A comparative study of Hf and Ta incorporations in the dielectric of Pd-WO3-SiC Schottky-diode hydrogen sensor

Y. Liu, Wing Man Tang, P. T. Lai

Research output: Journal article publicationJournal articleAcademic researchpeer-review

7 Citations (Scopus)


An investigation on the incorporation of two different kinds of high-κ dielectrics (HfO2and Ta2O5) in the dielectric of Pd-WO3-SiC Schottky diode is presented. It is found that while the surface morphology of the WO3and WHfO films is almost the same, the WTaO film has the smoothest surface due to suppression of oxygen vacancies in WO3by the Ta incorporation, as supported by XPS analysis. The current-voltage characteristics are examined under a wide range of temperature and hydrogen concentration. Upon exposure to 10,000 ppm H2/air, the diodes based on WHfO and WTaO show a maximum hydrogen response of 89 and 147 respectively, both higher than that (31) of the control sample with WO3. From the kinetics analysis, it is demonstrated that more hydrogen atoms are accumulated at the Pd/WHfO and Pd/WTaO interfaces than their Pd/WO3counterpart due to larger enthalpy change for hydrogen adsorption on passivated surface, resulting in a greater barrier-height variation at the interface and thus better sensing performance for the two devices with ternary oxide.
Original languageEnglish
Pages (from-to)725-729
Number of pages5
JournalSensors and Actuators, B: Chemical
Publication statusPublished - 15 Apr 2018


  • High-κ dielectric
  • Hydrogen sensor
  • Schottky diode
  • SiC

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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