Published in Nanotechnology 18, 044015 (2007).
Influence of Tip-induced Band Bending on Tunneling Spectra of Semiconductor
R. M. Feenstra (a), Y. Dong (a), M. P. Semtsiv (b) and W. T. Masselink (b)
(a) Dept. Physics, Carnegie Mellon University, Pittsburgh, PA 15213
(b) Department of Physics, Humboldt-Universitšt zu Berlin, D-10115 Berlin, Germany
A theory based on the Bardeen formalism is developed for computing the tunnel current
between a metal tip and a semiconductor surface. Tip-induced band bending in the
semiconductor is included, with the electrostatic potential computed in a fully three-
dimensional model whereas the tunnel current is computed in the limit of large tip radii.
Localized states forming at the semiconductor surface as well as wavefunction tailing
through the semiconductor depletion region are fully accounted for. Numerical results are
provided and compared with data obtained from p-type GaAs surfaces, and generalization
of the method to semiconductor heterojunctions is discussed.
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