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Question
Answer the following giving reasons:
Impurities are added to intrinsic semiconductors.
Solution
To improve a semiconductor's electrical conductivity, impurities are added. Doping is the process of introducing impurities into semiconductors to improve their electrical conductivity; these impurities are referred to as intrinsic semiconductors.
RELATED QUESTIONS
In an intrinsic semiconductor the energy gap Egis 1.2 eV. Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at 600K and that at 300K? Assume that the temperature dependence of intrinsic carrier concentration niis given by
`"n"_"i" = "n"_0 exp(- "E"_"g"/(2"k"_"BT"))`
where n0 is a constant.
Let np and ne be the numbers of holes and conduction electrons in an extrinsic semiconductor.
Let nh and ne be the number of holes and conduction electrons respectively in a semiconductor. Then ______.
Explain the following term:
Intrinsic semiconductor
An intrinsic semiconductor has a resistivity of 0.50 Ω m at room temperature. Find the intrinsic carrier concentration if the mobilities of electrons and holes are 0.39 m2V-1S-1 and O.11 m2 v-1S-1 respectively:
Hole is ______.
Two crystals C1 and C2, made of pure silicon, are doped with arsenic and aluminium respectively.
Why is doping of intrinsic semiconductors necessary?
What is meant by doping of an intrinsic semiconductor?
Name the two types of atoms used for doping of Ge/Si.
- Assertion (A): The resistance of an intrinsic semiconductor decreases with an increase in its temperature.
- Reason (R): The number of conduction electrons as well as hole increase in an intrinsic semiconductor with the rise in its temperature.
