GaN Resistive Gas Sensors for Hydrogen Detection
We report on the fabrication and testing of GaN resistive gas sensors for hydrogen detection. The Si-doped n-type GaN was grown by organometallic vapor phase epitaxy (OMVPE) on c-plane sapphire substrates. The device structure is simply a pair of metal ohmic contact pads. The sensors are sensitive to H2 gas over a wide range of concentration: the lowest concentration tested being ~0.1% H2 (in Ar), well below the lower combustion limit in air. No saturation of the signal is observed up to 100% H2 flow. In the continuous operation mode with varying H2 concentration, a clear and sharp response was recorded with no memory effects during ramping up and down cycles of H2 concentration. The change in current at a fixed voltage to hydrogen was found to change with sensor geometry. The possible gas sensing mechanisms are still under investigation.
Robert P. Devaty, David J. Larkin and Stephen E. Saddow
F. Yun et al., "GaN Resistive Gas Sensors for Hydrogen Detection", Materials Science Forum, Vols. 527-529, pp. 1553-1556, 2006