The isopropyl alcohol gas sensitivity of this material at 250C was found to depend upon the TiO2 content and the cation stoichiometric ratio. The sensitivity enhancement was related to the defect structure and electrical conductivity behavior of p-type donor-doped semiconducting oxides. A high resistivity, coupled with an increased number of point defects, due to the donor dopants, were suggested to be responsible for the high gas sensitivity of TiO2-doped samples. It was thought that the positively charged ionic-type defects, which were created by dopants, acted as trapping sites for the adsorption of O.

R.F.Huang, W.Y.Howng: Journal of Materials Research, 1996, 11[12], 3077-82