Advertisements
Advertisements
प्रश्न
Distinguish between 'intrinsic' and 'extrinsic' semiconductors
Advertisements
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. |
APPEARS IN
संबंधित प्रश्न
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?
Electronic configuration of germanium is 2, 8, 18 and 4. To make it extrinsic semiconductor small quantity of antimony is added. The correct statement is ____________.
A donor impurity results in ______.
Explain the following term:
Extrinsic semiconductor
In a pure semiconductor crystal of Si, if antimony is added then what type of extrinsic semiconductor is obtained. Draw the energy band diagram of this extrinsic semiconductor so formed.
Why are elemental dopants for Silicon or Germanium usually chosen from group XIII or group XV?
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.
- Assertion (A): Putting the p-type semiconductor slab directly in physical contact with the n-type semiconductor slab cannot form the pn junction.
- Reason (R): The roughness at contact will be much more than inter atomic crystal spacing and continuous flow of charge carriers is not possible.
With an increase in the temperature, the electrical conductivity of a semiconductor ______.
