Medium band gap polymer based solution-processed high-kappa composite gate dielectrics for ambipolar OFET

Canimkurbey B., Unay H., Cakirlar C., Buyukkose S., ÇIRPAN A., Berber S., ...More

JOURNAL OF PHYSICS D-APPLIED PHYSICS, vol.51, no.12, 2018 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 51 Issue: 12
  • Publication Date: 2018
  • Doi Number: 10.1088/1361-6463/aaad25
  • Journal Name: JOURNAL OF PHYSICS D-APPLIED PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: PMMA, Ta2O5, composite, OFETs, ambipolar, mobility, medium band gap polymers, FIELD-EFFECT TRANSISTORS, THIN-FILM TRANSISTORS, ATOMIC LAYER DEPOSITION, NANOCOMPOSITE, INSULATOR, FABRICATION, TRANSPORT, CIRCUITS, DEVICES
  • Middle East Technical University Affiliated: Yes

Abstract

The authors present a novel ambipolar organic filed-effect transistors (OFETs) composed of a hybrid dielectric thin film of Ta2O5: PMMA nanocomposite material, and solution processed poly(selenophene, benzotriazole and dialkoxy substituted [1,2-b: 4, 5-b'] dithiophene (P-SBTBDT)-based organic semiconducting material as the active layer of the device. We find that the Ta2O5: PMMA insulator shows n-type conduction character, and its combination with the p-type P-SBTBDT organic semiconductor leads to an ambipolar OFET device. Top-gated OFETs were fabricated on glass substrate consisting of interdigitated ITO electrodes. P-SBTBDT-based material was spin coated on the interdigitated ITO electrodes. Subsequently, a solution processed Ta2O5: PMMA nanocomposite material was spin coated, thereby creating the gate dielectric layer. Finally, as a gate metal, an aluminum layer was deposited by thermal evaporation. The fabricated OFETs exhibited an ambipolar performance with good air-stability, high field-induced current and relatively high electron and hole mobilities although Ta2O5: PMMA nanocomposite films have slightly higher leakage current compared to the pure Ta2O5 films. Dielectric properties of the devices with different ratios of Ta2O5: PMMA were also investigated. The dielectric constant varied between 3.6 and 5.3 at 100 Hz, depending on the Ta2O5: PMMA ratio.