pH-sensitive diamond field-effect transistors (FETs) with directly aminated channel surface

Kwang Soup Song, Yusuke Nakamura, Yuichi Sasaki, Munenori Degawa, Jung Hoon Yang, Hiroshi Kawarada

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

We have introduced pH sensors fabricated on diamond thin films through modification of the surface-terminated atom. We directly modified the diamond surface from hydrogen to amine or oxygen with ultraviolet (UV) irradiation under ammonia gas. The quantified amine site based on the spectra obtained by X-ray photoelectron spectroscopy (XPS) is 26% (2.6 × 1014 cm-2) with UV irradiation for 8 h and its coverage is dependent on the UV irradiation time. This directly aminated diamond surface is stable with long-term exposure in air and electrolyte solution. We fabricated diamond solution-gate field-effect transistors (SGFETs) without insulating layers on the channel surface. These diamond SGFETs with amine modified by direct amination are sensitive to pH (45 mV/pH) over a wide range from pH 2 to 12 and their sensitivity is dependent on the density of binding sites corresponding to UV irradiation time on the channel surface.

Original languageEnglish
Pages (from-to)3-8
Number of pages6
JournalAnalytica Chimica Acta
Volume573-574
DOIs
Publication statusPublished - 2006 Jul 28

Keywords

  • Diamond
  • Directly aminated channel surface
  • Solution-gate field-effect transistors (SGFETs)
  • X-ray photoelectron spectroscopy (XPS)
  • pH sensors

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy

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