Epitaxial silicon overgrowth of C60 on the Si(1 0 0)-2 × 1 surface

Scanning tunneling microscopy has been used to investigate silicon overgrowth of C60 on the Si(1 0 0)-2 × 1 surface. It can be shown that crystal morphology and quality is highly dependent on temperature and C60 coverage. A C60 coverage of 0.02 ML was used to show the initial stage of silicon overgrowth (1.5 ML of Si), medium stage with crater formation, crater diminution (10 ML of Si) and finally crater overgrowth (100 ML of Si). Crystal quality can be improved by annealing of the stack at 750 °C for several minutes, but SiC formation at 800 °C deteriorates the stack. Segregation of C60 plays an important role already at low coverage. Nevertheless, C60 can be enclosed into the crystal within a few monolayers. This has been proven by STM, TEM and SIMS analysis. Higher C60 coverage leads to 3D islanding, which was proven by STM and LEED, and eventually to polysilicon, shown by STM and TEM. Finally we give a short comparison to the Si(1 1 1)-7 × 7 surface.