A bimodal tomographic reconstruction technique combining EDS-STEM and HAADF-STEM.

A three-dimensional (3D) chemical characterization of nanomaterials can be obtained using tomography based on high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) or energy dispersive X-ray spectroscopy (EDS) STEM. These two complementary techniques have both advantages and disadvantages. The Z-contrast images have good image quality but lack robustness in the compositional analysis, while the elemental maps give more element-specific information, but at a low signal-to-noise ratio and a longer exposure time. Our aim is to combine these two types of complementary information in one single tomographic reconstruction process. Therefore, an imaging model is proposed combining both HAADF-STEM and EDS-STEM. Based on this model, the elemental distributions can be reconstructed using both types of information simultaneously during the reconstruction process. The performance of the new technique is evaluated using simulated data and real experimental data. The results demonstrate that combining two imaging modalities leads to tomographic reconstructions with suppressed noise and enhanced contrast.

[1]  D. Leonard,et al.  Four-dimensional STEM-EELS: enabling nano-scale chemical tomography. , 2009, Ultramicroscopy.

[2]  Gabor T. Herman,et al.  Fundamentals of Computerized Tomography: Image Reconstruction from Projections , 2009, Advances in Pattern Recognition.

[3]  Charles L. Lawson,et al.  Solving least squares problems , 1976, Classics in applied mathematics.

[4]  M. G. Burke,et al.  STEM-EDX tomography of bimetallic nanoparticles: A methodological investigation. , 2016, Ultramicroscopy.

[5]  Stephen J. Pennycook,et al.  Z-contrast stem for materials science , 1989 .

[6]  Habib Zaidi,et al.  The clinical role of fusion imaging using PET, CT, and MR imaging. , 2010, Magnetic resonance imaging clinics of North America.

[7]  T. Walther.  A new experimental procedure to quantify annular dark field images in scanning transmission electron microscopy , 2006, Journal of microscopy.

[8]  Jens Gregor,et al.  Computational Analysis and Improvement of SIRT , 2008, IEEE Transactions on Medical Imaging.

[9]  Eero P. Simoncelli,et al.  Image quality assessment: from error visibility to structural similarity , 2004, IEEE Transactions on Image Processing.

[10]  R. Pantel,et al.  Chemical 3D tomography of 28nm high K metal gate transistor: STEM XEDS experimental method and results. , 2013, Micron.

[11]  G. Lorimer,et al.  The quantitative analysis of thin specimens , 1975 .

[12]  P. Midgley,et al.  A novel 3D absorption correction method for quantitative EDX-STEM tomography. , 2016, Ultramicroscopy.

[13]  Sònia Estradé,et al.  EEL spectroscopic tomography: towards a new dimension in nanomaterials analysis. , 2012, Ultramicroscopy.

[14]  C. Lawson,et al.  Solving least squares problems , 1976, Classics in applied mathematics.

[15]  Bert Freitag,et al.  Enhanced Detection Sensitivity with a New Windowless XEDS System for AEM Based on Silicon Drift Detector Technology , 2010, Microscopy Today.

[16]  L. Liz‐Marzán,et al.  Monitoring galvanic replacement through three-dimensional morphological and chemical mapping. , 2014, Nano letters.

[17]  D. Van Dyck,et al.  Correction of non-linear thickness effects in HAADF STEM electron tomography , 2012 .

[18]  L. Kovarik,et al.  XEDS STEM tomography for 3D chemical characterization of nanoscale particles. , 2013, Ultramicroscopy.

[19]  A. Alavi,et al.  The Clinical Role of Fusion Imaging Using PET, CT, and MR Imaging. , 2008, PET clinics.

[20]  C. Kübel,et al.  Recent Advances in Electron Tomography: TEM and HAADF-STEM Tomography for Materials Science and Semiconductor Applications , 2005, Microscopy and Microanalysis.

[21]  L. López-Conesa,et al.  EELS tomography in multiferroic nanocomposites: from spectrum images to the spectrum volume. , 2014, Nanoscale.

[22]  B. Inkson,et al.  Three-dimensional chemical analysis of tungsten probes by energy dispersive x-ray nanotomography , 2007 .

[23]  G Lucas,et al.  Multivariate statistical analysis as a tool for the segmentation of 3D spectral data. , 2013, Micron.

[24]  Roy L. Streit,et al.  Poisson Point Processes: Imaging, Tracking, and Sensing , 2010 .

[25]  David B. Williams,et al.  The Transmission Electron Microscope , 2009 .

[26]  Avinash C. Kak,et al.  Principles of computerized tomographic imaging , 2001, Classics in applied mathematics.

[27]  Jan Sijbers,et al.  The ASTRA Toolbox: A platform for advanced algorithm development in electron tomography. , 2015, Ultramicroscopy.

[28]  L. Liz‐Marzán,et al.  A New Method for Quantitative XEDS Tomography of Complex Heteronanostructures , 2016 .

[29]  Brian F. G. Johnson,et al.  Z-Contrast tomography: a technique inthree-dimensional nanostructural analysis based on Rutherfordscattering , 2001 .

[30]  M. Treacy.  Z Dependence of Electron Scattering by Single Atoms into Annular Dark-Field Detectors , 2011, Microscopy and Microanalysis.

[31]  M. Albu,et al.  Nanoscale voxel spectroscopy by simultaneous EELS and EDS tomography. , 2014, Nanoscale.

[32]  P. Midgley,et al.  3D electron microscopy in the physical sciences: the development of Z-contrast and EFTEM tomography. , 2003, Ultramicroscopy.

[33]  M. G. Burke,et al.  Understanding the limitations of the Super-X energy dispersive x-ray spectrometer as a function of specimen tilt angle for tomographic data acquisition in the S/TEM , 2013 .