SCANNING TUNNELING SPECTROSCOPY OF DANGLING-BOND WIRES FABRICATED ON THE SI(100)-2X1-H SURFACE

The scanning tunnelling microscopy/spectroscopy (STM/STS) of atomic-sc ale dangling-bond (DB) wires on a hydrogen-terminated Si(100)-2x1-H su rface is studied. A single DB and a paired DB on a Si dimer, fabricate d by extracting hydrogen atoms from the hydrogen-terminated Si surface , are distinguished by STM and the DB wires are categorized into sever al types. In the case of DB wires made of paired DBs, the STS shows se miconductive electronic states with a band gap of approximately 0.5 eV . The DB wires made of both single and paired DBs show a finite densit y of states at Fermi energy and do not show semiconductive band gaps. The results are in good agreement with recent ''first-principles'' the oretical calculations.