Pt-AlGaN/GaN Hydrogen Sensor With Water-Blocking PMMA Layer

One of the biggest issues with GaN-based hydrogen sensors is their sensitivity to humidity in the ambient. We demonstrate that encapsulation of Pt-AlGaN/GaN Schottky diode with poly(methyl methacrylate) (PMMA) provides effective mitigation of the effects of water. Without PMMA encapsulation, the abs...

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Bibliographic Details
Published in:IEEE electron device letters 2017-05, Vol.38 (5), p.657-660
Main Authors: Sunwoo Jung, Kwang Hyeon Baik, Fan Ren, Pearton, Stephen J., Soohwan Jang
Format: Article
Language:English
Subjects:
Aluminum gallium nitride
Gallium nitride
GaN
Hydrogen
Moisture barrier
Schottky diodes
Sensitivity
sensor
Wide band gap semiconductors
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Summary:One of the biggest issues with GaN-based hydrogen sensors is their sensitivity to humidity in the ambient. We demonstrate that encapsulation of Pt-AlGaN/GaN Schottky diode with poly(methyl methacrylate) (PMMA) provides effective mitigation of the effects of water. Without PMMA encapsulation, the absolute current signal for detection of 500 ppm of H 2 was decreased by a factor of 8 in the presence of water. By sharp contrast, encapsulated diodes show no decrease in response in the presence of water. The relative current changes are of the order 2.8 × 10 5 % when 500 ppm H 2 is introduced to the surface of bare or PMMA encapsulated diodes in the absence of water or to encapsulated diode in the presence of water. Detection limits of ~100 ppm H 2 (0.01% by volume) were obtained with standard forward bias detection mode at 1.3 V.
ISSN:0741-3106
1558-0563
DOI:10.1109/LED.2017.2681114