Scanning tunneling spectroscopy and density functional calculation of silicon dangling bonds on the Si(100)-2 × 1:H surface

We studied electronic properties of atomic-scale dangling bond (DB) and DB wires on Si(100)-2 × 1:H surfaces using a ultrahigh vacuum scanning tunneling microscope (UHV-STM). The decay of the near-midgap DB-states induced by an unpaired DB depends on the crystalline orientation of the Si(100) surface. The decay length of the DB-states of an unpaired DB wire can be ~ 2.5 nm along the dimer row direction. The perturbation from an unpaired DB to an adjacent paired DB is also demonstrated. The results are in good agreement with density functional calculations.