Solids exhibit an amazing range of electrical conductivities, extending over 27 orders of magnitude ranging from 10^–20 to 10⁷ ohm^–1 m^–1.

Solids can be classified into three types on the basis of their conductivities.

(i) Conductors: The solids with conductivities ranging between 10⁴ to 10⁷ ohm^–1m^–1 are called conductors. Metals have conductivities in the order of 10⁷ ohm^–1m^–1 are good conductors.

(ii) Insulators: These are the solids with very low conductivities ranging between 10^–20 to 10^–10 ohm^–1m^–1.

(iii) Semiconductors: These are the solids with conductivities in the intermediate range from 10^–6 to 10⁴ ohm^–1m^–1.

Which of the following can act as electron rich impurity for silicon semiconductors?

Group 15 element

The correct answer is option 1. Group 15 element.

In semiconductor physics, the process of doping is crucial for controlling the electrical properties of semiconductor materials like silicon. Doping involves intentionally introducing impurities into a semiconductor crystal to alter its conductivity.

Electron Rich Impurities

An electron-rich impurity introduces extra electrons into the semiconductor lattice. This excess of electrons increases the concentration of charge carriers (electrons) in the material, enhancing its conductivity.

Group 15 Elements

Group 15 elements, also known as the nitrogen group, include phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). These elements have five valence electrons in their outermost shell.

When a Group 15 element is introduced as an impurity into a semiconductor crystal, such as silicon (Si), it substitutes some of the silicon atoms in the crystal lattice. Since Group 15 elements have one more valence electron than silicon, they provide an extra electron to the semiconductor lattice.

The extra electron provided by the Group 15 impurity becomes a free electron available for conduction.

These excess electrons significantly increase the concentration of charge carriers in the semiconductor material, making it conductive. The semiconductor doped with Group 15 elements becomes an n-type semiconductor, where "n" stands for negative charge carriers (electrons).

In summary, Group 15 elements, such as phosphorus, arsenic, and antimony, act as electron-rich impurities when doped into silicon semiconductors. They contribute extra electrons to the semiconductor lattice, enhancing its conductivity and turning it into an n-type semiconductor