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

Journal Article · Tue Mar 06 00:00:00 EST 2018 · ACS Nano

DOI:https://doi.org/10.1021/acsnano.7b06992· OSTI ID:1488924

Gao, Zhaoli ^[1]; Zhang, Qicheng ^[2]; Naylor, Carl H. ^[1]; Kim, Youngkuk ^[3]; Abidi, Irfan Haider ^[4]; Ping, Jinglei ^[1]; Ducos, Pedro ^[5]; Zauberman, Jonathan ^[1]; Zhao, Meng -Qiang ^[1]; Rappe, Andrew M.  ^[1]; Luo, Zhengtang  ^[4]; Ren, Li  ^[6]; Johnson, Alan T. Charlie  ^[1]

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1. Univ. of Pennsylvania, Philadelphia, PA (United States)
2. Univ. of Pennsylvania, Philadelphia, PA (United States); Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong)
3. Univ. of Pennsylvania, Philadelphia, PA (United States); Sungkyunkwan Univ., Suwon (Korea)
4. Hong Kong Univ. of Science and Technology, Kowloon (Hong Kong)
5. Univ. of Pennsylvania, Philadelphia, PA (United States); Univ. San Francisco de Quito, Quito (Ecuador)
6. South China Univ. of Technology, Guangzhou (People’s Republic of China)

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. Here, 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.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
• Sponsoring Organization: USDOE
• Grant/Contract Number: FG02-07ER46431
• OSTI ID: 1488924
• Journal Information: ACS Nano, Vol. 12, Issue 3; ISSN 1936-0851
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Bernal and 30° stacking order
bilayer graphene
high-yield synthesis
Ni−Cu gradient alloy
single-crystal