AlGaAs/InGaAs/GaAs transistor-based hydrogen sensing device grown by metal organic chemical vapor deposition

Ching Wen Hung, Han Lien Lin, Yan Ying Tsai, Po Hsien Lai, Ssu I. Fu, Huey Ing Chen, Wen Chau Liu

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)


By combining the advantages of a catalytic metal Pd with a high-performance AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistor (PHEMT), an interesting hydrogen sensor is fabricated and demonstrated. For the proposed device, a 50 Å undoped GaAs cap layer is grown to prevent the Al 0.24Ga0.76As Schottky layer from oxidizing and to reduce the Fermi level pinning effect. Experimentally, a high sensitivity SJ value of 275.8 μA/mm·ppm H2/air can be obtained at a hydrogen concentration of 14 ppm H2/air. Even at a very low hydrogen concentration (≤4.3 ppm H2/air) at 30°C, a significant current variation can be observed. In addition, a fast transient response is found. The adsorption time constant τa becomes only 2 s as the operating temperature is elevated to 160°C. Therefore, the proposed device reveals the promise for high-performance hydrogen sensor applications.

Original languageEnglish
Pages (from-to)680-684
Number of pages5
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Issue number2 A
Publication statusPublished - 2006 Feb 8

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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