Fig. 2
From: Probing the local nature of excitons and plasmons in few-layer MoS2
Scanning transmission electron microscopy (STEM) imaging and low-loss (LL) STEM electron-energy-loss (EEL) spectroscopy analysis of MoS2 from the edge to the inside of flake of increasing thickness. a High-resolution high-angle annular dark field (HAADF) STEM image showing the edge region of a mechanically exfoliated MoS2 flake. b HAADF STEM image showing the region of interest (ROI) (boxed area) of which monochromated LL-STEM-EELS were acquired. The edge of the flake as well as several steps were present in the ROI. c Integrated intensity map of the bulk plasmon peak (19.7–20.7 eV integration window) of the ROI showing the thickness variation (black = vacuum, from dark blue to white = increasing thickness of the material). The thinnest terrace is annotated T1, the second terrace annotated T2 and the thickest region is annotated T3; they were found to be 5, 8 and 10 layers thick, respectively. d Monochromated LL-STEM-EELS from the different areas as shown in b. The spectra shown were obtained from vacuum (black spectrum 1), aloof mode (spectra 2–4), the edge region (spectra 5–7), the first terrace T1 (spectrum 8), the step region to the second terrace T2 (spectrum 9), terrace T2 (spectrum 10), terrace 3 (spectrum 11) and terrace T4 (spectrum 12)
