Diffusional kinetics of SiGe dimers on Si(100) using atom-tracking scanning tunneling microscopy

Quantitative measurements of the diffusion of adsorbed mixed Ce-Si dimers o n the Si(100) surface have been made as a function of temperature using ato m-tracking scanning tunneling microscopy. These mixed dimers are distinguis hable from pure Si-Si dimers by their characteristic kinetics-a 180 degrees rotation between two highly buckled configurations. At temperatures at whi ch the mixed dimers diffuse, atomic-exchange events occur, in which the Ge atom in the adsorbed dimer exchanges with a substrate Si atom. Reexchange c an also occur when the diffusing Si-Si dimer revisits the original site of exchange.