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.