Fully electrical exciton quantum confinement in zero-dimensional structures

Quantum dots (QDs) are semiconductor nanostructures that confine particle motion in all three spatial dimensions, yielding discrete energy levels reminiscent of artificial atoms. Since their advent, QDs confining excitons - bound electron-hole pairs - have been pivotal, serving as emitters of light in commercial displays to sources of single photons for quantum information processing. Due to the limitations of current fabrication techniques, a key requirement in these applications that has remained unmet, is the realization of emitters that are identical, individually addressable, and bright.

Here, we overcome this hurdle and realize fully tunable QDs for excitons in a monolayer transition metal dichalcogenide semiconductor. Through precise design of gate electrodes, we dynamically modulate the in-plane electric fields in our device, enabling the tuning of QD resonance frequencies via the dc Stark effect. Simultaneously, the exciton confinement length is modified, directly impacting the emitter brightness. Our structure is distinct from previous implementations, as it realizes quantum-confined bosonic modes with a nonlinear response arising solely from exciton-exciton interactions. It holds promise as a foundational element of a strongly interacting many-body photonic system.