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प्रश्न
Distinguish between intrinsic and extrinsic semiconductor. (Give any two points).
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उत्तर
| 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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संबंधित प्रश्न
Distinguish between 'intrinsic' and 'extrinsic' semiconductors
In a p-type semiconductos, which of the following statement is true:
The number of silicon atoms per m3 is 5 × 1028. This is doped simultaneously with 5 × 1022 atoms per m3 of Arsenic and 5 × 1020 per m3 atoms of Indium. Calculate the number of electrons and holes. Given that ni= 1.5 × 1016 m−3. Is the material n-type or p-type?
In a p-type semiconductor, the acceptor impurity produces an energy level ______
Semiconductors formed by doping germanium (Ge) with aluminium (Z = 13) and antimony (Z = 51) are ______.
In n-type semiconductor majority carriers and minority carriers are respectively ______.
State how a p-type semiconductor will be obtained from a pure crystal of a semiconductor.
Explain the following term:
Extrinsic semiconductor
The conductivity of a semiconductor increases with increase in temperature because ______.
Sn, C, and Si, Ge are all group XIV elements. Yet, Sn is a conductor, C is an insulator while Si and Ge are semiconductors. Why?
Suppose a ‘n’-type wafer is created by doping Si crystal having 5 × 1028 atoms/m3 with 1 ppm concentration of As. On the surface 200 ppm Boron is added to create ‘P’ region in this wafer. Considering n i = 1.5 × 1016 m–3, (i) Calculate the densities of the charge carriers in the n and p regions. (ii) Comment which charge carriers would contribute largely for the reverse saturation current when diode is reverse biased.
Name the extrinsic semiconductors formed when pure germanium is doped with a trivalent impurity. Draw the energy band diagram of extrinsic semiconductors so formed.
Name the extrinsic semiconductors formed when pure germanium is doped with a Pentavalent impurity. Draw the energy band diagram of extrinsic semiconductors so formed.
In an extrinsic semiconductor, the number density of holes is 4 × 1020 m-3. If the number density of intrinsic carriers is 1.2 × 1015 m-3, the number density of electrons in it is ______.
With an increase in the temperature, the electrical conductivity of a semiconductor ______.
What type of semiconductor is obtained when a crystal of silicon is doped with a trivalent element?
What is the process of adding a suitable impurity to increase a semiconductor's electrical conductivity called?
What is a doped semiconductor called?
What is the impurity added to a semiconductor called?
What is the valency of silicon and germanium?
Which type of dopant is antimony (Sb)?
Which type of dopant is indium (In)?
Which type of dopant is aluminium (Al)?
Why are different impurities added to semiconductors?
