High‐Speed Electroluminescence Modulation in Monolayer WS<sub>2</sub>
Dohyun Kwak, Matthias Paur, Kenji Watanabe, Takashi Taniguchi, Thomas Mueller
Abstract
Abstract The high‐speed modulation of the nanoscale light sources is of fundamental interest in nanophotonics. Here, electrically driven light emission from a metal–insulator–semiconductor heterostructure consisting of graphene, hexagonal boron nitride (h‐BN), and monolayer tungsten disulfide (WS 2 ) is demonstrated. Electroluminescence in these devices originates from radiative recombination of majority carriers (electrons) accumulated by electrostatic doping and hot minority carriers (holes) injected into monolayer WS 2 from graphene through an ultrathin h‐BN tunnel barrier. The devices are electrically driven with a radio frequency signal and electrical modulation of the light emission at frequencies up to 1.5 GHz is demonstrated. The high‐speed WS 2 tunnel diodes provide a promising path for on‐chip nanophotonics.