Nanostructured Transition Metal Dichalcogenide Multilayers for Advanced Nanophotonics

Abstract

Transition metal dichalcogenides (TMDs) attract significant attention due to their exceptional optical, excitonic, mechanical, and electronic properties. Nanostructured multilayer TMDs were recently shown to be highly promising for nanophotonic applications, as motivated by their exceptionally high refractive indices and optical anisotropy. Here, this vision is extended to more sophisticated structures, such as periodic arrays of nanodisks and nanoholes with ultra sharp walls, as well as proof‐of‐concept all‐TMD waveguides and resonators. Specific focus is given to various advanced nanofabrication strategies, including careful selection of resists for electron beam lithography and etching methods, especially for non‐conductiven but relevant for nanophotonic applications substrates, such as SiO2. The specific materials studied here include semiconducting WS2, in‐plane anisotropic ReS2, and metallic TaSe2, TaS2, and NbSe2. The resulting nanostructures can potentially impact several nanophotonic and optoelectronic areas, including high‐index nanophotonics, plasmonics and on‐chip optical circuits. The knowledge of TMD material‐dependent nanofabrication parameters developed here will help broaden the scope of future applications of all‐TMD nanophotonics.

Enhanced Second-Order Nonlinearities at Strained Ultrasharp Zigzag Edges in Multilayer MoS2

“…32,72,73 The understanding of the mechanisms for the enrichment of TMD crystals with zigzag edges is also important for the development of next-generation nanopatterned catalysts, stretchable gas-sensing films, and metamaterials for all-TMD nanophotonics. 74,75 ■ ASSOCIATED CONTENT * sı Supporting Information…”

All-2D material photonic devices

“…34 All-2D material integrated nanophotonics is envisioned as a result of the recent interest in such 2D-based optical systems. 35,36 Light will be absorbed, contained, guided, and detected by an all-2D integrated chip. All-2D devices can provide a reduced footprint, greater energy efficiency, and enhanced light–matter interactions.…”

Indirect bandgap MoSe2 resonators for light-emitting nanophotonics

“…COMMUNICATION applications including lasers, 27,28 waveguides, 25,29,30 high harmonic generation, [30][31][32] bound states in the continuum, 33,34 etc.…”

“…Most recent studies have revealed many new outstanding properties of multilayered TMDCs, such as their giant optical anisotropy, 21 polarizing effects, 22 anapole–exciton polaritons, 23 exciton–plasmon–polaritons, 24 exciton–polariton transport, 25 second harmonic generation, 26 etc. All the above-mentioned properties make these materials a perfect candidate for a variety of nanophotonic applications including lasers, 27,28 waveguides, 25,29,30 high harmonic generation, 30–32 bound states in the continuum, 33,34 etc.…”