Introduction for HRTEM

Transmission and scanning transmission electron microscopes (S/TEM) are invaluable tools for the characterization of nanostructures, providing a range of different imaging modes, as well as access to information on elemental composition and electronic structure with high sensitivity. As materials research progressively begins to focus more and more on optimizing material function and behavior at the nanoscale, accurate information at this resolution becomes increasingly essential. High-resolution TEM (HRTEM) and STEM (HRSTEM) deliver the most detailed structural information possible in order to fundamentally characterize samples down to their atomic organization. This is invaluable to nanomaterials research as minor structural inconsistencies and variations can result in substantial changes to the properties of the material. For example, the crystal structure and atomic spacing of the atoms in platinum nanoparticles can have a drastic impact on their catalytic behavior in hydrogen fuel cells.

HRTEM microscopy

Thermo Fisher Scientific offers hardware and software innovations for HRTEM and HRSTEM analysis of a broad range of samples, including beam-sensitive materials. In particular, image quality is often reduced by the influence of drift, vibrations, or other instabilities during acquisition. Drift corrected frame integration (DCFI) is an acquisition method within the Thermo Scientific Velox Software that overcomes this problem, producing images with high contrast and a high signal-to-noise ratio. The addition of Integrated Differential Phase Contrast (iDPC) Software enables the collection of easily interpretable high-resolution images with more reliable, simultaneous imaging of light and heavy elements, even at low-dose conditions.

High-resolution transmission electron microscopes from Thermo Fisher Scientific

The Spectra S/TEM instruments take high-resolution imaging one step further with additional aberration correction via the S-CORR probe aberration corrector, allowing sub-Ermian (&lt0.8 Å) S/TEM imaging to be achieved on a regular basis. Finally, the new Talos and Spectra S/TEM instruments feature the Panther STEM detection system, which includes optimized mechanical alignment and detector geometry for better multi-signal acquisition and mechanical alignment accuracy. It offers higher throughput and easier operation with a linear gain/offset response and more flexible signal processing. With up to 16 zones and a new amplifier design with ultra-high electron sensitivity, more details can be observed for low-dose STEM.

With the combination of high-quality automated S/TEM instrumentation and leading software solutions, HRTEM and HRSTEM imaging are more accessible than ever, giving you the ability to gather unparalleled atomic-resolution information on your most challenging materials.

Gallium nitride imaged at atomic resolution

Figure 1: Gallium nitride [212] imaged with HAADF (DCFI) STEM at 300 kV, showing 40.5 pm Ga-Ga dumbbell splitting and 39 pm resolution in the fast Fourier transform on a wide gap (S-TWIN) pole piece.