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Zhang R, Wang W. Perfect optical absorption in a single array of folded graphene ribbons. OPTICS EXPRESS 2022; 30:44726-44740. [PMID: 36522891 DOI: 10.1364/oe.473747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/02/2022] [Indexed: 06/17/2023]
Abstract
Due to its one atom thickness, optical absorption (OA) in graphene is a fundamental and challenging issue. Practically, the patterned graphene-dielectric-metal structure is commonly used to achieve perfect OA (POA). In this work, we propose a novel scenario to solve this issue, in which POA is obtained by using free-standing folded graphene ribbons (FGRs). We show several local resonances, e.g. a dipole state (Mode-I) and a bound state in continuum (BIC, Mode-II), will cause very efficient OA. At normal incidence, by choosing appropriate folding angle θ, 50% absorptance by the two states is easily achieved; at oblique incidence, the two states will result in roughly 98% absorptance as incidence angle φ≈40∘. It is also interesting to see that the system has asymmetric OA spectra, e.g. POA of the former (latter) state existing in reverse (forward) incidence, respectively. Besides the angles θ and φ, POA here can also be actively tuned by electrostatic gating. As increasing Fermi level, POA of Mode-I will undergo a gradual blueshift, while that of Mode-II will experience a rapid blueshift and then be divided into three branches, due to Fano coupling to two guided modes. In reality, the achieved POA is well maintained even the dielectric substrates are used to support FGRs. Our work offers a remarkable scenario to achieve POA, and thus enhance light-matter interaction in graphene, which can build an alternative platform to study novel optical effects in general two-dimensional (2D) materials. The folding, mechanical operation in out-of-plane direction, may emerge as a new degree of freedom for optoelectronic device applications based on 2D materials.
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Ma Z, Tian Z, Li X, You C, Wang Y, Mei Y, Di Z. Self-Rolling of Monolayer Graphene for Ultrasensitive Molecular Sensing. ACS APPLIED MATERIALS & INTERFACES 2021; 13:49146-49152. [PMID: 34617726 DOI: 10.1021/acsami.1c12592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The controllable manipulation of graphene to create three-dimensional (3D) structures is an intriguing approach for favorably tuning its properties and creating new types of 3D devices. However, due to extremely low bending stiffnesses, it is rather challenging to construct monolayer graphene into stable 3D structures. Here, we demonstrate the stable formation of monolayer graphene microtubes with accompanying pre-patterned strain layers. The diameter of graphene microtubes can be effectively tuned by changing the thickness of the strain layers. Benefiting from a high surface-to-volume ratio of the tubular geometry, the 3D geometry leads to a prominent Raman enhancement, which was further applied to molecular sensing. The R6G molecules on graphene microtubes can be detected even for a concentration as low as 10-11 M. We believe that this method can be a generalized way to realize the 3D tubular structure of other 2D materials.
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Affiliation(s)
- Zhe Ma
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ziao Tian
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Xing Li
- Department of Materials Science, State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 200433, China
| | - Chunyu You
- Department of Materials Science, State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 200433, China
| | - Yalan Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yongfeng Mei
- Department of Materials Science, State Key Laboratory of ASIC and Systems, Fudan University, Shanghai 200433, China
| | - Zengfeng Di
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
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Yao W, Tang L, Nong J, Wang J, Yang J, Jiang Y, Shi H, Wei X. Electrically tunable graphene metamaterial with strong broadband absorption. NANOTECHNOLOGY 2021; 32:075703. [PMID: 33096539 DOI: 10.1088/1361-6528/abc44f] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The coupling system with dynamic manipulation characteristics is of great importance for the field of active plasmonics and tunable metamaterials. However, the traditional metal-based architectures suffer from a lack of electrical tunability. In this study, a metamaterial composed of perpendicular or parallel graphene-Al2O3-graphene stacks is proposed and demonstrated, which allows for the electric modulation of both graphene layers simultaneously. The resultant absorption of hybridized modes can be modulated to more than 50% by applying an external voltage, and the absorption bandwidth can reach 3.55 μm, which is 1.7 times enhanced than the counterpart of single-layer graphene. The modeling results demonstrate that the small relaxation time of graphene is of great importance to realize the broadband absorption. Moreover, the optical behaviors of the tunable metamaterial can be influenced by the incident polarization, the dielectric thickness, and especially by the Fermi energy of graphene. This work is of a crucial role in the design and fabrication of graphene-based broadband optical and optoelectronic devices.
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Affiliation(s)
- Wei Yao
- School of Optoelectronic Science and Engineering, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China
| | - Linlong Tang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China
| | - Jinpeng Nong
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China
| | - Jun Wang
- School of Optoelectronic Science and Engineering, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Jun Yang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China
| | - Yadong Jiang
- School of Optoelectronic Science and Engineering, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China
| | - Haofei Shi
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China
| | - Xingzhan Wei
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, People's Republic of China
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Vincent T, Hamer M, Grigorieva I, Antonov V, Tzalenchuk A, Kazakova O. Strongly Absorbing Nanoscale Infrared Domains within Strained Bubbles at hBN-Graphene Interfaces. ACS APPLIED MATERIALS & INTERFACES 2020; 12:57638-57648. [PMID: 33314909 DOI: 10.1021/acsami.0c19334] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Graphene has great potential for use in infrared (IR) nanodevices. At these length scales, nanoscale features, and their interaction with light, can be expected to play a significant role in device performance. Bubbles in van der Waals heterostructures are one such feature, which have recently attracted considerable attention, thanks to their ability to modify the optoelectronic properties of two-dimensional (2D) materials through strain. Here, we use scattering-type scanning near-field optical microscopy (sSNOM) to measure the nanoscale IR response from a network of variously shaped bubbles in hexagonal boron nitride (hBN)-encapsulated graphene. We show that within individual bubbles there are distinct domains with strongly enhanced IR absorption. The IR domain boundaries coincide with ridges in the bubbles, which leads us to attribute them to nanoscale strain domains. We further validate the strain distribution in the graphene by means of confocal Raman microscopy and vector decomposition analysis. This shows intricate and varied strain configurations, in which bubbles of different shape induce more bi- or uniaxial strain configurations. This reveals pathways toward future strain-based graphene IR devices.
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Affiliation(s)
- Tom Vincent
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K
- Department of Physics, Royal Holloway University of London, Egham TW20 0EX, U.K
| | - Matthew Hamer
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, U.K
- National Graphene Institute, University of Manchester, Manchester M13 9PL, U.K
| | - Irina Grigorieva
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, U.K
- National Graphene Institute, University of Manchester, Manchester M13 9PL, U.K
| | - Vladimir Antonov
- Department of Physics, Royal Holloway University of London, Egham TW20 0EX, U.K
- Skolkovo Institute of Science and Technology, Moscow 143026, Russia
| | - Alexander Tzalenchuk
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K
- Department of Physics, Royal Holloway University of London, Egham TW20 0EX, U.K
| | - Olga Kazakova
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K
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Dai C, Lin Z, Agarwal K, Mikhael C, Aich A, Gupta K, Cho JH. Self-Assembled 3D Nanosplit Rings for Plasmon-Enhanced Optofluidic Sensing. NANO LETTERS 2020; 20:6697-6705. [PMID: 32808792 DOI: 10.1021/acs.nanolett.0c02575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plasmonic sensors are commonly defined on two-dimensional (2D) surfaces with an enhanced electromagnetic field only near the surface, which requires precise positioning of the targeted molecules within hotspots. To address this challenge, we realize segmented nanocylinders that incorporate plasmonic (1-50 nm) gaps within three-dimensional (3D) nanostructures (nanocylinders) using electron irradiation triggered self-assembly. The 3D structures allow desired plasmonic patterns on their inner cylindrical walls forming the nanofluidic channels. The nanocylinders bridge nanoplasmonics and nanofluidics by achieving electromagnetic field enhancement and fluid confinement simultaneously. This hybrid system enables rapid diffusion of targeted species to the larger spatial hotspots in the 3D plasmonic structures, leading to enhanced interactions that contribute to a higher sensitivity. This concept has been demonstrated by characterizing an optical response of the 3D plasmonic nanostructures using surface-enhanced Raman spectroscopy (SERS), which shows enhancement over a 22 times higher intensity for hemoglobin fingerprints with nanocylinders compared to 2D nanostructures.
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Affiliation(s)
- Chunhui Dai
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zihao Lin
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Kriti Agarwal
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Carol Mikhael
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Anupam Aich
- Hematology/Oncology Division, Department of Medicine, University of California, Irvine, California 92697, United States
| | - Kalpna Gupta
- Hematology/Oncology Division, Department of Medicine, University of California, Irvine, California 92697, United States
- Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota 55455, United States
- SCIRE, Veterans Affairs Medical Center, Long Beach, California 90822, United States
| | - Jeong-Hyun Cho
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Ogata H, Yoshimoto S. Tuning of 2D Nanographene Adlayers on Au(111) by Electrodeposition of Metal Halide Complexes. ACS APPLIED MATERIALS & INTERFACES 2019; 11:46361-46367. [PMID: 31742378 DOI: 10.1021/acsami.9b15276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The electrodeposition of AuBr4- and PtBr42- onto an adlayer of circobiphenyl-a structurally defined nanographene with low symmetry-on a Au(111) electrode was investigated via electrochemical scanning tunneling microscopy (EC-STM) to control and understand the formation of characteristic nanoclusters. By immersing a circobiphenyl-coated Au(111) substrate in a 0.1 mM aqueous AuBr4- solution, AuBr4- was spontaneously reduced, and a characteristic mixed adlayer consisting of circobiphenyl molecules and Br- ions with monatomic Au islands was produced on the Au(111) surface. A similar electrodeposition process was performed in an aqueous solution of PtBr42-, and an identical mixed adlayer was obtained with Pt nanoclusters. The electrodeposition of Au and Pt complexes was facilitated by the "negatively charged" reconstructed Au(111) surface, which is stabilized by the formation of a highly ordered circobiphenyl adlayer. EC-STM revealed the formation of characteristic dimers of Pt clusters ranging 2-4 nm in diameter on the circobiphenyl adlayer. Thus, Br- metal complexes were found to play an important role in controlling the structure and size of a mixed adlayer containing Br- and the shape of Pt clusters.
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