Performance improvement of organic field-effect transistor ammonia gas sensor using ZnO/PMMA hybrid as dielectric layer

Shijiao Han, Wei Huang, Wei Shi, Junsheng Yu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


Ammonia (NH3) gas sensors based on organic field-effect transistor (OFET) using poly(methyl methacrylate) (PMMA) blending with zinc oxide (ZnO) nanoparticles as a gate dielectric layer were fabricated. Compared to those with the pure PMMA dielectric layer, the sensing properties of these devices using ZnO/PMMA hybrid as the gate dielectric layer were significantly improved when the sensors exposed to various concentrations of NH3, and the percentage response was nearly 10 folds higher than that using pure PMMA under 75 ppm NH3. Also, the results showed that there was a remarkable shift in the threshold-voltage as well as a change in field-effect mobility after exposed to NH3 gas. By analyzing the morphologies of the dielectrics and pentacene films and the electrical characteristics of OFET, it was found that ZnO/PMMA hybrid gate dielectric layer was responsible for the enhanced sensing properties. Also, the decreased grain size of pentacene was formed on the ZnO/PMMA hybrid dielectric, facilitating NH3 to diffuse into the conducting channel and then interact with the ZnO nanoparticles. Moreover, the environmental stability of the OFET sensors was measured after storing the sensors under ambient atmosphere for 40 days.

Original languageEnglish (US)
Pages (from-to)9-16
Number of pages8
JournalSensors and Actuators, B: Chemical
StatePublished - Nov 2014


  • Ammonia gas
  • OFET sensor
  • Organic field-effect transistor (OFET)
  • ZnO nanoparticles
  • ZnO/PMMA hybrid dielectric

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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