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Microscopic Study of the Structural Defects in Two-dimensional Materials Via Advanced Transmission Electron Microscopy


Speaker:Prof. Chuanhong Jin
Affiliation:EM Center, State Key Laboratory of Silicon Materials, School of Material Science and Engineering, Zhejiang University
Date:April 18, 2019 (Thursday)
Time:4:00 p.m.
Venue:Room 522, 5/F, Chong Yuet Ming Physics Building, HKU

Abstract

Structural imperfections like defects are inevitable in materials and play vital roles on affecting the properties. Their behaviors and effects will become even more profound when the material dimensionality reduces, e.g., to two dimension (2D), in which the formation, migration of structural defects are largely constrained to the basal plane. Scanning transmission electron microscopy, aided by the spherical aberration corrected electron optics and monochromated electron source, has been demonstrated as an effective tool to probe the atomic and electronic structures of 2D materials. In this talk, I will present a few examples that include: 1) the quantification of point defects in monolayer MoS2, 2) the formation mechanism of unusual grain boundaries in hexagonal BN (hBN), and 3) the buildup of full-space parameter grain boundaries in 2D hBN experimentally.

Reference:
[1] J. Hong, C. Jin et al., Nat. Commun. (2015); Nano Lett. (2017); D. Zhu, C. Jin et al., npj 2D Mater. and Appl. (2017).
[2] X. Ren, C. Jin et al., Phys. Rev. Mater. (2019) ; to be submitted.

Biography

Chuanhong Jin received his Ph.D. degree in 2006 from Institute of Physics, Chinese Academy of Sciences (CAS). He moved to the Nanotube Research Center in National Institute of Advanced Industrial Science and Technology (AIST) Japan, initially as a JSPS Postdoctoral Research Fellow, and later became a staff scientist in tenure-track. He joined the faculty of Zhejiang University in 2011 as a Professor at the Center for Electron Microscopy, State Key Laboratory of Silicon Materials and School of Materials Science and Engineering. Dr. Jin has expertise in studying the atomic and electronic structure of two-dimensional materials via advanced electron microscopy and spectroscopy, focusing mostly on defect physics. He is also interested in liquid-phase scanning/transmission electron microscopy and its applications in studying the nucleation, growth and oxidative etching of nanocrystals in solution.

Coffee and tea will be served 20 minutes prior to the seminar.

Anyone interested is welcome to attend.