Scanning tunneling spectroscopy examination of surface electronic structures of Si(111)(23×23)30°-Sn surface

Scanning tunneling spectroscopy (STS) measurements have been performed on Si(111)(23×23)30°-Sn surface. Tunneling spectral analysis of the energy of the surface states around the Fermi-level (Ef) indicates two filled and two empty states straddling Ef, showing a ∼ 1.6 eV surface bandgap. As part of the identification of these surface states, STS spectra were also taken on a coexisting well-known 3×3 surface, and the intrisic nature of these surface states is discussed.