Spatially Controlled Single Photon Emitters in hBN‐Capped WS2 Domes

• Published in: Advanced optical materials Vol. 11; no. 12
• Main Authors: Cianci, Salvatore, Blundo, Elena, Tuzi, Federico, Pettinari, Giorgio, Olkowska‐Pucko, Katarzyna, Parmenopoulou, Eirini, Peeters, Djero B. L., Miriametro, Antonio, Taniguchi, Takashi, Watanabe, Kenji, Babinski, Adam, Molas, Maciej R., Felici, Marco, Polimeni, Antonio
• Format: Journal Article
• Language: English
• Published: 19.06.2023
• Subjects: heterostructures; single photon emitters; strain; two‐dimensional materials
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202202953

Monolayers (MLs) of transition‐metal dichalcogenides host efficient single‐photon emitters (SPEs) usually associated to the presence of nanoscale mechanical deformations or strain. Large‐scale spatial control of strain would enhance the scalability of such SPEs and allow for their incorporation into photonic structures. Here, the formation of regular arrays of strained hydrogen‐filled one‐layer‐thick micro‐domes obtained by H‐ion irradiation and lithography‐based approaches is reported. Typically, the H2 liquefaction for temperatures T<32 K causes the disappearance of the domes preventing their use as potential SPEs. Here, it is shown that the dome deflation can be overcome by hBN heterostructuring, that is by depositing thin hBN flakes on the domes. This leads to the preservation of the dome structure at all temperatures, as found by micro‐Raman and micro‐photoluminescence (µ‐PL) studies. Eventually, spatially controlled hBN‐capped WS2 domes show the appearance, at 5 K, of intense emission lines originating from localized excitons, which are shown to behave as quantum emitters here. The electronic properties of the emitters are addressed by time‐resolved µ‐PL yielding time decays of 1–10 ns, and by magneto‐µ‐PL measurements. The latter provide an exciton magnetic moment a factor of two larger than the value observed in planar strain‐free MLs. The success of quantum technologies relies on the capability of producing efficient sources of single photons. 2D materials offer the unique opportunity of having such sources on an atomically thin surface from which photons can be extracted very efficiently. It is shown that building micrometric domes of 2D materials provides spatially ordered and scalable arrays of quantum emitters.