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Title: Patterning monolayer graphene with zigzag edges on hexagonal boron nitride by anisotropic etching

Abstract

Graphene nanostructures are potential building blocks for nanoelectronic and spintronic devices. However, the production of monolayer graphene nanostructures with well-defined zigzag edges remains a challenge. In this paper, we report the patterning of monolayer graphene nanostructures with zigzag edges on hexagonal boron nitride (h-BN) substrates by an anisotropic etching technique. We found that hydrogen plasma etching of monolayer graphene on h-BN is highly anisotropic due to the inert and ultra-flat nature of the h-BN surface, resulting in zigzag edge formation. The as-fabricated zigzag-edged monolayer graphene nanoribbons (Z-GNRs) with widths below 30 nm show high carrier mobility and width-dependent energy gaps at liquid helium temperature. These high quality Z-GNRs are thus ideal structures for exploring their valleytronic or spintronic properties.

Authors:
; ; ; ; ; ; ; ;  [1]; ;  [2];  [1];  [3];  [3]
  1. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
  2. National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)
  3. (China)
Publication Date:
OSTI Identifier:
22594397
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; BORON NITRIDES; CARRIER MOBILITY; CARRIERS; ENERGY GAP; ETCHING; GRAPHENE; HELIUM; HYDROGEN; LAYERS; LIQUIDS; NANOELECTRONICS; NANOSTRUCTURES; PLASMA; SUBSTRATES; SURFACES; WIDTH

Citation Formats

Wang, Guole, Wu, Shuang, Zhang, Tingting, Chen, Peng, Lu, Xiaobo, Wang, Shuopei, Wang, Duoming, Shi, Dongxia, Yang, Rong, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn, Watanabe, Kenji, Taniguchi, Takashi, Zhang, Guangyu, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn, Collaborative Innovation Center of Quantum Matter, Beijing 100190, and Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190. Patterning monolayer graphene with zigzag edges on hexagonal boron nitride by anisotropic etching. United States: N. p., 2016. Web. doi:10.1063/1.4959963.
Wang, Guole, Wu, Shuang, Zhang, Tingting, Chen, Peng, Lu, Xiaobo, Wang, Shuopei, Wang, Duoming, Shi, Dongxia, Yang, Rong, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn, Watanabe, Kenji, Taniguchi, Takashi, Zhang, Guangyu, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn, Collaborative Innovation Center of Quantum Matter, Beijing 100190, & Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190. Patterning monolayer graphene with zigzag edges on hexagonal boron nitride by anisotropic etching. United States. doi:10.1063/1.4959963.
Wang, Guole, Wu, Shuang, Zhang, Tingting, Chen, Peng, Lu, Xiaobo, Wang, Shuopei, Wang, Duoming, Shi, Dongxia, Yang, Rong, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn, Watanabe, Kenji, Taniguchi, Takashi, Zhang, Guangyu, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn, Collaborative Innovation Center of Quantum Matter, Beijing 100190, and Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190. 2016. "Patterning monolayer graphene with zigzag edges on hexagonal boron nitride by anisotropic etching". United States. doi:10.1063/1.4959963.
@article{osti_22594397,
title = {Patterning monolayer graphene with zigzag edges on hexagonal boron nitride by anisotropic etching},
author = {Wang, Guole and Wu, Shuang and Zhang, Tingting and Chen, Peng and Lu, Xiaobo and Wang, Shuopei and Wang, Duoming and Shi, Dongxia and Yang, Rong, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn and Watanabe, Kenji and Taniguchi, Takashi and Zhang, Guangyu, E-mail: ryang@iphy.ac.cn, E-mail: gyzhang@iphy.ac.cn and Collaborative Innovation Center of Quantum Matter, Beijing 100190 and Beijing Key Laboratory for Nanomaterials and Nanodevices, Beijing 100190},
abstractNote = {Graphene nanostructures are potential building blocks for nanoelectronic and spintronic devices. However, the production of monolayer graphene nanostructures with well-defined zigzag edges remains a challenge. In this paper, we report the patterning of monolayer graphene nanostructures with zigzag edges on hexagonal boron nitride (h-BN) substrates by an anisotropic etching technique. We found that hydrogen plasma etching of monolayer graphene on h-BN is highly anisotropic due to the inert and ultra-flat nature of the h-BN surface, resulting in zigzag edge formation. The as-fabricated zigzag-edged monolayer graphene nanoribbons (Z-GNRs) with widths below 30 nm show high carrier mobility and width-dependent energy gaps at liquid helium temperature. These high quality Z-GNRs are thus ideal structures for exploring their valleytronic or spintronic properties.},
doi = {10.1063/1.4959963},
journal = {Applied Physics Letters},
number = 5,
volume = 109,
place = {United States},
year = 2016,
month = 8
}
  • Here, chemical vapor deposition (CVD) has been established as the most effective way to grow large area two-dimensional materials. Direct study of the etching process can reveal subtleties of this competing with the growth reaction and thus provide the necessary details of the overall growth mechanism. Here we investigate hydrogen-induced etching of hBN and graphene and compare the results with the classical kinetic Wulff construction model. Formation of the anisotropically etched holes in the center of hBN and graphene single crystals was observed along with the changes in the crystals' circumference. We show that the edges of triangular holes inmore » hBN crystals formed at regular etching conditions are parallel to B-terminated zigzags, opposite to the N-terminated zigzag edges of hBN triangular crystals. The morphology of the etched hBN holes is affected by a disbalance of the B/N ratio upon etching and can be shifted toward the anticipated from the Wulff model N-terminated zigzag by etching in a nitrogen buffer gas instead of a typical argon. For graphene, etched hexagonal holes are terminated by zigzag, while the crystal circumference is gradually changing from a pure zigzag to a slanted angle resulting in dodecagons.« less
  • Results of ab initio study of magnetism and transport properties of charge carriers in zigzag graphene nanoribbons (ZGNR) on hexagonal boron nitride (h-BN(0001)) substrate are presented within the density functional theory framework. Peculiarities of the interface band structure and its role in the formation of magnetism and transport properties of the ZGNR/h-BN(0001) heterostructure have been studied using two different density functional approximations. The effect of the substrate and graphene nanoribbons width on the low-energy spectrum of π-electrons, local magnetic moments on atoms of interface, and charge carriers mobility in the ZGNR/h-BN(0001) heterostructures have been established for the first time. Themore » regularity consisting in the charge carrier mobility growth with decrease of dimers number in nanoribbon was also established. It is found that the charge carriers mobility in the N-ZGNR/h-BN(0001) (N—number of carbon (C) dimers) heterostructures is 5% higher than in freestanding ZGNR.« less
  • The paper presents the results of ab initio study of the opportunities for tuning the band structure, magnetic and transport properties of zigzag graphene nanoribbon (8-ZGNR) on hexagonal boron nitride (h-BN(0001)) semiconductor heterostructure by transverse electric field (E{sub ext}). This study was performed within the framework of the density functional theory (DFT) using Grimme's (DFT-D2) scheme. We established the critical values of E{sub ext} for the 8-ZGNR/h-BN(0001) heterostructure, thereby providing for semiconductor-halfmetal transition in one of electron spin configurations. This study also showed that the degeneration in energy of the localized edge states is removed when E{sub ext} is applied.more » In ZGNR/h-BN (0001) heterostructure, value of the splitting energy was higher than one in ZGNRs without substrate. We determined the effect of low E{sub ext} applied to the 8-ZGNR/h-BN (0001) semiconductor heterostructure on the preserved local magnetic moment (LMM) (0.3μ{sub B}) of edge carbon atoms. The transport properties of the 8-ZGNR/h-BN(0001) semiconductor heterostructure can be controlled using E{sub ext}. In particular, at a critical value of the positive potential, the electron mobility can increase to 7× 10{sup 5} cm{sup 2}/V s or remain at zero in the spin-up and spin-down electron subsystems, respectively. We established that magnetic moments (MMs), band gaps, and carrier mobility can be altered using E{sub ext}. These abilities enable the use of 8-ZGNR/h-BN(0001) semiconductor heterostructure in spintronics.« less