Spectrum imaging (SI) performed in the scanning transmission electron microscope (STEM) is a well proven technique for advanced materials characterization due to the wide variety of signals provided, combined with the high spatial resolution provided by the STEM. Morphological and crystallographic information may be determined from imaging and diffraction methods such as 4DSTEM, where composition may be determined from spectroscopic techniques such as energy dispersive (x-ray) spectroscopy (EDS) and electron-energy loss spectroscopy (EELS). EELS has the further capability of probing local electronic structure, enabling local measurement of chemical bonding, changes in oxidation state, phonon and/or electronic band structure characterization.

For in-situ STEM analysis, the capability to capture data at: high speed, high dose efficiency, and high insitu stimulus resolution is critical. A CMOS based transmission electron counting detector incorporated into an optimized post-column energy filter is a well proven platform for performing both STEM EELS and 4DSTEM experiments. Synchronization of an in-situ stimulus to a multiple pass SI experiment has also previously been demonstrated as an effective methodology for maximizing the in-situ stimulus resolution [1].