Highly Tunable Defect-Bound Excitons Complexes in WSe₂

Individual excitons, bound electron-hole pairs, can serve as sources of single photons, a fundamental building block for quantum communication and computation. The ability to engineer precise energy-tunable single emitters based on these excitonic states could lead to efficient and reliable photon sources for quantum information processing applications. Transition metal dichalcogenides (TMDs) are emerging as a promising platform for exploring rich excitonic physics. In this work, we report a novel series of excitonic emission lines in WSe₂. We demonstrate that these new excitonic states are highly tunable through both doping and electric fields. Our experimental observation of their strong power saturation behavior at low electron doping also suggests the origin to be defect-localized excitons. Our findings pave the way for the development of precise energy-tunable, homogeneous single emitters and the exploration of collective quantum optical phenomena using intrinsic defect-bound excitons in atomic-thin 2D semiconductors.