Chemistry Reference
In-Depth Information
potential. The characteristics of the
i-V
curves are independent of solution agitation
and potential scanning rate indicating that mass transport in the electrolyte has very
little effect. For
n
-Si the current is proportional to the light intensity and is only limited
by the saturation photocurrent. The photon efficiency is about 4 indicating a current
quadrupling effect; for every photon-generated electron, three electrons are injected
from the states at the interface.
8.2.3. Effective Dissolution Valence and Hydrogen Evolution
As discussed in Chapter 5, the effective dissolution valence of silicon,
n
, can vary
between 2 and 4 depending on the type of silicon, potential, and illumination intensity.
In general,
n
increases with increasing anodic current density for all types of silicon
substrates as shown in Fig. 5.21. The value of
n
sharply changes at the peak current
