Studying of the Biexciton Characteristics in Monolayer MoS2

In two-dimensional transition metal dichalcogenides (TMDCs), the understanding of exciton, trion, and biexciton has improved significantly. However, the characteristics of the biexciton and the 0.02corresponding interaction mechanism still need further discussion. Here, transient absorption (TA) spectroscopy accompanied by a strong probe laser is employed to investigate the ultrafast biexciton characteristics in monolayer MoS2. The B-B biexciton would appear under the condition of weak probe laser with the pump photon energy of 3.10 eV. As the intensity of probe laser increases, the A-A and B-B biexciton would form together. Their binding energy are estimated to 34.6 and 54.6 meV according to the TA spectra, and the corresponding lifetime are 21.6 and 7.5 ps, respectively. The probe intensity dependent peak shift behavior of A-A and the B-B biexciton suggests that the short-range interactions should be responsible for the biexciton annihilation process. These results can help explain the ultrafast exciton dynamics in the monolayer TMDCs for a broader range of fundamental research and practical applications.