Resumo

ANGELES CHAVEZ, Carlos. The role of the contrast transfer function in the formation of atomic resolution images of nanoparticles. Mundo nano [online]. 2020, vol.13, n.25, pp.9-27.  Epub 25-Nov-2020. ISSN 2448-5691.  https://doi.org/10.22201/ceiich.24485691e.2020.25.69617.

High resolution transmission electron microscopy results can be quantitatively interpreted if an optimum adjustment is performed in the optical-electronic of the instrument during the atomic resolution images acquisition. This work qualitatively describes the principles of imaging formation by using the theory of electron diffraction and electronic-optics. At the end, the process is summarized through two parameters: contrast transfer function (CTF) and defocus of the image. The result is the modulation of the amplitude and phase in the CTF in order to obtain stronger phase contrast on the d-spacing of the nanoparticle under observation. Brighter or darker contrasts can be achieved from Scherzer focus and at values of bigger negative defocus. In this way, dark contrasts of WOx clusters on crystalline lattice of bright contrast corresponding to the m-ZrO2 nanoparticle through a controlled and precise manipulation of the defocus was evidenced.

Palavras-chave : high resolution transmission electron microscopy (HRTEM); atomic resolution; CFT; nanoparticle; phase contrast.

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