Solid-state single-quantum emitters are crucial resources for on-chip photonic quantum technologies and require efficient cavity–emitter coupling to realize quantum networks beyond the single-node level1,2. Monolayer WSe2, a transition metal dichalcogenide semiconductor, can host randomly located quantum emitters3,4,5,6, while nanobubbles7 as well as lithographically defined arrays of pillars in contact with the transition metal dichalcogenide act as spatially controlled stressors8,9. The induced strain can then create excitons at defined locations. This ability to create zero-dimensional (0D) excitons anywhere within a 2D material is promising for the development of scalable quantum technologies, but so far lacks mature cavity integration and suffers from low emitter quantum yields. Here we demonstrate a deterministic approach to achieve Purcell enhancement at lithographically defined locations using the sharp corners of a metal nanocube for both electric field enhancement and to deform a 2D material. This nanoplasmonic platform allows the study of the same quantum emitter before and after coupling. For a 3 × 4 array of quantum emitters we show Purcell factors of up to 551 (average of 181), single-photon emission rates of up to 42 MHz and a narrow exciton linewidth as low as 55 μeV. Furthermore, the use of flux-grown WSe2 increases the 0D exciton lifetimes to up to 14 ns and the cavity-enhanced quantum yields from an initial value of 1% to up to 65% (average 44%).
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The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.
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The authors thank M. Begliarbekov for supporting the development of the electron-beam lithography process at the City University of New York Advanced Science Research Center (ASRC) nanofabrication facility, and L. Dai for help with designing Fig. 1a. The authors acknowledge financial support to S.S. from the National Science Foundation (NSF) under awards DMR-1506711 and DMR-1809235 and to J.C.H. under awards DMR-1507423 and DMR-1809361. S.S. acknowledges financial support for the attoDRY1100 under NSF award ECCS-MRI-1531237.
The authors declare no competing interests.
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Luo, Y., Shepard, G.D., Ardelean, J.V. et al. Deterministic coupling of site-controlled quantum emitters in monolayer WSe2 to plasmonic nanocavities. Nature Nanotech 13, 1137–1142 (2018). https://doi.org/10.1038/s41565-018-0275-z