Crystalline Bilayer Graphene with Preferential Stacking from Ni-Cu Gradient Alloy

Zhaoli Gao, Qicheng Zhang, Carl H. Naylor, Youngkuk Kim, Irfan Haider Abidi, Jinglei Ping, Pedro Ducos, Jonathan Zauberman, Meng Qiang Zhao, Andrew M. Rappe, Zhengtang Luo, Li Ren, Alan T.Charlie Johnson

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


We developed a high-yield synthesis of highly crystalline bilayer graphene (BLG) with two preferential stacking modes using a Ni-Cu gradient alloy growth substrate. Previously reported approaches for BLG growth include flat growth substrates of Cu or Ni-Cu uniform alloys and "copper pocket" structures. Use of flat substrates has the advantage of being scalable, but the growth mechanism is either "surface limited" (for Cu) or carbon precipitation (for uniform Ni-Cu), which results in multicrystalline BLG grains. For copper pockets, growth proceeds through a carbon back-diffusion mechanism, which leads to the formation of highly crystalline BLG, but scaling of the copper pocket structure is expected to be difficult. Here we demonstrate a Ni-Cu gradient alloy that combines the advantages of these earlier methods: the substrate is flat, so easy to scale, while growth proceeds by a carbon back-diffusion mechanism leading to high-yield growth of BLG with high crystallinity. The BLG layer stacking was almost exclusively Bernal or twisted with an angle of 30°, consistent with first-principles calculations we conducted. Furthermore, we demonstrated scalable production of transistor arrays based crystalline Bernal-stacked BLG with a band gap that was tunable at room temperature.

Original languageEnglish (US)
Pages (from-to)2275-2282
Number of pages8
JournalACS Nano
Issue number3
StatePublished - Mar 27 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


  • Bernal and 30° stacking order
  • Ni-Cu gradient alloy
  • bilayer graphene
  • high-yield synthesis
  • single-crystal


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