When observing a substance using light, the appearance of the substance changes depending on the energy (color) of the light.Similarly, when observing a substance using electrons, the appearance of the substance changes greatly depending on the energy of the electrons.Therefore, in order to understand matter in detail, it is necessary to observe changes in the appearance of matter while changing the energy of light and electrons.This is the technology of spectroscopic microscopy.
This time, research teams such as Tokyo University of Science have developed a technology to realize a spectroscopic electron microscope with a wide dynamic range, which was difficult to put into practical use, by a new method.
In the conventional method, observation is performed by irradiating while changing the energy of the monochromatic electron beam, but in the new method, the secondary electrons generated when the substance is irradiated with the monochromatic electron beam is used as the beam source. A shift in thinking has been made.Since secondary electrons have a wide energy distribution, it is possible to measure in a wide energy range at once only by devising a measurement mode and mathematical statistical processing of the data.
In order to realize this technology, the problem was to remove the background signal contained in the secondary electrons. For this, we applied the four-point measurement method developed in astronomy to accurately obtain the weak star signal. bottom.It was also confirmed that the measured values subjected to statistical processing were in good agreement with the theoretical values.
It can be said that this technology is important for the research of nano-thin films, which are usually difficult to detect even their existence and it is difficult to ensure quality uniformity over a large area.
Paper information: [Nature Communications] Virtual substrate method for nanomaterials characterization
