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Dawood OM, Gupta RK, Monteverde U, Alqahtani FH, Kim HY, Sexton J, Young RJ, Missous M, Migliorato MA. Dynamic modulation of the Fermi energy in suspended graphene backgated devices. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS 2019; 20:568-579. [PMID: 31231447 PMCID: PMC6567091 DOI: 10.1080/14686996.2019.1612710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/18/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
Freestanding (suspended) graphene films, with high electron mobility (up to ~200,000 cm2V-1s-1), good mechanical and electronic properties, could resolve many of the current issues that are hampering the upscaling of graphene technology. Thus far, attempts at reliably fabricating suspended graphene devices comprising metal contacts, have often been hampered by difficulties in exceeding sizes of 1 µm in diameter, if using UV lithography. In this work, area of suspended graphene large enough to be utilized in microelectronic devices, have been obtained by suspending a CVD graphene film over cavities, with top contacts defined through UV lithography with both wet and dry etching. An area of up to 160 µm2 can be fabricated as backgated devices. The suspended areas exhibit rippling of the surfaces which simultaneously introduces both tensile and compressive strain on the graphene film. Finally, the variations of the Fermi level in the suspended graphene areas can be modulated by applying a potential difference between the top contacts and the backgate. Having achieved large area suspended graphene, in a manner compatible with CMOS fabrication processes, together with enabling the modulation of the Fermi level, are substantial steps forward in demonstrating the potential of suspended graphene-based electronic devices and sensors.
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Affiliation(s)
- Omar M. Dawood
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
- School of Materials, University of Manchester, Manchester, UK
- Department of Physics, College of Education for Pure Science, University of Anbar, Anbar, Iraq
| | - Rakesh Kumar Gupta
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
- Manchester Institute of Biotechnology, University of Manchester, Manchester, UK
| | - Umberto Monteverde
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
| | - Faisal H. Alqahtani
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
- Physics Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia
| | - Hong-Yeol Kim
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
| | - James Sexton
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
| | - Robert J. Young
- School of Materials, University of Manchester, Manchester, UK
- National Graphene Institute, University of Manchester, Manchester, UK
| | - Mohamed Missous
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
| | - Max A. Migliorato
- School of Electrical and Electronic Engineering, University of Manchester, Manchester, UK
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Deng B, Wu J, Zhang S, Qi Y, Zheng L, Yang H, Tang J, Tong L, Zhang J, Liu Z, Peng H. Anisotropic Strain Relaxation of Graphene by Corrugation on Copper Crystal Surfaces. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1800725. [PMID: 29717818 DOI: 10.1002/smll.201800725] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/26/2018] [Indexed: 06/08/2023]
Abstract
Corrugation is a ubiquitous phenomenon for graphene grown on metal substrates by chemical vapor deposition, which greatly affects the electrical, mechanical, and chemical properties. Recent years have witnessed great progress in controlled growth of large graphene single crystals; however, the issue of surface roughness is far from being addressed. Here, the corrugation at the interface of copper (Cu) and graphene, including Cu step bunches (CuSB) and graphene wrinkles, are investigated and ascribed to the anisotropic strain relaxation. It is found that the corrugation is strongly dependent on Cu crystallographic orientations, specifically, the packed density and anisotropic atomic configuration. Dense Cu step bunches are prone to form on loose packed faces due to the instability of surface dynamics. On an anisotropic Cu crystal surface, Cu step bunches and graphene wrinkles are formed in two perpendicular directions to release the anisotropic interfacial stress, as revealed by morphology imaging and vibrational analysis. Cu(111) is a suitable crystal face for growth of ultraflat graphene with roughness as low as 0.20 nm. It is believed the findings will contribute to clarifying the interplay between graphene and Cu crystal faces, and reducing surface roughness of graphene by engineering the crystallographic orientation of Cu substrates.
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Affiliation(s)
- Bing Deng
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Juanxia Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Shishu Zhang
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Yue Qi
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Liming Zheng
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Hao Yang
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Jilin Tang
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Lianming Tong
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jin Zhang
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Beijing Graphene Institute (BGI), Beijing, 100094, China
| | - Zhongfan Liu
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Beijing Graphene Institute (BGI), Beijing, 100094, China
| | - Hailin Peng
- Center for Nanochemistry (CNC), Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences (BNLMS), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Beijing Graphene Institute (BGI), Beijing, 100094, China
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Zhou R, Yasuda S, Minamimoto H, Murakoshi K. Sensitive Raman Probe of Electronic Interactions between Monolayer Graphene and Substrate under Electrochemical Potential Control. ACS OMEGA 2018; 3:2322-2328. [PMID: 31458531 PMCID: PMC6641367 DOI: 10.1021/acsomega.7b01928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/12/2018] [Indexed: 06/10/2023]
Abstract
In situ electrochemical Raman spectroscopic measurements of defect-free monolayer graphene on various substrates were performed under electrochemical potential control. The G and 2D Raman band wavenumbers (ωG, ω2D) of graphene were found to depend upon the electrochemical potential, i.e., the charge density of graphene. The values of ωG and ω2D also varied depending on the choice of substrates. On metal substrates where graphene was synthesized by chemical vapor deposition, a strong blue shift of ω2D was induced, which could not account for the strain and charge doping. We attributed the blue shift of ω2D to a change in the electronic properties of graphene induced by distinct electronic interactions with the metal substrates. To explain the unique characteristics in the Raman spectrum of graphene on various substrates, a novel mechanism is proposed considering reduction of the Fermi velocity in graphene owing to dielectric screening from the metal substrates.
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Affiliation(s)
- Ruifeng Zhou
- Institute
for International Collaboration, Hokkaido
University, Sapporo, Hokkaido 060-0815, Japan
- Department
of Chemistry, Faculty of Science, Hokkaido
University, N10W8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Satoshi Yasuda
- Department
of Chemistry, Faculty of Science, Hokkaido
University, N10W8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Hiro Minamimoto
- Department
of Chemistry, Faculty of Science, Hokkaido
University, N10W8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
| | - Kei Murakoshi
- Department
of Chemistry, Faculty of Science, Hokkaido
University, N10W8, Kita-ku, Sapporo, Hokkaido 060-0810, Japan
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Trudeau C, Dion-Bertrand LI, Mukherjee S, Martel R, Cloutier SG. Electrostatic Deposition of Large-Surface Graphene. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E116. [PMID: 29329220 PMCID: PMC5793614 DOI: 10.3390/ma11010116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/19/2017] [Accepted: 01/11/2018] [Indexed: 11/24/2022]
Abstract
This work describes a method for electrostatic deposition of graphene over a large area using controlled electrostatic exfoliation from a Highly Ordered Pyrolytic Graphite (HOPG) block. Deposition over 130 × 130 µm² with 96% coverage is achieved, which contrasts with sporadic micro-scale depositions of graphene with little control from previous works on electrostatic deposition. The deposition results are studied by Raman micro-spectroscopy and hyperspectral analysis using large fields of view to allow for the characterization of the whole deposition area. Results confirm that laser pre-patterning of the HOPG block prior to cleaving generates anchor points favoring a more homogeneous and defect-free HOPG surface, yielding larger and more uniform graphene depositions. We also demonstrate that a second patterning of the HOPG block just before exfoliation can yield features with precisely controlled geometries.
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Affiliation(s)
- Charles Trudeau
- Department of Electrical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Ouest, Montréal, QC H3C 1K3, Canada.
| | | | - Sankha Mukherjee
- Department of Mechanical Engineering, McGill University, 845 Sherbrook Ouest, Montréal QC H3A 0G4, Canada.
| | - Richard Martel
- Department of Chemistry, Université de Montreal, 2900 Édouard-Montpetit, Montréal QC H3C 3J7, Canada.
| | - Sylvain G Cloutier
- Department of Electrical Engineering, École de Technologie Supérieure, 1100 Notre-Dame Ouest, Montréal, QC H3C 1K3, Canada.
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Chen C, Wu JZ, Lam KT, Hong G, Gong M, Zhang B, Lu Y, Antaris AL, Diao S, Guo J, Dai H. Graphene nanoribbons under mechanical strain. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2015; 27:303-309. [PMID: 25355690 DOI: 10.1002/adma.201403750] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Revised: 09/15/2014] [Indexed: 05/28/2023]
Abstract
Uniaxial strains are introduced into individual graphene nanoribbons (GNRs) with highly smooth edges to investigate the strain effects on Raman spectroscopic and electrical properties of GNRs. It is found that uniaxial strain downshifts the Raman G-band frequency of GNRs linearly and tunes their bandgap significantly in a non-monotonic manner. The strain engineering of GNRs is promising for potential electronics and photonics applications.
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Affiliation(s)
- Changxin Chen
- Department of Chemistry and Laboratory for Advanced Materials, Stanford University, Stanford, California, 94305, USA; Key Laboratory for Thin Film and Micro fabrication of the Ministry of Education, National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Department of Micro/Nano Electronics, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, PR China
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Huang CH, Lin HY, Huang CW, Liu YM, Shih FY, Wang WH, Chui HC. Probing substrate influence on graphene by analyzing Raman lineshapes. NANOSCALE RESEARCH LETTERS 2014; 9:64. [PMID: 24506825 PMCID: PMC3924919 DOI: 10.1186/1556-276x-9-64] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/19/2014] [Indexed: 06/03/2023]
Abstract
We provide a new approach to identify the substrate influence on graphene surface. Distinguishing the substrate influences or the doping effects of charged impurities on graphene can be realized by optically probing the graphene surfaces, included the suspended and supported graphene. In this work, the line scan of Raman spectroscopy was performed across the graphene surface on the ordered square hole. Then, the bandwidths of G-band and 2D-band were fitted into the Voigt profile, a convolution of Gaussian and Lorentzian profiles. The bandwidths of Lorentzian parts were kept as constant whether it is the suspended and supported graphene. For the Gaussian part, the suspended graphene exhibits much greater Gaussian bandwidths than those of the supported graphene. It reveals that the doping effect on supported graphene is stronger than that of suspended graphene. Compared with the previous studies, we also used the peak positions of G bands, and I2D/IG ratios to confirm that our method really works. For the suspended graphene, the peak positions of G band are downshifted with respect to supported graphene, and the I2D/IG ratios of suspended graphene are larger than those of supported graphene. With data fitting into Voigt profile, one can find out the information behind the lineshapes.
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Affiliation(s)
- Chen-Han Huang
- Center for Nano Bio-Detection, National Chung Cheng University, Chiayi 621, Taiwan
| | - Hsing-Ying Lin
- Center for Nano Bio-Detection, National Chung Cheng University, Chiayi 621, Taiwan
| | - Cheng-Wen Huang
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Yi-Min Liu
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
| | - Fu-Yu Shih
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipe 10617, Taiwan
| | - Wei-Hua Wang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipe 10617, Taiwan
| | - Hsiang-Chen Chui
- Department of Photonics, National Cheng Kung University, Tainan 70101, Taiwan
- Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan
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