Observation of carrier dynamics in MoS₂ thin layer by femtosecond transient absorption microscopy

Abstract

Since the Nobel Prize was awarded in 2010 to Andre Geim and Konstantin Novoselov for their work on graphene, research in two-dimensional materials has attracted much attention. Transition metal dichalcogenides, which consist of transition metal atoms and chalcogen atoms other than oxygen, have potential applications in various electronics fields. However, there have been few observations of the transition processes of these electronic states, and the mechanisms of their functions are still unclear. In this study, the carrier dynamics of mechanically exfoliated MoS2 film were observed using femtosecond transient absorption microscopy. The time constant of carrier relaxation at the thin region was shorter than those of the thick. Electronic state differences and carrier trapping on the surface state regulate the lifetime of carriers in MoS2.