Linearly Polarized Electroluminescence from MoS ₂ Monolayers Deposited on Metal Nanoparticles: Toward Tunable Room‐Temperature Single‐Photon Sources

Break junctions in noble-metal films can exhibit electroluminescence (EL) through inelastic electron tunneling. The EL spectrum be tuned by depositing a single-layer crystal of transition-metal dichalcogenide (TMDC) on top. Whereas the emission from gaps between silver or gold nanoparticles formed break junction is spectrally broad, hybrid metal/TMDC structure shows distinct luminescence TMDC material. individual hotspots found to linearly polarized, with polarization axis apparently oriented randomly. Surprisingly, degree retained monolayer at room temperature. In analogy polarized photoluminescence experiments, such interpreted as signature valley-selective transitions, suggesting that spin-flip transitions and dephasing for excitons K valleys are limited importance. However, may also originate metal under electromigration which constitute optical antenna structures. Such antennae change over time since jumps observed bare silver-nanoparticle films. Remarkably, photon-correlation spectroscopy reveals gold-nanoparticle signatures deterministic single-photon EL, route designing room-temperature sources tunable photon energy choice overlayer.