Engineering Physics

8.15 p-n junction biasing

The free carriers can be made to cross the junction by increasing their kinetic energy by some external means. The kinetic energy (K.E) of carriers can be increased by applying electic potential externally across the junction. As the electric potential across the junction increases, the K.E of free electrons also increases. When the K.E of carriers attain the energy of the potential barrier (eV_B) between p-region and n-region, the carriers start crossing the junction.

Suppose the positive terminal of a battery is connected to the p-type and the negative terminal to the n-type of a p-n junction, a large current flows through the junction, and the p-n junction is said to be forward biased. If terminals of battery are ...