Study of a new field-effect resistive hydrogen sensor based on a Pd/ Oxide/AlGaAs transistor

Ching Wen Hung, Hung Chi Chang, Yan Ying Tsai, Po Hsien Lai, Ssu I. Fu, Tzu Pin Chen, Huey Ing Chen, Wen Chau Liu

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23 Citations (Scopus)


A new and interesting field-effect resistive hydrogen sensor, based on the current-voltage characteristics in the linear region of an AlGaAs-based pseudomorphic high-electron-mobility transistor structure and high hydrogen sensitivity of a palladium (Pd) metal, is studied and demonstrated. An oxide layer between Pd and AlGaAs is used to increase the number of hydrogen adsorption sites, and improve hydrogen detection sensitivity. A simple model is employed to interpret the hydrogen adsorption and sensing mechanism. The dissociation of H2, diffusion of H atoms and formation of a dipolar layer cause a significant decrease in channel resistance. In comparison with other resistor-type hydrogen sensors, the studied device demonstrates the considerable advantages of lower detection limit (< 4.3 ppm H2/air) and higher sensitivity (24.7% in 9970 ppm H2/air) at room temperature. Also, the studied device exhibits a smaller resistance (several 10 Ω) and a smaller operating voltage (≤ 0.3 V) which are superior to other resistive sensors with typically larger resistances (ranged from kiloohms to megaohms) and larger voltages (≥ 1 V). Consequentially, the studied resistive sensor provides the promise for low-power GaAs-based electronic and microelectromechanical-system applications.

Original languageEnglish
Pages (from-to)1224-1231
Number of pages8
JournalIEEE Transactions on Electron Devices
Issue number5
Publication statusPublished - 2007 May

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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