Article
Energetics and Kinetics of Surface States at n-Type Silicon Surfaces in Aqueous Fluoride Solutions
Journal of Physical Chemistry
(1996)
Abstract
Electrochemical impedance spectroscopy (EIS) was used to analyze the energetics and kinetics of processes occurring at n-type silicon (111) surfaces in 1 M NH4F solutions in the pH range 3−11 in the dark. An additional impedance parallel to that of the space charge layer was observed due to electrically active surface states. The surface states are located energetically at about 0.38 eV below the conduction band and have a capture cross section of 1 × 10-16 cm2. The rate constant for thermal excitation of electrons from the surface states into the conduction band is essentially independent of pH, indicating the surface states are physically the same on both hydrogen terminated and oxidized silicon surfaces. The density of surface states is 2 × 1010 cm-2 at pH 3, characteristic of the hydrogen terminated surface, and increases to 1 × 1012 cm-2 at pH 11, corresponding to an oxide passivated surface.
Disciplines
Publication Date
1996
DOI
https://doi.org/10.1021/jp952129e
Citation Information
Peter M. Hoffmann, Gerko Oskam, John C. Schmidt and Peter C. Searson. "Energetics and Kinetics of Surface States at n-Type Silicon Surfaces in Aqueous Fluoride Solutions" Journal of Physical Chemistry (1996) Available at: http://works.bepress.com/peter_m_hoffmann/41/