Photoinduced Carrier Dynamics of Spectral Overlapping in Self-Assembled Mos2/Graphene Heterostructures

Abstract

Ultrafast photogenerated carrier dynamics plays an indispensable role in the performance of two-dimensional optoelectronic materials and devices. The femtosecond transient absorption (TA) spectroscopy is a powerful tool to study those ultrafast dynamics. However, the transient absorption spectra may exhibit strong spectral overlapping, so unambiguous identification of the detailed dynamics of each individual effect become challenging. Here, the ultrafast carrier dynamics of spectral overlapping in self-assembled MoS2/graphene heterostructures is investigated by the femtosecond time-resolved TA microscopy and followed by detailed spectral decomposition analysis. In MoS2/graphene heterostructures, the direct and indirect recombination processes are prolonged due to the charge transfer between MoS2 and graphene, resulting in the longer carrier relaxation time in the heterostructures.

Keywords: Two dimensional materials, Heterostructures, Ultrafast spectroscopy, Carrier dynamics, Femtosecond transient absorption, Spectral Overlapping