清华大学材料科学与工程研究院《材料科学论坛》

学术报告

报告题目：Phase imaging in STEM: Integrated Differential Phase Contrast (iDPC)

报告人：Ivan Lazic博士，Thermo Fisher Scientific公司

报告时间：6月18日（星期二）下午2点30分

地点：清华大学主楼11区（东配楼）二层，电子显微镜中心228房间

联系人：钟虓龑老师 62782347

Abstract

A state of the art direct phase STEM imaging technique called Integrated Differential Phase Contrast STEM (iDPC-STEM) [1, 2] will be presented, both from fundamental and theoretical point of view up to practical implementation and applications. Beside regular conditions, iDPC-STEM ability will be demonstrated also at the limit of resolution, contrast and dose [3] for wide variety of samples.

First, it will be shown that iDPC-STEM is an elegant solution to the well-known phase problem in TEM, with the full capacity to resolve the atoms at sub-Å scale from 30 keV to 300 keV under various (including extreme) conditions.

Second, its ability to image both light and heavy elements together, long range fields (such as strain and build in contact potentials), metallization and thickness variations, both for amorphous and crystalline materials, thin as well as thick samples will be demonstrated. For the reference, simultaneous results with ADF-STEM will be presented in most of the cases.

Finally, it will be shown that, using iDPC-STEM, clear and unambiguous imaging of extremely light elements, including hydrogen, is possible as well as low dose imaging of beam sensitive materials. Images of Zeolites (ZSM-5), Hexachloro Phthalocyanines (Cl16CuPc) with angstrom and sub angstrom resolution respectively and Metal Organic Frameworks (MOFs) using dose of only 120 e-/Å2 while demonstrating resolution of 1.6 Å will be presented. Biological cryo single particle analysis micrograph examples, such as Tobacco Mosaic Virus (TMV) will be included for completeness.

Biography

Dr. Ivan Lazić is currently a technical and a project lead at Thermo Fischer Scientific, Department of Materials & Structural Analysis in Eindhoven, The Netherlands. Since 2011 he holds a position of a senior scientist working on fundamental understanding of the contrast formation and detection in (Scanning) Transmission Electron Microscopy (S)TEM. His main focus is on improvement of the existing imaging and detection techniques as well as on investigating and suggesting a novel ones. He is main inventor and developer of the iDPC-STEM, coinventor and developer of Segmented Ptychography, and a contributor to other (S)TEM related innovations. In parallel, he focuses on developing theoretical and analytical description of (S)TEM imaging.

He presented his work on various occasions as invited speaker in Europe, including UK (Oxford), US (including Princeton), Japan, South Korea, India and Australia. He is an author of many journal papers, patents and a book chapter on STEM.

Prior to this, he accomplished a post-doctorate at Delft University of Technology (TU Delft), The Netherlands, Faculty of Applied Sciences and Kavli Institute of Nanoscience, working on ultimate resolution of electron and ion beam induced deposition and lithography (EBID, IBID and EBL).

Dr. Lazić obtained his PhD degree in 2009 from TU Delft, The Netherlands, Department of Material Science and Engineering (Thesis: Atomic scale simulations of oxide and metal film growth). Previously he graduated and received his master degree in 2003 at University of Belgrade, Serbia, Faculty of Electrical Engineering, Department of Physical Electronics, Optoelectronics and Laser engineering (Thesis: Electron transport and photon emission in Si/Ge hetero-structures of quantum cascade lasers). As an undergraduate he carried out an internship at Swiss Federal Institute of Technology, ETH, Zürich, Switzerland, Department of Physical Electronics.