▎ 摘　　要

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 similar to 1 nm and microholes can be formed in graphene sheet on the substrate at laser fluence similar to 0.04 J/cm(2) well below the experimentally known graphene ablation threshold >= 0.25 J/cm(2). 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. (C) 2014 Elsevier Ltd. All rights reserved.