Reverse Biasing of pn junction diode
Reverse Biasing of pn junction diode
When the p-side of the junction diode is connected to low potential and the n-side of the junction diode is connected to high potential, the junction diode is said to be in reverse bias.
The direction of applied voltage is the same as the direction of barrier potential. The depletion region thickness increases due to the change in the electric field (due to the resistance of the depletion layer increasing) and the effective barrier potential is (VB + V).
When the diode is in reverse bias, the electric field direction of the junction is such that a small voltage is sufficient to sweep the minority carriers from one side of the junction to the other side of the junction. This drifting of minority charge carriers gives rise to a current which is almost independent of the applied voltage and is called reverse saturation current. This current is dependent on the concentration of the minority carrier on either side of the junction. The value of reverse voltage across the pn-junction at which reverse current increases sharply is known as breakdown voltage (Vbr).