# STM Images of Point Defects

| This is a STM image of a Pt surface. Vacancies are clearly visible
| Next we see the clean {111} Si surface in ultra high vacuum conditions (otherwise the surface would immediately oxidize and we would see amorphous SiO2).
| The {111} surface looks not as one would expect from a straight model - it has "reconstructed". This means that the surface layer formed a two-dimensional crystal that is totally different from the fcc Si lattice (it has a so-called 7 × 7 symmetry). Still, point defects are clearly visible.
| These fantastic pictures are all over the world. I do not know whom I should acknowledge, sorry.

With frame

4.2.1 Point Defects in Non-Equilibrium

© H. Föll (Defects - Script)