Moisture Insensitive PMMA Coated Pt-AlGaN/GaN Diode Hydrogen Sensor and Its Thermal Stability

Baik, Kwang Hyeon; Jung, Sunghwan; Ren, F.; Pearton, S. J.; Jang, Soohwan

doi:10.1149/2.002107jss

Cited by 10 publications

(10 citation statements)

References 46 publications

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“…The relative current change for PMMA-coated diode sensors reached the maximum value of 805% in wet H 2 ambient conditions at room temperature. The PMMA layer performed well in ZnO SBDs as a membrane layer, which selectively blocked water molecules, as previously reported by the authors [21,22]. Figure 4b presents the transient change in SBH of Pt/ZnO SBDs in dry H 2 and PMMA-coated Pt/ZnO diodes in wet H 2 ambient conditions.…”

Section: Methodssupporting

confidence: 80%

“…The increase in operation temperature and the addition of select dopants were proposed to mitigate the effects of water on the sensitivity [19,20]. In the case of diode-based gas sensors, the sensitivity and selectivity were reported to be severely degraded in humid air conditions [21][22][23]. Under the exposure of water vapor, the surface-active sites for gas adsorption can be blocked by water molecules, thus resulting in the sensitivity drop in the presence of water vapor.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogen Sensing Performance of ZnO Schottky Diodes in Humid Ambient Conditions with PMMA Membrane Layer

Jang

Jung

Baik

2020

Sensors

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Enhanced hydrogen sensing performance of Pt Schottky diodes on ZnO single crystal wafers in humid ambient conditions is reported using a polymethylmethacrylate (PMMA) membrane layer. ZnO diode sensors showed little change in forward current when switching to wet ambient H2 conditions with 100% relative humidity. This sensitivity drop in the presence of water vapor can be attributed to surface coverage of hydroxyl groups on the Pt surface in humid ambient conditions. The hydrogen sensitivity of PMMA-coated diode sensors recovered up to 805% in wet H2 ambient conditions at room temperature. The PMMA layer can selectively filter water vapor and allow H2 molecules to pass through the membrane layer. It is clear that the PMMA layer can effectively serve as a moisture barrier because of low water vapor permeability and its hydrophobicity. In both dry and wet conditions, ZnO diodes exhibited relatively fast and stable on/off switching in each cycle with good repeatability.

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Section: Methodssupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Hydrogen Sensing Performance of ZnO Schottky Diodes in Humid Ambient Conditions with PMMA Membrane Layer

Jang

Jung

Baik

2020

Sensors

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“…Polymethylmethacrylate (PMMA) polymer has good properties for use in electronic and storage devices and sensors. Also, it is noted to have a good thermal stability under different environmental conditions [19,22]. Polydimethylsiloxane (PDMS) is a polymer used because of its low cost, high thermal expansion coefficient, and good adhesion to silicon.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Detection with SAW Polymer/Quantum Dots Sensitive Films

Constantinoiu

Viespe

2019

Sensors

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Regarding the use of hydrogen as a fuel, it is necessary to measure its concentration in air at room temperature. In this paper, sensitive composite films have been developed for surface acoustic wave (SAW) sensors, using quantum dots (QDs) and polymers. Si/SiO2 QDs were used due to having a high specific surface area, which considerably improves the sensitivity of the sensors compared to those that only have a polymer. Si/SiO2 QDs were obtained by laser ablation and analyzed by X-ray diffraction and transmission electron microscopy (TEM). Two types of polymers were used: polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA). Polymer and polymer with QDs compositions were deposited on the sensor substrate by drop casting. A heat treatment was performed on the films at 80 °C with a thermal dwell of two hours. The sensors obtained were tested at different hydrogen concentrations at room temperature. A limit of detection (LOD) of 452 ppm was obtained by the sensor with PDMS and Si/SiO2 QDs, which was heat treated. The results demonstrated the potential of using QDs to improve the sensitivity of the SAW sensors and to achieve a heat treatment that increases its adsorption capacity of the gas molecules.

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“…[6][7][8][9][10] Various types of sensors based on the GaN, including Schottky diode, nanowire and AlGaN/GaN high electron mobility transistor (HEMT) have been reported for fast and sensitive detection of hydrogen. [6][7][8][9][10][11][12][13][14][15][16] The authors have reported several GaN based hydrogen sensors. The responsivities of the devices to hydrogen exposures were improved by employing Pt nanonetwork sensing material, 11,12 photo-chemically roughened GaN surface, 7,8 and different crystal planes 9,10,13 .…”

mentioning

confidence: 99%

“…Also, the effect of the humidity on hydrogen sensor performance was mitigated by using the moisture barrier encapsulation. [14][15][16] One of the remaining issues with GaN based hydrogen sensor is the effect of ambient temperature on sensing signal. The current level or resistance of the semiconductor based sensor is affected by the temperature.…”

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confidence: 99%

AlGaN/GaN Heterostructure Based Hydrogen Sensor with Temperature Compensation

Baik

Jang

2020

ECS J. Solid State Sci. Technol.

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One of the issues in GaN based hydrogen sensors is that the sensor signal is affected by the ambient temperature as well as hydrogen exposed to the device. This may trigger a false arm in safety system and a malfunction of hydrogen fuel cell vehicle. We demonstrate an AlGaN/GaN-based hydrogen gas sensor set with simple temperature compensation structure to overcome the effect of the ambient temperature on hydrogen sensing performance. When the sensor set is exposed to hydrogen ambient, hydrogen molecules decompose only on the Pt diode of the set, resulting in compensation of the ambient temperature effect on the output signal. The sensor set showed very stable output voltage change of 0.635 V for the temperature fluctuation from 25 °C to 200 °C at the constant input bias of 5 V. The serially-connected diode set exhibited sensitive voltage response to 500–5000 ppm hydrogen exposure at 25 °C. In addition, the diode set presented a reliable output voltage responsivity to the repeated hydrogen exposures under temperature changing condition.

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Moisture Insensitive PMMA Coated Pt-AlGaN/GaN Diode Hydrogen Sensor and Its Thermal Stability

Cited by 10 publications

References 46 publications

Hydrogen Sensing Performance of ZnO Schottky Diodes in Humid Ambient Conditions with PMMA Membrane Layer

Hydrogen Sensing Performance of ZnO Schottky Diodes in Humid Ambient Conditions with PMMA Membrane Layer

Hydrogen Detection with SAW Polymer/Quantum Dots Sensitive Films

AlGaN/GaN Heterostructure Based Hydrogen Sensor with Temperature Compensation

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