Correlative micro-diffraction and differential phase contrast study of mean inner potential and subtle beam-specimen interaction

Wu M, Spiecker E (2017)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2017

Journal

Ultramicroscopy Elsevier

Publisher: Elsevier B.V.

Book Volume: 176

Pages Range: 233-245

DOI: 10.1016/j.ultramic.2017.03.029

Abstract

We present a correlative micro-diffraction and differential phase contrast (DPC) study within scanning transmission electron microscopy (STEM) on the determination of mean inner potential (MIP) and explain the origin of subtle beam-specimen interactions at the edge of wedge-shaped crystals using both experiment and simulation. Our measurement of MIP of Si and GaAs resulted in 12.48 ± 0.22 V and 14.15 ± 0.22 V, respectively, from directly evaluating beam refraction in micro-diffraction mode. DPC-STEM measurements gave very similar values. Fresnel fringes within the diffraction disk resulting from interaction of the highly coherent electron beam with the aperture are observed and a numerical simulation scheme is implemented to reproduce the effect of the specimen on the fringe pattern. Perfect agreement between experiment and simulation has been achieved in terms of subtle displacements of the fringes upon approaching the sample edge with the electron probe. The existence of the fringes has minor effect on the DPC-STEM signal, which is well below the noise level of our setup at practically reasonable acquisition times. We suggest the possibility to perform pseudo-contactless probing of weak potential differences in beam sensitive samples by evaluating the subtle displacements of Fresnel fringes quantitatively.

Authors with CRIS profile

Mingjian Wu Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Erdmann Spiecker Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)

Additional Organisation(s)

Graduiertenkolleg 1896/2 In situ Mikroskopie mit Elektronen, Röntgenstrahlen und Rastersonden Exzellenz-Cluster Engineering of Advanced Materials (EAM) Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)

How to cite

APA:

Wu, M., & Spiecker, E. (2017). Correlative micro-diffraction and differential phase contrast study of mean inner potential and subtle beam-specimen interaction. Ultramicroscopy, 176, 233-245. https://doi.org/10.1016/j.ultramic.2017.03.029

MLA:

Wu, Mingjian, and Erdmann Spiecker. "Correlative micro-diffraction and differential phase contrast study of mean inner potential and subtle beam-specimen interaction." Ultramicroscopy 176 (2017): 233-245.

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