▎ 摘 要
The possibility of laser induced modification of local mechanical properties of polycrystalline chemical vapor deposition graphene on silicon substrate in air has been demonstrated. Nanosecond laser pulses (wavelength 532 nm) with focal spot diameter similar to 1 mu m were used. Samples were placed and irradiated inside a scanning probe microscope (SPM) that allowed in situ studies of surface morphology and mechanical phase contrast in SPM tapping mode before and after multipulsed laser treatment. It was found that along with local profile transformation of graphene sheet (formation of nanopits and nanobumps), transformation of mechanical properties of graphene on a substrate structure took place. Such laser modified graphene area is larger than (but of the order of) the irradiation spot size. Its appearance is related to laser induced radial extension of an adsorbed water nanolayer intercalated between graphene and substrate. It is shown that the process of water layer lateral migration has a reversible character. This effect is proved by laser spot shift and sequential irradiation.