contact with 3600 ppm H2 containing dry air than with the same concentration of CH4 over 623–773 K. The thin film with columnar structure showed that the conductivity in contact with 3600 ppm CH4 containing air was approximately equal to that with the same concentration of H2 at 773 K. The morphological control of the thin film results in a notable change in gas sensing properties of the SnO2 thin film.