Ultrafast Dynamical Studies of Two Dimensional Transition Metal Dichalcogenides

Layer transition metal dichalcogenides (TMDCs) have attracted great attention due to their unique electronic and optical properties. Specifically, single-layer semiconducting TMDCs with their direct band gaps in the visible to near-infrared wavelength show great promise in boosting several applications in electronics, spintronics, optoelectronics, energy harvesting, etc. Different from the most famous monolayer material, graphene, they have more than one crystal structure, providing a tantalizing platform to investigate structural phase transition and possible photoinduced hidden phases. In this dissertation, we use femtosecond pump-probe techniques to explore the laser-induced phenomena in semimetal Td-MoTe2, as well as characterize the elastics properties of MoTe2 and 2H-SnS2 single crystal. Moreover, we also investigate the exciton emission properties and dynamics in the bilayer of MoS2/WS2 heterostructure.