▎ 摘　　要

In this work, the effect of the ion fluence-dependent defect formation on the modification of surface electronic and optical properties of graphene has been investigated. The chemical vapor deposited (CVD) graphene samples were irradiated with 70 MeV Si+5 swift heavy ions (SHI) with varying fluence to study the defect formation mechanism and the role of ion beam fluence in modulating its surface electronic property such as work function. At a low ion dose, acceptor doping via vacancy creation was observed. The redshift in absorption peak position, the blueshift in Raman peak position, and the enhancement in work function values are indicators of such doping effect at low fluence. In contrast, the dense electronic excitation-dominated extended defects were realized at a higher ion dose showing strain-induced modifications in the optoelectronic properties of graphene. This work offers an effective strategy to control defect formation and systematically alter graphene's optical and electronic properties. The experimental findings will be useful for the applicability of graphene under extreme radiation conditions and space research.