Performance enhancement mechanisms of passivated InN/GaN-heterostructured ion-selective field-effect-transistor pH sensors

Ching Ting Lee, Ying Shuo Chiu, Xin Qiang Wang

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

The InN/GaN heterostructure with high sheet electron concentration was utilized to fabricate the ion-selective field-effect-transistor (ISFET) pH sensors. To improve the sensing performances of the InN/GaN-heterostructured ISFET pH sensors, the PEC passivation treatment was applied to reduce the surface states resided on the sensing membrane and to suppress the Fermi level pining effect. Consequently, the passivated InN/GaN-heterostructured pH sensors exhibited a linear pH response with a sensing sensitivity of 52.04 mV/pH, while the unpassivated one showed a nonlinear behavior, especially in low pH (<7) region, with an average sensitivity of 34.75 mV/pH. The improvement of the sensing response in acid solution was attributed to the decrease of the surface states density on the sensing membrane by the PEC passivation function. Furthermore, it was demonstrated that the experimental data can be well described by the site-binding model. Based on the model, the sensing parameters were derived. The resulting sensitivity parameter value for the passivated sensor was 1.18, obviously larger than the value 0.37 for the unpassivated one. The selectivity coefficients of the passivated InN/GaN-heterostructured pH sensors for interfering ions of sodium and potassium are -7.62 and -7.901, respectively.

Original languageEnglish
Pages (from-to)810-815
Number of pages6
JournalSensors and Actuators, B: Chemical
Volume181
DOIs
Publication statusPublished - 2013 Mar 25

All Science Journal Classification (ASJC) codes

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

Fingerprint Dive into the research topics of 'Performance enhancement mechanisms of passivated InN/GaN-heterostructured ion-selective field-effect-transistor pH sensors'. Together they form a unique fingerprint.

  • Cite this