Spontaneous Hot-Electron Light Emission from Electron-Fed Optical Antennas
- Mickael Buret
- ,
- Alexander V. Uskov
- ,
- Jean Dellinger
- ,
- Nicolas Cazier
- ,
- Marie-Maxime Mennemanteuil
- ,
- Johann Berthelot
- ,
- Igor V. Smetanin
- ,
- Igor E. Protsenko
- ,
- Gérard Colas-des-Francs
- , and
- Alexandre Bouhelier
Abstract

Nanoscale electronics and photonics are among the most promising research areas providing functional nanocomponents for data transfer and signal processing. By adopting metal-based optical antennas as a disruptive technological vehicle, we demonstrate that these two device-generating technologies can be interfaced to create an electronically driven self-emitting unit. This nanoscale plasmonic transmitter operates by injecting electrons in a contacted tunneling antenna feedgap. Under certain operating conditions, we show that the antenna enters a highly nonlinear regime in which the energy of the emitted photons exceeds the quantum limit imposed by the applied bias. We propose a model based upon the spontaneous emission of hot electrons that correctly reproduces the experimental findings. The electron-fed optical antennas described here are critical devices for interfacing electrons and photons, enabling thus the development of optical transceivers for on-chip wireless broadcasting of information at the nanoscale.
Cited By
This article is cited by 75 publications.
- Florian Dell’Ova, Konstantin Malchow, Rémi Chassagnon, Olivier Heintz, Nicolas Pocholle, Gérard Colas des Francs, Erik Dujardin, Alexandre Bouhelier. Hot Carrier-Induced Nonlinear Photoluminescence in a Thin Indium Tin Oxide Layer Patterned by Ga Ion Beam Milling. ACS Applied Optical Materials 2023, 1 (1) , 244-251. https://doi.org/10.1021/acsaom.2c00046
- Yunxuan Zhu, Longji Cui, Mahdiyeh Abbasi, Douglas Natelson. Tuning Light Emission Crossovers in Atomic-Scale Aluminum Plasmonic Tunnel Junctions. Nano Letters 2022, 22 (20) , 8068-8075. https://doi.org/10.1021/acs.nanolett.2c02013
- Philipp Grimm, Stefan Zeißner, Maximilian Rödel, Simon Wiegand, Sebastian Hammer, Monika Emmerling, Enno Schatz, René Kullock, Jens Pflaum, Bert Hecht. Color-Switchable Subwavelength Organic Light-Emitting Antennas. Nano Letters 2022, 22 (3) , 1032-1038. https://doi.org/10.1021/acs.nanolett.1c03994
- Anna Rosławska, Pablo Merino, Abhishek Grewal, Christopher C. Leon, Klaus Kuhnke, Klaus Kern. Atomic-Scale Structural Fluctuations of a Plasmonic Cavity. Nano Letters 2021, 21 (17) , 7221-7227. https://doi.org/10.1021/acs.nanolett.1c02207
- Alberto Martín-Jiménez, Koen Lauwaet, Óscar Jover, Daniel Granados, Andrés Arnau, Vyacheslav M. Silkin, Rodolfo Miranda, Roberto Otero. Electronic Temperature and Two-Electron Processes in Overbias Plasmonic Emission from Tunnel Junctions. Nano Letters 2021, 21 (16) , 7086-7092. https://doi.org/10.1021/acs.nanolett.1c00951
- Fangwei Wang, Yan Liu, Thorin Jake Duffin, Vijith Kalathingal, Siping Gao, Wenrui Hu, Yongxin Guo, Soo-Jin Chua, Christian A. Nijhuis. Silicon-Based Quantum Mechanical Tunnel Junction for Plasmon Excitation from Low-Energy Electron Tunneling. ACS Photonics 2021, 8 (7) , 1951-1960. https://doi.org/10.1021/acsphotonics.0c01913
- Longji Cui, Yunxuan Zhu, Peter Nordlander, Massimiliano Di Ventra, Douglas Natelson. Thousand-fold Increase in Plasmonic Light Emission via Combined Electronic and Optical Excitations. Nano Letters 2021, 21 (6) , 2658-2665. https://doi.org/10.1021/acs.nanolett.1c00503
- Guy Shalem, Omer Erez-Cohen, Diana Mahalu, Israel Bar-Joseph. Light Emission in Metal–Semiconductor Tunnel Junctions: Direct Evidence for Electron Heating by Plasmon Decay. Nano Letters 2021, 21 (3) , 1282-1287. https://doi.org/10.1021/acs.nanolett.0c03945
- E-Dean Fung, Latha Venkataraman. Too Cool for Blackbody Radiation: Overbias Photon Emission in Ambient STM Due to Multielectron Processes. Nano Letters 2020, 20 (12) , 8912-8918. https://doi.org/10.1021/acs.nanolett.0c03994
- Adrian Agreda, Sviatlana Viarbitskaya, Igor V. Smetanin, Alexander V. Uskov, Gérard Colas des Francs, Alexandre Bouhelier. Electrostatic Control over Optically Pumped Hot Electrons in Optical Gap Antennas. ACS Photonics 2020, 7 (8) , 2153-2162. https://doi.org/10.1021/acsphotonics.0c00623
- Longji Cui, Yunxuan Zhu, Mahdiyeh Abbasi, Arash Ahmadivand, Burak Gerislioglu, Peter Nordlander, Douglas Natelson. Electrically Driven Hot-Carrier Generation and Above-Threshold Light Emission in Plasmonic Tunnel Junctions. Nano Letters 2020, 20 (8) , 6067-6075. https://doi.org/10.1021/acs.nanolett.0c02121
- Jin Qin, Yingjian Liu, Huiwen Luo, Zhongjun Jiang, Wenshan Cai, Liang Wang. Tunable Light Emission by Electrically Excited Plasmonic Antenna. ACS Photonics 2019, 6 (10) , 2392-2396. https://doi.org/10.1021/acsphotonics.9b00954
- Adrian Agreda, Deepak K. Sharma, Sviatlana Viarbitskaya, Romain Hernandez, Benoît Cluzel, Olivier Demichel, Jean-Claude Weeber, Gérard Colas des Francs, G.V. Pavan Kumar, Alexandre Bouhelier. Spatial Distribution of the Nonlinear Photoluminescence in Au Nanowires. ACS Photonics 2019, 6 (5) , 1240-1247. https://doi.org/10.1021/acsphotonics.9b00181
- Hasan Göktaş, Fikri Serdar Gökhan, Volker J. Sorger. Electrical-Driven Plasmon Source of Silicon Based on Quantum Tunneling. ACS Photonics 2018, 5 (12) , 4928-4936. https://doi.org/10.1021/acsphotonics.8b01106
- Upkar Kumar, Sviatlana Viarbitskaya, Aurélien Cuche, Christian Girard, Sreenath Bolisetty, Raffaele Mezzenga, Gérard Colas des Francs, Alexandre Bouhelier, Erik Dujardin. Designing Plasmonic Eigenstates for Optical Signal Transmission in Planar Channel Devices. ACS Photonics 2018, 5 (6) , 2328-2335. https://doi.org/10.1021/acsphotonics.8b00137
- Surya Prakash Gurunarayanan, Niels Verellen, Vyacheslav S. Zharinov, Finub James Shirley, Victor V. Moshchalkov, Marc Heyns, Joris Van de Vondel, Iuliana P. Radu, and Pol Van Dorpe . Electrically Driven Unidirectional Optical Nanoantennas. Nano Letters 2017, 17 (12) , 7433-7439. https://doi.org/10.1021/acs.nanolett.7b03312
- Srinivas Ganti, Peter J. King, Erhan Arac, Karl Dawson, Mikko J. Heikkilä, John H. Quilter, Billy Murdoch, Peter Cumpson, and Anthony O’Neill . Voltage Controlled Hot Carrier Injection Enables Ohmic Contacts Using Au Island Metal Films on Ge. ACS Applied Materials & Interfaces 2017, 9 (33) , 27357-27364. https://doi.org/10.1021/acsami.7b06595
- Alexander V. Uskov, Jacob B. Khurgin, Mickael Buret, Alexandre Bouhelier, Igor V. Smetanin, and Igor E. Protsenko . Biased Nanoscale Contact as Active Element for Electrically Driven Plasmonic Nanoantenna. ACS Photonics 2017, 4 (6) , 1501-1505. https://doi.org/10.1021/acsphotonics.7b00272
- Klaus Kuhnke, Christoph Große, Pablo Merino, and Klaus Kern . Atomic-Scale Imaging and Spectroscopy of Electroluminescence at Molecular Interfaces. Chemical Reviews 2017, 117 (7) , 5174-5222. https://doi.org/10.1021/acs.chemrev.6b00645
- Yuval Vardi, Eyal Cohen-Hoshen, Guy Shalem, and Israel Bar-Joseph . Fano Resonance in an Electrically Driven Plasmonic Device. Nano Letters 2016, 16 (1) , 748-752. https://doi.org/10.1021/acs.nanolett.5b04622
- Yuankai Tang, Hayk Harutyunyan. Optical Properties of Plasmonic Tunneling Junctions. The Journal of Chemical Physics 2023, https://doi.org/10.1063/5.0128822
- Ryo Yonemoto, Toma Babe, Rieko Ueda, Akira Otomo, Yutaka Noguchi. Electrically induced light emission via nanoscale vacuum discharge in nanogap electrodes without luminescent molecules. Journal of Applied Physics 2022, 132 (17) , 174303. https://doi.org/10.1063/5.0102395
- Maoning Wang, Tao Wang, Oluwafemi S. Ojambati, Thorin Jake Duffin, Keehoon Kang, Takhee Lee, Elke Scheer, Dong Xiang, Christian A. Nijhuis. Plasmonic phenomena in molecular junctions: principles and applications. Nature Reviews Chemistry 2022, 6 (10) , 681-704. https://doi.org/10.1038/s41570-022-00423-4
- Saurabh Kishen, Jinal Tapar, Naresh Kumar Emani. Tunable directional emission from electrically driven nano-strip metal–insulator–metal tunnel junctions. Nanoscale Advances 2022, 4 (17) , 3609-3616. https://doi.org/10.1039/D2NA00149G
- Andreea Radulescu, Vijith Kalathingal, Zhe Wang, Christian A. Nijhuis. Coherence Between Different Propagating Surface Plasmon Polariton Modes Excited by Quantum Mechanical Tunnel Junctions. Advanced Optical Materials 2022, 10 (3) , 2101804. https://doi.org/10.1002/adom.202101804
- Anne Nguyen, Jean-Jacques Greffet. Efficiency optimization of mid-infrared incandescent sources with time-varying temperature. Optical Materials Express 2022, 12 (1) , 225. https://doi.org/10.1364/OME.443129
- Léo Wojszvzyk, Anne Nguyen, Anne-Lise Coutrot, Cheng Zhang, Benjamin Vest, Jean-Jacques Greffet. An incandescent metasurface for quasimonochromatic polarized mid-wave infrared emission modulated beyond 10 MHz. Nature Communications 2021, 12 (1) https://doi.org/10.1038/s41467-021-21752-w
- Jibo Tang, Huatian Hu, Xiaobo He, Yuhao Xu, Yuan Zhang, Zhiqiang Guan, Shunping Zhang, Hongxing Xu. Switchable Electrically Driven Optical Antenna Based on Ultrathin Amorphous Silica. Advanced Optical Materials 2021, 9 (19) , 2100191. https://doi.org/10.1002/adom.202100191
- Yan Liu, Soo-Jin Chua, Siping Gao, Wenrui Hu, Yongxin Guo. Electroluminescence in plasmonic actuator based on Au/SiO 2 /n-Si tunnel junction. Nanophotonics 2021, 10 (13) , 3487-3496. https://doi.org/10.1515/nanoph-2021-0287
- Anne Nguyen, Léo Wojszvzyk, Anne-Lise Coutrot, Benjamin Vest, Jean-Jacques Greffet, , , . Fast modulation and polarization control of infrared emission by incandescent metasurfaces. 2021, 60. https://doi.org/10.1117/12.2594428
- A. Ciattoni, C. Conti, A. Marini. Electric Directional Steering of Cathodoluminescence From Graphene-Based Hybrid Nanostructures. Physical Review Applied 2021, 15 (5) https://doi.org/10.1103/PhysRevApplied.15.054016
- Andreea Radulescu, Ksenia S. Makarenko, Thanh Xuan Hoang, Vijith Kalathingal, Thorin J. Duffin, Hong-Son Chu, Christian A. Nijhuis. Geometric control over surface plasmon polariton out-coupling pathways in metal-insulator-metal tunnel junctions. Optics Express 2021, 29 (8) , 11987. https://doi.org/10.1364/OE.413698
- Konstantin Malchow, Alexandre Bouhelier. Photon bunching of the nonlinear photoluminescence emitted by plasmonics metals. Journal of the Optical Society of America B 2021, 38 (2) , 576. https://doi.org/10.1364/JOSAB.411507
- Jihye Lee, Jong-Souk Yeo. On-Chip Nanoscale Light Source Based on Quantum Tunneling: Enabling Ultrafast Quantum Device and Sensing Applications. Applied Science and Convergence Technology 2021, 30 (1) , 6-13. https://doi.org/10.5757/ASCT.2021.30.1.6
- Nannan Li, Yunhe Lai, Shiu Hei Lam, Haoyuan Bai, Lei Shao, Jianfang Wang. Directional Control of Light with Nanoantennas. Advanced Optical Materials 2021, 9 (1) , 2001081. https://doi.org/10.1002/adom.202001081
- Youngsang Kim, Charles H. Ang, Kwissy Ang, Soon W. Chang. Electromigrated nanogaps: A review on the fabrications and applications. Journal of Vacuum Science & Technology B 2021, 39 (1) , 010802. https://doi.org/10.1116/6.0000866
- Yunxuan Zhu, Longji Cui, Douglas Natelson. Hot-carrier enhanced light emission: The origin of above-threshold photons from electrically driven plasmonic tunnel junctions. Journal of Applied Physics 2020, 128 (23) , 233105. https://doi.org/10.1063/5.0024392
- Christian Ott, Stephan Götzinger, Heiko B. Weber. Thermal origin of light emission in nonresonant and resonant nanojunctions. Physical Review Research 2020, 2 (4) https://doi.org/10.1103/PhysRevResearch.2.042019
- Ksenia S. Makarenko, Thanh Xuan Hoang, Thorin J. Duffin, Andreea Radulescu, Vijith Kalathingal, Henri J. Lezec, Hong‐Son Chu, Christian A. Nijhuis. Efficient Surface Plasmon Polariton Excitation and Control over Outcoupling Mechanisms in Metal–Insulator–Metal Tunneling Junctions. Advanced Science 2020, 7 (8) , 1900291. https://doi.org/10.1002/advs.201900291
- Mickaël Buret, Igor V. Smetanin, Alexander V. Uskov, Gérard Colas des Francs, Alexandre Bouhelier. Effect of quantized conductivity on the anomalous photon emission radiated from atomic-size point contacts. Nanophotonics 2020, 9 (2) , 413-425. https://doi.org/10.1515/nanoph-2019-0325
- Zhipeng Sun, Mingming Jiang, Wangqi Mao, Caixia Kan, Chongxin Shan, Dezhen Shen. Nonequilibrium hot-electron-induced wavelength-tunable incandescent-type light sources. Photonics Research 2020, 8 (1) , 91. https://doi.org/10.1364/PRJ.8.000091
- Markus Parzefall, Áron Szabó, Takashi Taniguchi, Kenji Watanabe, Mathieu Luisier, Lukas Novotny. Light from van der Waals quantum tunneling devices. Nature Communications 2019, 10 (1) https://doi.org/10.1038/s41467-018-08266-8
- Liang Wang, Yingjian Liu, Jin Qin, , , . Electrically driven plasmonic antenna. 2019, 8. https://doi.org/10.1117/12.2538155
- Markus Parzefall, Lukas Novotny. Optical antennas driven by quantum tunneling: a key issues review. Reports on Progress in Physics 2019, 82 (11) , 112401. https://doi.org/10.1088/1361-6633/ab4239
- Tao Wang, Wei Du, Nikodem Tomczak, Lejia Wang, Christian A. Nijhuis. In Operando Characterization and Control over Intermittent Light Emission from Molecular Tunnel Junctions via Molecular Backbone Rigidity. Advanced Science 2019, 6 (20) , 1900390. https://doi.org/10.1002/advs.201900390
- Ludivine Emeric, Claire Deeb, Fabrice Pardo, Jean-Luc Pelouard. Critical coupling and extreme confinement in nanogap antennas. Optics Letters 2019, 44 (19) , 4761. https://doi.org/10.1364/OL.44.004761
- Zhanguo Li, Gaohang He, Mingming Jiang, Jiaolong Ji, Chongxin Shan, Dezhen Shen. Electrical-pumping spasing action from cross-stacked microwires. Journal of Materials Chemistry C 2019, 7 (35) , 10933-10944. https://doi.org/10.1039/C9TC03537K
- Léo Wojszvzyk, Hector Monin, Jean‐Jacques Greffet. Light Emission by a Thermalized Ensemble of Emitters Coupled to a Resonant Structure. Advanced Optical Materials 2019, 7 (14) , 1801697. https://doi.org/10.1002/adom.201801697
- Arindam Dasgupta, Marie-Maxime Mennemanteuil, Mickaël Buret, Nicolas Cazier, Gérard Colas-des-Francs, Alexandre Bouhelier. Optical wireless link between a nanoscale antenna and a transducing rectenna. Nature Communications 2018, 9 (1) https://doi.org/10.1038/s41467-018-04382-7
- Pierre Février, Julien Gabelli. Tunneling time probed by quantum shot noise. Nature Communications 2018, 9 (1) https://doi.org/10.1038/s41467-018-07369-6
- Woongkyu Park, Youjin Lee, Taehee Kang, Jeeyoon Jeong, Dai-Sik Kim. Terahertz-driven polymerization of resists in nanoantennas. Scientific Reports 2018, 8 (1) https://doi.org/10.1038/s41598-018-26214-w
- Marie-Maxime Mennemanteuil, Gérard Colas-des-Francs, Mickaël Buret, Arindam Dasgupta, Alexander Cuadrado, Javier Alda, Alexandre Bouhelier. Laser-induced thermoelectric effects in electrically biased nanoscale constrictions. Nanophotonics 2018, 7 (12) , 1917-1927. https://doi.org/10.1515/nanoph-2018-0083
- Kai Braun, Florian Laible, Otto Hauler, Xiao Wang, Anlian Pan, Monika Fleischer, Alfred J. Meixner. Active optical antennas driven by inelastic electron tunneling. Nanophotonics 2018, 7 (9) , 1503-1516. https://doi.org/10.1515/nanoph-2018-0080
- I. V. Smetanin, A. Bouhelier, A. V. Uskov. Coherent Excitation of Optical Oscillations in a Metal Nanosphere by a 2D Electric Current. Journal of Russian Laser Research 2018, 39 (5) , 484-491. https://doi.org/10.1007/s10946-018-9743-z
- F.A. Shuklin, J.B. Khurgin, I.V. Smetanin, I.E. Protsenko, A. Bouhelier, I.S. Mukhin, A.V. Uskov. Stimulated emission of phonons and plasmons by ballistic electrons in nanoscale contacts. 2018, 429-429. https://doi.org/10.1109/LO.2018.8435781
- Ludivine Emeric, Claire Deeb, Jean-Luc Pelouard, Alan Durnez, Fabrice Pardo, Nathalie Bardou, Riad Haïdar, , , , . Investigating the optical properties of nanogap optical antennas. 2018, 111. https://doi.org/10.1117/12.2306849
- Jean-Jacques Greffet, Patrick Bouchon, Giovanni Brucoli, François Marquier. Light Emission by Nonequilibrium Bodies: Local Kirchhoff Law. Physical Review X 2018, 8 (2) https://doi.org/10.1103/PhysRevX.8.021008
- Yang Liu, Mingming Jiang, Zhenzhong Zhang, Binghui Li, Haifeng Zhao, Chongxin Shan, Dezhen Shen. Electrically excited hot-electron dominated fluorescent emitters using individual Ga-doped ZnO microwires via metal quasiparticle film decoration. Nanoscale 2018, 10 (12) , 5678-5688. https://doi.org/10.1039/C8NR00715B
- Arindam Dasgupta, Mickaël Buret, Nicolas Cazier, Marie-Maxime Mennemanteuil, Reinaldo Chacon, Kamal Hammani, Jean-Claude Weeber, Juan Arocas, Laurent Markey, Gérard Colas des Francs, Alexander Uskov, Igor Smetanin, Alexandre Bouhelier. Electromigrated electrical optical antennas for transducing electrons and photons at the nanoscale. Beilstein Journal of Nanotechnology 2018, 9 , 1964-1976. https://doi.org/10.3762/bjnano.9.187
- Vijith Kalathingal, Paul Dawson, J. Mitra. Scanning tunnelling microscope light emission: Finite temperature current noise and over cut-off emission. Scientific Reports 2017, 7 (1) https://doi.org/10.1038/s41598-017-03766-x
- Wei Du, Tao Wang, Hong-Son Chu, Christian A. Nijhuis. Highly efficient on-chip direct electronic–plasmonic transducers. Nature Photonics 2017, 11 (10) , 623-627. https://doi.org/10.1038/s41566-017-0003-5
- Peter-Jan Peters, Fei Xu, Kristen Kaasbjerg, Gianluca Rastelli, Wolfgang Belzig, Richard Berndt. Quantum Coherent Multielectron Processes in an Atomic Scale Contact. Physical Review Letters 2017, 119 (6) https://doi.org/10.1103/PhysRevLett.119.066803
- I E Protsenko, A V Uskov, Xue-Wen Chen, Hongxing Xu. Plasmonic superradiance of two emitters near a metal nanorod. Journal of Physics D: Applied Physics 2017, 50 (25) , 254003. https://doi.org/10.1088/1361-6463/aa6fd4
- Alexander Cuadrado, José Manuel López-Alonso, Francisco Javier González, Javier Alda. Spectral Response of Metallic Optical Antennas Driven by Temperature. Plasmonics 2017, 12 (3) , 553-561. https://doi.org/10.1007/s11468-016-0297-z
- A. V. Uskov, J. B. Khurgin, I. V. Smetanin, I. E. Protsenko, I. S. Mukhin, A. O. Goludok, M. Buret, A. Bouhelier. New approaches to electrically driven nanoantennas. 2017, 3847-3853. https://doi.org/10.1109/PIERS.2017.8262430
- , , Alexander V. Uskov, Jacob B. Khurgin, Alexandre Bouhelier, Mikael Buret, Igor E. Protsenko, Igor V. Smetanin. Electrically-driven optical antennas enabled by mesoscopic contacts. 2017, 1010204. https://doi.org/10.1117/12.2249619
- Markus Parzefall, Palash Bharadwaj, Lukas Novotny. Antenna-Coupled Tunnel Junctions. 2017, 211-236. https://doi.org/10.1007/978-3-319-45820-5_10
- B Rogez, S Cao, G Dujardin, G Comtet, E Le Moal, A Mayne, E Boer-Duchemin. The mechanism of light emission from a scanning tunnelling microscope operating in air. Nanotechnology 2016, 27 (46) , 465201. https://doi.org/10.1088/0957-4484/27/46/465201
- A. V. Uskov, I. V. Smetanin, I. E. Protsenko, J. B. Khurgin, M. Buret, A. Bouhelier. Nanoscale constriction as a source of plasmons for plasmonic nanocircuitries. 2016, 376-378. https://doi.org/10.1109/MetaMaterials.2016.7746405
- Tao Wang, Christian A. Nijhuis. Molecular electronic plasmonics. Applied Materials Today 2016, 3 , 73-86. https://doi.org/10.1016/j.apmt.2016.03.001
- A. V. Uskov, I. V. Smetanin, I. E. Protsenko, J. B. Khurgin, M. Buret, A. Bouhelier. Metal mesoscopic contact as a source of plasmons for plasmonic nanocircuitries. 2016, R9-3-R9-3. https://doi.org/10.1109/LO.2016.7549903
- T. Malinowski, H. R. Klein, M. Iazykov, Ph. Dumas. Infrared light emission from nano hot electron gas created in atomic point contacts. EPL (Europhysics Letters) 2016, 114 (5) , 57002. https://doi.org/10.1209/0295-5075/114/57002
- Guillaume Schull. Launching plasmons with molecules. Nature Photonics 2016, 10 (4) , 208-209. https://doi.org/10.1038/nphoton.2016.42
- N. Cazier, M. Buret, A. V. Uskov, L. Markey, J. Arocas, G. Colas Des Francs, A. Bouhelier. Electrical excitation of waveguided surface plasmons by a light-emitting tunneling optical gap antenna. Optics Express 2016, 24 (4) , 3873. https://doi.org/10.1364/OE.24.003873
- Alexander V. Uskov, Jacob B. Khurgin, Igor E. Protsenko, Igor V. Smetanin, Alexandre Bouhelier. Excitation of plasmonic nanoantennas by nonresonant and resonant electron tunnelling. Nanoscale 2016, 8 (30) , 14573-14579. https://doi.org/10.1039/C6NR01931E