Crystalline Bilayer Graphene with Preferential Stacking from Ni–Cu Gradient Alloy
| Autor: | Alan T. Johnson, Carl H. Naylor, Zhengtang Luo, Qicheng Zhang, Pedro Ducos, Jinglei Ping, Li Ren, Irfan Haider Abidi, Meng-Qiang Zhao, Youngkuk Kim, Zhaoli Gao, Jonathan Zauberman, Andrew M. Rappe |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Precipitation (chemistry) Alloy General Engineering Stacking General Physics and Astronomy chemistry.chemical_element 02 engineering and technology Substrate (electronics) engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Copper 0104 chemical sciences Crystallinity chemistry Chemical engineering engineering General Materials Science 0210 nano-technology Bilayer graphene Single crystal |
| Zdroj: | ACS Nano. 12:2275-2282 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/acsnano.7b06992 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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