Systematic doping control of CVD graphene transistors with functionalized aromatic self-assembled monolayers

Nathan Cernetic, Sanfeng Wu, Joshua A. Davies, Benjamin W. Krueger, Daniel O. Hutchins, Xiaodong Xu, Hong Ma, Alex K.Y. Jen

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

Recent reports have shown that self-assembled monolayers (SAMs) can induce doping effects in graphene transistors. However, a lack of understanding persists surrounding the quantitative relationship between SAM molecular design and its effects on graphene. In order to facilitate the fabrication of next-generation graphene-based devices it is important to reliably and predictably control the properties of graphene without negatively impacting its intrinsic high performance. In this study, SAMs with varying dipole magnitudes/directions are utilized and these values are directly correlated to changes in performance seen in graphene transistors. It is found that, by knowing the z-component of the SAM dipole, one can reliably predict the shift in graphene charge neutrality point after taking into account the influence of the metal electrodes (which also play a role in doping graphene). This relationship is verified through density functional theory and comprehensive device studies utilizing atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and electrical characterization of graphene transistors. It is shown that properties of graphene transistors can be predictably controlled with SAMs when considering the total doping environment. Additionally, it is found that methylthio-terminated SAMs strongly interact with graphene allowing for a cleaner graphene transfer and enhanced charge mobility.

Original languageEnglish (US)
Pages (from-to)3464-3470
Number of pages7
JournalAdvanced Functional Materials
Volume24
Issue number22
DOIs
StatePublished - Jun 11 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Keywords

  • doping
  • field effect transistors
  • graphene
  • phosphonic acid
  • self-assembled monolayers

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    Cernetic, N., Wu, S., Davies, J. A., Krueger, B. W., Hutchins, D. O., Xu, X., Ma, H., & Jen, A. K. Y. (2014). Systematic doping control of CVD graphene transistors with functionalized aromatic self-assembled monolayers. Advanced Functional Materials, 24(22), 3464-3470. https://doi.org/10.1002/adfm.201303952