AlGaN/GaN heterostructure based hydrogen sensor with temperature compensation

One of the issues in GaN based hydrogen sensors is that the sensor signal is affected by the ambient temperature as well as hydrogen exposed to the device. This may trigger a false arm in safety system and a malfunction of hydrogen fuel cell vehicle. We demonstrate an AlGaN/GaN-based hydrogen gas sensor set with simple temperature compensation structure to overcome the effect of the ambient temperature on hydrogen sensing performance. When the sensor set is exposed to hydrogen ambient, hydrogen molecules decompose only on the Pt diode of the set, resulting in compensation of the ambient temperature effect on the output signal. The sensor set showed very stable output voltage change of 0.635 V for the temperature fluctuation from 25 °C to 200 °C at the constant input bias of 5 V. The serially-connected diode set exhibited sensitive voltage response to 500–5000 ppm hydrogen exposure at 25 °C. In addition, the diode set presented a reliable output voltage responsivity to the repeated hydrogen exposures under temperature changing condition.