Characteristics of diamond electrolyte solution-gate FETs (SGFETs) and applications to biosensor

Kwang Soup Song*, Hiroshi Kawarada

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

4 Citations (Scopus)


A diamond electrolyte solution-gate FET (SGFET) for use in electrolyte solutions has been fabricated for the first time. Perfect device characteristics (pinch-off and saturation in IDS-VDS) have been obtained with bias voltages within the potential window of diamond. The hydrogen-terminated (H-terminated) diamond surface was sensitive to halogen ions at approximately 30 mV/decade. We modified the H-terminated diamond surface with oxygen by treatment with ozone. Partially oxygen-terminated sites were insulating and insensitive to halogen ions. The H-terminated channel surface was modified to be partially amine-oxygen-terminated (H-A-O-terminated) to achieve pH sensitivity when irradiated with UV light in an ammonia solution. The pH sensitivity of a diamond surface modified was about 50 mV/pH unit from pH 2 to 10. We immobilized specific enzymes (urease and glucose oxidase) on the modified channel surface. The sensitivities to urea and glucose were approximately 30 mV/decade and 20 mV/decade, respectively.

Original languageEnglish
Article numberNDFCT 497
Pages (from-to)325-335
Number of pages11
JournalNew Diamond and Frontier Carbon Technology
Issue number6
Publication statusPublished - 2005 Dec 7


  • Biosensor
  • Diamond SGFETs
  • Enzyme
  • Halogen ions
  • pH

ASJC Scopus subject areas

  • Materials Science(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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