Fabrication and gas sensing characteristics of pure and Pt-doped gamma-Fe2O3 thin film

The gamma -Fe2O3 thin films were prepared by the reduction and the oxidatio n of Fe-O thin films processed by plasma-enhanced chemical vapor deposition (PECVD) technique. The phase transformation of Fe-O thin films was mainly controlled by the substrate temperature and rf power. The Fe-O amorphous ph ase was initially obtained at the deposition rf power over 150 W. The Fe-O amorphous phase could be transformed into gamma -Fe2O3 phase under the cont rolled reduction and oxidation at 280-320 degreesC. Based on the result of sensing characteristics, the prepared gamma -Fe2O3 thin film showed the exc ellent sensitivity to i-C4H10 and H-2 gas. The sensitivities of gamma -Fe2O 3 thin film to i-C4H10 and Hz gas were 60 and 90% in 500 ppm environments a nd 76 and 96% in 3000 ppm environments, respectively. On the other hand, th e Pt-addition to y-Fe2O3 thin film does not improve the gas sensitivity in H-2 atmosphere. (C) 2001 Elsevier Science B.V. All rights reserved.