Dielectric Nanowire Hybrids for Plasmon-Enhanced Light–Matter Interaction in 2D Semiconductors

Abstract

Monolayer transition metal dichalcogenides (TMDs) with a direct band gap are suitable for various optoelectronic applications such as ultrathin light emitters and absorbers. However, their weak light absorption caused by the atomically thin layer hinders more versatile applications for high optical gains. Although plasmonic hybridization with metal nanostructures significantly enhances light−matter interactions, the corrosion, instability of the metal nanostructures, and the undesired effects of direct metal−semiconductor contact act as obstacles to its practical application. Herein, we propose a dielectric nanostructure for plasmon-enhanced light−matter interaction of TMDs. TiO 2 nanowires (NWs), as an example, are hybridized with a MoS 2 monolayer on various substrates. The structure is implemented by placing a monolayer MoS 2 between a TiO 2 NW for a photonic scattering effect and metallic substrates with a spacer for the plasmonic Purcell effect. Here, the thin dielectric spacer is aimed at minimizing emission quenching from direct metal contact, while maximizing optical field localization in ultrathin MoS 2 near the TiO 2 NW. An effective emission enhancement factor of ∼22 is attained for MoS 2 near the NW of the hybrid structure compared to the one without NWs. Our work is expected to facilitate a hybridized platform based on 2D semiconductors for high-performance and robust optoelectronics via engineering dielectric nanostructures with plasmonic materials.

Tuning the Plasmonic Response of AuGe Nanoparticles on GaAs Substrates: Implications for Photodetectors

“…The effective permittivity is represented as an integration of all Lorentzian terms. 10,24 Solid-state band theory of materials models a realistic picture about the joint density of states where allowed transitions are integrated for a given optical energy. 23,24 The interband losses with this theoretical band structure become predictable for a transition between energy bands, reflecting in imaginary permittivity "ε 2 ".…”

“…The merging of visible spectrum plasmonic response into a semiconductor, especially III−V (direct band gap), is challenging. 24 The metal- induced losses can be further reduced by controlling the metalfree electron density, that is, metal can be made less metallic by doping or GaAs density of states can be increased so that it becomes more metallic.…”

Van der Waals heterostructures with one-dimensional atomic crystals

“…A great enhancement of excitation efficiency in the regions outside the distinct excitonic absorption transitions was clearly observed, implying a significant excitation energy transfer from the encapsulated dye molecules to the SWCNT. 2D h-BN is considered as an ideal template to integrate 1D materials for novel photophysics studies [181,184,185]. Zhang and co-workers demonstrated the Cherenkov radiation in vdW heterostructure composed of 1D Ag nanowire and 2D h-BN layers, and observed the phonon polariton wakes from the propagating competition between 1D plasmons and phonon polaritons (Fig.…”

MoS2 with Stable Photoluminescence Enhancement under Stretching via Plasmonic Surface Lattice Resonance

“…Alternatively, one can create oxygen-bonding-based defects or cracks in chemically doped TMDs [ 14 ] and significantly enhance the optical emission from these sites. In the second approach, researchers usually apply different nanophotonic structures [ 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ] to TMDs to dramatically increase the light–matter interactions of TMDs. For example, the use of different photonic crystal (PhC) structures [ 15 , 16 , 17 ] with photonic bands and bandgaps for guiding and locally confining optical waves can efficiently accumulate photons in spatial and temporal domains.…”

“…Generally, SLR has additionally enhanced field intensity and narrower spectral linewidth, while it can significantly tune the wavelength by changing the lattice parameters. In recent years, by combining different TMDs with various PhC and plasmonic nanostructures [ 30 ], researchers have successfully enhanced their light emissions of TMDs by more than one order [ 21 , 22 , 23 , 24 , 25 , 26 ]. However, most demonstrations have still been on hard substrates, while only a few reports [ 30 ] have studied the emission enhancement in a deformable platform.…”