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Park T, Kim M, Lee EK, Hur J, Yoo H. Overcoming Downscaling Limitations in Organic Semiconductors: Strategies and Progress. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2306468. [PMID: 37857588 DOI: 10.1002/smll.202306468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 09/30/2023] [Indexed: 10/21/2023]
Abstract
Organic semiconductors have great potential to revolutionize electronics by enabling flexible and eco-friendly manufacturing of electronic devices on plastic film substrates. Recent research and development led to the creation of printed displays, radio-frequency identification tags, smart labels, and sensors based on organic electronics. Over the last 3 decades, significant progress has been made in realizing electronic devices with unprecedented features, such as wearable sensors, disposable electronics, and foldable displays, through the exploitation of desirable characteristics in organic electronics. Neverthless, the down-scalability of organic electronic devices remains a crucial consideration. To address this, efforts are extensively explored. It is of utmost importance to further develop these alternative patterning methods to overcome the downscaling challenge. This review comprehensively discusses the efforts and strategies aimed at overcoming the limitations of downscaling in organic semiconductors, with a particular focus on four main areas: 1) lithography-compatible organic semiconductors, 2) fine patterning of printing methods, 3) organic material deposition on pre-fabricated devices, and 4) vertical-channeled organic electronics. By discussing these areas, the full potential of organic semiconductors can be unlocked, and the field of flexible and sustainable electronics can be advanced.
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Affiliation(s)
- Taehyun Park
- Department of Chemical and Biological Engineering, Gachon University, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Minseo Kim
- Department of Electronic Engineering, Gachon University, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Eun Kwang Lee
- Department of Chemical Engineering, Pukyong National University, Busan, 48513, Republic of Korea
| | - Jaehyun Hur
- Department of Chemical and Biological Engineering, Gachon University, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Hocheon Yoo
- Department of Electronic Engineering, Gachon University, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
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2
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Ayaz RMA, Koucheh AB, Sendur K. Broadband-Tunable Vanadium Dioxide (VO 2)-Based Linear Optical Cavity Sensor. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:328. [PMID: 38392701 PMCID: PMC10892060 DOI: 10.3390/nano14040328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 01/13/2024] [Accepted: 01/15/2024] [Indexed: 02/24/2024]
Abstract
Sensors fabricated by using a silicon-on-insulator (SOI) platform provide promising solutions to issues such as size, power consumption, wavelength-specific nature of end reflectors and difficulty to detect ternary mixture. To address these limitations, we proposed and investigated a broadband-thermally tunable vanadium dioxide (VO2)-based linear optical cavity sensor model using a finite element method. The proposed structure consists of a silicon wire waveguide on a silicon-on-insulator (SOI) platform terminated with phase-change vanadium oxide (VO2) on each side to provide light confinement. A smooth transmission modulation range of 0.8 (VO2 in the insulator state) and 0.03 (VO2 in the conductive phase state) in the 125 to 230 THz spectral region was obtained due to the of Fabry-Pérot (FP) effect. For the 3.84 μm cavity length, the presented sensor resulted in a sensitivity of 20.2 THz/RIU or 179.56 nm/RIU, which is approximately two orders of magnitude higher than its counterparts in the literature. The sensitivity of the 2D model showed direct relation with the length of the optical cavity. Moreover, the change in the resonating mode line width Δν of approximately 6.94 THz/RIU or 59.96 nm/RIU was also observed when the sensor was subjected to the change of the imaginary part k of complex refractive index (RI). This property of the sensor equips it for the sensing of aternary mixture without using any chemical surface modification. The proposed sensor haspotential applications in the areas of chemical industries, environmental monitoring and biomedical sensing.
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Affiliation(s)
- Rana M. Armaghan Ayaz
- Faculty of Engineering and Natural Sciences, Sabanci University, 34956 Istanbul, Turkey; (R.M.A.A.); (A.B.K.)
- Institute of Mechanical Intelligence, Scuola Superiore Sant’Anna, 56124 Pisa, Italy
| | - Amin Balazadeh Koucheh
- Faculty of Engineering and Natural Sciences, Sabanci University, 34956 Istanbul, Turkey; (R.M.A.A.); (A.B.K.)
| | - Kursat Sendur
- Faculty of Engineering and Natural Sciences, Sabanci University, 34956 Istanbul, Turkey; (R.M.A.A.); (A.B.K.)
- Center of Excellence for Functional Surfaces and Interfaces, Sabanci University, 34956 Istanbul, Turkey
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3
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Li D, Xu C, Xie J, Lee C. Research Progress in Surface-Enhanced Infrared Absorption Spectroscopy: From Performance Optimization, Sensing Applications, to System Integration. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2377. [PMID: 37630962 PMCID: PMC10458771 DOI: 10.3390/nano13162377] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/13/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023]
Abstract
Infrared absorption spectroscopy is an effective tool for the detection and identification of molecules. However, its application is limited by the low infrared absorption cross-section of the molecule, resulting in low sensitivity and a poor signal-to-noise ratio. Surface-Enhanced Infrared Absorption (SEIRA) spectroscopy is a breakthrough technique that exploits the field-enhancing properties of periodic nanostructures to amplify the vibrational signals of trace molecules. The fascinating properties of SEIRA technology have aroused great interest, driving diverse sensing applications. In this review, we first discuss three ways for SEIRA performance optimization, including material selection, sensitivity enhancement, and bandwidth improvement. Subsequently, we discuss the potential applications of SEIRA technology in fields such as biomedicine and environmental monitoring. In recent years, we have ushered in a new era characterized by the Internet of Things, sensor networks, and wearable devices. These new demands spurred the pursuit of miniaturized and consolidated infrared spectroscopy systems and chips. In addition, the rise of machine learning has injected new vitality into SEIRA, bringing smart device design and data analysis to the foreground. The final section of this review explores the anticipated trajectory that SEIRA technology might take, highlighting future trends and possibilities.
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Affiliation(s)
- Dongxiao Li
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; (D.L.); (C.X.); (J.X.)
- Center for Intelligent Sensors and MEMS (CISM), National University of Singapore, Singapore 117608, Singapore
| | - Cheng Xu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; (D.L.); (C.X.); (J.X.)
- Center for Intelligent Sensors and MEMS (CISM), National University of Singapore, Singapore 117608, Singapore
| | - Junsheng Xie
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; (D.L.); (C.X.); (J.X.)
- Center for Intelligent Sensors and MEMS (CISM), National University of Singapore, Singapore 117608, Singapore
| | - Chengkuo Lee
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore; (D.L.); (C.X.); (J.X.)
- Center for Intelligent Sensors and MEMS (CISM), National University of Singapore, Singapore 117608, Singapore
- NUS Suzhou Research Institute (NUSRI), Suzhou 215123, China
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4
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Li T, Bandari VK, Schmidt OG. Molecular Electronics: Creating and Bridging Molecular Junctions and Promoting Its Commercialization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209088. [PMID: 36512432 DOI: 10.1002/adma.202209088] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 11/28/2022] [Indexed: 06/02/2023]
Abstract
Molecular electronics is driven by the dream of expanding Moore's law to the molecular level for next-generation electronics through incorporating individual or ensemble molecules into electronic circuits. For nearly 50 years, numerous efforts have been made to explore the intrinsic properties of molecules and develop diverse fascinating molecular electronic devices with the desired functionalities. The flourishing of molecular electronics is inseparable from the development of various elegant methodologies for creating nanogap electrodes and bridging the nanogap with molecules. This review first focuses on the techniques for making lateral and vertical nanogap electrodes by breaking, narrowing, and fixed modes, and highlights their capabilities, applications, merits, and shortcomings. After summarizing the approaches of growing single molecules or molecular layers on the electrodes, the methods of constructing a complete molecular circuit are comprehensively grouped into three categories: 1) directly bridging one-molecule-electrode component with another electrode, 2) physically bridging two-molecule-electrode components, and 3) chemically bridging two-molecule-electrode components. Finally, the current state of molecular circuit integration and commercialization is discussed and perspectives are provided, hoping to encourage the community to accelerate the realization of fully scalable molecular electronics for a new era of integrated microsystems and applications.
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Affiliation(s)
- Tianming Li
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Vineeth Kumar Bandari
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
| | - Oliver G Schmidt
- Research Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, 09126, Chemnitz, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology, 09111, Chemnitz, Germany
- Nanophysics, Dresden University of Technology, 01069, Dresden, Germany
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5
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Cheng T, Zhu Z, Wang X, Zhu L, Li A, Jiang L, Cao Y. Atomic layer deposition assisted fabrication of large-scale metal nanogaps for surface enhanced Raman scattering. NANOTECHNOLOGY 2023; 34:265301. [PMID: 36996801 DOI: 10.1088/1361-6528/acc8d9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 03/30/2023] [Indexed: 06/19/2023]
Abstract
Metal nanogaps can confine electromagnetic field into extremely small volumes, exhibiting strong surface plasmon resonance effect. Therefore, metal nanogaps show great prospects in enhancing light-matter interaction. However, it is still challenging to fabricate large-scale (centimeter scale) nanogaps with precise control of gap size at nanoscale, limiting the practical applications of metal nanogaps. In this work, we proposed a facile and economic strategy to fabricate large-scale sub-10 nm Ag nanogaps by the combination of atomic layer deposition (ALD) and mechanical rolling. The plasmonic nanogaps can be formed in the compacted Ag film by the sacrificial Al2O3deposited via ALD. The size of nanogaps are determined by the twice thickness of Al2O3with nanometric control. Raman results show that SERS activity depends closely on the nanogap size, and 4 nm Ag nanogaps exhibit the best SERS activity. By combining with other porous metal substrates, various sub-10 nm metal nanogaps can be fabricated over large scale. Therefore, this strategy will have significant implications for the preparation of nanogaps and enhanced spectroscopy.
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Affiliation(s)
- Tangjie Cheng
- Institute of Micro-nano Photonics and Quantum Manipulation, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, People's Republic of China
| | - Zebin Zhu
- Institute of Micro-nano Photonics and Quantum Manipulation, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, People's Republic of China
| | - Xinxin Wang
- Institute of Micro-nano Photonics and Quantum Manipulation, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, People's Republic of China
| | - Lin Zhu
- National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Aidong Li
- National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Liyong Jiang
- Institute of Micro-nano Photonics and Quantum Manipulation, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, People's Republic of China
| | - Yanqiang Cao
- Institute of Micro-nano Photonics and Quantum Manipulation, School of Science, Nanjing University of Science and Technology, Nanjing, 210094, People's Republic of China
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Shi J, Yoo D, Vidal-Codina F, Baik CW, Cho KS, Nguyen NC, Utzat H, Han J, Lindenberg AM, Bulović V, Bawendi MG, Peraire J, Oh SH, Nelson KA. A room-temperature polarization-sensitive CMOS terahertz camera based on quantum-dot-enhanced terahertz-to-visible photon upconversion. NATURE NANOTECHNOLOGY 2022; 17:1288-1293. [PMID: 36329270 DOI: 10.1038/s41565-022-01243-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Detection of terahertz (THz) radiation has many potential applications, but presently available detectors are limited in many aspects of their performance, including sensitivity, speed, bandwidth and operating temperature. Most do not allow the characterization of THz polarization states. Recent observation of THz-driven luminescence in quantum dots offers a possible detection mechanism via field-driven interdot charge transfer. We demonstrate a room-temperature complementary metal-oxide-semiconductor THz camera and polarimeter based on quantum-dot-enhanced THz-to-visible upconversion mechanism with optimized luminophore geometries and fabrication designs. Besides broadband and fast responses, the nanoslit-based sensor can detect THz pulses with peak fields as low as 10 kV cm-1. A related coaxial nanoaperture-type device shows a to-date-unexplored capability to simultaneously record the THz polarization state and field strength with similar sensitivity.
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Affiliation(s)
- Jiaojian Shi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Daehan Yoo
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA
| | - Ferran Vidal-Codina
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chan-Wook Baik
- Advanced Sensor Lab, Samsung Advanced Institute of Technology, Suwon, Republic of Korea
| | - Kyung-Sang Cho
- Advanced Sensor Lab, Samsung Advanced Institute of Technology, Suwon, Republic of Korea
| | - Ngoc-Cuong Nguyen
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Hendrik Utzat
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- College of Chemistry, University of California, Berkeley, CA, USA
| | - Jinchi Han
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Aaron M Lindenberg
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
| | - Vladimir Bulović
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Moungi G Bawendi
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jaime Peraire
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, USA.
| | - Keith A Nelson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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7
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Huang G, Liu K, Shi G, Guo Q, Li X, Liu Z, Ma W, Wang T. Elevating Surface-Enhanced Infrared Absorption with Quantum Mechanical Effects of Plasmonic Nanocavities. NANO LETTERS 2022; 22:6083-6090. [PMID: 35866846 DOI: 10.1021/acs.nanolett.2c01042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Plasmonic nanocavities, with the ability to localize and concentrate light into nanometer-scale dimensions, have been widely used for ultrasensitive spectroscopy, biosensing, and photodetection. However, as the nanocavity gap approaches the subnanometer length scale, plasmonic enhancement, together with plasmonic enhanced optical processes, turns to quenching because of quantum mechanical effects. Here, instead of quenching, we show that quantum mechanical effects of plasmonic nanocavities can elevate surface-enhanced infrared absorption (SEIRA) of molecular moieties. The plasmonic nanocavities, nanojunctions of gold and cadmium oxide nanoparticles, support prominent mid-infrared plasmonic resonances and enable SEIRA of an alkanethiol monolayer (CH3(CH2)n-1SH, n = 3-16). With a subnanometer cavity gap (n < 6), plasmonic resonances turn to blue shift and the SEIRA signal starts a pronounced increase, benefiting from the quantum tunneling effect across the plasmonic nanocavities. Our findings demonstrate the new possibility of optimizing the field enhancement and SEIRA sensitivity of mid-infrared plasmonic nanocavities.
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Affiliation(s)
- Guangyan Huang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Kaizhen Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Guangyi Shi
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Qianqian Guo
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Xiang Li
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Zeke Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Wanli Ma
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
| | - Tao Wang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, Jiangsu, P.R. China
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8
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Lawson ZR, Preston AS, Korsa MT, Dominique NL, Tuff WJ, Sutter E, Camden JP, Adam J, Hughes RA, Neretina S. Plasmonic Gold Trimers and Dimers with Air-Filled Nanogaps. ACS APPLIED MATERIALS & INTERFACES 2022; 14:28186-28198. [PMID: 35695394 DOI: 10.1021/acsami.2c04800] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The subwavelength confinement of light energy in the nanogaps formed between adjacent plasmonic nanostructures provides the foundational basis for nanophotonic applications. Within this realm, air-filled nanogaps are of central importance because they present a cavity where application-specific nanoscale objects can reside. When forming such configurations on substrate surfaces, there is an inherent difficulty in that the most technologically relevant nanogap widths require closely spaced nanostructures separated by distances that are inaccessible through standard electron-beam lithography techniques. Herein, we demonstrate an assembly route for the fabrication of aligned plasmonic gold trimers with air-filled vertical nanogaps having widths that are defined with spatial controls that exceed those of lithographic processes. The devised procedure uses a sacrificial oxide layer to define the nanogap, a glancing angle deposition to impose a directionality on trimer formation, and a sacrificial antimony layer whose sublimation regulates the gold assembly process. By further implementing a benchtop nanoimprint lithography process and a glancing angle ion milling procedure as additional controls over the assembly, it is possible to deterministically position trimers in periodic arrays and extend the assembly process to dimer formation. The optical response of the structures, which is characterized using polarization-dependent spectroscopy, surface-enhanced Raman scattering, and refractive index sensitivity measurements, shows properties that are consistent with simulation. This work, hence, forwards the wafer-based processing techniques needed to form air-filled nanogaps and place plasmonic energy at site-specific locations.
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Affiliation(s)
- Zachary R Lawson
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Arin S Preston
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Matiyas T Korsa
- Computational Materials Group, SDU Centre for Photonics Engineering, Mads Clausen Institute, University of Southern Denmark, 5230 Odense, Denmark
| | - Nathaniel L Dominique
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Walker J Tuff
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Eli Sutter
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Jost Adam
- Computational Materials Group, SDU Centre for Photonics Engineering, Mads Clausen Institute, University of Southern Denmark, 5230 Odense, Denmark
| | - Robert A Hughes
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Svetlana Neretina
- College of Engineering, University of Notre Dame, Notre Dame, Indiana 46556, United States
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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9
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Luo S, Hoff BH, Maier SA, de Mello JC. Scalable Fabrication of Metallic Nanogaps at the Sub-10 nm Level. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2102756. [PMID: 34719889 PMCID: PMC8693066 DOI: 10.1002/advs.202102756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/09/2021] [Indexed: 06/01/2023]
Abstract
Metallic nanogaps with metal-metal separations of less than 10 nm have many applications in nanoscale photonics and electronics. However, their fabrication remains a considerable challenge, especially for applications that require patterning of nanoscale features over macroscopic length-scales. Here, some of the most promising techniques for nanogap fabrication are evaluated, covering established technologies such as photolithography, electron-beam lithography (EBL), and focused ion beam (FIB) milling, plus a number of newer methods that use novel electrochemical and mechanical means to effect the patterning. The physical principles behind each method are reviewed and their strengths and limitations for nanogap patterning in terms of resolution, fidelity, speed, ease of implementation, versatility, and scalability to large substrate sizes are discussed.
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Affiliation(s)
- Sihai Luo
- Department of ChemistryNorwegian University of Science and Technology (NTNU)TrondheimNO‐7491Norway
| | - Bård H. Hoff
- Department of ChemistryNorwegian University of Science and Technology (NTNU)TrondheimNO‐7491Norway
| | - Stefan A. Maier
- Nano‐Institute MunichFaculty of PhysicsLudwig‐Maximilians‐Universität MünchenMünchen80539Germany
- Blackett LaboratoryDepartment of PhysicsImperial College LondonLondonSW7 2AZUK
| | - John C. de Mello
- Department of ChemistryNorwegian University of Science and Technology (NTNU)TrondheimNO‐7491Norway
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10
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Kim JM, Lee C, Lee Y, Lee J, Park SJ, Park S, Nam JM. Synthesis, Assembly, Optical Properties, and Sensing Applications of Plasmonic Gap Nanostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006966. [PMID: 34013617 DOI: 10.1002/adma.202006966] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Plasmonic gap nanostructures (PGNs) have been extensively investigated mainly because of their strongly enhanced optical responses, which stem from the high intensity of the localized field in the nanogap. The recently developed methods for the preparation of versatile nanogap structures open new avenues for the exploration of unprecedented optical properties and development of sensing applications relying on the amplification of various optical signals. However, the reproducible and controlled preparation of highly uniform plasmonic nanogaps and the prediction, understanding, and control of their optical properties, especially for nanogaps in the nanometer or sub-nanometer range, remain challenging. This is because subtle changes in the nanogap significantly affect the plasmonic response and are of paramount importance to the desired optical performance and further applications. Here, recent advances in the synthesis, assembly, and fabrication strategies, prediction and control of optical properties, and sensing applications of PGNs are discussed, and perspectives toward addressing these challenging issues and the future research directions are presented.
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Affiliation(s)
- Jae-Myoung Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Chungyeon Lee
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Yeonhee Lee
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Jinhaeng Lee
- Department of Chemistry, Sungkyunkwan University, Suwon, 16419, South Korea
| | - So-Jung Park
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 03760, South Korea
| | - Sungho Park
- Department of Chemistry, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jwa-Min Nam
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
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11
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Asghari A, Wang C, Yoo KM, Rostamian A, Xu X, Shin JD, Dalir H, Chen RT. Fast, accurate, point-of-care COVID-19 pandemic diagnosis enabled through advanced lab-on-chip optical biosensors: Opportunities and challenges. APPLIED PHYSICS REVIEWS 2021; 8:031313. [PMID: 34552683 PMCID: PMC8427516 DOI: 10.1063/5.0022211] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 05/21/2021] [Indexed: 05/14/2023]
Abstract
The sudden rise of the worldwide severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in early 2020 has called into drastic action measures to perform instant detection and reduce the rate of spread. Common clinical and nonclinical diagnostic testing methods have been partially effective in satisfying the increasing demand for fast detection point-of-care (POC) methods to slow down further spread. However, accurate point-of-risk diagnosis of this emerging viral infection is paramount as the need for simultaneous standard operating procedures and symptom management of SARS-CoV-2 will be the norm for years to come. A sensitive, cost-effective biosensor with mass production capability is crucial until a universal vaccination becomes available. Optical biosensors can provide a noninvasive, extremely sensitive rapid detection platform with sensitivity down to ∼67 fg/ml (1 fM) concentration in a few minutes. These biosensors can be manufactured on a mass scale (millions) to detect the COVID-19 viral load in nasal, saliva, urine, and serological samples, even if the infected person is asymptotic. Methods investigated here are the most advanced available platforms for biosensing optical devices that have resulted from the integration of state-of-the-art designs and materials. These approaches include, but are not limited to, integrated optical devices, plasmonic resonance, and emerging nanomaterial biosensors. The lab-on-chip platforms examined here are suitable not only for SARS-CoV-2 spike protein detection but also for other contagious virions such as influenza and Middle East respiratory syndrome (MERS).
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Affiliation(s)
- Aref Asghari
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Chao Wang
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Kyoung Min Yoo
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Ali Rostamian
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78758, USA
| | - Xiaochuan Xu
- Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757, USA
| | - Jong-Dug Shin
- Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757, USA
| | - Hamed Dalir
- Omega Optics, Inc., 8500 Shoal Creek Blvd., Austin, Texas 78757, USA
| | - Ray T. Chen
- Author to whom correspondence should be addressed:
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12
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Shi H, Zhu X, Zhang S, Wen G, Zheng M, Duan H. Plasmonic metal nanostructures with extremely small features: new effects, fabrication and applications. NANOSCALE ADVANCES 2021; 3:4349-4369. [PMID: 36133477 PMCID: PMC9417648 DOI: 10.1039/d1na00237f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/14/2021] [Indexed: 06/14/2023]
Abstract
Surface plasmons in metals promise many fascinating properties and applications in optics, sensing, photonics and nonlinear fields. Plasmonic nanostructures with extremely small features especially demonstrate amazing new effects as the feature sizes scale down to the sub-nanometer scale, such as quantum size effects, quantum tunneling, spill-out of electrons and nonlocal states etc. The unusual physical, optical and photo-electronic properties observed in metallic structures with extreme feature sizes enable their unique applications in electromagnetic field focusing, spectra enhancing, imaging, quantum photonics, etc. In this review, we focus on the new effects, fabrication and applications of plasmonic metal nanostructures with extremely small features. For simplicity and consistency, we will focus our topic on the plasmonic metal nanostructures with feature sizes of sub-nanometers. Subsequently, we discussed four main and typical plasmonic metal nanostructures with extremely small features, including: (1) ultra-sharp plasmonic metal nanotips; (2) ultra-thin plasmonic metal films; (3) ultra-small plasmonic metal particles and (4) ultra-small plasmonic metal nanogaps. Additionally, the corresponding fascinating new effects (quantum nonlinear, non-locality, quantum size effect and quantum tunneling), applications (spectral enhancement, high-order harmonic wave generation, sensing and terahertz wave detection) and reliable fabrication methods will also be discussed. We end the discussion with a brief summary and outlook of the main challenges and possible breakthroughs in the field. We hope our discussion can inspire the broader design, fabrication and application of plasmonic metal nanostructures with extremely small feature sizes in the future.
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Affiliation(s)
- Huimin Shi
- Center for Research on Leading Technology of Special Equipment, School of Mechanical and Electrical Engineering, Guangzhou University Guangzhou 510006 China
| | - Xupeng Zhu
- School of Physics Science and Technology, Lingnan Normal University Zhanjiang 524048 China
| | - Shi Zhang
- College of Mechanical and Vehicle Engineering, Hunan University Changsha 410082 China
| | - Guilin Wen
- Center for Research on Leading Technology of Special Equipment, School of Mechanical and Electrical Engineering, Guangzhou University Guangzhou 510006 China
| | | | - Huigao Duan
- College of Mechanical and Vehicle Engineering, Hunan University Changsha 410082 China
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13
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Luo S, Mancini A, Berté R, Hoff BH, Maier SA, de Mello JC. Massively Parallel Arrays of Size-Controlled Metallic Nanogaps with Gap-Widths Down to the Sub-3-nm Level. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100491. [PMID: 33939199 DOI: 10.1002/adma.202100491] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Metallic nanogaps (MNGs) are fundamental components of nanoscale photonic and electronic devices. However, the lack of reproducible, high-yield fabrication methods with nanometric control over the gap-size has hindered practical applications. A patterning technique based on molecular self-assembly and physical peeling is reported here that allows the gap-width to be tuned from more than 30 nm to less than 3 nm. The ability of the technique to define sub-3-nm gaps between dissimilar metals permits the easy fabrication of molecular rectifiers, in which conductive molecules bridge metals with differing work functions. A method is further described for fabricating massively parallel nanogap arrays containing hundreds of millions of ring-shaped nanogaps, in which nanometric size control is maintained over large patterning areas of up to a square centimeter. The arrays exhibit strong plasmonic resonances under visible light illumination and act as high-performance substrates for surface-enhanced Raman spectroscopy, with high enhancement factors of up to 3 × 108 relative to thin gold films. The methods described here extend the range of metallic nanostructures that can be fabricated over large areas, and are likely to find many applications in molecular electronics, plasmonics, and biosensing.
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Affiliation(s)
- Sihai Luo
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway
| | - Andrea Mancini
- Nano-Institute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, München, 80539, Germany
| | - Rodrigo Berté
- Nano-Institute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, München, 80539, Germany
| | - Bård H Hoff
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway
| | - Stefan A Maier
- Nano-Institute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, München, 80539, Germany
- Blackett Laboratory, Department of Physics, Imperial College London, London, SW7 2AZ, UK
| | - John C de Mello
- Department of Chemistry, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway
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14
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Design of a Hyperbolic Metamaterial as a Waveguide for Low-Loss Propagation of Plasmonic Wave. Symmetry (Basel) 2021. [DOI: 10.3390/sym13020291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A stratiform hyperbolic metamaterial comprises multiple units of symmetrical metal-dielectric film, stacked to have a precisely equivalent refractive index, admittance, and iso-frequency curve. A metamaterial that is composed of stacks of symmetrical films as a waveguide to couple a diffracted wave into a horizontally propagating plasmonic wave is designed herein. By tuning the parameters of the constituent thin films within a hyperbolic metamaterial, both the loss of the plasmonic wave and admittance matching are minimized and optimized, respectively.
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15
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Su Y, Geng Z, Fang W, Lv X, Wang S, Ma Z, Pei W. Route to Cost-Effective Fabrication of Wafer-Scale Nanostructure through Self-Priming Nanoimprint. MICROMACHINES 2021; 12:121. [PMID: 33498873 PMCID: PMC7911382 DOI: 10.3390/mi12020121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/17/2021] [Accepted: 01/21/2021] [Indexed: 11/17/2022]
Abstract
Nanoimprint technology is powerful for fabricating nanostructures in a large area. However, expensive equipment, high cost, and complex process conditions hinder the application of nano-imprinting technology. Therefore, double-layer self-priming nanoimprint technology was proposed to fabricate ordered metal nanostructures uniformly on 4-inch soft and hard substrates without the aid of expensive instruments. Different nanostructure (gratings, nanoholes and nanoparticles) and different materials (metal and MoS2) were patterned, which shows wide application of double-layer self-priming nanoimprint technology. Moreover, by a double-layer system, the width and the height of metal can be adjusted through the photoresist thickness and developing condition, which provide a programmable way to fabricate different nanostructures using a single mold. The double-layer self-priming nanoimprint method can be applied in poor condition without equipment and be programmable in nanostructure parameters using a single mold, which reduces the cost of instruments and molds.
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Affiliation(s)
- Yue Su
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (Y.S.); (W.F.); (X.L.); (Z.M.); (W.P.)
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaoxin Geng
- School of Information Engineering, Minzu University of China, Beijing 100081, China
| | - Weihao Fang
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (Y.S.); (W.F.); (X.L.); (Z.M.); (W.P.)
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoqing Lv
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (Y.S.); (W.F.); (X.L.); (Z.M.); (W.P.)
| | - Shicai Wang
- State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;
| | - Zhengtai Ma
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (Y.S.); (W.F.); (X.L.); (Z.M.); (W.P.)
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (Y.S.); (W.F.); (X.L.); (Z.M.); (W.P.)
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16
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Calm YM, D'Imperio L, Nesbitt NT, Merlo JM, Rose AH, Yang C, Kempa K, Burns MJ, Naughton MJ. Optical confinement in the nanocoax: coupling to the fundamental TEM-like mode. OPTICS EXPRESS 2020; 28:32152-32164. [PMID: 33115178 DOI: 10.1364/oe.402723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
The nanoscale coaxial cable (nanocoax) has demonstrated optical confinement in the visible and the near infrared. We report on a novel nanofabrication process which yields optically addressable, sub-µm diameter, and high aspect ratio metal-insulator-metal nanocoaxes made by atomic layer deposition of Pt and Al2O3. We observe sub-diffraction-limited optical transmission via the fundamental, TEM-like mode by excitation with a radially polarized optical vortex beam. Our experimental results are based on interrogation with a polarimetric imager. Finite element method numerical simulations support these results, and their uniaxial symmetry was exploited to model taper geometries with both an electrically large volume, (15λ)3, and a nanoscopic exit aperture, (λ/200)2.
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17
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Vidal-Codina F, Martín-Moreno L, Ciracì C, Yoo D, Nguyen NC, Oh SH, Peraire J. Terahertz and infrared nonlocality and field saturation in extreme-scale nanoslits. OPTICS EXPRESS 2020; 28:8701-8715. [PMID: 32225489 DOI: 10.1364/oe.386405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/09/2020] [Indexed: 06/10/2023]
Abstract
With advances in nanofabrication techniques, extreme-scale nanophotonic devices with critical gap dimensions of just 1-2 nm have been realized. The plasmonic response in these extreme-scale gaps is significantly affected by nonlocal electrodynamics, quenching field enhancement and blue-shifting the resonance with respect to a purely local behavior. The extreme mismatch in lengthscales, ranging from millimeter-long wavelengths to atomic-scale charge distributions, poses a daunting computational challenge. In this paper, we perform computations of a single nanoslit using the hybridizable discontinuous Galerkin method to solve Maxwell's equations augmented with the hydrodynamic model for the conduction-band electrons in noble metals. This method enables the efficient simulation of the slit while accounting for the nonlocal interactions between electrons and the incident light. We study the impact of gap width, film thickness and electron motion model on the plasmon resonances of the slit for two different frequency regimes: (1) terahertz frequencies, which lead to 1000-fold field amplitude enhancements that saturate as the gap shrinks; and (2) the near- and mid-infrared regime, where we show that narrow gaps and thick films cluster Fabry-Pérot (FP) resonances towards lower frequencies, derive a dispersion relation for the first FP resonance, in addition to observing that nonlocality boosts transmittance and reduces enhancement.
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18
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Liu Z, Liu G, Liu X, Fu G. Plasmonic sensors with an ultra-high figure of merit. NANOTECHNOLOGY 2020; 31:115208. [PMID: 31751986 DOI: 10.1088/1361-6528/ab5a00] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We propose and numerically demonstrate a high-quality hybridized resonant platform, composed of a one-dimensional metal grating and a dielectric cavity. Under a moderate oblique illumination, an ultra-high spectral quality (Q) factor of 1375 is achieved, which shows orders of magnitude larger than that of the system under normal excitation. The high-Q mode results from the strong coupling effect between the surface plasmon polariton of the metal grating and the photonic mode of the dielectric cavity. Based on this hybridized plasmonic resonator, a high-performance sensing scheme with the spectral sensitivity (S) up to 800 nm/RIU (refractive index unit, RIU) is further introduced. Moreover, the figure of merit reaches 1337, indicating a new record for both the localized or propagating surface plasmons based sensors. These features could find applications in sensing and detecting devices, plasmonic switches, and light flow modulators.
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Affiliation(s)
- Zhengqi Liu
- Jiangxi Key Laboratory of Nanomaterials and Sensors, Provincial Key Laboratory of Optoelectronic and Telecommunication, College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, Jiangxi, People's Republic of China
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19
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Qin J, Cheng W, Han B, Du Y, Han Z, Zhao Z. Ultrasensitive detection of saccharides using terahertz sensor based on metallic nano-slits. Sci Rep 2020; 10:3712. [PMID: 32111980 PMCID: PMC7048833 DOI: 10.1038/s41598-020-60732-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/14/2020] [Indexed: 11/09/2022] Open
Abstract
Unambiguous identification of trace amounts of biochemical molecules in a complex background using terahertz spectroscopy is extremely challenging owing to the extremely small absorption cross sections of these molecules in the terahertz regime. Herein, we numerically propose a terahertz nonresonant nano-slits structure that serves as a powerful sensor. The structure exhibits strongly enhanced electric field in the slits (five orders of magnitude), as well as high transmittance over an extra-wide frequency range that covers the characteristic frequencies of most molecules. Fingerprint features of lactose and maltose are clearly detected using this slits structure, indicating that this structure can be used to identify different saccharides without changing its geometrical parameters. The absorption signal strengths of lactose and maltose with a thickness of 200 nm are strongly enhanced by factors of 52.5 and 33.4, respectively. This structure is very sensitive to thin thickness and is suitable for the detection of trace sample, and the lactose thickness can be predicted on the basis of absorption signal strength when the thickness is less than 250 nm. The detection of a mixture of lactose and maltose indicates that this structure can also achieve multi-sensing which is very difficult to realize by using the resonant structures.
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Affiliation(s)
- Jianyuan Qin
- Center for Terahertz Research, China Jiliang University, Hangzhou, 310018, China.
| | - Wei Cheng
- Center for Terahertz Research, China Jiliang University, Hangzhou, 310018, China
| | - Baojuan Han
- Center for Terahertz Research, China Jiliang University, Hangzhou, 310018, China
| | - Yong Du
- Center for Terahertz Research, China Jiliang University, Hangzhou, 310018, China
| | - Zhanghua Han
- Advanced Launching Co-innovation Center, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Zongshan Zhao
- College of Environmental Science and Engineering, Qingdao University, Qingdao, 266071, China
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20
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Kim I, Mun J, Hwang W, Yang Y, Rho J. Capillary-force-induced collapse lithography for controlled plasmonic nanogap structures. MICROSYSTEMS & NANOENGINEERING 2020; 6:65. [PMID: 34567676 PMCID: PMC8433176 DOI: 10.1038/s41378-020-0177-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/23/2020] [Accepted: 04/26/2020] [Indexed: 05/22/2023]
Abstract
The capillary force effect is one of the most important fabrication parameters that must be considered at the micro/nanoscale because it is strong enough to deform micro/nanostructures. However, the deformation of micro/nanostructures due to such capillary forces (e.g., stiction and collapse) has been regarded as an undesirable and uncontrollable obstacle to be avoided during fabrication. Here, we present a capillary-force-induced collapse lithography (CCL) technique, which exploits the capillary force to precisely control the collapse of micro/nanostructures. CCL uses electron-beam lithography, so nanopillars with various shapes can be fabricated by precisely controlling the capillary-force-dominant cohesion process and the nanopillar-geometry-dominant collapse process by adjusting the fabrication parameters such as the development time, electron dose, and shape of the nanopillars. CCL aims to achieve sub-10-nm plasmonic nanogap structures that promote extremely strong focusing of light. CCL is a simple and straightforward method to realize such nanogap structures that are needed for further research such as on plasmonic nanosensors.
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Affiliation(s)
- Inki Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Jungho Mun
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Wooseup Hwang
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Younghwan Yang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
- National Institute of Nanomaterials and Technology (NINT), Pohang, 37673 Republic of Korea
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21
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Jeong J, Kim D, Seo M, Kim DS. Strongly Localized ohmic Absorption of Terahertz Radiation in Nanoslot Antennas. NANO LETTERS 2019; 19:9062-9068. [PMID: 31710500 DOI: 10.1021/acs.nanolett.9b04117] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ohmic absorption of light is an indication of a light-matter interaction within metals, where many interesting phenomena and application potentials can be found. To realize the ohmic absorption of light at long wavelengths, where metals are highly reflective, one can use a metamaterial absorber design to concentrate the electromagnetic field within a thin metal film. This concept has enabled thinning of perfect absorbers from a quarter-wave thickness to several tens of nanometers, greatly improving the utility and efficiency of light-metal interactions. Further improvements on the performance are expected if the absorption can be additionally focused laterally, which is a possibility not yet explored. In this study, we report that nanoslot antennas can be a unique ohmic absorber of the low-frequency radiations, where it can incorporate 70% of incident light to ohmic absorption, focused laterally onto 1% of the unit cell area. The inductive field that drives both field enhancement and ohmic absorption is localized within a skin depth distance from the slots with amplitude being as large as 30% of the incident field. Mode-matching calculations and terahertz spectroscopy measurements confirm the inductive and localized nature of the absorption. The strong confinement of the inductive field and of the resulting ohmic absorption is expected to open a new venue in nanocalorimetry, optical nonlinearities of metals, and bolometer applications.
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Affiliation(s)
- Jeeyoon Jeong
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Republic of Korea
| | - Dasom Kim
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Republic of Korea
- Department of Physics and Center for Atom Scale Electromagnetism , Ulsan National Institute of Science and Technology , 50 UNIST-gil , Ulsan 44919 , Republic of Korea
| | - Minah Seo
- Sensor System Research Center , Korea Institute of Science and Technology , Seoul 02792 , Republic of Korea
| | - Dai-Sik Kim
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Republic of Korea
- Department of Physics and Center for Atom Scale Electromagnetism , Ulsan National Institute of Science and Technology , 50 UNIST-gil , Ulsan 44919 , Republic of Korea
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22
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Yoo D, Vidal-Codina F, Ciracì C, Nguyen NC, Smith DR, Peraire J, Oh SH. Modeling and observation of mid-infrared nonlocality in effective epsilon-near-zero ultranarrow coaxial apertures. Nat Commun 2019; 10:4476. [PMID: 31578373 PMCID: PMC6775091 DOI: 10.1038/s41467-019-12038-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/17/2019] [Indexed: 11/09/2022] Open
Abstract
With advances in nanofabrication techniques, extreme-scale nanophotonic devices with critical gap dimensions of just 1-2 nm have been realized. Plasmons in such ultranarrow gaps can exhibit nonlocal response, which was previously shown to limit the field enhancement and cause optical properties to deviate from the local description. Using atomic layer lithography, we create mid-infrared-resonant coaxial apertures with gap sizes as small as 1 nm and observe strong evidence of nonlocality, including spectral shifts and boosted transmittance of the cutoff epsilon-near-zero mode. Experiments are supported by full-wave 3-D nonlocal simulations performed with the hybridizable discontinuous Galerkin method. This numerical method captures atomic-scale variations of the electromagnetic fields while efficiently handling extreme-scale size mismatch. Combining atomic-layer-based fabrication techniques with fast and accurate numerical simulations provides practical routes to design and fabricate highly-efficient large-area mid-infrared sensors, antennas, and metasurfaces.
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Affiliation(s)
- Daehan Yoo
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Ferran Vidal-Codina
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Cristian Ciracì
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, Via Barsanti 14, 73010, Arnesano (LE), Italy.
| | - Ngoc-Cuong Nguyen
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - David R Smith
- Center for Metamaterial and Integrated Plasmonics, Department of Electrical and Computer Engineering, Pratt School of Engineering, Duke University, Durham, NC, 27708, USA
| | - Jaime Peraire
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
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23
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Craig BJ, Meng J, Shrestha VR, Cadusch JJ, Crozier KB. Mid- to long-wave infrared computational spectroscopy using a subwavelength coaxial aperture array. Sci Rep 2019; 9:13537. [PMID: 31537829 PMCID: PMC6753135 DOI: 10.1038/s41598-019-49593-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 08/22/2019] [Indexed: 11/24/2022] Open
Abstract
Miniaturized spectrometers are advantageous for many applications and can be achieved by what we term the filter-array detector-array (FADA) approach. In this method, each element of an optical filter array filters the light that is transmitted to the matching element of a photodetector array. By providing the outputs of the photodetector array and the filter transmission functions to a reconstruction algorithm, the spectrum of the light illuminating the FADA device can be estimated. Here, we experimentally demonstrate an array of 101 band-pass transmission filters that span the mid- to long-wave infrared (6.2 to 14.2 μm). Each filter comprises a sub-wavelength array of coaxial apertures in a gold film. As a proof-of-principle demonstration of the FADA approach, we use a Fourier transform infrared (FTIR) microscope to record the optical power transmitted through each filter. We provide this information, along with the transmission spectra of the filters, to a recursive least squares (RLS) algorithm that estimates the incident spectrum. We reconstruct the spectrum of the infrared light source of our FTIR and the transmission spectra of three polymer-type materials: polyethylene, cellophane and polyvinyl chloride. Reconstructed spectra are in very good agreement with those obtained via direct measurement by our FTIR system.
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Affiliation(s)
- Benjamin J Craig
- School of Physics, University of Melbourne, Victoria, 3010, Australia
| | - Jiajun Meng
- Department of Electrical and Electronic Engineering, University of Melbourne, Victoria, 3010, Australia
| | | | - Jasper J Cadusch
- Department of Electrical and Electronic Engineering, University of Melbourne, Victoria, 3010, Australia
| | - Kenneth B Crozier
- School of Physics, University of Melbourne, Victoria, 3010, Australia. .,Department of Electrical and Electronic Engineering, University of Melbourne, Victoria, 3010, Australia.
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24
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Size and shape control of a variety of metallic nanostructures using tilted, rotating evaporation and lithographic lift-off techniques. Sci Rep 2019; 9:7682. [PMID: 31118461 PMCID: PMC6531472 DOI: 10.1038/s41598-019-44074-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/05/2019] [Indexed: 11/29/2022] Open
Abstract
Here, we demonstrate a simple top-down method for nanotechnology whereby electron beam (ebeam) lithography can be combined with tilted, rotated thermal evaporation to control the topography and size of an assortment of metallic objects at the nanometre scale. In order to do this, the evaporation tilt angle is varied between 1 and 24°. The technique allows the 3-dimensional tailoring of a range of metallic object shapes from sharp, flat bottomed spikes to hollow cylinders and rings—all of which have rotational symmetry and whose critical dimensions are much smaller than the lithographic feature size. The lithographic feature size is varied from 400 nm down to 40 nm. The nanostructures are characterized using electron microscopy techniques—the specific shape can be predicted using topographic modelling of the deposition. Although individual nanostructures are studied here, the idea can easily be extended to fabricate arrays for e.g. photonics and metamaterials. Being a generic technique—depending on easily controlled lithographic and evaporation parameters—it can be readily incorporated into any standard planar process and could be adapted to suit other thin-film materials deposited using physical means.
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25
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Plasmonics for Biosensing. MATERIALS 2019; 12:ma12091411. [PMID: 31052240 PMCID: PMC6539671 DOI: 10.3390/ma12091411] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/19/2019] [Accepted: 04/24/2019] [Indexed: 12/14/2022]
Abstract
Techniques based on plasmonic resonance can provide label-free, signal enhanced, and real-time sensing means for bioparticles and bioprocesses at the molecular level. With the development in nanofabrication and material science, plasmonics based on synthesized nanoparticles and manufactured nano-patterns in thin films have been prosperously explored. In this short review, resonance modes, materials, and hybrid functions by simultaneously using electrical conductivity for plasmonic biosensing techniques are exclusively reviewed for designs containing nanovoids in thin films. This type of plasmonic biosensors provide prominent potential to achieve integrated lab-on-a-chip which is capable of transporting and detecting minute of multiple bio-analytes with extremely high sensitivity, selectivity, multi-channel and dynamic monitoring for the next generation of point-of-care devices.
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26
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Gu P, Zhou Z, Zhao Z, Möhwald H, Li C, Chiechi RC, Shi Z, Zhang G. 3D zig-zag nanogaps based on nanoskiving for plasmonic nanofocusing. NANOSCALE 2019; 11:3583-3590. [PMID: 30729970 DOI: 10.1039/c8nr08946a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We combine anisotropic wet etching and nanoskiving to create a novel three-dimensional (3D) nanoantenna for plasmonic nanofocusing, vertically aligned zig-zag nanogaps, constituted of nanogaps with defined angles. Instead of conventional lithography, we used the thickness of a self-assembled monolayer (SAM) to define nanogaps with high throughput, and anisotropic etching of Si V-grooves to naturally define ultra-sharp tips. Both nanogaps and sharp tips can synergistically squeeze the electro-magnetic (EM) field and excite 3D nanofocusing, enabling great potential applications in chemical sensing and plasmonic devices. The dependence of the EM field enhancement on structural features is systematically investigated and optimized. We found that the field enhancement and confinement are stronger at the tipped-nanogap compared to what standalone tips or nanogaps produce. The intensity of surface-enhanced Raman spectroscopy (SERS) recorded on the 70.5° tipped-nanogaps is 45 times higher than that recorded with linear nanogaps and 5 times higher than that recorded with tip-only nanowires, which is attributed to the integration of the tip and gap in plasmonic nanostructures. This proposed nanofabrication technique and the resulting structures equipped with a strongly enhanced EM field will promote broad applications for nanophotonics and surface-enhanced spectroscopy.
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Affiliation(s)
- Panpan Gu
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, P.R. China.
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Yang Y, Gu C, Li J. Sub-5 nm Metal Nanogaps: Physical Properties, Fabrication Methods, and Device Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1804177. [PMID: 30589217 DOI: 10.1002/smll.201804177] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/29/2018] [Indexed: 05/26/2023]
Abstract
Sub-5 nm metal nanogaps have attracted widespread attention in physics, chemistry, material sciences, and biology due to their physical properties, including great plasmon-enhanced effects in light-matter interactions and charge tunneling, Coulomb blockade, and the Kondo effect under an electrical stimulus. These properties especially meet the needs of many cutting-edge devices, such as sensing, optical, molecular, and electronic devices. However, fabricating sub-5 nm nanogaps is still challenging at the present, and scaled and reliable fabrication, improved addressability, and multifunction integration are desired for further applications in commercial devices. The aim of this work is to provide a comprehensive overview of sub-5 nm nanogaps and to present recent advancements in metal nanogaps, including their physical properties, fabrication methods, and device applications, with the ultimate aim to further inspire scientists and engineers in their research.
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Affiliation(s)
- Yang Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
| | - Changzhi Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Junjie Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, P. R. China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China
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28
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Chen C, Mohr DA, Choi HK, Yoo D, Li M, Oh SH. Waveguide-Integrated Compact Plasmonic Resonators for On-Chip Mid-Infrared Laser Spectroscopy. NANO LETTERS 2018; 18:7601-7608. [PMID: 30216715 DOI: 10.1021/acs.nanolett.8b03156] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The integration of nanoplasmonic devices with a silicon photonic platform affords a new approach for efficient light delivery by combining the high field enhancement of plasmonics and the ultralow propagation loss of dielectric waveguides. Such a hybrid integration obviates the need for a bulky free-space optics setup and can lead to fully integrated, on-chip optical sensing systems. Here, we demonstrate ultracompact plasmonic resonators directly patterned atop a silicon waveguide for mid-infrared spectroscopic chemical sensing. The footprint of the plasmonic nanorod resonators is as small as 2 μm2, yet they can couple with the mid-infrared waveguide mode efficiently. The plasmonic resonance is directly measured through the transmission spectrum of the waveguide with a coupling efficiency greater than 70% and a field intensity enhancement factor of over 3600 relative to the evanescent waveguide field intensity. Using this hybrid device and a tunable mid-infrared laser source, surface-enhanced infrared absorption spectroscopy of both a thin poly(methyl methacrylate) film and an octadecanethiol monolayer is successfully demonstrated.
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Affiliation(s)
- Che Chen
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Daniel A Mohr
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Han-Kyu Choi
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Daehan Yoo
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Mo Li
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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29
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Sharac N, Giles AJ, Perkins K, Tischler J, Bezares F, Prokes SM, Folland TG, Glembocki OJ, Caldwell JD. Implementation of plasmonic band structure to understand polariton hybridization within metamaterials. OPTICS EXPRESS 2018; 26:29363-29374. [PMID: 30470101 DOI: 10.1364/oe.26.029363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 08/14/2018] [Indexed: 06/09/2023]
Abstract
Gap surface plasmons (GSPs) serve a diverse range of plasmonic applications, including energy harvesting, communications, molecular sensing, and optical detection. GSPs may be realized where tightly spaced plasmonic structures exhibit strong spatial overlap between the evanescent fields. We demonstrate that within similar, nested geometries that the near-fields of the GSPs within the individual nanostructures are hybridized. This creates two or more distinct resonances exhibiting near-field distributions extended over adjacent spatial regions. In contrast, dissimilar, nested structures exhibit two distinct resonances with nominally uncoupled near-fields, resulting in two or more individual antenna resonance modes. We deploy plasmonic band structure calculations to provide insight into the type and degree of hybridization within these systems, comparing the individual components. This understanding can be used in the optimized design of polaritonic metamaterial structures for desired applications.
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30
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Mohr DA, Yoo D, Chen C, Li M, Oh SH. Waveguide-integrated mid-infrared plasmonics with high-efficiency coupling for ultracompact surface-enhanced infrared absorption spectroscopy. OPTICS EXPRESS 2018; 26:23540-23549. [PMID: 30184853 DOI: 10.1364/oe.26.023540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 08/11/2018] [Indexed: 06/08/2023]
Abstract
Waveguide-integrated plasmonics is a growing field with many innovative concepts and demonstrated devices in the visible and near-infrared. Here, we extend this body of work to the mid-infrared for the application of surface-enhanced infrared absorption (SEIRA), a spectroscopic method to probe molecular vibrations in small volumes and thin films. Built atop a silicon-on-insulator (SOI) waveguide platform, two key plasmonic structures useful for SEIRA are examined using computational modeling: gold nanorods and coaxial nanoapertures. We find resonance dips of 90% in near diffraction-limited areas due to arrays of our structures and up to 50% from a single resonator. Each of the structures is evaluated using the simulated SEIRA signal from poly(methyl methacrylate) and an octadecanethiol self-assembled monolayer. The platforms we present allow for a compact, on-chip SEIRA sensing system with highly efficient waveguide coupling in the mid-IR.
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31
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Yoo D, Gurunatha KL, Choi HK, Mohr DA, Ertsgaard CT, Gordon R, Oh SH. Low-Power Optical Trapping of Nanoparticles and Proteins with Resonant Coaxial Nanoaperture Using 10 nm Gap. NANO LETTERS 2018; 18:3637-3642. [PMID: 29763566 DOI: 10.1021/acs.nanolett.8b00732] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present optical trapping with a 10 nm gap resonant coaxial nanoaperture in a gold film. Large arrays of 600 resonant plasmonic coaxial nanoaperture traps are produced on a single chip via atomic layer lithography with each aperture tuned to match a 785 nm laser source. We show that these single coaxial apertures can act as efficient nanotweezers with a sharp potential well, capable of trapping 30 nm polystyrene nanoparticles and streptavidin molecules with a laser power as low as 4.7 mW. Furthermore, the resonant coaxial nanoaperture enables real-time label-free detection of the trapping events via simple transmission measurements. Our fabrication technique is scalable and reproducible, since the critical nanogap dimension is defined by atomic layer deposition. Thus our platform shows significant potential to push the limit of optical trapping technologies.
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Affiliation(s)
- Daehan Yoo
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Kargal L Gurunatha
- Department of Electrical and Computer Engineering , University of Victoria , Victoria , British Columbia V8P 5C2 , Canada
| | - Han-Kyu Choi
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Daniel A Mohr
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Christopher T Ertsgaard
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Reuven Gordon
- Department of Electrical and Computer Engineering , University of Victoria , Victoria , British Columbia V8P 5C2 , Canada
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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32
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Cai H, Meng Q, Zhao H, Li M, Dai Y, Lin Y, Ding H, Pan N, Tian Y, Luo Y, Wang X. High-Throughput Fabrication of Ultradense Annular Nanogap Arrays for Plasmon-Enhanced Spectroscopy. ACS APPLIED MATERIALS & INTERFACES 2018; 10:20189-20195. [PMID: 29799180 DOI: 10.1021/acsami.8b04810] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The confinement of light into nanometer-sized metallic nanogaps can lead to an extremely high field enhancement, resulting in dramatically enhanced absorption, emission, and surface-enhanced Raman scattering (SERS) of molecules embedded in nanogaps. However, low-cost, high-throughput, and reliable fabrication of ultra-high-dense nanogap arrays with precise control of the gap size still remains a challenge. Here, by combining colloidal lithography and atomic layer deposition technique, a reproducible method for fabricating ultra-high-dense arrays of hexagonal close-packed annular nanogaps over large areas is demonstrated. The annular nanogap arrays with a minimum diameter smaller than 100 nm and sub-1 nm gap width have been produced, showing excellent SERS performance with a typical enhancement factor up to 3.1 × 106 and a detection limit of 10-11 M. Moreover, it can also work as a high-quality field enhancement substrate for studying two-dimensional materials, such as MoSe2. Our method provides an attractive approach to produce controllable nanogaps for enhanced light-matter interaction at the nanoscale.
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Affiliation(s)
| | | | | | | | - Yanmeng Dai
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering , Shenzhen University , Shenzhen 518060 , China
| | | | | | | | - Yangchao Tian
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei 230027 , China
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33
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Khademi A, Dewolf T, Gordon R. Quantum plasmonic epsilon near zero: field enhancement and cloaking. OPTICS EXPRESS 2018; 26:15656-15664. [PMID: 30114823 DOI: 10.1364/oe.26.015656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/23/2018] [Indexed: 06/08/2023]
Abstract
We investigate the effect of the electron wave function producing permittivity (epsilon) near zero in sub-nanometer gaps and at surfaces. The field enhancement is calculated for gaps and nanoparticles, as well as the absorption from nanoparticles. Our modified quantum corrected model shows reduced absorption for nanoparticles due to "cloaking" of the epsilon near zero region, which has lower loss than the bulk region. We demonstrate that a modified quantum corrected model finite-difference time-domain simulation of metal slits with sub-nanometer gaps are in good agreement with the analytic expression for the quantum corrected plasmonic resonance wavelength as a function of gap size coming from Re{ε} = 0.
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34
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Yoo D, Mohr DA, Vidal-Codina F, John-Herpin A, Jo M, Kim S, Matson J, Caldwell JD, Jeon H, Nguyen NC, Martin-Moreno L, Peraire J, Altug H, Oh SH. High-Contrast Infrared Absorption Spectroscopy via Mass-Produced Coaxial Zero-Mode Resonators with Sub-10 nm Gaps. NANO LETTERS 2018; 18:1930-1936. [PMID: 29437401 DOI: 10.1021/acs.nanolett.7b05295] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We present a wafer-scale array of resonant coaxial nanoapertures as a practical platform for surface-enhanced infrared absorption spectroscopy (SEIRA). Coaxial nanoapertures with sub-10 nm gaps are fabricated via photolithography, atomic layer deposition of a sacrificial Al2O3 layer to define the nanogaps, and planarization via glancing-angle ion milling. At the zeroth-order Fabry-Pérot resonance condition, our coaxial apertures act as a "zero-mode resonator (ZMR)", efficiently funneling as much as 34% of incident infrared (IR) light along 10 nm annular gaps. After removing Al2O3 in the gaps and inserting silk protein, we can couple the intense optical fields of the annular nanogap into the vibrational modes of protein molecules. From 7 nm gap ZMR devices coated with a 5 nm thick silk protein film, we observe high-contrast IR absorbance signals drastically suppressing 58% of the transmitted light and infer a strong IR absorption enhancement factor of 104∼105. These single nanometer gap ZMR devices can be mass-produced via batch processing and offer promising routes for broad applications of SEIRA.
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Affiliation(s)
- Daehan Yoo
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Daniel A Mohr
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Ferran Vidal-Codina
- Department of Aeronautics and Astronautics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Aurelian John-Herpin
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015 , Switzerland
| | - Minsik Jo
- Department of Physics and Department of Energy Systems Research , Ajou University , Suwon 16499 , Korea
| | - Sunghwan Kim
- Department of Physics and Department of Energy Systems Research , Ajou University , Suwon 16499 , Korea
| | - Joseph Matson
- Department of Mechanical Engineering , Vanderbilt University , Nashville , Tennessee 37212 , United States
| | - Joshua D Caldwell
- Department of Mechanical Engineering , Vanderbilt University , Nashville , Tennessee 37212 , United States
| | - Heonsu Jeon
- Department of Physics and Astronomy , Seoul National University , Seoul 08826 , Korea
| | - Ngoc-Cuong Nguyen
- Department of Aeronautics and Astronautics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Luis Martin-Moreno
- Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza , E-50009 Zaragoza , Spain
| | - Jaime Peraire
- Department of Aeronautics and Astronautics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Hatice Altug
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL) , Lausanne 1015 , Switzerland
| | - Sang-Hyun Oh
- Department of Electrical and Computer Engineering , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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35
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Ma H, Li S, Wei Y, Jiang L, Li J. Fabrication of two-dimensional (2D) ordered microsphere aligned by supramolecular self-assembly of Formyl-azobenzene and dipeptide. J Colloid Interface Sci 2018; 514:491-495. [DOI: 10.1016/j.jcis.2017.12.054] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 02/04/2023]
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36
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Pan R, Yang Y, Wang Y, Li S, Liu Z, Su Y, Quan B, Li Y, Gu C, Li J. Nanocracking and metallization doubly defined large-scale 3D plasmonic sub-10 nm-gap arrays as extremely sensitive SERS substrates. NANOSCALE 2018; 10:3171-3180. [PMID: 29364303 DOI: 10.1039/c7nr08646f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Considering the technological difficulties in the existing approaches to form nanoscale gaps, a convenient method to fabricate three-dimensional (3D) sub-10 nm Ag/SiNx gap arrays has been demonstrated in this study, controlled by a combination of stress-induced nanocracking of a SiNx nanobridge and Ag nanofilm deposition. This scalable 3D plasmonic nanogap is specially suspended above a substrate, having a tunable nanogap width and large height-to-width ratio to form a nanocavity underneath. As a surface-enhanced Raman scattering (SERS) substrate, the 3D Ag/SiNx nanogap shows a large Raman enhancement factor of ∼108 and extremely high sensitivity for the detection of Rhodamine 6G (R6G) molecules, even down to 10-16 M, indicating an extraordinary capability for single-molecule detection. Further, we verified that the Fabry-Perot resonance occurred in the deep SiNx nanocavity under the Ag nanogap and contributed prominently to a tremendous enhancement of the local field in the Ag-nanogap zone and hence ultrasensitive SERS detection. This method circumvents the technological limitations to fabricate a sub-10 nm metal nanogap with unique features for wide applications in important scientific and technological areas.
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Affiliation(s)
- Ruhao Pan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
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37
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Tai Y, Lubineau G. "Self-Peel-Off" Transfer Produces Ultrathin Polyvinylidene-Fluoride-Based Flexible Nanodevices. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2017; 4:1600370. [PMID: 28435776 PMCID: PMC5396151 DOI: 10.1002/advs.201600370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/29/2016] [Indexed: 06/07/2023]
Abstract
Here, a new strategy, self-peel-off transfer, for the preparation of ultrathin flexible nanodevices made from polyvinylidene-fluoride (PVDF) is reported. In this process, a functional pattern of nanoparticles is transferred via peeling from a temporary substrate to the final PVDF film. This peeling process takes advantage of the differences in the work of adhesion between the various layers (the PVDF layer, the nanoparticle-pattern layer and the substrate layer) and of the high stresses generated by the differential thermal expansion of the layers. The work of adhesion is mainly guided by the basic physical/chemical properties of these layers and is highly sensitive to variations in temperature and moisture in the environment. The peeling technique is tested on a variety of PVDF-based functional films using gold/palladium nanoparticles, carbon nanotubes, graphene oxide, and lithium iron phosphate. Several PVDF-based flexible nanodevices are prepared, including a single-sided wireless flexible humidity sensor in which PVDF is used as the substrate and a double-sided flexible capacitor in which PVDF is used as the ferroelectric layer and the carrier layer. Results show that the nanodevices perform with high repeatability and stability. Self-peel-off transfer is a viable preparation strategy for the design and fabrication of flexible, ultrathin, and light-weight nanodevices.
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Affiliation(s)
- Yanlong Tai
- Division of Physical Science and EngineeringKing Abdullah University of Science and Technology (KAUST)COHMAS LaboratoryThuwal23955‐6900Saudi Arabia
| | - Gilles Lubineau
- Division of Physical Science and EngineeringKing Abdullah University of Science and Technology (KAUST)COHMAS LaboratoryThuwal23955‐6900Saudi Arabia
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38
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Chen X, Lindquist NC, Klemme DJ, Nagpal P, Norris DJ, Oh SH. Split-Wedge Antennas with Sub-5 nm Gaps for Plasmonic Nanofocusing. NANO LETTERS 2016; 16:7849-7856. [PMID: 27960527 PMCID: PMC5159698 DOI: 10.1021/acs.nanolett.6b04113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/20/2016] [Indexed: 05/23/2023]
Abstract
We present a novel plasmonic antenna structure, a split-wedge antenna, created by splitting an ultrasharp metallic wedge with a nanogap perpendicular to its apex. The nanogap can tightly confine gap plasmons and boost the local optical field intensity in and around these opposing metallic wedge tips. This three-dimensional split-wedge antenna integrates the key features of nanogaps and sharp tips, i.e., tight field confinement and three-dimensional nanofocusing, respectively, into a single platform. We fabricate split-wedge antennas with gaps that are as small as 1 nm in width at the wafer scale by combining silicon V-grooves with template stripping and atomic layer lithography. Computer simulations show that the field enhancement and confinement are stronger at the tip-gap interface compared to what standalone tips or nanogaps produce, with electric field amplitude enhancement factors exceeding 50 when near-infrared light is focused on the tip-gap geometry. The resulting nanometric hotspot volume is on the order of λ3/106. Experimentally, Raman enhancement factors exceeding 107 are observed from a 2 nm gap split-wedge antenna, demonstrating its potential for sensing and spectroscopy applications.
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Affiliation(s)
- Xiaoshu Chen
- Department
of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Nathan C. Lindquist
- Department
of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Physics
Department, Bethel University, Saint Paul, Minnesota 55112, United States
| | - Daniel J. Klemme
- Department
of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Prashant Nagpal
- Chemical
and Biological Engineering, University of
Colorado, Boulder, Colorado 80303, United
States
| | - David J. Norris
- Optical
Materials Engineering Laboratory, ETH Zurich, 8092 Zurich, Switzerland
| | - Sang-Hyun Oh
- Department
of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Saleh AAE, Sheikhoelislami S, Gastelum S, Dionne JA. Grating-flanked plasmonic coaxial apertures for efficient fiber optical tweezers. OPTICS EXPRESS 2016; 24:20593-20603. [PMID: 27607663 DOI: 10.1364/oe.24.020593] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Subwavelength plasmonic apertures have been foundational for direct optical manipulation of nanoscale specimens including sub-100 nm polymeric beads, metallic nanoparticles and proteins. While most plasmonic traps result in two-dimensional localization, three-dimensional manipulation has been demonstrated by integrating a plasmonic aperture on an optical fiber tip. However, such 3D traps are usually inefficient since the optical mode of the fiber and the subwavelength aperture only weakly couple. In this paper we design more efficient optical-fiber-based plasmonic tweezers combining a coaxial plasmonic aperture with a plasmonic grating coupler at the fiber tip facet. Using full-field finite difference time domain analysis, we optimize the grating design for both gold and silver fiber-based coaxial tweezers such that the optical transmission through the apertures is maximized. With the optimized grating, we show that the maximum transmission efficiency increases from 2.5% to 19.6% and from 1.48% to 16.7% for the gold and silver structures respectively. To evaluate their performance as optical tweezers, we calculate the optical forces and the corresponding trapping potential on dielectric particles interacting with the apertures. We demonstrate that the enahncement in the transmission translates into an equivalent increase in the optical forces. Consequently, the optical power required to achieve stable optical trapping is significantly reduced allowing for efficient localization and 3D manipulation of sub-30 nm dielectric particles.
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40
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Cai H, Wu Y, Dai Y, Pan N, Tian Y, Luo Y, Wang X. Wafer scale fabrication of highly dense and uniform array of sub-5 nm nanogaps for surface enhanced Raman scatting substrates. OPTICS EXPRESS 2016; 24:20808-20815. [PMID: 27607684 DOI: 10.1364/oe.24.020808] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Metallic nanogap is very important for a verity of applications in plasmonics. Although several fabrication techniques have been proposed in the last decades, it is still a challenge to produce uniform nanogaps with a few nanometers gap distance and high throughput. Here we present a simple, yet robust method based on the atomic layer deposition (ALD) and lift-off technique for patterning ultranarrow nanogaps array. The ability to accurately control the thickness of the ALD spacer layer enables us to precisely define the gap size, down to sub-5 nm scale. Moreover, this new method allows to fabricate uniform nanogaps array along different directions densely arranged on the wafer-scale substrate. It is demonstrated that the fabricated array can be used as an excellent substrate for surface enhanced Raman scatting (SERS) measurements of molecules, even on flexible substrates. This uniform nanogaps array would also find its applications for the trace detection and biosensors.
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