Question

A pure semiconductor like $$\mathrm{Ge}$$ or $$\mathrm{Si}$$, when doped with a small amount of suitable impurity, becomes an extrinsic semiconductor. In thermal equilibrium, the electron and hole concentration in it are related to the concentration of intrinsic charge carriers. A p-type or n-type semiconductor can be converted into a p-n junction by doping it with suitable impurity. Two processes, diffusion and drift take place during formation of a p-n junction. A semiconductor diode is basically a p-n junction with metallic contacts provided at the ends for the application of an external voltage. A p-n junction diode allows currents to pass only in one direction when it is forward biased. Due to this property, a diode is widely used to rectify alternating voltages, in half-wave or full wave configuration.

Initially during the formation of a p-n junction ______.

पर्याय

• diffusion current is large and drift current is small.

• diffusion current is small and drift current is large.

• both the diffusion and the drift currents are large.

• both the diffusion and the drift currents are small.

Answer 1

Initially during the formation of a p-n junction diffusion current is large and drift current is small.

Explanation:

Initially, during the formation of the p-n junction, diffusion of majority charge carriers takes place from p·side to n-side, which constitutes the diffusion current. Thus, the diffusion current is large and the drift current is small.