Quantum mechanics

Materials science

Nuclear physics

Atomic physics

Helium

Quantum optics

Photonics

Photon

Physics

Nanotechnology

Exciton

Ionization

Irradiation

Optics

Photoionization

Molecular physics

Condensed matter physics

Quantum

Monolayer

Electron

Optoelectronics

Nature Communications

Quantum light sources in solid-state systems are of major interest as a basic ingredient for integrated quantum photonic technologies. The ability to tailor quantum emitters via site-selective defect engineering is essential for realizing scalable architectures. However, a major difficulty is that defects need to be controllably positioned within the material. Here, we overcome this challenge by controllably irradiating monolayer MoS2 using a sub-nm focused helium ion beam to deterministically create defects. Subsequent encapsulation of the ion exposed MoS2 flake with high-quality hBN reveals spectrally narrow emission lines that produce photons in the visible spectral range. Based on ab-initio calculations we interpret these emission lines as stemming from the recombination of highly localized electron-hole complexes at defect states generated by the local helium ion exposure. Our approach to deterministically write optically active defect states in a single transition metal dichalcogenide layer provides a platform for realizing exotic many-body systems, including coupled single-photon sources and interacting exciton lattices that may allow the exploration of Hubbard physics.

Site-selectively generated photon emitters in monolayer MoS2 via local helium ion irradiation