Enhancement of trimethylamine sensitivity of MOCVD-SnO2 thin film gas sensor by thorium

A thin film SnO2-based trimethylamine (TMA) gas sensor has been developed by using metallorganic chemical vapor deposition (MOCVD) technique. The effects of temperature and thorium dopant on the sensitivity of the sensor have been studied. The peak sensitivity of the sensor to TMA was found at 290°C. Thorium was an excellent sensitizer, which could increase the sensitivity to 300 ppm TMA from 5.9 to 142. The MOCVD-SnO2 element was capable of detecting TMA gas in a level of 10 ppm with short response time (16 s) with little interference of NH3.