11 July

DFT modeling of 2D Materials for Novel Device Applications

Monday 11 July 2022, 12:00pm

ICN2 Seminar Room, Campus UAB

By ProfKyeongjae (KJ) Cho, Department of Materials Science & Engineering, The University of Texas at Dallas, Richardson, USA

Abstract: Over the last three decades, nanoscale materials have been extensively investigated for both academic research and practical industrial applications. Nanomaterials are broadly classified by the number of nanoscale dimensions of the material systems (in practice, indicated by the number of macroscopic dimensions): 0D (fullerenes and nanoparticles), 1D (nantobubes and nanowires), and 2D (graphene, h-BN, TMDs) nanomaterials. In this talk, I will discuss about the modeling research on 2D materials, with emphasis on transition metal dichalcogenides (TMDs). 2D compound semiconductors (TMDs; MX2 with M = transition metal, X = chalcogen) are the recent focus of diverse research activities as a promising 2D device materials. TMDs are covalently bonded 2D layers stacked together with weakly interacting van der Waals gaps, and there have been diverse TMD samples prepared by exfoliation, CVD and MBE growth for material study and device applications. In spite of such increasing research activities, their material properties and how to control them within device structures are not fully understood yet, and topics of ongoing research. To explore possible materials properties and to facilitate the experimental device material development efforts, we have applied predictive first principles modeling method to examine TMD materials properties. We have performed predictive density functional theory (DFT) studies of TMD material properties including band alignments in heterostrucures, TMD-metal contacts, TMD-oxide interface, and TMD defect and dopant properties. Furthermore, to guide the experiment efforts to grow high quality TMD samples, we have investigate the kinetics of precursor reactions and the nucleation and growth of TMD samples using DFT and kinetic Monte Carlo simulations. In this talk, we will discuss the calculated atomic and electronic structure information of TMDs and their heterostructures, controlled growth of TMD samples, and their implications for nanoscale device applications in the context of close collaboration with experimental research groups.

This work was supported by Creative Materials Discovery Program of KNRF and ASCENT, one of six centers in JUMP, a Semiconductor Research Corporation (SRC) program sponsored by DARPA.

Bio sketch : KJ Cho has received his bachelor’s degree (1986) and Master degree (1988) in Physics from the Seoul National University, and PhD (1994) in Physics from MIT. He has worked as a postdoctoral associate (1994-1995) and research scientist (1995-1997) at MIT with a joint appointment at Harvard University during 1995-1996. During 1997-2006, he has worked as an assistant professor in the Mechanical Engineering Department (with a courtesy appointment in the Materials Science and Engineering Department) at Stanford University. In 2006, he has joined as a tenured associate professor and is currently working as a full professor in the Materials Science and Engineering at the University of Texas at Dallas. He has received Frederich E. Terman Award from the Packard Foundation in 1997, and he was elected as a Fellow in the Institute of Physics in 2004. He was elected as a fellow of the American Physical Society in 2016. He has received Full Professor Research Award, UTD Annual ECS Award (2018). He has published more than 390 journal articles and 47 conference papers (Google Scholar: h-index = 81, total citation = 34,337; SCI: h-index = 71, total citation = 25,589; SCOPUS: h-index = 74, total citation = 27,871).

Hosted by Prof. Stephan Roche, Theoretical and Computational Nanoscience Group Leader at ICN2.