A Novel Mechanism Based on Oxygen Vacancies to Describe Isobutylene and Ammonia Sensing of p-Type Cr<sub>2</sub>O<sub>3</sub> and Ti-Doped Cr<sub>2</sub>O<sub>3</sub> Thin Films
Pengfei Zhou,
Jone-Him Tsang,
Chris Blackman,
Yanbai Shen,
Jinsheng Liang,
James A. Covington,
John Saffell,
Ehsan Danesh
Affiliations
Pengfei Zhou
Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China
Jone-Him Tsang
Department of Chemistry, University College London, London WC1H 0AJ, UK
Chris Blackman
Department of Chemistry, University College London, London WC1H 0AJ, UK
Yanbai Shen
School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China
Jinsheng Liang
Key Laboratory of Special Functional Materials for Ecological Environment and Information, Hebei University of Technology, Ministry of Education, Tianjin 300130, China
James A. Covington
School of Engineering, University of Warwick, Coventry CV4 7AL, UK
John Saffell
NosmoTech Ltd., Cambridge CB3 0AZ, UK
Ehsan Danesh
Advanced Sensing Technologies Ltd., London N12 8FA, UK
Gas sensors based on metal oxide semiconductors (MOS) have been widely used for the detection and monitoring of flammable and toxic gases. In this paper, p-type Cr2O3 and Ti-doped Cr2O3 (CTO) thin films were synthesized using an aerosol-assisted chemical vapor deposition (AACVD) method. Detailed analysis of the thin films deposited, including structural information, their elemental composition, oxidation state, and morphology, was investigated using XRD, Raman analysis, SEM, and XPS. All the gas sensors based on pristine Cr2O3 and CTO exhibited a reversible response and good sensitivity to isobutylene (C4H8) and ammonia (NH3) gases. Doping Ti into the Cr2O3 lattice improves the response of the CTO-based sensors to C4H8 and NH3. We describe a novel mechanism for the gas sensitivity of p-type metal oxides based on variations in the oxygen vacancy concentration.
