Achieving High Purity Quantum Emission in WSe₂

Single photons are pivotal ingredients of quantum communication, enabling quantum key distribution and the interconnection of quantum networks. On the other hand, such quantum applications poses a demand on the purity of single photons. Two-dimensional (2D) materials, with their exceptional light-matter interaction properties and readiness to integrate with photonic structures on-chip, have emerged as a promising platform for next-generation optoelectronics and quantum information. In particular, single photon emission has been realized in a number of 2D materials. On the other hand, achieving a high purity single-photon source on 2D materials remains a pressing challenge. In this work, we developed effective approaches enhance single-photon purity from 2D transition metal dichalcogenides (TMDs) by suppressing parasitic radiative decay processes. By judiciously engineering the morphology of 2D WSe₂ and dichroism of light, we successfully mitigated broad defect-bound excitonic emission in WSe₂, significantly improving the purity of single photon emission to over 98%, one of the highest reported in 2D TMDs.