Semiconductor Electronics Materials Devices And Simple Circuits

The donor level is found only in n-type semiconductors. The donor level lies closely below the bottom of the conduction band. In the figure shown, below conduction band there are donor levels per of energy At low temperatures, small fraction of donors will be ionised and practically all donor levels will be filled with electrons.
Note: is called as ionisation energy of donors.

Carbon , germanium (Ge) and silicon (Si) are semiconductros. They lie in 1VA group of periodic table.


Thus, it is obvious that

Barrier potential of a p-n junction diode does not depend on diode design.

At room temperature, a few electrons in valence band acquire energy greater than the forbidden energy gap and move to conduction band. Hence, at room temperature a pure semiconductor behaves slightly as a conductor.