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प्रश्न
Two crystals C1 and C2, made of pure silicon, are doped with arsenic and aluminium respectively.
Identify the extrinsic semiconductors so formed.
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उत्तर
Arsenic is pentavalent. So, C1 doped with arsenic will form an n-type semiconductor.
Aluminium is trivalent. So, C2 doped with aluminium will form a p-type semiconductor.
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संबंधित प्रश्न
Distinguish between 'intrinsic' and 'extrinsic' semiconductors
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A donor impurity results in ______.
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In p-type semiconductor, ______.
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.
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 ______.
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- Reason (R): The roughness at contact will be much more than inter atomic crystal spacing and continuous flow of charge carriers is not possible.
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