Hybrid dielectrics composed of Al2O3 and phosphonic acid self-assembled monolayers for performance improvement in low voltage organic field effect transistors

Sukjae Jang, Dabin Son, Sunbin Hwang, Minji Kang, Seoung Ki Lee, Dae Young Jeon, Sukang Bae, Sang Hyun Lee, Dong Su Lee, Tae Wook Kim

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Low voltage operational organic transistors (< 4 V) based on pentacene were successfully fabricated with hybrid dielectric films composed of aluminum oxide using atomic layer deposition and various phosphonic acid-based self-assembled monolayers as the gate dielectrics. High capacitances up to 279 nF/cm2, low leakage current densities of 10−8 A/cm2 at 6 V, and high breakdown fields up to 7.5 MV/cm were obtained. The transistors with the octadecylphosphonic acid hybrid dielectric exhibited an improved saturation mobility of 0.58 cm2/Vs, a subthreshold slope of 151 mV/decade, a threshold voltage of − 1.84 V and an on–off current ratio of 106. The low surface energies of the self-assembled monolayers having non-polar terminal groups, such as methyl and pentafluorophenoxy, improved the carrier conduction of the transistors due to the pentacene growth with an edge-on orientation for low voltage operation. The pentafluorophenoxy end-group showed an accumulation of holes at the semiconductor-dielectric interface.

Original languageEnglish
Article number20
JournalNano Convergence
Volume5
Issue number1
DOIs
Publication statusPublished - Dec 1 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)

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