Low-Temperature Scanning Tunneling Spectroscopy of Semiconductor Surfaces
R.M. Feenstra a , G. Meyer b , F. Moresco c and K.H. Rieder c
a Department of Physics, Carnegie Mellon University Pittsburgh, Pennsylvania 15213, USA
b Paul Drude Institut für Festkörperelektronik Hausvogteiplatz 5-7, 10117 Berlin, Germany
c Institut für Experimentalphysik, Freie Universität Berlin Arnimallee 14, 14195 Berlin, Germany
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Low-temperature scanning tunneling spectroscopy measurements on semiconductor surface are described. We consider both surfaces which do not possess surface states within the bulk bandgap, such as GaAs(110), and surfaces which do have states within the gap, such as Ge(111)2x1 and Ge(111)c(2x8). Band bending in the semiconductor due to the electric field in the vacuum penetrating the semiconductor is found to be a substantial effect in the former case. Transport limitations in the semiconductor give rise to additional voltage drops, which can be observed by making measurements over a wide range of tunnel current magnitudes.
DOI: 10.12693/APhysPolA.104.205
PACS numbers: 73.20.Hb, 71.20.Nr, 68.37.Ef