Application 1: phonon of hBN
Vibrational spectrum of optical phonon from Hexagonal BN ΔE: 20meV @30kV
Low-loss EELS map of a hexagonal boron nitride (h-BN) with a monochromatic probe using a 0.1 μm slit. probe size = 1 nm, probe current = 10 pA, acquisition time for each pixel = 0.3 seconds. (a) shows the ADF-STEM image the mapping area. (b) shows the extracted low-loss spectrum from the edge of the specimen indicated with the framed yellow square in Fig. (a). This spectrum, measured with ΔE = 22 meV, showed a peak corresponding to an optical phonon at 170 meV. (c) shows the EELS map at the phonon energy. The phonon intensity was delocalized at the vacuum area > 100 nm beyond the sample edge due to the delocalization of inelastical scattering of electrons.
Application 2: surface plasmon resonance
Surface plasmon resonance (Gold nano-rod) ΔE: 30meV @60kV
The results of EELS map to obtain the surface plasmon resonance using gold nano-rod, recorded at 60 kV with the energy spread of 30 meV. The probe current was 75 pA and acquisition time per pixel was 0.15 seconds.
(a) HAADF, (b) low loss spectrum extracted from data cube of the spectrum imaging, (c) EELS maps of 0.1 eV energy width
Application 3: vibrational spectrum of a molecule
Vibrational spectrum of C-H stretching from ionic liquid ΔE: 30meV @60kV
(a) Structure of ionic liquid C2mim-TFSI, which is composed of [C2mim+] cation and [TFSI-] anion.
(b) The EEL spectra, calculated and experimental IR spectra with energy scale.
EELS magnified by ×1, ×10 and ×250 spectra are shown. In the ×250 magnified EEL spectrum, a broad peak, indicated by an arrow, appears at -0.4 eV,. This low-energy peak was confirmed to match the vibrational peaks in the IR spectrum (~3000cm-1) and was attributed to the C-H stretching vibrations of the [C2mim+] cations using theoretical calculations.
Sample courtesy of Dr. Mizoguchi, The University of Tokyo
T. Miyata, et al.: (2014) in Microscopy