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

Journal article
(Original article)


Publication Details

Author(s): Wu M, Spiecker E
Journal: Ultramicroscopy
Publisher: Elsevier B.V.
Publication year: 2017
Volume: 176
Pages range: 233-245
ISSN: 1879-2723
Language: English


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.











FAU Authors / FAU Editors

Spiecker, Erdmann Prof. Dr.
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)
Wu, Mingjian Dr.
Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)


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


Research Fields

A2 Nanoanalysis and Microscopy
Exzellenz-Cluster Engineering of Advanced Materials


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://dx.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.

BibTeX: 

Last updated on 2019-29-05 at 08:26