To design highly efficient and broadband nanometer-sized absorbers based on the atomically thin transition metal dichalcogenides (TMDCs), we propose utilizing inclined gold gratings on MoS2 monolayer. In the case of gold gratings with zero inclination, coverage of the absorption spectrum in the entire visible range occurs between the values of 42% to 73%. Considerable increase in the absorbed light occurs by introducing 13 nm inclination to the gold gratings with equal values of the grating’s period and width as 60 nm. With the application of this grating, maximum absorption of 88% is reached and the absorption bandwidth covers the entire visible spectrum with only 12% variation of the absorption value relative to this maximum (88%). Footprints of resonant excitation of two different modes in the absorber structure are evident: the named “reflection” mode and localized surface plasmons (LSPs). Inclination of the gratings leads the LSP modes to slide toward the MoS2 and causes a remarkable increment in the absorption efficiency. An impressive absorption value of 56% in MoS2 monolayer is gained by the gold grating’s inclination of 17 nm. The designed absorber paves a new way in designing TMDC-based absorbers with extended bandwidths and higher efficiencies.
The nanometer-sized absorber that we introduced in this paper consists of a monolayer of atomically thin MoS2 on a silica substrate covered by inclined gold gratings. By selecting the period of the gold grating of the order of the incident light wavelength, both surface plasmon polaritons (SPPs) and localized surface plasmons (LSPs) can be excited in the structure at the visible spectrum. By selecting different values of the gold ribbon’s widths, we show that the excited modes can be adjusted to SPPs, LSPs, or SPPs and LSPs together. With the excitation of SPPs, the narrowband absorption peak wavelength, and with the excitation of LSPs, the FWHM of the absorption peak can be adjusted by the ribbon’s geometry parameters. In the case of simultaneous excitation of SPPs and LSPs, by increasing the ribbons’ inclination, the LSP peaks will redshift, while the SPP peaks blueshift, which leads to wider absorption peaks. The effect of increasing the ribbons’ height is opposite to that of the ribbons’ inclination, which is accompanied by the SPP peak red shift and LSP peak blue shift. This way, the more the height of the ribbons, the less the absorption peak bandwidth is. This paper’s results are a promising guide for designing plasmonic absorbers with desired bandwidths and peak wavelengths, which are widely demanded in designing photovoltaics and photonic sensors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.