Stable hydrogen sensors from AlGaN/GaN heterostructure diodes with TiB 2-based Ohmic contacts

Hung Ta Wang, T. J. Anderson, B. S. Kang, F. Ren, Changzhi Li, Zhen Ning Low, Jenshan Lin, B. P. Gila, S. J. Pearton, A. Osinsky, Amir Dabiran

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39 Scopus citations


The use of TiB 2-based Ohmic contacts on Pt-gate AlGaN/GaN heterostructure diode hydrogen sensors is shown to provide very stable operation for detection of 1% H 2 in air under field conditions where temperature is allowed to vary. In contrast, the use of more conventional Ti/Al/Pt/Au Ohmic contacts led to higher background variations in current that affect the ultimate detection threshold of the sensors. Combined with a differential pair geometry that compares current from an active diode with Pt-gate contact and a passive diode with Ti/Au gate, the more stable TiB 2-based Ohmic contacts reduce false alarms due to ambient temperature changes. The diodes exhibit a change in forward current of more than 1 m.A at 1.5 V when 1% H 2 is introduced into an air ambient.

Original languageEnglish
Article number252109
JournalApplied Physics Letters
Issue number25
StatePublished - 2007


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