We have identified excited exciton states in monolayers of MoS2 and WS2 supported on fused silica by means of photoluminescence excitation spectroscopy. In monolayer WS2, the positions of the excited A exciton states imply an exciton binding energy of 0.32 eV. In monolayer MoS2, excited exciton transitions are observed at energies of 2.24 and 2.34 eV. Assigning these states to the B exciton Rydberg series yields an exciton binding energy of 0.44 eV.
作者：Heather M, Hill；Albert F, Rigosi；Cyrielle, Roquelet；Alexey, Chernikov；Timothy C, Berkelbach；David R, Reichman；Mark S, Hybertsen；Louis E, Brus；Tony F, Heinz
来源：Nano letters 2015 年 15卷 5期
