A novel 3D absorption correction method for quantitative EDX-STEM tomography.
This paper presents a novel 3D method to correct for absorption in energy dispersive X-ray (EDX) microanalysis of heterogeneous samples of unknown structure and composition. By using STEM-based tomography coupled with EDX, an initial 3D reconstruction is used to extract the location of generated X-rays as well as the X-ray path through the sample to the surface. The absorption correction needed to retrieve the generated X-ray intensity is then calculated voxel-by-voxel estimating the different compositions encountered by the X-ray. The method is applied to a core/shell nanowire containing carbon and oxygen, two elements generating highly absorbed low energy X-rays. Absorption is shown to cause major reconstruction artefacts, in the form of an incomplete recovery of the oxide and an erroneous presence of carbon in the shell. By applying the correction method, these artefacts are greatly reduced. The accuracy of the method is assessed using reference X-ray lines with low absorption.
Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire, UK. Electronic address: pierre.burdet@a3.epfl.ch.
Pierre
P
Burdet
Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire, UK.
Z
Z
Saghi
Nanotechnology on Surfaces Laboratory, Materials Science Institute of Seville (ICMS), CSIC-University of Seville, C/ Americo Vespucio 49, 41092 Seville, Spain.
A N
AN
Filippin
Nanotechnology on Surfaces Laboratory, Materials Science Institute of Seville (ICMS), CSIC-University of Seville, C/ Americo Vespucio 49, 41092 Seville, Spain.
A
A
Borrás
Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge CB3 0FS, Cambridgeshire, UK.
P A
PA
Midgley
3D chemical analysis; Absorption correction; Electron tomography; Energy dispersive X-ray spectrometry; Quantification