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Past Events
Public Seminar of PhD Candidate:
Scanning Tunnelling Microscopic Study of Transition Metal Dichalcogenide Ultrathin Films
| Speaker: | Mr. Jinglei CHEN |
| Affiliation: | The University of Hong Kong |
| Date: | November 22, 2017 (Wednesday) |
| Time: | 2:30 p.m. |
| Venue: | Rm 518, 5/F, Chong Yuet Ming Physics Building, HKU |
Abstract
Transition-metal dichalcogenides (TMDCs) are an important family of two-dimensional (2D) materials that have attracted extensive research attention in recent years. They exhibit extraordinary electronic and optoelectronic properties and promise for future nano-device applications.
In this study, both monolayer and bilayer WSe2 and MoTe2 are fabricated by molecular-beam epitaxy (MBE) and their structural and electronic properties are investigated by scanning tunneling microscopy and spectroscopy (STM/S). In particular, quantum quasi-particle interference (QPI) is revealed in monolayer WSe2, which affirms strong spin–valley coupling and large spin splitting of the Q-valley electrons. Electronic band bending at bilayer WSe2 steps is noted signifying Fermi level pinning effect. In monolayer MoTe2, both the 2H semiconducting and 1T' semi-metallic phases are obtained and their tuning by changing the MBE conditions is demonstrated. By STM/S measurements, quantum dot states and quantum inter-valley interference patterns in the 2H and 1T’ domains, respectively, are also recorded and discussed.
Anyone interested is welcome to attend.