Abstract
Abstract Polycrystalline n-type semiconducting metal oxides such as ZnO and SnO2 have been used in commercial gas-sensing devices for many years, the mode of operation being based on the decrease in surface electrical resistance in the presence of reducing gases. Although the polycrystalline materials are highly sensitive to these gases, a major disadvantage is their lack of selectivity. Studies of single crystals of ZnO and SnO2 have shown that the single crystals are selective to carbon monoxide (CO) over methane (CH4). In this paper we describe the results of electrical studies performed on single crystals of TiO2 in the presence of gas mixtures. It is found that these crystals are also highly selective to CO in air but only in their stoichiometric form and the effect is to decrease the conductivity. The results can be explained in terms of the crystals behaving as extrinsic p-type semiconductors at the temperatures where they respond to the gases.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
