Question

Doping of silicon with arsenic leads to which type of semiconductor?

Answer 1

Hint: Arsenic is a chemical element in which there are five electrons in the outermost shell which are called valence electrons. Thus it is known as pentavalent element. When any pentavalent element is mixed with pure semiconductor, it forms a n-type semiconductor.

Complete answer:
The outermost shell of arsenic has five electrons and silicon has four electrons. These electrons are called valence electrons. Thus when silicon is doped with arsenic, then the four electrons of arsenic bonds with four electrons of silicon. The bond they form is covalent bond. One electron is still free which is responsible for the conduction.
As we know in a n-type semiconductor the majority charge carrier is electron and is also denoted by a positive ion which means deficiency holes. Therefore, an n-type semiconductor is formed.

Additional information:
Semiconductor is an electronic device. Its conductivity falls between conductor and insulator. Based on the bonding and valence electrons on the outermost shell it can be divided into two types- p-type semiconductor and n-type semiconductor. Both n-type and p-type semiconductors are extrinsic semiconductors because n-type is formed by doping of pentavalent impurity atoms and p-type by doping trivalent impurity atoms. Impurity atoms provide extra electrons for better conductivity.
Hence, doping of silicon with arsenic leads to formation of n-type semiconductor.

Note:
N-type semiconductor is formed when elements of the fifth group element of periodic table are doped. Electrons are the majority charge carrier in n-type semiconductor while holes as minority. In p-type semiconductor holes are the majority charge carriers and electrons are the minority charge carriers. Majority charge carriers play a significant role in semiconductors.