Comparison of hydrogen sensing characteristics for Pd/GaN and Pd/Al0.3Ga0.7As Schottky diodes

Huang, Jingwen; Hsu, Wei-Chou; Chen, Yeong-Jia; Wang, Tzong-Bin; Lin, Kun-Wei; Chen, Huey-Ing; Liu, Wen‐Chau

doi:10.1016/j.snb.2005.11.020

Cited by 75 publications

(37 citation statements)

References 26 publications

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“…This logarithmic relation between the detection current variation and the hydrogen concentration is suitable for the high-sensitive hydrogen sensors. A similar logarithmic relation between the variation of the Schottky barrier height and the hydrogen concentration has been reported by several authors [4,7,15]. These results indicate that the hydrogen gas changes the gate potential, and hence affects the electron density of the two-dimensional electron gas.…”

Section: Methodssupporting

confidence: 88%

Detection of ppm‐order hydrogen gas by Pd/AlGaN/GaN high electron mobility transistor‐based sensors

Nakamura

Takahashi

Okumura

2009

Phys. Status Solidi (c)

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The hydrogen sensing properties of AlGaN/GaN high electron mobility transistors with Pd gate electrodes are demonstrated under various hydrogen concentrations. Remarkable current variation, as high as 1.7 mA at the drain‐source voltage of 4 V and gate‐source voltage of 0 V, was observed at 140 °C even at 1 part per million (ppm) hydrogen concentration. The logarithmic relation between the detection current variation and the hydrogen concentration was observed. By using the least‐square fit to the experimental data, the reliable lower detection value of hydrogen concentration for the present device can be estimated to be about 0.45 ppm, i.e., 450 parts per billion (ppb) as a current variation of 1 mA. In addition, the turn‐on and turn‐off transient times have been estimated to be approximately 23 and 33 seconds at 160 °C, respectively, in the case of the 100 ppm hydrogen gas. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Methodssupporting

confidence: 88%

Detection of ppm‐order hydrogen gas by Pd/AlGaN/GaN high electron mobility transistor‐based sensors

Nakamura

Takahashi

Okumura

2009

Phys. Status Solidi (c)

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“…For example, under 8000 ppm H 2 in air, the ˚B of MIS structure is 93.2 meV, about tenfold larger than that of the MS (8.8 meV). This also confirms that the effective catalytic dissociation of hydrogen molecules and adsorption of hydrogen atoms are further improved due to the trapping sites of surface oxygen atoms at the Pd/TiO 2 interface [3,26]. Fig.…”

Section: Device Measurement and Discussionsupporting

confidence: 71%

“…The accumulated hydrogen atoms form a dipolar layer near the interface. The dipole layer leads to a shift of electrostatic potential of n-LTPS and consequently causes a significant decrease of the Schottky barrier height [3], thus raising the electrons to inject from the metal side into the n-LTPS layer. A higher hydrogen concentration causes a lower in the Schottky barrier height, thus resulting in a larger injection current [21][22][23][24][25][26].…”

Section: Device Measurement and Discussionmentioning

confidence: 99%

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Improving hydrogen detecting performance of a Pd/n-LTPS/glass thin film Schottky diode with a TiO2 interface layer

Chou

Fang

Chiang

et al. 2008

Sensors and Actuators B: Chemical

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“…(59) and (52)]. The above considered mechanisms responsible for the MOS-diode response appear to be realized in the Schottky-barrier diodes as well [21][22][23].…”

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confidence: 99%

Basic physics of semiconductor hydrogen sensors

Gaman

2008

Russ Phys J

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The most probable physical models of hydrogen sensors based on thin stannic oxide films, MOS-structures, and tunnel MOS-diodes are discussed. The emphasis is on the mechanisms of formation of sensor response to hydrogen. The analytical equations describing the dependence of the response on the hydrogen concentration n Н 2 are derived for all types of sensors. The relations describing the dependences of the SnO 2 -sensor conductivity and response on the absolute humidity of a gas mixture are given. It is shown that the relaxation time τ rel of the response of SnO 2 -and MOS-structure sensors is determined by the relaxation time τ а of hydrogen atom adsorption on the SnO 2 and SiO 2 surfaces, respectively. For the MOS-diodes, τ rel = τ а at n Н 2 <3⋅10 3 ppm and τ rel = τ d at n Н 2 ≥ 7.5⋅10 3 ppm, where τ d is the relaxation time of hydrogen atom diffusion through an SiO 2 layer.

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Comparison of hydrogen sensing characteristics for Pd/GaN and Pd/Al0.3Ga0.7As Schottky diodes

Cited by 75 publications

References 26 publications

Detection of ppm‐order hydrogen gas by Pd/AlGaN/GaN high electron mobility transistor‐based sensors

Detection of ppm‐order hydrogen gas by Pd/AlGaN/GaN high electron mobility transistor‐based sensors

Improving hydrogen detecting performance of a Pd/n-LTPS/glass thin film Schottky diode with a TiO2 interface layer

Basic physics of semiconductor hydrogen sensors

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