Formation Processes of the Au/Si (111) γ (√3×√3) R30° Surface

We have investigated formation processes of the γ (√3×√3) R30° (γ√3) reconstructed surface for the Au/Si (111) system by using Auger electron spectroscopy, reflection high energy electron diffraction and scanning tunneling microscopy. Depositing Au onto the Si (111) - (7 × 7) substrate at a temperature of 600°C, we have successfully obtained the well-defined γ√3 surface with a single domain, which is extremely flat at an atomic scale. On the basis of the analysis of the surface composition, we have demonstrated that one monolayer of Au constitutes the γ√3 surface. Furthermore, it has been revealed that excess Au atoms at the surface contribute not to the formation of the surface reconstruction but to that of the liquid islands of Au.