Scanning tunneling microscopy/spectroscopy of dangling-bond wires fabricated on the Si(100)-2×1-H surface

We present a scanning tunneling microscopy/spectroscopy (STM/STS) study of atomic-scale dangling-bond (DB) wires on a hydrogen-terminated Si(100)-2×1-H surface. In the case of DB wires made of paired DBs, the STS shows semiconductive electronic states with a band gap of approximately 0.5 eV. The DB wires made of both single and paired DBs show a finite density of states at Fermi energy and do not show semiconductive band gaps. We have succeeded in making an atomic-scale wire that has a finite density of states at Fermi energy on a semiconductive surface. The results are in good agreement with a recent first-principles theoretical calculations.