1
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Zhang Z, Xie J, Zhao W, Qi R, Sanborn C, Wang S, Kahn S, Watanabe K, Taniguchi T, Zettl A, Crommie M, Wang F. Engineering correlated insulators in bilayer graphene with a remote Coulomb superlattice. Nat Mater 2024; 23:189-195. [PMID: 38177380 DOI: 10.1038/s41563-023-01754-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 11/06/2023] [Indexed: 01/06/2024]
Abstract
Electron superlattices allow the engineering of correlated and topological quantum phenomena. The recent emergence of moiré superlattices in two-dimensional heterostructures has led to exciting discoveries related to quantum phenomena. However, the requirement for the moiré pattern poses stringent limitations, and its potential cannot be switched on and off. Here, we demonstrate remote engineering and on/off switching of correlated states in bilayer graphene. Employing a remote Coulomb superlattice realized by localized electrons in twisted bilayer WS2, we impose a Coulomb superlattice in the bilayer graphene with period and strength determined by the twisted bilayer WS2. When the remote superlattice is turned off, the two-dimensional electron gas in the bilayer graphene is described by a Fermi liquid. When it is turned on, correlated insulating states at both integer and fractional filling factors emerge. This approach enables in situ control of correlated quantum phenomena in two-dimensional materials hosting a two-dimensional electron gas.
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Affiliation(s)
- Zuocheng Zhang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Jingxu Xie
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USA
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Wenyu Zhao
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Ruishi Qi
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Collin Sanborn
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Shaoxin Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Salman Kahn
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Alex Zettl
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Michael Crommie
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.
- Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Kavli Energy NanoSciences Institute, University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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2
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Shi W, Kahn S, Leconte N, Taniguchi T, Watanabe K, Crommie M, Jung J, Zettl A. High-Order Fractal Quantum Oscillations in Graphene/BN Superlattices in the Extreme Doping Limit. Phys Rev Lett 2023; 130:186204. [PMID: 37204892 DOI: 10.1103/physrevlett.130.186204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 01/23/2023] [Accepted: 04/03/2023] [Indexed: 05/21/2023]
Abstract
Recent studies of van der Waals (vdW) heterostructures and superlattices have shown intriguing quantum phenomena, but these have been largely explored only in the moderate carrier density regime. Here, we report the probe of high-temperature fractal Brown-Zak (BZ) quantum oscillations through magnetotransport in the extreme doping regimes by applying a newly developed electron beam doping technique. This technique gives access to both ultrahigh electron and hole densities beyond the dielectric breakdown limit in graphene/BN superlattices, enabling the observation of nonmonotonic carrier-density dependence of fractal BZ states and up to fourth-order fractal BZ features despite strong electron-hole asymmetry. Theoretical tight-binding simulations qualitatively reproduce all observed fractal BZ features and attribute the nonmonotonic dependence to the weakening of superlattice effects at high carrier densities.
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Affiliation(s)
- Wu Shi
- State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai 200433, China
- Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy NanoSciences Institute at the University of California and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Salman Kahn
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy NanoSciences Institute at the University of California and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Nicolas Leconte
- Departmement of Physics, University of Seoul, Seoul 02504, Korea
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Michael Crommie
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy NanoSciences Institute at the University of California and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeil Jung
- Departmement of Physics, University of Seoul, Seoul 02504, Korea
- Department of Smart Cities, University of Seoul, Seoul 02504, Korea
| | - Alex Zettl
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy NanoSciences Institute at the University of California and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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3
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Su C, Zhang F, Kahn S, Shevitski B, Jiang J, Dai C, Ungar A, Park JH, Watanabe K, Taniguchi T, Kong J, Tang Z, Zhang W, Wang F, Crommie M, Louie SG, Aloni S, Zettl A. Tuning colour centres at a twisted hexagonal boron nitride interface. Nat Mater 2022; 21:896-902. [PMID: 35835818 DOI: 10.1038/s41563-022-01303-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
The colour centre platform holds promise for quantum technologies, and hexagonal boron nitride has attracted attention due to the high brightness and stability, optically addressable spin states and wide wavelength coverage discovered in its emitters. However, its application is hindered by the typically random defect distribution and complex mesoscopic environment. Here, employing cathodoluminescence, we demonstrate on-demand activation and control of colour centre emission at the twisted interface of two hexagonal boron nitride flakes. Further, we show that colour centre emission brightness can be enhanced by two orders of magnitude by tuning the twist angle. Additionally, by applying an external voltage, nearly 100% brightness modulation is achieved. Our ab initio GW and GW plus Bethe-Salpeter equation calculations suggest that the emission is correlated to nitrogen vacancies and that a twist-induced moiré potential facilitates electron-hole recombination. This mechanism is further exploited to draw nanoscale colour centre patterns using electron beams.
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Affiliation(s)
- Cong Su
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA
| | - Fang Zhang
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics, Southern University of Science and Technology, Shenzhen, China
- Institute of Applied Physics and Materials Engineering, University of Macau, Macau, China
| | - Salman Kahn
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Brian Shevitski
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jingwei Jiang
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Chunhui Dai
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA
| | - Alex Ungar
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA
| | - Ji-Hoon Park
- Electrical Engineering and Computer Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kenji Watanabe
- Research Centre for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Centre for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Jing Kong
- Electrical Engineering and Computer Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Zikang Tang
- Institute of Applied Physics and Materials Engineering, University of Macau, Macau, China
| | - Wenqing Zhang
- Department of Physics, Southern University of Science and Technology, Shenzhen, China
| | - Feng Wang
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA
| | - Michael Crommie
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA
| | - Steven G Louie
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Shaul Aloni
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Alex Zettl
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Kavli Energy NanoSciences Institute at the University of California, Berkeley, CA, USA.
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4
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Lee K, Utama MIB, Kahn S, Samudrala A, Leconte N, Yang B, Wang S, Watanabe K, Taniguchi T, Altoé MVP, Zhang G, Weber-Bargioni A, Crommie M, Ashby PD, Jung J, Wang F, Zettl A. Ultrahigh-resolution scanning microwave impedance microscopy of moiré lattices and superstructures. Sci Adv 2020; 6:eabd1919. [PMID: 33298449 PMCID: PMC7725474 DOI: 10.1126/sciadv.abd1919] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/22/2020] [Indexed: 05/31/2023]
Abstract
Two-dimensional heterostructures composed of layers with slightly different lattice vectors exhibit new periodic structure known as moiré lattices, which, in turn, can support novel correlated and topological phenomena. Moreover, moiré superstructures can emerge from multiple misaligned moiré lattices or inhomogeneous strain distributions, offering additional degrees of freedom in tailoring electronic structure. High-resolution imaging of the moiré lattices and superstructures is critical for understanding the emerging physics. Here, we report the imaging of moiré lattices and superstructures in graphene-based samples under ambient conditions using an ultrahigh-resolution implementation of scanning microwave impedance microscopy. Although the probe tip has a gross radius of ~100 nm, spatial resolution better than 5 nm is achieved, which allows direct visualization of the structural details in moiré lattices and the composite super-moiré. We also demonstrate artificial synthesis of novel superstructures, including the Kagome moiré arising from the interplay between different layers.
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Affiliation(s)
- Kyunghoon Lee
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - M Iqbal Bakti Utama
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Salman Kahn
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Nicolas Leconte
- Department of Physics, University of Seoul, Seoul, South Korea
| | - Birui Yang
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
| | - Shuopei Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - M Virginia P Altoé
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing, China
| | | | - Michael Crommie
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Paul D Ashby
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jeil Jung
- Department of Physics, University of Seoul, Seoul, South Korea
| | - Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alex Zettl
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA.
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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5
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Abstract
Layer-stacking domain wall in bilayer graphene is one type of topological defects that can greatly affect the electronic properties of bilayer graphene and therefore lead to nontrivial transport behaviors. An outstanding question on the layer stacking domain wall is how the electrons hop between two adjacent stacking domains. Here we report the first experimental observation of electronic transport across bilayer graphene domain walls by combining near-field infrared nanoscopy and scanning voltage microscopy techniques. We observe markedly different electron transport behaviors across the tensile- and shear-type domain walls. The tensile-type domain wall is highly reflective of low-energy incident electrons, but becomes more transparent when the electron density and the Fermi energy are increased by electrostatic gating. In contrast, the shear-type domain wall is always highly transparent at different gate voltages. Such soliton-dependent electronic transport can open up new routes to engineer novel nanoelectronic devices based on layer-stacking domain walls in bilayer graphene.
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Affiliation(s)
- Lili Jiang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
| | - Sheng Wang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Sihan Zhao
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
| | - Michael Crommie
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Regan EC, Wang D, Jin C, Bakti Utama MI, Gao B, Wei X, Zhao S, Zhao W, Zhang Z, Yumigeta K, Blei M, Carlström JD, Watanabe K, Taniguchi T, Tongay S, Crommie M, Zettl A, Wang F. Mott and generalized Wigner crystal states in WSe 2/WS 2 moiré superlattices. Nature 2020; 579:359-363. [PMID: 32188951 DOI: 10.1038/s41586-020-2092-4] [Citation(s) in RCA: 244] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/21/2020] [Indexed: 11/09/2022]
Abstract
Moiré superlattices can be used to engineer strongly correlated electronic states in two-dimensional van der Waals heterostructures, as recently demonstrated in the correlated insulating and superconducting states observed in magic-angle twisted-bilayer graphene and ABC trilayer graphene/boron nitride moiré superlattices1-4. Transition metal dichalcogenide moiré heterostructures provide another model system for the study of correlated quantum phenomena5 because of their strong light-matter interactions and large spin-orbit coupling. However, experimental observation of correlated insulating states in this system is challenging with traditional transport techniques. Here we report the optical detection of strongly correlated phases in semiconducting WSe2/WS2 moiré superlattices. We use a sensitive optical detection technique and reveal a Mott insulator state at one hole per superlattice site and surprising insulating phases at 1/3 and 2/3 filling of the superlattice, which we assign to generalized Wigner crystallization on the underlying lattice6-11. Furthermore, the spin-valley optical selection rules12-14 of transition metal dichalcogenide heterostructures allow us to optically create and investigate low-energy excited spin states in the Mott insulator. We measure a very long spin relaxation lifetime of many microseconds in the Mott insulating state, orders of magnitude longer than that of charge excitations. Our studies highlight the value of using moiré superlattices beyond graphene to explore correlated physics.
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Affiliation(s)
- Emma C Regan
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USA.,Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Danqing Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Graduate Group in Applied Science and Technology, University of California at Berkeley, Berkeley, CA, USA.,Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Chenhao Jin
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, NY, USA
| | - M Iqbal Bakti Utama
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Materials Science and Engineering, University of California at Berkeley, Berkeley, CA, USA
| | - Beini Gao
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Department of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Wei
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,School of Physics, University of the Chinese Academy of Sciences, Beijing, China
| | - Sihan Zhao
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Wenyu Zhao
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Zuocheng Zhang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA
| | - Kentaro Yumigeta
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Mark Blei
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Johan D Carlström
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Department of Physics, Lund University, Lund, Sweden
| | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba, Japan
| | | | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, USA
| | - Michael Crommie
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Kavli Energy NanoSciences Institute at University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Alex Zettl
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA.,Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Kavli Energy NanoSciences Institute at University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA, USA. .,Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,Kavli Energy NanoSciences Institute at University of California Berkeley and Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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7
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Llinas JP, Fairbrother A, Borin Barin G, Shi W, Lee K, Wu S, Yong Choi B, Braganza R, Lear J, Kau N, Choi W, Chen C, Pedramrazi Z, Dumslaff T, Narita A, Feng X, Müllen K, Fischer F, Zettl A, Ruffieux P, Yablonovitch E, Crommie M, Fasel R, Bokor J. Short-channel field-effect transistors with 9-atom and 13-atom wide graphene nanoribbons. Nat Commun 2017; 8:633. [PMID: 28935943 PMCID: PMC5608806 DOI: 10.1038/s41467-017-00734-x] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 07/25/2017] [Indexed: 11/29/2022] Open
Abstract
Bottom-up synthesized graphene nanoribbons and graphene nanoribbon heterostructures have promising electronic properties for high-performance field-effect transistors and ultra-low power devices such as tunneling field-effect transistors. However, the short length and wide band gap of these graphene nanoribbons have prevented the fabrication of devices with the desired performance and switching behavior. Here, by fabricating short channel (Lch ~ 20 nm) devices with a thin, high-κ gate dielectric and a 9-atom wide (0.95 nm) armchair graphene nanoribbon as the channel material, we demonstrate field-effect transistors with high on-current (Ion > 1 μA at Vd = −1 V) and high Ion/Ioff ~ 105 at room temperature. We find that the performance of these devices is limited by tunneling through the Schottky barrier at the contacts and we observe an increase in the transparency of the barrier by increasing the gate field near the contacts. Our results thus demonstrate successful fabrication of high-performance short-channel field-effect transistors with bottom-up synthesized armchair graphene nanoribbons. Graphene nanoribbons show promise for high-performance field-effect transistors, however they often suffer from short lengths and wide band gaps. Here, the authors use a bottom-up synthesis approach to fabricate 9- and 13-atom wide ribbons, enabling short-channel transistors with 105 on-off current ratio.
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Affiliation(s)
- Juan Pablo Llinas
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Andrew Fairbrother
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, CH-8600, Switzerland
| | - Gabriela Borin Barin
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, CH-8600, Switzerland
| | - Wu Shi
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Physics, UC Berkeley, Berkeley, CA, 94720, USA
| | - Kyunghoon Lee
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Shuang Wu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Byung Yong Choi
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.,Flash PA Team, Semiconductor Memory Business, Samsung Electronics Co. Ltd., Gyeonggi-do, Korea
| | - Rohit Braganza
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jordan Lear
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA
| | - Nicholas Kau
- Department of Physics, UC Berkeley, Berkeley, CA, 94720, USA
| | - Wonwoo Choi
- Department of Physics, UC Berkeley, Berkeley, CA, 94720, USA
| | - Chen Chen
- Department of Physics, UC Berkeley, Berkeley, CA, 94720, USA
| | | | - Tim Dumslaff
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Akimitsu Narita
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Xinliang Feng
- Center for Advancing Electronics Dresden, Department of Chemistry and Food Chemistry, TU Dresden, Mommsenstrasse 4, Dresden, 01062, Germany
| | - Klaus Müllen
- Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, 55128, Germany
| | - Felix Fischer
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Chemistry, UC Berkeley, Berkeley, CA, 94720, USA.,Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alex Zettl
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Physics, UC Berkeley, Berkeley, CA, 94720, USA.,Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Pascal Ruffieux
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, CH-8600, Switzerland
| | - Eli Yablonovitch
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Michael Crommie
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Physics, UC Berkeley, Berkeley, CA, 94720, USA.,Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Roman Fasel
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, Dübendorf, CH-8600, Switzerland.,Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland
| | - Jeffrey Bokor
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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8
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Khademhosseini A, Chan WWC, Chhowalla M, Glotzer SC, Gogotsi Y, Hafner JH, Hammond PT, Hersam MC, Javey A, Kagan CR, Kotov NA, Lee ST, Li Y, Möhwald H, Mulvaney PA, Nel AE, Parak WJ, Penner RM, Rogach AL, Schaak RE, Stevens MM, Wee ATS, Brinker J, Chen X, Chi L, Crommie M, Dekker C, Farokhzad O, Gerber C, Ginger DS, Irvine DJ, Kiessling LL, Kostarelos K, Landes C, Lee T, Leggett GJ, Liang XJ, Liz-Marzán L, Millstone J, Odom TW, Ozcan A, Prato M, Rao CNR, Sailor MJ, Weiss E, Weiss PS. Nanoscience and Nanotechnology Cross Borders. ACS Nano 2017; 11:1123-1126. [PMID: 28199099 DOI: 10.1021/acsnano.7b00953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
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9
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Jiang L, Shi Z, Zeng B, Wang S, Kang JH, Joshi T, Jin C, Ju L, Kim J, Lyu T, Shen YR, Crommie M, Gao HJ, Wang F. Soliton-dependent plasmon reflection at bilayer graphene domain walls. Nat Mater 2016; 15:840-4. [PMID: 27240109 DOI: 10.1038/nmat4653] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/04/2016] [Indexed: 05/23/2023]
Abstract
Layer-stacking domain walls in bilayer graphene are emerging as a fascinating one-dimensional system that features stacking solitons structurally and quantum valley Hall boundary states electronically. The interactions between electrons in the 2D graphene domains and the one-dimensional domain-wall solitons can lead to further new quantum phenomena. Domain-wall solitons of varied local structures exist along different crystallographic orientations, which can exhibit distinct electrical, mechanical and optical properties. Here we report soliton-dependent 2D graphene plasmon reflection at different 1D domain-wall solitons in bilayer graphene using near-field infrared nanoscopy. We observe various domain-wall structures in mechanically exfoliated graphene bilayers, including network-forming triangular lattices, individual straight or bent lines, and even closed circles. The near-field infrared contrast of domain-wall solitons arises from plasmon reflection at domain walls, and exhibits markedly different behaviours at the tensile- and shear-type domain-wall solitons. In addition, the plasmon reflection at domain walls exhibits a peculiar dependence on electrostatic gating. Our study demonstrates the unusual and tunable coupling between 2D graphene plasmons and domain-wall solitons.
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Affiliation(s)
- Lili Jiang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhiwen Shi
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Bo Zeng
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Sheng Wang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Ji-Hun Kang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Trinity Joshi
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Chenhao Jin
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Long Ju
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Jonghwan Kim
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
| | - Tairu Lyu
- Physics Department, Tsinghua University, Beijing 100084, China
| | - Yuen-Ron Shen
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Michael Crommie
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Hong-Jun Gao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Vazquez-Mena O, Bosco JP, Ergen O, Rasool HI, Fathalizadeh A, Tosun M, Crommie M, Javey A, Atwater HA, Zettl A. Performance enhancement of a graphene-zinc phosphide solar cell using the electric field-effect. Nano Lett 2014; 14:4280-4285. [PMID: 25058004 DOI: 10.1021/nl500925n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The optical transparency and high electron mobility of graphene make it an attractive material for photovoltaics. We present a field-effect solar cell using graphene to form a tunable junction barrier with an Earth-abundant and low cost zinc phosphide (Zn3P2) thin-film light absorber. Adding a semitransparent top electrostatic gate allows for tuning of the graphene Fermi level and hence the energy barrier at the graphene-Zn3P2 junction, going from an ohmic contact at negative gate voltages to a rectifying barrier at positive gate voltages. We perform current and capacitance measurements at different gate voltages in order to demonstrate the control of the energy barrier and depletion width in the zinc phosphide. Our photovoltaic measurements show that the efficiency conversion is increased 2-fold when we increase the gate voltage and the junction barrier to maximize the photovoltaic response. At an optimal gate voltage of +2 V, we obtain an open-circuit voltage of V oc = 0.53 V and an efficiency of 1.9% under AM 1.5 1-sun solar illumination. This work demonstrates that the field effect can be used to modulate and optimize the response of photovoltaic devices incorporating graphene.
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Affiliation(s)
- Oscar Vazquez-Mena
- Department of Physics, University of California , Berkeley, California 94720, United States
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Ju L, Velasco J, Huang E, Kahn S, Nosiglia C, Tsai HZ, Yang W, Taniguchi T, Watanabe K, Zhang Y, Zhang G, Crommie M, Zettl A, Wang F. Photoinduced doping in heterostructures of graphene and boron nitride. Nat Nanotechnol 2014; 9:348-52. [PMID: 24727687 DOI: 10.1038/nnano.2014.60] [Citation(s) in RCA: 133] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 02/21/2014] [Indexed: 05/15/2023]
Abstract
The design of stacks of layered materials in which adjacent layers interact by van der Waals forces has enabled the combination of various two-dimensional crystals with different electrical, optical and mechanical properties as well as the emergence of novel physical phenomena and device functionality. Here, we report photoinduced doping in van der Waals heterostructures consisting of graphene and boron nitride layers. It enables flexible and repeatable writing and erasing of charge doping in graphene with visible light. We demonstrate that this photoinduced doping maintains the high carrier mobility of the graphene/boron nitride heterostructure, thus resembling the modulation doping technique used in semiconductor heterojunctions, and can be used to generate spatially varying doping profiles such as p-n junctions. We show that this photoinduced doping arises from microscopically coupled optical and electrical responses of graphene/boron nitride heterostructures, including optical excitation of defect transitions in boron nitride, electrical transport in graphene, and charge transfer between boron nitride and graphene.
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Affiliation(s)
- L Ju
- 1] Department of Physics, University of California, Berkeley, California 94720, USA [2]
| | - J Velasco
- 1] Department of Physics, University of California, Berkeley, California 94720, USA [2]
| | - E Huang
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - S Kahn
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - C Nosiglia
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Hsin-Zon Tsai
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - W Yang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - T Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - K Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Y Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - G Zhang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - M Crommie
- 1] Department of Physics, University of California, Berkeley, California 94720, USA [2] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [3] Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - A Zettl
- 1] Department of Physics, University of California, Berkeley, California 94720, USA [2] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [3] Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
| | - F Wang
- 1] Department of Physics, University of California, Berkeley, California 94720, USA [2] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [3] Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA
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Alemán B, Regan W, Aloni S, Altoe V, Alem N, Girit C, Geng B, Maserati L, Crommie M, Wang F, Zettl A. Transfer-free batch fabrication of large-area suspended graphene membranes. ACS Nano 2010; 4:4762-8. [PMID: 20604526 DOI: 10.1021/nn100459u] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We demonstrate a process for batch production of large-area (100-3000 microm(2)) patterned free-standing graphene membranes on Cu scaffolds using chemical vapor deposition (CVD)-grown graphene. This technique avoids the use of silicon and transfers of graphene. As one application of this technique, we fabricate transmission electron microscopy (TEM) sample supports. TEM characterization of the graphene membranes reveals relatively clean, highly TEM-transparent, single-layer graphene regions ( approximately 50% by area) and, despite the polycrystalline nature of CVD graphene, membrane yields as high as 75-100%. This high yield verifies that the intrinsic strength and integrity of CVD-grown graphene films is sufficient for sub-100 microm width membrane applications. Elemental analysis (electron energy loss spectroscopy (EELS) and X-ray energy-dispersive spectroscopy (EDS)) of the graphene membranes reveals some nanoscaled contamination left over from the etching process, and we suggest several ways to reduce this contamination and improve the quality of the graphene for electronic device applications. This large-scale production of suspended graphene membranes facilitates access to the two-dimensional physics of graphene that are suppressed by substrate interactions and enables the widespread use of graphene-based sample supports for electron and optical microscopy.
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Affiliation(s)
- Benjamín Alemán
- Department of Physics, University of California at Berkeley, California 94720, USA
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13
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Affiliation(s)
- Feng Wang
- Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA.
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