First Brillouin zone of FCC lattice and the band diagram (Do you see any gaps?)

Here is one with a gap !

Band diagram of silicon

This type of bandgap is called an “indirect bandgap” material.

It is all about exciting electrons from the valence band.

P-type semiconductor: Si doped with a 3 valence element that substitutes Si atoms in the lattice. Carriers are mainly holes

N-type semiconductor: Si doped with a 5 valence element that substitutes Si atoms in the lattice. Carriers are electrons.

Facts:Facts:

-Doping a semiconductor with a second element that has excess or fewer valence electrons than the number of bonds in pure Si changes the carrier amount and their types.

-How “semiconduction” is manipulated has nothing to do with only single n-doped pr p-doped crystal.

-When a p-doped crystal is brought into contact with an n-doped one, interesting things happen.

-These “interesting things” determine how a transistor functions…

-Every transistor is, this way or that way, a p-n junction.

Before any potential applied

After potential applied