Hole injection from scanning tunneling microscope tips was found to enhance diffusion of Cl atoms on Si(111)-(7x7) surface. The sample bias dependence exhibited a broad peak centered at a sample bias, Vs ≈ -2.0V and the diffusion rate at the peak bias voltage depended linearly on the injected current. The effect spreads laterally along the surface over a range of ≈10nm from the position of the tip, but not to extend beyond step edges. These facts were well interpreted by a model in which holes injected mainly into a surface band which peaked at Vs = -1.8V propagated along the surface and became localized at Cl sites; thus somehow leading to destabilization or weakening of the bonds that resulted in Cl atom movements such as diffusion.

Chlorine Atom Diffusion on Si(111)-(7x7) Surface Enhanced by Hole Injection from Scanning Tunnelling Microscope Tips. Y.Nakamura, Y.Mera, K.Maeda: Surface Science, 2002, 497[1-3], 166-70