Chemistry Reference
In-Depth Information
Reaction intermediates are a special group of surface states that can cause band
edge shift (or Fermi level pinning). When this occurs, the flatband potential tends to
change with current. Figure 2.32 shows that the flatband potential of
n
-type silicon in
KCl changes with photocurrent which induces surface
states.
93
a density of
This result can be used to explain the difference between the flatband poten-
tials determined by Mott-Schottky plot and by measurement of the onset potential for
photocurrent.
94
Flatband potential shift may also result from deposition of metallic and organic
species, which act as surface states.
83,402,808,1015
Figure 2.33 shows that the flatband poten-
tial of an
n
-Si electrode in acetonitrile solution containing redox couples changes with
The
shift
of 0.55V shown in Fig. 2.32 corresponds to
