i. When a diode is connected in a zero bias condition, no external potential energy is applied to the p-n junction.
ii. The potential barrier that exists in a junction prevents the diffusion of any more majority carriers across it. However, some minority carriers (few free electrons in the p-region and few holes in the n-region) drift across the junction.
iii. An equilibrium is established when the majority carriers are equal in number (ne = nh) and both moving in opposite directions. The net current flowing across the junction is zero. This is a state of‘ dynamic equilibrium’.
iv. The minority carriers are continuously generated due to thermal energy.
v. When the temperature of the p-n junction is raised, this state of equilibrium is changed.
vi. This results in generating more minority carriers and an increase in the leakage current. An electric current, however, cannot flow through the diode because it is not connected in any electric circuit
