Studies of polycrystalline pentacene thin-film transistors at the microscopic level

Horng Long Cheng, Wei Yang Chou, Chia Wei Kuo, Yu Shen Mai, Fu Ching Tang, Szu Hao Lai

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)


The electronic transport properties of polycrystalline pentacene-based thin film transistors (TFTs) were investigated at the microscopic level using microRaman spectroscopy. All the pentacene film, which were thermally evaporated as a layer with thickness of 70 nm, featured polycrystalline structure with only "thin film" phase polymorph and grain morphology as verified by x-ray diffraction (XRD) measurements. We have investigated the molecular vibrational modes of pentacene in the active channel during operations the organic TFT devices using in-situ Raman spectroscopy. Extra vibrational modes resulting from vibrational coupling effect in pentacene film were studied. The interlayer and intralayer intermolecular vibrational coupling energy was calculated from the Davydov splitting using a simple coupled-oscillator model. The results suggest that the C-H in-plane bending vibrational coupling energy of pentacene molecules in solid film is affected by operating device. Additionally, the aromatic C-C stretching vibrational modes also were investigated. However, it is rather difficult to obtain the variations of lattice parameters of pentacene film in a very small active channel by using electron diffraction and XRD. At the same time, MicroRaman technique provides the capability to explore the intermolecular coupling and molecular structure modifications.

Original languageEnglish
Title of host publicationOrganic Field-Effect Transistors V
Publication statusPublished - 2006
EventOrganic Field-Effect Transistors V - San Diego, CA, United States
Duration: 2006 Aug 132006 Aug 15

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOrganic Field-Effect Transistors V
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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