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 statements is related to the process of 'Doping'?

Increasing conductivity of semiconductors by adding small amount of impurity

The correct answer is option 2. Increasing conductivity of semiconductors by adding small amount of impurity.

Doping is a process used in semiconductor technology to intentionally introduce impurities into a semiconductor material. This process alters the electrical properties of the semiconductor, making it more suitable for specific applications in electronic devices like diodes, transistors, and integrated circuits.

Types of Impurities: Doping typically involves adding small amounts of specific impurity atoms to the semiconductor crystal lattice. These impurities are classified into two main types:

(i) Donor Impurities: These impurities introduce extra electrons into the semiconductor lattice, increasing its conductivity. Common donor impurities include elements like phosphorus, arsenic, and antimony.

(ii) Acceptor Impurities: These impurities create "holes" in the semiconductor lattice, effectively increasing the mobility of positive charge carriers (holes) and thus increasing conductivity. Common acceptor impurities include elements like boron, aluminum, and gallium.

Impact on Conductivity:

(i) Adding donor impurities increases the number of free electrons in the semiconductor, leading to an increase in conductivity. This process is called n-type doping.

(ii) Adding acceptor impurities increases the number of "holes" in the semiconductor, which act as positive charge carriers. This also leads to an increase in conductivity, especially when the holes are mobile. This process is called p-type doping.

Controlled Process:

Doping is a highly controlled process where the concentration and type of impurities are carefully chosen to achieve the desired electrical properties in the semiconductor.

The concentration of dopant atoms determines the level of conductivity enhancement or suppression in the semiconductor material. Higher dopant concentrations lead to higher conductivity.

Significance of Doping:

Doping allows semiconductor manufacturers to precisely tailor the electrical properties of semiconductor materials to meet the requirements of various electronic devices.

By strategically doping semiconductors, it is possible to create materials with specific conductivities, carrier mobilities, and other electrical characteristics, enabling the fabrication of high-performance electronic components.

In summary, doping is the deliberate introduction of impurities into semiconductor materials to modify their electrical properties. By controlling the type and concentration of dopants, semiconductor manufacturers can manipulate conductivity and other key characteristics, enabling the production of advanced electronic devices.