Abstract
Atomically thin two-dimensional transition metal dichalcogenides (TMDs) have recently attracted scientists’ interests due to their extraordinary potentials for ultrathin electronics and optoelectronics. They are also promising candidates for new concept devices in spintronics and valleytronics. MoSe2 and WSe2 are two important members of the TMD family. A dense triangular network of one-dimensional (1D) metallic modes in a continuous and uniform monolayer of MoSe2 grown by molecular-beam epitaxy (MBE) has been observed which attributes to inversion domain boundary (IDB) defects in the sample. However, such line defects can be found neither in monolayer of WSe2 grown by MBE nor in MoSe2 grown by other methods, e.g. chemical vapor deposition (CVD). The possible growth mechanism of such line defects will be discussed. Heterostructure is another important aspect of semiconductor studies. Lots of high-speed electronics and optoelectronic devices are based on heterostructures between semiconductors with different bandgaps. I will present some works in heterostructures between MoSe2 and WSe2 grown by MBE.