Abstract: Application relevant materials are usually polycrystalline, and one of the major challenges in structural analysis resides in accurately identifying the grain boundary orientation and size distribution over a wide field of view with enough spatial resolution to capture tens-of-nanometer sized domains. Four-dimensional scanning transmission electron microscopy (4D-STEM) now enables the fast collection of nano-beam electron diffraction patterns on a two-dimensional array of spatial positions in which various computational analyses can reveal structural variations on a pixel-by-pixel basis over different scales while reducing knock-on damage in samples which have been traditionally very challenging to characterize. In this poster, we will showcase our advancements in the field of transmission electron microscopy and nanoscience with an emphasis on understanding effects of strain and defects in low-dimensional materials including the first demonstration of true transmission electron microscopy-based automated orientation mapping, which has significant follow-on impact for electron scattering based nanoscale structure characterization in mission relevant materials.
Bio: Dr. Pettes’s contributions to advancing state-of-the-art in materials physics focus on developing fundamental physical understanding of materials to impart new functionalities relevant to applications in energy, optical communications, and mechanical performance. His research has received recognition by the American Society of Mechanical Engineers (ASME Fellow 2023), Department of Energy (LDRD Early Career Research Award 2019), the National Science Foundation (CAREER Award 2016, Graduate Research Fellowship 2006) and National Academy of Engineering (US-EU FOE 2019, FOEE 2016) among others. He has published 84 peer reviewed journal articles, 1 U.S. patent, and 2 pending U.S. patents that have been cited over 8,500 times with an h-index of 36 (Google Scholar). He has built his research capabilities through projects in DOE Basic Energy Sciences, LDRD DR/ER-Seedlings/ECR/Reserve, National Science Foundation, and several projects with the LANL National Security Education Center IMS/ISTI/CSES programs (US$7.8M awarded as PI, US$14.8M total). His role in scientific leadership and line management in the Center for Integrated Nanotechnologies allows him to assist ~150 employees with program/career development, workforce development, operational excellence, and safe conduct of research all while working to shape and implement senior management’s vision and priorities.