▎ 摘　　要

The optical biosensors based on the plasmonic technology are an important research item in the field of biophotonics. The graphene-molybdenum disulfide (MoS2) based hybrid structures are very effective in designing and fabricating of the sensitive optical biosensors. In this paper, we propose a nanostructure Ag/MoS2/graphene as an optical biosensor with high performance and sensitivity. The proposed configuration for this surface plasmon resonance (SPR) optical biosensor is Kretschmann. Herein, the enhancement of sensitivity for the proposed SPR optical biosensor is investigated in different states. By determining of the numbers of MoS2 layer and the thickness of the metal layer, we increased the sensitivity of the proposed biosensor. The maximum sensitivity similar to 190 degrees/RIU is achieved. For this ultra-sensitive SPR biosensor with maximum sensitivity, the numbers of MoS2 and graphene layer is 2 and the resonance wavelength is determined 680nm.