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

Abstract

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.

Abstract

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.