摘要

Transition-metal dichalcogenide (TMD) monolayers represent an important family of two-dimensional (2D) materials that have drawn tremendous research attention in recent years. They possess many interesting properties and hold potentials of future device applications. Currently, the majority of research works on TMDs are based on exfoliated or chemical vapor deposited samples. In this talk, I shall describe our efforts and progress in growing TMDs by molecular beam epitaxy (MBE) [1]. Using scanning tunneling microscopy (STM), interesting features, some of which are specific to the MBE-grown films, are revealed. Examples include networks of inversion domain boundaries in epitaxial MoSe2 and MoTe2 [2,3], point defects and the induced inter-valley scattering [4]. Results of intentional doping of TMDs by impurity atoms, such as N, will also be presented [5].  

References:

[1] H. Liu, et al., New J. Phys. 17, 053023 (2015)

[2] H. Liu, et al., Phys. Rev. Lett. 113, 066105 (2014)

[3] J. Chen, et al., ACS Nano. 11, 3282 (2017)

[4] H. Liu, et al., Nat. Comm. 6, 8180 (2015)

[5] Y.P. Xia, et al., 2D Mater. 5, 041005 (2018)

报告人简介

Professor Maohai XIE received his bachelor degree in electronic engineering from Tianjin University, China, master degree in physics from Institute of Semiconductors, Chinese Academy of Sciences, and PhD in physics from University of London, Imperial College of Science, Technology and Medicine, UK. From June 1995 to July 1997, he was a postdoctoral research fellow at Imperial College in London. Since August 1997, he has worked in Physics Department, The University of Hong Kong as assistant, associate and full professor consecutively, and served as the head of Physics Department, HKU, since January 2017. He was also the Vice President and President of Hong Kong Physical Society from 2009 to 2013, and serves as the editor board members of Philosophical Transactions A, the Royal Society and of Proceedings of the Royal Society A: Mathematical, Physical & Engineering Sciences. Professor Xie’s research is on experimental surface and materials science, in particular on thin film growth by molecular-beam epitaxy, and surface characterization by scanning tunneling microscopy, electron diffraction, and photoelectron spectroscopy.