UCLA

Monolayer (MoL) and multilayer (MuL) MoS2are extremely fascinating materials for optoelectronics, particularly in scenarios involving high excitation carrier densities. Consequently, it is essential to understand the various processes and their associated time scales in MoL and MuL two-dimensional materials under such high excitation densities. Here, we demonstrate that carrier dynamics in MoL and MuL MoS2exhibit distinctly different behaviors above the Mott density, with MoL showing faster carrier relaxation and enhanced many-body interactions compared to MuL. Despite the similarity in band structure near theK-point and the formation of A-excitons, pronounced differences in the transient response are observed, highlighting the influence of the overall band structure. Exciton dissociation, band gap renormalization, and intervalley relaxation play a consequential role in dictating the ultrafast transient properties of these samples. The study in this paper provides a detailed understanding of the fundamental optoelectronic properties of the two-dimensional MoS2at high excitation densities, paving the way for its potential applications in various photonic and optoelectronic domains.