Abstract
An outstanding challenge in quantum photonics is scalability, which requires positioning of single quantum emitters in a deterministic fashion. Site positioning progress has been made in established platforms including defects in diamond and self-assembled quantum dots, albeit often with compromised coherence and optical quality. The emergence of single quantum emitters in layered transition metal dichalcogenide semiconductors offers new opportunities to construct a scalable quantum architecture. Here, using nanoscale strain engineering, we deterministically achieve a two-dimensional lattice of quantum emitters in an atomically thin semiconductor. We create point-like strain perturbations in mono- and bi-layer WSe2 which locally modify the band-gap, leading to efficient funnelling of excitons towards isolated strain-tuned quantum emitters that exhibit high-purity single photon emission. We achieve near unity emitter creation probability and a mean positioning accuracy of 120±32 nm, which may be improved with further optimization of the nanopillar dimensions.
Highlights
An outstanding challenge in quantum photonics is scalability, which requires positioning of single quantum emitters in a deterministic fashion
Nanoscale strain engineering of the electronic band structure to create quantum confinement has long been pursued in bulk semiconductors
Robust strain-induced quantum confinement of carriers suitably isolated from detrimental surface states in bulk systems has not been realized due to the combination of: (i) the limited elastic strain possible before plastic deformation and (ii) small vertical strain propagation distances
Summary
An outstanding challenge in quantum photonics is scalability, which requires positioning of single quantum emitters in a deterministic fashion. We create point-like strain perturbations in mono- and bi-layer WSe2 which locally modify the band-gap, leading to efficient funnelling of excitons towards isolated strain-tuned quantum emitters that exhibit high-purity single photon emission. Mono-layer (1L) WSe2 is a direct band-gap 2D semiconductor with a dark excitonic ground state[6,7] In this system, at sufficiently low temperatures, a dense ensemble of localized excitons emerges at lower energy than the broad (few meV) delocalized 2D excitons[8,9,10]. The strain tuned quantum emitters at the nanopillar locations will dominate the photoluminescence (PL) spectrum at low temperature and excitation power due to efficient exciton funnelling from the surrounding high band-gap regions to the single lowest energy localized exciton
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