Characteristics of chemiresistive-type ammonia sensor based on Ga2O3 thin film functionalized with platinum nanoparticles

A new chemiresistive-type ammonia (NH3) gas sensor based on gallium oxide (Ga2O3) thin film functionalized with platinum (Pt) nanoparticles (NPs) is fabricated and investigated. The Pt NP/Ga2O3 gas sensor exhibits p-type conductive resistor, which can be attributed to the formation of inversion (hole) layer on the surface of the Ga2O3 thin film. For the employment of Pt NPs, it could effectively expand the specific surface area and enhance the catalytic activity. A high sensing response ratio SR of 6.88 under 1000 ppm NH3/air gas and a relatively low detecting level of 1 ppm NH3/air are obtained at operation temperature of 225 °C. The studied device shows the advantages of a simple structure, easy fabrication, and high sensing response ratio. Therefore, the studied Pt NP/Ga2O3 thin film structure provides a good potential for high-performance ammonia sensing applications.