Proximity Engineering of the van der Waals Interaction in Multilayered Graphene

Sera Kim, Jongho Park, Dinh Loc Duong, Suyeon Cho, Sung Wng Kim, Heejun Yang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The van der Waals (vdW) interaction in two-dimensional (2D)-layered materials affects key characteristics of electronic devices, such as the contact resistance, with a vertical heterostructure geometry. While various functionalizations to manipulate the properties of 2D materials have shown issues such as defect generation or have a limited spatial range for the methods, engineering the vdW interaction in nondestructive ways for device applications has not been tried or properly achieved yet. Here, we introduce the proximity engineering of the vdW interaction in multilayered graphene, which is observed as modified interlayer distances and deviated stacking orders by Raman spectroscopy. A 2D electride, [Ca2N]+·e-, possessing a low-work function of 2.6 eV, was used to trigger an avalanche of electrons over tens of graphene layers, exceeding the conventional spatial-range limit (∼1 nm) by screening with a carrier density of 1014 cm-2. Our proximity engineering reduces the vdW interaction in a nondestructive way and achieves a promising graphene-metal contact resistance of 500 ω·μm without using complicated edge contacts, which demonstrates a way to use moderately decoupled graphene layers for device applications.

Original languageEnglish
JournalACS Applied Materials and Interfaces
DOIs
StatePublished - 2019

Bibliographical note

Funding Information:
A novel and nondestructive way of electron doping up to 10 14 cm –2 over a long vertical distance in multilayered graphene (up to 5 nm) was developed by proximity engineering with a 2D electride, [Ca 2 N] + ·e – . Raman spectra and transport studies demonstrate that the individual graphene layers are moderately decoupled and twisted by the avalanche of electrons in the multilayered graphene, which is supported by first-principles calculations. The proximity engineering improves the top contact resistance for the first time, making it nine times lower than that of pristine multilayered graphene without using complicated fabrication methods for the edge contact. These findings pave the way to use moderately decoupled graphene layers for device applications.

Funding Information:
This work is supported by the National Research Foundation of Korea (NRF) under grant no. NRF-2017R1A2B2008366. S.C. was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2017R1A2B4010423). D.L.D. was supported by the Institute for Basic Science (IBS-R011-D1), Korea. J.P. and S.W.K. were supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science, ICT & Future Planning) (No. 2015M3D1A1070639).

Publisher Copyright:
© 2019 American Chemical Society.

Keywords

  • contact resistance
  • electride
  • multilayered graphene
  • proximity engineering
  • van der Waals interaction

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