Probing the electrical switching of a memristive optical antenna by STEM EELS

• Published in: Nature communications Vol. 7; no. 1; p. 12162
• Main Authors: Schoen, David T., Holsteen, Aaron L., Brongersma, Mark L.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14.07.2016; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/1075/401; 639/624/399/1015; 639/624/400/1021; 639/766/930/527; Antennas; Electrodes; Electrons; Humanities and Social Sciences; multidisciplinary; Optical properties; Science; Science (multidisciplinary); Spectrum analysis
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms12162

The scaling of active photonic devices to deep-submicron length scales has been hampered by the fundamental diffraction limit and the absence of materials with sufficiently strong electro-optic effects. Plasmonics is providing new opportunities to circumvent this challenge. Here we provide evidence for a solid-state electro-optical switching mechanism that can operate in the visible spectral range with an active volume of less than (5 nm) 3 or ∼10 −6   λ 3 , comparable to the size of the smallest electronic components. The switching mechanism relies on electrochemically displacing metal atoms inside the nanometre-scale gap to electrically connect two crossed metallic wires forming a cross-point junction. These junctions afford extreme light concentration and display singular optical behaviour upon formation of a conductive channel. The active tuning of plasmonic antennas attached to such junctions is analysed using a combination of electrical and optical measurements as well as electron energy loss spectroscopy in a scanning transmission electron microscope. Scaling of photonic devices requires materials with sufficiently strong elecro-optic effects. Here, Schoen et al. demonstrate and analyze single electrically induced switching events that can operate in the visible with a small active volume using electron energy loss in a scanning transmission electron microscope.