In: Physics
A trivalent impurity is added to silicon to create?
Answer- To create a P type semiconductor.
Explanation- silicon has four valance electrons. The conductivity is smaller than a conductor but greater than an inductor. Hence, it is called an intrinsic semiconductor. The reason it is called an intrinsic semiconductor is because the charge carriers required to conduct electricity are present internally. To increase the conductivity of an intrinsic semiconductor, We can add an impurity. This impurity can be pentavalent or trivalent. When trivalent atoms are added to silicon, they replace the silicon atoms at some places. As they have only three valance electrons, a hole is created for each trivalent atom. These holes participate in the process of conduction. As a hole is created due to absence of an electron, it is treated as a positive charge and hence the name P type extrinsic semiconductor. The reason is is called extrinsic is because charge carriers are edged externally.