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Academic Calendar

Event Scheduled for Dec 3, 2018

Event: MSE Seminar Speaker - Dr. Santhana Eswara

Location: BPB-131

Time: 02:45 pm

Details of Event:
MSE invites you to a seminar by:
Dr. Santhana Eswara
Advanced Instrumentation for Ion Nano-Analytics (AINA), MRT Department, Luxembourg Institute of Science and Technology (LIST)
Monday, December 3, 2018
Biology/Physics Building, Room 131, at 2:45 p.m.
“New in-situ techniques for correlative microscopy: TEM-SIMS and HIM-SIMS”
Abstract: Development of innovative characterization tools is of paramount importance to advance the frontiers of science and technology in nearly all areas of research. In order to overcome the limitations of individual techniques, correlative microscopy has been recognized as a powerful approach to obtain complementary information about the investigated materials. High-resolution imaging techniques such as Transmission Electron Microscopy (TEM) or Helium Ion Microscopy (HIM) offer excellent spatial resolution. However, the analytical techniques associated with TEM such as Energy Dispersive X-ray spectroscopy (EDX) or Electron Energy-Loss Spectroscopy (EELS) are inadequate for the analysis of (i) isotopes, (ii) trace concentrations (< 0.1 at. % or < 1000 ppm) and (iii) light elements (H, Li, B). Likewise, for the case of HIM, until recently there was no direct possibility to perform elemental mapping because sub-30 keV He+ or Ne+ ion irradiation do not excite X-ray emission. Secondary Ion Mass Spectrometry (SIMS), on the other hand, has several advantages such as the possibility to analyze elements and isotopes of all elements of the periodic table while also providing high-sensitivity to detect even trace concentrations. However, the main drawbacks of SIMS are (i) difficulty in quantification and (ii) lateral resolution of SIMS imaging is fundamentally limited by ion-solid interaction volume to ~10nm (the resolution of commercial SIMS instruments is limited to 50nm because of the brightness of the used primary ion source technology). Owing to the complementary strengths of SIMS imaging, we developed new instrumentations for correlative microscopy combining in-situ (i) TEM-SIMS1 and (ii) HIM-SIMS2.
In this presentation, we will discuss the instrumentation development aspects of the TEM-SIMS and HIM-SIMS techniques. With selected examples from our recent work in materials science3 and beyond4, we will show the powerful correlative microscopy possibilities that emerge by in-situ and ex-situ analysis. Image correlation methodology will be also discussed4.
[1] L. Yedra, S. Eswara, D. Dowsett, T. Wirtz, In-situ Isotopic Analysis at Nanoscale using Parallel Ion Electron Spectrometry: A Powerful New Paradigm for Correlative Microscopy, Sci. Rep. 6, 28705, 2016
[2] P. Gratia et al, Intrinsic Halide Segregation at Nanometer Scale Determines the High Efficiency of Mixed Cation/Mixed Halide Perovskite Solar Cells, J. Am. Chem. Soc. 138 (49) 15821–15824, 2016
[3] A. Ingenito et al, A passivating contact for silicon solar cells formed during a single firing thermal annealing, Nature Energy, 3, 800-808, 2018
[4] F. Vollnhals et al, Correlative Microscopy Combining Secondary Ion Mass Spectrometry and Electron Microscopy: Comparison of Intensity–Hue–Saturation and Laplacian Pyramid Methods for Image Fusion, Anal. Chem. 89, 10702–10710, 2017
Bio: Dr. Santhana Eswara obtained his PhD in Materials Science and Engineering in 2008 from the University of Virginia, USA. He then did post-doctoral research in Paris (France) and in Ulm (Germany) focusing on Transmission Electron Microscopy techniques for materials research. Since 2013, he is a permanent researcher at the Luxembourg Institute of Science and Technology where he is primarily engaged in developing and applying innovative tools for microscopy and microanalysis using electrons and ions. His research has been published in nearly 30 leading international peer-reviewed journals.

Target Audience: Not Available

Sponsored By: Materials Science and Engineering Department

Pamphlet/Flyer: No Pamphlet/Flyer Available

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