Provides knowledge about depletion region basics

The P-type material has positive majority charge carriers, holes, which are
free to move about the crystal lattice.

The N-type material has mobile negative majority carriers, electrons.

Near the junction, the N-type material electrons diffuse across the junction,
combining with holes in P-type material.

The region of the P-type material near the junction takes on a net negative
charge because of the electrons attracted.

Since electrons departed the N-type region, it takes on a localized positive
charge.

The thin layer of the crystal lattice between these charges has been
depleted of majority carriers, thus, is known as the depletion region.

It becomes nonconductive intrinsic semiconductor material. In effect, we
have nearly an insulator separating the conductive P and N doped regions.




This separation of charges at the PN junction constitutes a potential barrier.
This potential barrier must be overcome by an external voltage source to
make the junction conduct.

The formation of the junction and potential barrier happens during the
manufacturing process.