Unveiling the Optical Emission Channels of Monolayer Semiconductors Coupled to Silicon Nanoantennas

Abstract

Monolayers (MLs) of transition metal dichalcogenides (TMDs) such as WSe2 and MoSe2 can be placed by dry stamping directly on broadband dielectric resonators, which have the ability to enhance the spontaneous emission rate and brightness of solid-state emitters at room temperature. We show strongly enhanced emission and directivity modifications in room-temperature photoluminescence mapping experiments. By varying TMD material (WSe2 vs MoSe2) transferred on silicon nanoresonators with various designs (planarized vs nonplanarized), we experimentally separate the different physical mechanisms that govern the global light emission enhancement. For WSe2 and MoSe2, we address the effects of Mie resonances and strain in the monolayer. For WSe2, an important additional contribution comes from out-of-plane exciton dipoles. This paves the way for more targeted designs of TMD-Si nanoresonator structures for room-temperature applications.

Highly Polarized Single Photons from Strain-Induced Quasi-1D Localized Excitons in WSe2

“… 3 , 4 Excitons localized by atomic defects or by a topography-induced dot-shaped strain potential in WSe 2 have been reported to typically exhibit single photon emission characteristics. 5 − 9 The emission of two-dimensional (2D) WSe 2 can be easily tuned by electric field, 5 magnetic field, 6 , 8 and mechanical strain 10 − 18 because it is both atomically thin and flexible. 19 , 20 Moreover, it is straightforward to integrate WSe 2 quantum emitters with plasmonic structures 21 and photonic waveguides.…”

“…The quantum emission of localized excitons serves as an essential building block of quantum optics , and quantum information technology. , Excitons localized by atomic defects or by a topography-induced dot-shaped strain potential in WSe 2 have been reported to typically exhibit single photon emission characteristics. − The emission of two-dimensional (2D) WSe 2 can be easily tuned by electric field, magnetic field, , and mechanical strain − because it is both atomically thin and flexible. , Moreover, it is straightforward to integrate WSe 2 quantum emitters with plasmonic structures and photonic waveguides. , Therefore, quantum emitters based on WSe 2 represent a potentially powerful platform for the exploration of quantum photonics concepts. However, emitters must also offer indistinguishability, brightness, and either well-defined spatial modes or polarization modes to be of use in quantum information technology. , At present semiconductor quantum dot technology that has matured over decades is well ahead to fulfill such key requirements. ,,, While progress in achieving these with localized excitons from WSe 2 and more generally 2D materials is rapid, a significant amount of work remains to be done.…”

Enhanced Light Emission from Monolayer MoS2 by Doubly Resonant Spherical Si Nanoantennas

“…For example, there is a dip in the experimental enhancement factor spectra around 660 nm. This may arise from a slight red-shift of the 1L-MoS 2 PL peak by placing a NP on top probably due to the strain ,, (see Figure S6 in the Supporting Information). Since the PL peak of the reference is around 660 nm and that of Si NP/1L-MoS 2 heterostructures is around 675 nm, the division results in a dip around 660 nm.…”

Tip-Enhanced Raman Spectroscopy and Tip-Enhanced Photoluminescence of MoS2 Flakes Decorated with Gold Nanoparticles

“…Enhanced PL and change of work function has been reported by decorating the surface of MoS 2 with gold nanoparticles. , These findings help improve plasmonic device performance and optimize photoelectronic specifications . When overlaid with such metal particles or coated over nanoantennas, the optical absorption and photoluminescence of TMDs can be enhanced through localized surface plasmons. , Also, propagating surface plasmon polaritons (SSPs) at the interface of TMDs and metal nanoparticles results in plasmon–exciton coupling and superfast transfer of hot electrons. , It is thus important to measure the interplay between the exciton and the plasmon modes that can potentially be tuned to increase the yield of electron transfer or excitation efficiency in these TMDs hybrids …”