Ultra-Long Lifetimes of Single Quantum Emitters in Monolayer WSe2/hBN Heterostructures

Here, ultra-long lifetimes of defect-trapped single quantum emitters (SQEs) in monolayer WSe2/hBN heterostructures are reported. The lifetimes of these SQEs are approximately 225 ns, more than two orders of magnitude larger than what has been previously reported for defect-trapped excitons in WSe2. These SQEs consist of co-linearly polarized doublet peaks with a fine structure splitting of 0.45 meV. Second-order correlation measurements show antibunched single-photon emission with a g((2)) value of approximate to 0.13. Through numerical analysis and modeling, it is shown how such long-lifetime single emitters can arise from bright and dark exciton coupling in antisite defects on the W sites. Additionally, high-quality single-photon emission over a wide range of lifetimes-from 2 ns to over 200 ns-is also reported, suggesting a variety of other possible defect structures present. The flexibility to generate high fidelity single-photon emission, over a wide range of lifetimes in a single material system, has potential in many optical quantum computing applications from high-bit-rate single-photon sources to quantum memory devices.