Influence of mild fluorination on strain and charge doping in graphene

Abstract

Fluorinated graphene is a chemically modified form of graphene in which fluorine atoms are covalently bonded to the carbon lattice. Its technological significance stems from the unique combination of properties introduced by fluorination, including tunable electronic and optical characteristics, enhanced chemical stability, and dielectric behavior. Conventional fluorination techniques, however, often introduce substantial structural defects and inhomogeneities, which not only degrade device performance and limit practical applications, but also obscure the relationship between fluorine-induced structural distortion and doping effects. This study demonstrates that mild gas-phase fluorination using XeF2 enables non-destructive and controllable functionalization, preserving the crystalline integrity of monolayer graphene while simultaneously inducing tensile strain and p-type doping. Raman mapping and frequency correlation analysis of the G and 2D peaks reveal that mild fluorination leads to spatially uniform tensile strain and hole doping across the graphene sheet. These changes provide direct, spatially resolved insights into the relative variations in strain and carrier concentration. Taken together, these findings offer comprehensive experimental evidence that mild XeF2 fluorination is an effective strategy for strain and charge carrier engineering in graphene, supporting its integration into next-generation flexible electronics, two-dimensional field-effect transistors, and optoelectronic devices where precise control of doping and strain is critical.