Zhu, YunxuanCui, LongjiAbbasi, MahdiyehNatelson, Douglas2022-11-032022-11-032022Zhu, Yunxuan, Cui, Longji, Abbasi, Mahdiyeh, et al.. "Tuning Light Emission Crossovers in Atomic-Scale Aluminum Plasmonic Tunnel Junctions." <i>Nano Letters,</i> 22, no. 20 (2022) American Chemical Society: 8068-8075. https://doi.org/10.1021/acs.nanolett.2c02013.https://hdl.handle.net/1911/113786Atomic-sized plasmonic tunnel junctions are of fundamental interest, with great promise as the smallest on-chip light sources in various optoelectronic applications. Several mechanisms of light emission in electrically driven plasmonic tunnel junctions have been proposed, from single-electron or higher-order multielectron inelastic tunneling to recombination from a steady-state population of hot carriers. By progressively altering the tunneling conductance of an aluminum junction, we tune the dominant light emission mechanism through these possibilities for the first time, finding quantitative agreement with theory in each regime. Improved plasmonic resonances in the energy range of interest increase photon yields by 2 orders of magnitude. These results demonstrate that the dominant emission mechanism is set by a combination of tunneling rate, hot carrier relaxation time scales, and junction plasmonic properties.engThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society.Journal articlePlasmonicsnanoscale junctionatomic-sized light emissionhot-carrier dynamicselectron inelastic tunnelinghttps://doi.org/10.1021/acs.nanolett.2c02013