On the hydrogen sensing characteristics of a Pd/AlGaN/GaN heterostructure field-effect transistor (HFET)

The interesting temperature-dependent hydrogen sensing characteristics of a Pd/AlGaN/GaN heterostructure field-effect transistor (HFET) are studied and demonstrated. Remarkable hydrogen sensing performance is found at a very low concentration of hydrogen gases (≤1 ppm H2/air). In addition, a good transistor switching behavior with the high drain current on/off value of 93,680 is obtained for 1% ppm H2/air gas at 523 K. The fast transient response as comparable with a Schottky-type hydrogen sensor is also observed. Based on these advantages, the studied device shows a promise for high-performance, high-temperature electronics, and micro electro-mechanical system (MEMS) applications.