Laser-induced local profile transformation of multilayered graphene on a substrate

Multi-layered graphene deposited on silicon wafer was irradiated in air by sequences of nanosecond laser pulses. It is shown that ultra-shallow craters (cavities) with depth of ~1nm and microholes can be formed in graphene sheet on the substrate at laser fluence ~0.04J/cm2 well below the experimentally known graphene ablation threshold ≥0.25J/cm2. Influence of intensity and number of laser pulses on the depth and roughness of the cavities are described. We suggest that the observed effects are related to laser heating and boiling of the adsorbate at graphene-silicon interface. [Display omitted] •Multi-layered graphene on Si/SiO2 was irradiated by series of nanosecond laser pulses.•~1nm deep craters in graphene sheet were formed at laser fluence ~0.04J/cm2.•The number of graphene layers after ~0.04J/cm2 irradiation remains the same.•Microholes in graphene sheet were formed at higher fluences.•Possible transformation mechanisms are discussed.