Tin oxide gas sensor on tin oxide microheater for high-temperature methane sensing

Abstract Despite the ever-increasing demand for methane detectors in residential and industrial locations, a long life semiconductor-based methane sensor is yet elusive. The problem is rooted in the high decomposition temperature of the methane molecule. Here, we disclose a tin oxide gas sensor heated up to its operating temperature using a ten micron-thick undoped tin oxide microheater which can operate at temperatures as high as 850 °C, sufficient for the spontaneous pyrolysis of methane. Operating at temperatures above 700 °C, the device selectively senses methane in atmospheres contaminated with CO and H2. The response and recovery times are both ~10 s, and the CH4 detection limit is 50 ppm, rendering the developed sensor appropriate for online measurement of methane level in hot exhaust gases. Operating continuously at 700 °C in air, the device exhibits no noticeable aging in a test duration of 30 days.