Electrically driven photon emission from individual atomic defects in monolayer WS₂.

Area of Science:

• Quantum optics
• Materials science
• Condensed matter physics

Background:

• Quantum dot-like single-photon sources in transition metal dichalcogenides (TMDs) show promise but suffer from ill-defined atomic structures and spectral variability.
• Developing stable and tunable single-photon emitters is crucial for quantum technologies.

Purpose of the Study:

• To demonstrate electrically stimulated photon emission from individual atomic defects in monolayer WS2.
• To correlate photon emission directly with the local atomic and electronic structure of these defects.
• To establish a new platform for tunable, atomic-scale single-photon sources.

Main Methods:

• Utilized inelastic electron tunneling from a metallic tip into discrete defect states in WS2.
• Employed tip plasmons to mediate coupling to the optical far field for photon emission.
• Mapped emission at the atomic scale and correlated it with electronic defect orbitals.

Main Results:

• Achieved electrically stimulated photon emission from individual atomic defects in monolayer WS2.
• Demonstrated that the transition energy is controllable via applied tip-sample voltage.
• Observed that emission maps closely resemble electronic defect orbitals, confirming the origin of the optical transitions.

Conclusions:

• Inelastic charge carrier injection into localized defect states is a viable method for creating single-photon sources.
• This approach enables electrically driven, broadly tunable, and atomic-scale single-photon emitters.
• The findings provide a powerful platform for advancing quantum optical applications using two-dimensional materials.