1. AlGaN/GaN Schottky diode hydrogen sensor performance at high temperatures with different catalytic metals
- Author
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Junghui Song, Jeffrey S. Flynn, George R. Brandes, and Wu Lu
- Subjects
Hydrogen ,Chemistry ,business.industry ,Aluminium nitride ,Schottky barrier ,Analytical chemistry ,Schottky diode ,chemistry.chemical_element ,Gallium nitride ,Heterojunction ,Condensed Matter Physics ,Hydrogen sensor ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Materials Chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Diode - Abstract
Schottky diodes on AlGaN/GaN heterostructures with Pt, IrPt, and PdAg catalytic metals are fabricated and characterized from 200 °C to 800 °C for H 2 sensing. Over this large range of temperature, the forward current of all the diodes increases with exposure to H 2 gas, which is attributed to Schottky barrier height reduction caused by the atomic hydrogen absorption on the metal–oxide interface. The results indicate that AlGaN/GaN heterostructure Schottky diodes are capable of high-temperature H 2 sensor operation up to 800 °C. As temperature increases, the hydrogen detection sensitivity of Pt and IrPt diodes improves due to the more effective H 2 dissociation. However, the sensitivity of PdAg diodes degrades with the increase of temperature due to thermal instability of PdAg. At a range of temperature from 200 °C to 300 °C, PdAg diodes exhibit significant higher sensitivity compared with Pt and IrPt diodes. IrPt and Pt diodes show higher sensitivity at temperatures above 400 °C.
- Published
- 2005