Hydrogen-sensitive characteristics of a novel Pd/InP MOS Schottky diode hydrogen sensor

Wen Chau Liu, Hsi Jen Pan, Huey Ing Chen, Kun Wei Lin, Shiou Ying Cheng, Kuo Hui Yu

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66 Citations (Scopus)


Steady-state and transient hydrogen-sensing characteristics of a novel Pd/InP metal-oxide-semiconductor (MOS) Schottky diode under atmospheric conditions are presented and studied. In presence of oxide layer, the significant increase of barrier height improves the hydrogen sensitivity even at lower operating temperatures. Even at a very low hydrogen concentration environment, e.g., 15 ppm H 2 in air, a significant response is obtained. Two effects, i.e., the removal of Fermi-level pinning caused by the donor level in the oxide and the reduction of Pd metal work function dominate the hydrogen sensing mechanism. Furthermore, the reaction kinetics incorporating the water formation upon hydrogen adsorption is investigated. The initial heat of adsorption for the Pd/oxide interface is estimated to be 0.42 eV/hydrogen atom. The coverage dependent heat of adsorption plays an important role in hydrogen response under steady-state conditions. In accordance with the Temkin isotherm behavior, the theoretical prediction of interface coverage agrees well with the experimental results over more than three decades of hydrogen partial pressure.

Original languageEnglish
Pages (from-to)1938-1944
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number9
Publication statusPublished - 2001 Sep 1

All Science Journal Classification (ASJC) codes

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

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