Question

The valence of an impurity added to germanium crystal in order to convert it into a P− type semiconductor is
A. 6
B. 5
C. 4
D. 3

Answer 1

Hint:Trivalent impurity atom i.e., atoms having 3 valence electrons, when added to a pure semiconductor, produce additional free electrons which are donor electrons to the semiconductor.

Complete step by step solution:
1.Doping is the addition of impurities to intrinsic semiconductors in order to change their characteristics.
2.To dope silicon and germanium, typically trivalent and pentavalent elements are utilised.
3. When a trivalent impurity is used to dope an intrinsic semiconductor, the result is a P-Type semiconductor.
4.A p-type semiconductor results from implanting a dopant atom.
5.The answer is option D -3 valence electrons.

Hence, the correct option is D.

Additional information: A semiconductor material has electrical conductivity that is in the range of an insulator like glass and a conductor like metallic copper. As the temperature increases, its resistivity decreases; metals respond in the reverse way.
Diodes, transistors, and integrated circuits are just a few of the different types of electronic devices that are made using semiconductors.

Properties of semiconductor:
1. A semiconductor has a higher resistivity than a conductor but a lower resistance than an insulator.
2. The temperature coefficient of resistance for semiconductors is negative. In layman's terms, semiconductor resistance lowers as temperature rises and vice versa.
3. Semiconductors act as insulators when the temperature is 0 kelvin. It functions as a conductor when the temperature rises.
4. When impurities are added, the conductivity of the semiconductors rises. Doping is the process of introducing impurities into semiconductors.

Note: An inherent semiconductor doped with boron (B) or indium is known as a p-type semiconductor. Boron from Group III has three valence electrons, while silicon from Group IV has four.