Chemistry Reference
In-Depth Information
Figure 6.19 shows the dark
i-V
curves Si and
n-
Si
10M HF + 0.5M HBr + 10
of p-
for the reactions
solution.
14
The
involving the reduction of in mM
cathodic current on
p-
Si in the dark is due to hole injection into the valence band. On
the other hand, the cathodic plateau current on
n-
Si is much larger than on
p-
Si indi-
cating that the reduction process is mainly a conduction band process. When conduc-
tion band electrons are not available, the reduction of
may proceed via the valence
band as is the case with
-Si in the dark. The current plateau at cathodic potentials on
both
p-
Si and
n
-Si is limited by the diffusion of
p
The small plateau current on
p-
Si
indicates that only a small fraction of
is reduced electrochemically and most of the
