Photoinduced carrier dynamics of spectral overlapping in self-assembled MoS₂/graphene heterostructures

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