Properties of Semiconductors

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.