Abstract
n-type semiconductive oxides such as SnO2 and ZnO have been used in the gas sensor applications. The change in the material conditions under an operating condition was investigated with respect to the optical and electric properties. The optical absorption between 300-600 nm was enhanced when a thin-film of SnO2 was exposed to 0.5 % H2-N2 gas at 300 deg.C, whereas such absorption change was not observed in ZnO up to 400 deg.C. While the change of the electric conductivity depended on the change in both carrier density and mobility in SnO2, that in ZnO was mainly due to mobility change. Difference between SnO2 and ZnO was detected in the response against 0.5 % H2/N2.
