High-temperature Pt Schottky barrier gas sensor on p-type GaN

In this report, Pt Schottky barriers to p-type GaN are described. The response of the sensors to argon (Ar) and 10 percent methane (CH/sub 4/) in Ar at temperatures from 50-500/spl deg/C and the thermal stability of the sensors have been investigated by long term annealing at 500/spl deg/C in nitrogen. When exposed to changes in ambient, changes in the surface potential lead to large changes in channel current. The results indicated that Pt sensors on p-type GaN for Ar and 10 percent CH/sub 4/ in Ar detection with this temperature range. Sensor response has been characterized by current-voltage measurements, revealing it ability to detect 10 percent CH/sub 4/ in Ar from 50-500/spl deg/C and Ar from 150-500/spl deg/C. This is roughly double the detection sensitivity of comparable GaN Schottky gas sensors tested under the same conditions, confirming that the Pt/p-type GaN based sensors has advantages for applications requiring the ability to detect combustion gases even at room temperature.