Fig. 1: Characterizations of the heterostructure, including an SEM image, a band alignment diagram and reflectance spectra.
From: Direct observation of ultrafast plasmonic hot electron transfer in the strong coupling regime
a Schematic of the Au grating/MoS2/Al2O3/Au/Si sandwiched heterostructure. b Cross-sectional SEM view of a typical MIM heterostructure, imaged at a 52° tilted angle. The inset shows a top-view SEM image for gratings with a 700 ± 5 nm period. The gray area corresponds to the substrate, while the dark gray represents the MoS2 monolayer. c The band alignment diagram of the Au grating and MoS2 monolayer. Plasmonic hot electrons were pumped at 780 nm, and the transient absorption of the A exciton in the MoS2 monolayer was monitored by a 650 nm probe pulse. d Experimentally measured reflectance spectra of the MoS2 monolayer, Au grating and Au grating/MoS2 at the substrate with a 600 ± 5 nm grating period (solid lines). Reflectance spectra with plasmonic structures were also simulated by the finite-difference time-domain (FDTD) method (dashed lines), which show good agreement with the measurements. SEM scanning electron microscopy
