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Molecular Arrangement and Charge Transfer in C60/Graphene Heterostructures

Top: Charge difference density for C60/G assuming a dimer/hole orientation. Bottom: TEM image of a ~15 nm thick C60 film deposited on suspended graphene under UHV conditions. High crystallinity is clearly observed. Inset: blow-up of the yellow box region highlights the close-packed structure of the C60s (bright dots correspond to the projected lattice images of the C60 molecular columns).

Scientific Achievement
Charge transfer between C60 and graphene is sensitive to the nature of the underlying supporting substrate and to the crystallinity and local orientation of the C60.

Significance and Impact
High electron and hole mobilities are preserved in graphene with crystalline C60 overlayers, which has ramifications for organic high-mobility field-effect devices.

Research Details

  • Studied the molecular orientation, electronic structure, and local charge transfer at the interface region of C60 deposited on graphene, with and without supporting substrates.
  • Employed ab initio density functional theory with van der Waals interactions and experimentally characterized interface devices using high-resolution TEM and electronic transport.
  • C60 molecules interfaced to graphene are orientationally locked into position.

C. Ojeda-Aristizabal, E. J. G. Santos, S. Onishi, A. Yan, H. I. Rasool, S. Kahn, Y. Lv, D.W. Latzke, J. Velasco, Jr., M.F. Crommie, M. Sorensen, K. Gotlieb, C.-Y. Lin, K. Watanabe, T. Taniguchi, A. Lanzara, A. Zettl, ACS Nano 2017 11 (5), 4686-4693