Improved hydrogen detection sensitivity in N-polar GaN Schottky diodes
- 25 May 2009
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 94 (21), 212108
- https://doi.org/10.1063/1.3148369
Abstract
Pt/GaN Schottky diodes fabricated on m -plane (N-polar) layers grown on sapphire exhibit much larger responses to dilute concentrations (4% in N 2 ) of hydrogen at room temperature than comparable Ga-polar devices. This is consistent with previous density functional theory indicating a very high affinity of hydrogen for the N-face surface of GaN. The rectifying current-voltage characteristics of N-face diodes make a transition to more Ohmic-like behavior after hydrogen exposure, leading to very large ( ∼ 10 6 ) maximum percentage changes in current relative to Ga-face ( ∼ 10 % ) or AlGaN/GaN heterostructure diodes ( ∼ 170 % ) . The strong affinity of the N face of GaN for hydrogen also leads to a slower recovery of these diodes when hydrogen is removed from the ambient.Keywords
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