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प्रश्न
Distinguish between 'intrinsic' and 'extrinsic' semiconductors
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उत्तर
| Intrinsic Semiconductor | Extrinsic Semiconductor |
| It is a pure semiconductor material with no impurity atoms in it. | It is prepared by doping a small quantity of impurity atoms to the pure semiconductor. |
| The number of free electrons in the conduction band and the number of holes in valence band is exactly equal. | The number of free electrons and holes is never equal. There is an excess of electrons in n-type semiconductors and an excess of holes in p-type semiconductors. |
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संबंधित प्रश्न
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?
A donor impurity results in ______.
The electron and hole concentration in a semiconductor in thermal equilibrium is given by ______.
Explain the following term:
Extrinsic semiconductor
The conductivity of a semiconductor increases with increase in temperature because ______.
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.
Two crystals C1 and C2, made of pure silicon, are doped with arsenic and aluminium respectively.
Identify the extrinsic semiconductors so formed.
Name the extrinsic semiconductors formed when pure germanium is doped with a trivalent impurity. Draw the energy band diagram of extrinsic semiconductors so formed.
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?
