When p-type (+)and n-type (-) materials are placed in contact with each other, the junction behaves very differently than either type of material alone.
Specifically, current will flow readily in one direction (forward biased) but not in the other (reverse biased), creating the basic diode.

~10min

~4min – PN + LED + Photoelectric effect & Solar Cell.

Key Terms:
PN Junction, Depletion Zone, Equilibrium of junction, Reverse bias, Forward bias, negative/positive ion.

– In the p-type region there are holes from the acceptor impurities and in the n-type region there are extra electrons.