Semiconductors are materials that have the conductivity between a conductor and an insulator. The most popular semiconductors are silicon and germanium. Semiconductors are of two types- Intrinsic semiconductors and Extrinsic semiconductors. Intrinsic semiconductors are pure semiconductors, they will not have any impurities added to it.
Extrinsic semiconductors are semiconductors with impurities. The conductivity of a semiconductor can be greatly improved by adding impurities. The process of adding impurity is called doping. Depending on the type of impurity added, the extrinsic semiconductor is further divided into two types – N-Type semiconductors and P-Type semiconductors. When a pentavalent impurity is added to the pure semiconductor it becomes an n-type semiconductor. In an n-type semiconductor, electrons are the majority carriers and holes are the minority carriers. When a trivalent impurity is added to the materials it becomes a p-type semiconductor. Holes are the majority carriers and electrons are the minority carriers in a p-type semiconductor.
4 Important Properties of Semiconductors
Property 1:The resistivity of a semiconductor is less than an insulator but higher than a conductor.
Property 2: Semiconductors show a negative temperature coefficient of resistance. In simple words, the resistance of the semiconductors decreases as the temperature increases and vice-versa.
Property 3: At zero kelvin, semiconductors behave as insulators. As the temperature is increased it works as a conductor
Property 4: The conductivity of the semiconductors increases when impurities are added. The process of adding impurities to semiconductors is called doping.
Semiconductors Video Lesson – Important Topics
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Semiconductors Important JEE Main Questions
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Frequently Asked Questions on Properties of Semiconductors
How does the resistance of a semiconductor vary with temperature?
The resistance of the semiconductor decreases exponentially with an increase in temperature.
What is doping of a semiconductor?
It is the process of adding impure atoms to an intrinsic semiconductor crystal to increase its electrical conductivity.
Mention two examples of extrinsic semiconductors.
n-type semiconductors
p-type semiconductors
What is a hole in a semiconductor?
The vacancy for an electron in the valence band is called a hole in a semiconductor. It acts as a positive charge of magnitude +e.
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