We report ultrafast pump-probe spectroscopy examining exciton dynamics in atomically thin MoS2. Spectrally- and temporally-resolved measurements are performed to investigate the interaction dynamics of two important direct-gap excitons (A and B) and their associated broadening kinetics. The two excitons show strongly correlated inter-excitonic dynamic, in which the transient blue-shifted excitonic absorption originates from the internal A-B excitonic interaction. The observed complex spectral response is determined by the exciton collision-induced linewidth broadening; the broadening of the B exciton linewidth in turn lowers the peak spectral amplitude of the A exciton. Resonant excitation at the B exciton energy reveals that inter-excitonic scattering plays a more important role in determining the broadening kinetics than free-carrier scattering.
@article{arxiv.1308.2023,
title = {Exciton dynamics in atomically thin MoS2: inter-excitonic interaction and broadening kinetics},
author = {Sangwan Sim and Jusang Park and Jeong-Gyu Song and Chihun In and Yun-Shik Lee and Hyungjun Kim and Hyunyong Choi},
journal= {arXiv preprint arXiv:1308.2023},
year = {2015}
}