Fermi-level pinning at the Sb/GaAs(110) surface studied by scanning tunneling spectroscopy

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. © 1988 The American Physical Society.