| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5423298 | Surface Science | 2011 | 6 Pages |
Structural changes of graphite surfaces induced by femtosecond (fs) laser excitation at a fluence regime above 75Â mJ/cm2 are reported. Direct imagings of excited surfaces by means of scanning tunneling microscopy have revealed that fs-excitations induce nanometer-scaled craters, together with sp3-type interlayer-bonded domains. The nano-craters are characterized by atomically-flat bottom and two atomic-steps in depth, indicating the exfoliation of fragmentary intact-sheets of double-layer of graphite. The theoretical simulation has shown that the required energy for the double-layer ablation is much lowered by the help of interlayer-bond formation, compared to the sequential removal of individual graphene layers. Based on the experimental and theoretical results, the exfoliation of double graphite layers, that is a novel mode of laser-ablation observed first, indicates clearly that the formation of strong interlayer bonds between the two atomic layers is a crucial step in the ablation process.
Research highlights⺠In situ STM observation of fs-laser excited graphite surface. ⺠Nano-scale circular craters formed by fs-laser excitation. ⺠A novel mode of laser ablation including the removal of double-layer graphite layers. ⺠Interlayer bond and sp3-domain formation in graphite. ⺠The adiabatic path for the removal of dimerized carbons.
