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Question
Distinguish between intrinsic and extrinsic semiconductor. (Give any two points).
Solution
| Intrinsic semiconductors | Extrinsic semiconductors | |
| 1) | Semiconductor in the pure form is known as intrinsic semiconductor. |
The semiconductor, resulting from mixing of impurity in it, is known as extrinsic semiconductor |
| 2) | Their conductivity is low | Their conductivity is high. |
| 3) | Its electrical conductivity is a function of temperature alone. |
Its electrical conductivity depends upon the temperature as well as on the quantity of impurity atoms doped in the structure |
| 4) | The number of free electrons in conduction band is equal to the number of holes in valence band. |
In these semiconductors, number of free electrons and number of holes are unequal |
| 5) | These are not practically used | These are practically used |
| 6) | In these, the Fermi energy level lies in the middle of valence band and conduction band. | In these, the Fermi energy level shifts towards valence or conduction energy band. |
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