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<p>Hydrogen (H₂) is a key clean-energy carrier in the transition to sustainable energy systems, but its extreme flammability and low ignition energy demand highly reliable leakage-monitoring technologies for safe deployment. This study presents a MEMS AlGaN/GaN high-electron-mobility transistor (HEMT) H₂ sensor that achieves high sensitivity and fast detection of trace hydrogen in air. The device implements a four-HEMT Wheatstone bridge—two Pd-gated sensing HEMTs and two passivated reference HEMTs—with an integrated microheater, all monolithically fabricated on a suspended GaN membrane. Pd-catalyzed H₂ dissociation and spillover lower the effective gate work function and modulate the Schottky barrier, and the differential readout suppresses common-mode drift. At 315 °C, the sensor achieves a limit of detection (LOD) of 0.1 ppm with a corresponding sensitivity of 1.48 mV/V/ppm. A combined device model and noise analysis further projects a detection limit approaching the ppb level. The baseline-corrected output is monotonic and well described by a four-parameter logistic model, thereby defining a practical, quantifiable working range of 0.1–1000 ppm (spanning four orders of magnitude). At 1000 ppm, the response and recovery times are 5.7 s and 26.2 s, respectively. The sensor exhibits high selectivity to H₂ with negligible cross-sensitivity to typical interferents (e.g., alcohols, SO₂, CH<sub>4</sub>, NH₃, H₂S, CO), along with outstanding repeatability over multiple cycles and long-term stability. This integrated, differential architecture is therefore suited for trace-level hydrogen-leak detection and early warning in applications such as semiconductor manufacturing and fuel-cell systems.</p><p></p>

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AlGaN/GaN HEMT H₂ sensor with integrated Wheatstone bridge and on-chip microheater for 0.1-ppm detection

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年6月30日

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  • Yu Yu,
  • Yan Liu,
  • Wenbin Ren,
  • Yunpeng Liu,
  • Yulong Zhang,
  • Zihan Wang,
  • Qiming Zhuo,
  • Zewen Liu,
  • Tao Wang,
  • Jianwen Sun

摘要

Hydrogen (H₂) is a key clean-energy carrier in the transition to sustainable energy systems, but its extreme flammability and low ignition energy demand highly reliable leakage-monitoring technologies for safe deployment. This study presents a MEMS AlGaN/GaN high-electron-mobility transistor (HEMT) H₂ sensor that achieves high sensitivity and fast detection of trace hydrogen in air. The device implements a four-HEMT Wheatstone bridge—two Pd-gated sensing HEMTs and two passivated reference HEMTs—with an integrated microheater, all monolithically fabricated on a suspended GaN membrane. Pd-catalyzed H₂ dissociation and spillover lower the effective gate work function and modulate the Schottky barrier, and the differential readout suppresses common-mode drift. At 315 °C, the sensor achieves a limit of detection (LOD) of 0.1 ppm with a corresponding sensitivity of 1.48 mV/V/ppm. A combined device model and noise analysis further projects a detection limit approaching the ppb level. The baseline-corrected output is monotonic and well described by a four-parameter logistic model, thereby defining a practical, quantifiable working range of 0.1–1000 ppm (spanning four orders of magnitude). At 1000 ppm, the response and recovery times are 5.7 s and 26.2 s, respectively. The sensor exhibits high selectivity to H₂ with negligible cross-sensitivity to typical interferents (e.g., alcohols, SO₂, CH4, NH₃, H₂S, CO), along with outstanding repeatability over multiple cycles and long-term stability. This integrated, differential architecture is therefore suited for trace-level hydrogen-leak detection and early warning in applications such as semiconductor manufacturing and fuel-cell systems.