Regensburg 2004 – scientific programme
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O: Oberflächenphysik
O 40: Halbleiteroberflächen und -grenzflächen
O 40.5: Talk
Thursday, March 11, 2004, 16:45–17:00, H45
Importance of carrier dynamics and conservation of momentum in atom-selective STM imaging of semiconductor surfaces — •Philipp Ebert1, Nikos Jäger1, Eicke Weber2, and Knut Urban1 — 1Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich — 2University of California and Lawrence Berkeley National Laboratory
Scanning tunneling microscopy and spectroscopy measurements on the GaAs(110) surface with complementary theoretical calculations are performed to clarify the effects involved in the tunneling of unpinned semiconductor surfaces. We show that the flatband and tip-induced band bending as well as equilibrium conditions are insufficient to describe the effects involved. Instead, carrier dynamics and conservation of momentum of the tunneling electrons need to be taken into account for a complete description of the contributions of the valence or conduction band states. The results allow us to understand the unique properties needed to achieve the atom-selective imaging on semiconductor surfaces as well as the determination of the band gap energy.