Active control of excitonic strong coupling and electroluminescence in electrically driven plasmonic nanocavities
Junsheng Zheng, Alexey V. Krasavin, Ruoxue Yang, Zhenxin Wang, Yuanjia Feng, Longhua Tang, Linjun Li, Xin Guo, Daoxin Dai, Anatoly V. Zayats, Limin Tong, Pan Wang
Abstract
Enhancement and active control of light-matter interactions at the atomic scale is important for developing next-generation nanophotonic and quantum optical devices. Here, we demonstrate electric control of excitonic strong coupling and electroluminescence (EL) by integrating a semiconductor monolayer into a nanometer gap of single electrically driven nanocube-on-mirror plasmonic nanocavities, which provide unmatched optical and electrical confinement. In particular, in a strongly coupled system of nanocavity plasmons and tungsten diselenide (WSe 2 ) excitons, an ultrastrong electric field generated in the nanocavity gap enables reversible modulation of the Rabi splitting between ~108 and 102 milli–electron volts with a bias of only 2.5 volts. In the quantum tunneling regime (realized by decreasing the gap size), by injection of carriers into a nanocavity-integrated tungsten disulfide (WS 2 ) monolayer, spectrally tunable EL (controlled by the bias polarity) is achieved with a room-temperature quantum efficiency reaching ~3.5%, showing an improvement of more than 10 3 times over previous works.