The role of OTS density on pentacene and C60 nucleation, thin film growth, and transistor performance

Ajay Virkar, Stefan Mannsfeld, Joon Hak Oh, Michael F. Toney, Yih Horng Tan, Gang-yu Liu, J. Campbell Scott, Robert Miller, Zhenan Bao

Research output: Contribution to journalArticlepeer-review

207 Scopus citations


In organic thin film transistors (OTFTs), charge transport occurs in the first few monolayers of the semiconductor near the semiconductor/dielectric interface. Previous work has investigated the roles of dielectric surface energy, roughness, and chemical functionality on performance. However, large discrepancies in performance, even with apparently identical surface treatments, indicate that additional surface parameters must be identified and controlled in order to optimize OTFTs. Here, a crystalline, dense octadecylsilane (OTS) surface modification layer is found that promotes twodimensional semiconductor growth. Higher mobility is consistently achieved for films deposited on crystalline OTS compared to on disordered OTS, with mobilities as high as 5.3 and 2.3 cm2 V-1 s-1 for C60 and pentacene, respectively. This is a significant step toward morphological control of organic semiconductors which is directly linked to their thin film charge carrier transport.

Original languageEnglish (US)
Pages (from-to)1962-1970
Number of pages9
JournalAdvanced Functional Materials
Issue number12
StatePublished - Jun 23 2009

ASJC Scopus subject areas

  • Biomaterials
  • Electrochemistry
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials


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