Comprehensive study of a Pd-GaAs high electron mobility transistor (HEMT)-based hydrogen sensor

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

研究成果: Review article同行評審

29 引文 斯高帕斯(Scopus)


An interesting Pd-GaAs high electron mobility transistor (HEMT) hydrogen sensor is fabricated and studied. For the studied device, a 5 nm-thick undoped GaAs cap layer is grown to suppress the oxidation of the underneath Al0.24Ga0.76As layer. Comprehensive analysis on the electrical properties including equilibrium adsorption (steady-state) and kinetic adsorption (transient) is presented. Experimentally, a high current variation of 17.1 mA/mm is obtained in 9970 ppm H2/air gas at 323 K. A high channel conductance variation of 25.1 mS/mm is also found under the same conditions. This indicates that, in hydrogen-containing ambience, the channel resistance reduces in the linear region of transistor operation. The reaction enthalpy and entropy are -112.74 kJ mol-1 and -367.39 J mol-1 K-1, respectively. This interprets that the hydrogen adsorption process is exothermic and the hydrogen atoms are more ordered when they are adsorbed in a dipolar layer at the metal-semiconductor interface. In the transient analysis, the rate constants of the studied device can be calculated. Then the activation energy of about 33.09 kJ mol-1 is obtained.

頁(從 - 到)81-88
期刊Sensors and Actuators, B: Chemical
出版狀態Published - 2007 3月 8

All Science Journal Classification (ASJC) codes

  • 電子、光磁材料
  • 儀器
  • 凝聚態物理學
  • 表面、塗料和薄膜
  • 金屬和合金
  • 電氣與電子工程
  • 材料化學


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