Fermi-Level Pinning at the Sb/GaAs(110) Surface Studied by Scanning Tunneling Spectroscopy

Abstract
Antimony overlayers on the GaAs(110) surface have been studied by scanning tunneling microscopy and spectroscopy. On ordered Sb terraces, a characteristic spectrum of surface states is observed. Near the edges of Sb islands, additional states are found within the band-gap region. These band-gap states comprise two separate bands of filled and empty states, with the surface Fermi level pinned between the two bands.