Question

During reverse bias of the diode there is a small current of the order of micro ampere due to _____.

Answer 1

We are looking for the charge carrier in this case. If a diode is reverse biased, the voltage at the cathode is higher than that at the anode.

Complete step by step answer:
In a standard diode, forward biasing occurs when the voltage across a diode permits the natural flow of current, whereas reverse biasing denotes a voltage across the diode in the opposite direction. In Reverse biased diode due to thermal energy a small number of minority charge Carriers produced in the depletion region
Thus, the correct answer is minority charge carrier.

Additional Information: If we were to make electrical connections at the ends of both the N-type and the P-type materials and then connect them to a battery source, an additional energy source now exists to overcome the potential barrier. The effect of adding this additional energy source results in the free electrons being able to cross the depletion region from one side to the other. The behaviour of the PN junction with regards to the potential barrier’s width produces an asymmetrical conducting two terminal device, better known as the PN Junction Diode. A PN Junction Diode is one of the simplest semiconductor devices around, and which has the characteristic of passing current in only one direction only. However, unlike a resistor, a diode does not behave linearly with respect to the applied voltage as the diode has an exponential current-voltage relationship and therefore we cannot describe its operation by simply using an equation such as Ohm’s law.

Note: If you need a current one-way valve, the forward and reverse bias behaviour in diodes makes them the perfect component for the job. Zener and avalanche diodes expand this ability even further. When this bias is reversed, the Zener diode allows current flow at a certain carefully controlled voltage level.