Practical Electron Microscopy and Database

The degree and amount of the information revealed by electron microscopes (EMs) mainly depends on six factors:
         i) The resolving power of the microscope (e.g. usually < 0.3 nm for TEM);
         ii) The energy spread of the electron beam;
         iii) The quality of the EM sample (e.g. the cleanness and thickness of the specimen for TEM);
         iv) The knowledge of electron-matter interaction and electron optics;
         v) The operation skills of EMs;
         vi) The composition and stability of the specimen.
i) and ii) depend mainly on how thick your pocket is, meaning the more money you spend, the better the microscope parameters; iii) - v) depends on your experimental skill and background; while vi) depends on your luck and/or choice of experimental system.

Since some EM operation tips from experiences and theoretical understandings are very tricky, and thus can hardly be described in words, for instance, in literature or through emails, it is suggested to visit experienced laboratories to ask for assistance.

In aberration-corrected EMs (electron microscopes) a combination of hexapole or octupole lenses are used in a aberration corrector which lacks rotational (circular) symmetry and thus doesn’t have to have a positive spherical aberration like conventional, round magnetic lenses.

Some "smart" TEM experiments which are not normally performed are:
         i) Energy-selecting slit before the ADF detector. [1]
         ii) Angular selecting aperture before the spectrometer. [2]
         iii) Off-axis positioned filter entrance aperture. [3]

The success of research Electron Microscopy (EM) experiments is pivotal in advancing our understanding of material properties at the nanoscale. Through careful preparation, precise instrument calibration, and rigorous experimental design, EM studies have consistently yielded high-resolution images and critical data, enabling researchers to explore the intricate structures and compositions of materials. The ability to combine various EM techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS), has further enhanced the scope and depth of these investigations. Successful EM experiments have not only provided valuable insights into the physical and chemical states of materials but have also driven innovation in fields ranging from semiconductor technology to biomaterials. By continuously refining these methodologies and integrating advanced computational tools, the research community continues to push the boundaries of what can be observed and analyzed, leading to groundbreaking discoveries and technological advancements.

[1] Haider M 1989 Ultramicroscopy 28, 240.
[2] Bleloch AL, Castell MR, Howie A and Walsh CA 1994 Ultramicroscopy 54, 107.
[3] Walther T and Humphreys CJ 1997 Inst. Phys. Conf. Ser. 153, 303.