THE ADSORPTION OF C6H5CL ON SI(111)7X7 STUDIED BY STM

The adsorption of chlorobenzene on Si(111)7 X 7 at room temperature wa s studied by scanning tunneling microscopy (STM). Selective chemisorpt ion was observed at different adatom sites. It was found that the cent er adatoms were more reactive than the corner adatoms, and the faulted half of the unit cell was more reactive than the unfaulted. The mecha nism is discussed in terms of the electronic and atomic structures in Si(111)7 X 7. Both preferences indicate that chlorobenzene was present initially in a mobile precursor state.