New approaches to electrically driven nanoantennas

Electrically Driven Optical Antennas represent promising issues for integrated plasmonic nanosources. However, their low quantum efficiency (QE) remains a major hurdle. To address this issue, we analyze the different light emission mechanisms in planar nanoscale devices. We found that the electrical properties of the device are dictating the processes at play. For low device conductance, photons are essentially emitted by inelastic tunneling events and the applied voltage sets the highest photon energy. For high conductance gap antennas, we show that the spectrum released by the device originates from the spontaneous emission of out-of-equilibrium electronic distribution. We then propose a novel route for increasing the QE. Estimation shows that if the nanoantennas are excited by electrons passing ballistically through mesoscopic contacts constituting the antenna, the excitation QE may reach ∼ 0.01–0.1. Finally, we explore an alternative approach based on charge injection in semiconductor Mie resonators.