Question
Distinguish between intrinsic and extrinsic semiconductors.
Solution
Intrinsic and extrinsic semiconductors can be differentiated as follows:
| Intrinsic | Extrinsic |
| 1. It is a pure semiconductor and no impurities are added to it. | 1. It is prepared by doping a small quantity of impurity atoms to the pure semiconducting material. |
| 2. Number of free electrons in conduction band is equal to the number of holes in valence band. | 2. Number of free electrons and holes vary in n-type and p-type semiconductor. There is excess of electrons in n-type and excess of holes in p-type. |
| 3. It's electrical conductivity is low. | 3. Electrical conductivity is high. |
| 4. Electrical conductivity is solely a function of temperature. | 4. Electrical conductivity depends upon temperature as well as on the quantity of dopants. |
