High-temperature Pd Schottky diode gas sensor on p-type GaN

In this report, Pd Schottky diodes to p-type GaN are described. The response of the diodes to nitrogen and 2 percent hydrogen in nitrogen at temperatures from 50-500 C and the thermal stability of the diodes during long term annealing at 500 C have been investigated by long term annealing at 500 C in Ar. When exposed to changes in ambient, changes in the surface potential will lead to large changes in channel current The results indicate that Pd diodes on p-type GaN appear promising for nitrogen and 2 percent hydrogen in nitrogen detection in this temperature range. The characteristics of Pd Schottky diodes on p-type GaN in nitrogen and 2 percent hydrogen in nitrogen are reported in this report This response has been characterized by current-voltage measurements, revealing that the diodes are able to detect 2 percent hydrogen in nitrogen from 50-500 C and nitrogen from 150-500 C This is roughly double the detection sensitivity of comparable GaN Schottky gas sensors tested under the same conditions, confirming that the Pd/p-type GaN based diode has advantages for applications requiring the ability to detect combustion gases even at room temperature.