Electronic bond rupture of Si atoms on Si(1 1 1)-(2×1) induced by 1.16-eV photon excitation

A scanning tunneling microscopy study has revealed that 1.16-eV photon excitation induces electronic bond rupture of Si atoms on Si(1 1 1)-(2×1) surface. Monovacancy formation at perfect surface sites is the primary step of the structural changes, and it is followed by efficient formation of vacancy clusters with two distinctive forms: a vacancy string aligned on the Si chain one-dimensionally and a vacancy island developed two-dimensionally on the surface. The mechanism and kinetics of this photoinduced process is discussed based on the experimental results.