  Transition metal dichalcogenide (TMD) single photon emitters (SPEs) offer
numerous advantages to quantum information applications, such as high single
photon purity and deterministic positioning. Strain in the host monolayer,
induced by underlying dielectric Mie resonators, is known to localize their
formation to positions co-located with near-field photonic hotspots providing
further control over their optical properties. However, traditional materials
used for the fabrication of nanoresonators, such as silicon or gallium
phosphide (GaP), often require a high refractive index substrate resulting in
losses of the emitted light and limited photonic enhancement. Here, we use
nanoantennas (NAs) fabricated from multilayer TMDs, which allow complete
flexibility with the choice of substrate due to the adhesive van der Waals
forces, enabling high refractive index contrast or the use of highly reflective
metallic surfaces. We demonstrate the localized formation of SPEs in WSe$_2$
monolayers transferred onto WS$_2$ NAs on both SiO$_2$ and Au substrates,
enabling strong photonic enhancements and increased single photon collection.
We provide evidence for enhanced quantum efficiencies (QE) reaching an average
value of 43% (7%) for SPEs on WS$_2$ NAs on a SiO$_2$ (Au) substrate. We
further combine the advantages offered by both dielectric and metallic
substrates to numerically simulate an optimized NA geometry for maximum WSe$_2$
single photon excitation, emission, collection. Thus, the fluorescence is
enhanced by a factor of over 4 orders of magnitude compared to vacuum and 5
orders of magnitude compared to a flat SiO$_2$/Si surface. Our work showcases
the advantages offered by employing TMD material nanoresonators on various
substrates for SPE formation and photonic enhancement.
