Room-Temperature Low-Voltage Control of Excitonic Emission in Transition Metal Dichalcogenide Monolayers

Charge doping of materials with 2D and 3D quantum confinement is a flexible tool to tailor their excitonic emission. Here, using electron doping experiments on transition metal dichalcogenide (TMD) monolayers, reversible tuning of charged exciton emission within a redshift of up to 75 meV is demonstrated by applying very modest voltages (corresponding roughly to the band gap of TMDs), while also controlling the radiative lifetime and intensity. It is found that the neutral exciton ionization dynamics at increasing electron doping follows the Fermi–Dirac distribution, which allows to determine the size of the band gap as well as to extract experimental values for effective masses of electrons and holes at room temperature. The tunable excitonic emission, preserving coherence at room temperature, holds great promise for quantum technologies requiring deterministic coupling with integrated photonic and plasmonic devices.