Creating single photon emitters for quantum technologies

Image: Ajit Kumar Dash, OUSUMS Lab

Quantum technologies (quantum computing, sensing, and communication) are emerging as a transformative force in this information age. At their core lies the critical need for reliable sources of single photons, known as single photon emitters (SPEs).

Recently, defects in atomically thin, two-dimensional (2D) semiconductors were shown to be potential SPE candidates. The deterministic creation of ideal SPEs in 2D materials is necessary for integration into practical photonic devices but is an outstanding problem. In other words, creating SPEs at exact locations is a fundamentally and technologically challenging problem, the solution of which can lead to high-performing quantum devices.

Researchers at the Department of Physics, led by PhD student Ajit Kumar Dash and PI Akshay Singh, with collaborators at CeNSE (IISc), CNRS (France) and NIMS (Japan), have developed a fundamentally different approach for generating SPEs in a single layer of 2D semiconducting MoS₂. The team used ultra-low energy (<5 keV) electron beam irradiation, and created environmentally stable SPEs with high spatial resolution (~50 nm, and extendable down to 10 nm). This is a disruptive technology for creating SPEs in 2D materials and similar materials. It can also enable novel fundamental physics concerning defect-defect coupling and electron-matter interactions.

From left to right: Akshay Singh (PI), Ajit Kumar Dash (lead author), Sharad Kumar Yadav

Reference:
Dash AK, Yadav SK, Roux S, Singh MP, Watanabe K, Taniguchi T, Naik A, Robert C, Marie X, Singh A, Quantum Light Generation with Ultra-High Spatial Resolution in 2D Semiconductors via Ultra-Low Energy Electron Irradiation, Advanced Functional Materials (2025).  https://doi.org/10.1002/adfm.202421684

Lab website:
https://physics.iisc.ac.in/~aksy/