Figure 3: STM images after H dosing at 1,100 K of G/SiC and computer simulation.
From: Graphene etching on SiC grains as a path to interstellar polycyclic aromatic hydrocarbons formation
(a) 100 × 100 nm2, −1,100 mV. Wide view of a region where the graphene has been reduced to a stripe with rounded edges on the centre of the image. On the right part of the image, a region of BLG seems unaltered. The upper inset shows a high-resolution image of a kink where single-layer graphene, BLG and the modified etched substrate coexist. (b) STM image of a hole in the middle of a graphene terrace. These holes are observed after H treatment at high temperatures and they evidence etching through edges and defects. 70 × 70 nm2, −1.1 V. (c) Atomically resolved STM image of a subsurface trimmer 2.5 × 2.5 nm2, −400 mV. (d) Initial and final frames of the graphene surface extracted from a movie of DFT molecular dynamics calculations of the G/H/SiC system. The distance between graphene layers expand from 7% at room temperature to about 62% at 1,000 K, and finally, after 250 fs (MD time), the topmost layer disrupt in the form of small carbonaceous species. In this case, benzene rings (blue oval), acetylene molecule (black oval), methylene radical (orange oval) or PAHs (red oval) can be identified.
