Hi,
A Schottky barrier means that the current can flow from one direction
but not the other. As a result, its current-voltage characteristic is
just that of a diode. So, it is blocking in one direction and
non-blocking in another. For example, usually, if a metal is in contact
with an n-type semiconductor, current can flow from metal to n-type but
not from n-type to metal (of course, it means electron can flow from n
to metal but not from metal to n).
However, if we heavily dope the semiconductor (e.g. >1E20cm^-3), now
the barrier is very thin and quantum tunneling is possible. Then there
is no blocking behavior and the current can flow in both direction.
This is Ohmic now.
If you want to know more about Schottky barrier, you may refer to our
database:
http://www.kodkodkod.com/files/thermionic.htm
Here you will know why a schottky barrier behaves like a diode.
Regards,
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