Achieving ~1 Å resolution in Tb3Sc2Al3O12 STEM EELS mapping with GIF Continuum K3
Instruments used
Background
Electron energy loss spectroscopy (EELS) spectrum imaging (SI) combined with aberration-corrected STEM enables the simultaneous characterization of structural and chemical changes at the angstrom scale. However, long acquisition times, sample drift, and beam induced sample damage make atomically resolved EELS SI challenging relative to annular dark-field (ADF) STEM imaging.
Direct detection single electron counting cameras improve the detection limit for ionization edges in EELS spectra due to their high sensitivity. This allows SI data to be collected at significantly reduced total dose, reducing the acquisition time necessary for high-spatial resolution data capture. Multi-pass SI collection via DigitalMicrograph® combined with the high spectral rate of the K3 camera fractionates the total dose over several passes, allowing the user to perform drift correction at a high enough frequency to avoid image distortion. Furthermore, the single electron sensitivity of the K3 camera prevents read-noise from compromising the spectra’s signal-to-noise ratio (SNR) for sub-millisecond dwell times.