SALVE III Research
Scientists rely on experimental data to gain new insights into so far undiscovered structures, phenomena and processes. In the frame of SALVE we aim to provide new experimental data that will help researchers to gain new views into matter.
Image formation in transmission electron microscopy often produces irreversible damage to the objects resulting from the interactions of the incident electrons with the atoms of the specimen. SALVE is a contribution to research on electron beam - sensitive objects that currently cannot be imaged at their atomic level due to radiation damage effects at medium voltages and that can, under certain circumstances, be imaged at lower voltages.
Within the frame of the SALVE project we aim to demonstrate the state of the art of CC/CS–correction in a new FEI platform operating at 20 - 80 kV. First papers using CC/CS-correction were published in 2009. Until today, four high-voltage dedicated CC/CS-correctors have been produced worldwide (all manufactured by CEOS). The CC/CS-corrector is predominantly used at lower voltages of 80kV (60%), in contrast to AC-HRTEM in general, where the proportion of lower voltages is only about 30% (Fig. 1, the corresponding references can be found here). Due to the decrease of resolution at lower voltages CC/CS correction is required to achieve high performance of the microscope at lower voltages.
The research on low-voltage high-resolution transmission electron microscopy opens an exciting new era and will be request from tomorrow’s research and industry. This is also reflected in the very high percentage of publications with high impact factor (> 10) in low-voltage HRTEM, which is 30%, and thus higher by a factor of 3 than in medium voltage HRTEM (Fig 2).
We begin this section 'Research' by providing an overview of the rediscovery of low energies in HRTEM. Furthermore, the research in SALVE III is described. It consists of application investigation and the understanding of radiation damage processes in general by application of low dose protocols and conduction of sets of systematic experiments and theoretical calculations for the image formation at low voltages and radiation damage. Another topic is sample and substrate preparation of materials in order to fulfil the stringent requirements for samples to be studied at low voltages. Of course, research and development on the increase of resolution by means of novel correctors and the introduction of new components for contrast improvement as well as the improvement of environmental conditions for realizing the instrumental resolution is a main topic in SALVE III.
The description of SALVE III research is accessible via the sub-menu on the left side or the following interactive Fig. 3. SALVE III has 5 Work Packages - A: HRTEM, B: Spectroscopy, C: Software development and data evaluation, D: In-situ TEM and devices, and E: outreach.
Figure 3: SALVE research interactive graph (click on the topics to see a description). The color corresponds to the responsible SALVE III project partner.
- Lee, Z., Rose, H., Lehtinen, O., Biskupek, J., & Kaiser, U. (2014). Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images. Ultramicroscopy, 145: 3-12, doi: 10.1016/j.ultramic.2014.01.010
- Lee, Z., Rose, H., Hambach, R., Wachsmuth, P., & Kaiser, U. (2013). The influence of inelastic scattering on EFTEM images—exemplified at 20kV for graphene and silicon. Ultramicroscopy, 134: 102-112, doi: 10.1016/j.ultramic.2013.05.020
- Lee, Z., Meyer, J. C., Rose, H., & Kaiser, U. (2012). Optimum HRTEM image contrast at 20kV and 80kV—Exemplified by graphene. Ultramicroscopy, 112: 39-46, doi: 10.1016/j.ultramic.2011.10.009