Monochromated STEM with a 30 meV-wide, atom-sized electron probe.

Nanoscale mapping of optical band gaps using monochromated electron energy loss spectroscopy.

Using monochromated electron energy loss spectroscopy in a probe-corrected scanning transmission electron microscope we demonstrate band gap mapping in ZnO/ZnCdO thin films with a spatial resolution below 10 nm and spectral precision of 20 meV.

Recent Applications of Sub-20 meV Monochromated STEM-EELS : from Phonon to Core Losses in Real and Momentum Spaces

Energy-Filtered High-Angle Dark Field Mapping of Ultra-Light Elements

Using the High Energy Resolution Monochromated EELS-STEM (HERMES) system we recently introduced [1] together with Gatan’s Enfinium spectrometer with upgraded ultra-high stability power supplies [2], energy resolution as low as 14 meV has been demonstrated in electron energy loss spectra (EELS) acquired in 0.1 s (Fig. 1), and sub-20 meV resolution has become typical for routine acquisitions of s...

Exciton mapping at subwavelength scales in two-dimensional materials.

Spatially resolved electron-energy-loss spectroscopy (EELS) is performed at diffuse interfaces between MoS2 and MoSe2 single layers. With a monochromated electron source (20 meV) we successfully probe excitons near the interface by obtaining the low loss spectra at the nanometer scale. The exciton maps clearly show variations even with a 10 nm separation between measurements; consequently, the ...

Reconciling Theory and Experiment in High-resolution Electron Energy-loss Spectroscopy of Plasmon Modes in Individual Nanostructures

Surface plasmon resonances within metal and hybrid nanostructures result from the oscillation of valence electrons in response to an external field [1]. These resonances can strongly dominate the optical response of such structures, and their characteristics are controlled by the composition and geometry of the material. The ability to predictably control these phenomena is enabling a host of n...