Energy Band Diagram Of Intrinsic Semiconductor

A semiconductor is a material having conductivity greater than an insulator and lesser than a metal. The main property of semiconductors is the bandgap, a range of forbidden energies within the material’s electronic structure. Semiconductors are divided into (1)Intrinsic semiconductors and (2)Extrinsic semiconductors. The most common intrinsic semiconductor elements are germanium (Ge) and silicon (Si). They have four electrons in their valence shell (tetravalent). At absolute zero temperature, they form a covalent bond with the atom. Extrinsic semiconductors have no intrinsic properties like Intrinsic semiconductors.’ p-type and n-type semiconductors are examples of Extrinsic semiconductors.

P-type Semiconductors

There is a special technique in the process of preparation of p-type semiconductors. P-type semiconductors are prepared by doping a pure semiconductor with a trivalent impurity (B, Al, In, Ga). The impurity’s three valence electrons bond with three of the semiconductor’s four valence electrons. Electrons are mostly transported with the help of positively charged ‘holes’ in this type of semiconductor. Through this key concept, one can answer ‘what is a p-type semiconductor?’. 

Now, the next step is all about giving p-type semiconductor examples. Here it is-Boron doped Silicon, Aluminium doped Silicon, Boron doped Germanium, etc., are examples of p-type semiconductors.  P-type semiconductors are neutral.In this case,I = Ih and nh >> ne.Holes are the majority, and electrons are the minority here in terms of numbers.

Properties of p-type semiconductors

1. The p-type semiconductors are impure or extrinsic. Here trivalent atoms are doped with intrinsic semiconductors to produce p-type semiconductors.
2. In p-type semiconductors, the concentration of holes is greater than the concentration of electrons which implies holes are the majority carriers in p-type semiconductors.
3. The movement of holes inside them causes the main current flow in p-type semiconductors.
4. p-type semiconductors show greater conductivity than pure or intrinsic semiconductors.
5. At very high temperatures, a p-type semiconductor behaves like an intrinsic semiconductor.

Conduction through P-type Semiconductor

In p-type semiconductors, holes can be created through the trivalent impurity. The majority of the charge carriers available within the valence band are directed in the direction of the -Ve terminal. When the holes do the flowing current through the crystal, this conductivity is called p-type or positive conductivity. In this conductivity type, the outer electrons can flow from one covalent to another. The conductivity of the p-type is almost less than the n-type semiconductor. The existing electrons within the conduction band of the n-type semiconductor are more variable when compared to holes in the valence band of a p-type semiconductor. The hole’s mobility is lesser when they are more bound toward the nucleus. The electron-hole formation can be done even at room temperature. These electrons will be available in small quantities and carry less current within these semiconductors.

Manufacturing of p-type Semiconductors

P-type semiconductors are manufactured by doping the pure semiconductor material. The amount of impurity added is very small compared to the number of semiconductors. The exact characteristics of the semiconductor can be changed by changing the amount of ‘dopant’ which is added. In p-type semiconductors, the number of holes is much greater than that of thermally produced electrons.

Application in Everyday life

Semiconductors have a lot of applications in today’s modern world and our day-to-day life. They are used to manufacture temperature sensors, microchips which are widely used in self-driving cars, small scale electronic devices,3D printers, which are used to do various 3-D model making and experiments, calculators to do different simple and complex calculations, solar panels for harvesting energy from sunlight, computers and other electronic devices. They are also used to make transistors, MOSFET, which is used as switches in various electrical circuits.

Application in Industry

There are a lot of applications of semiconductors in the industry. Semiconductors have special physical and chemical properties. Such special properties allow them to do different functions like- transistors, LEDs, and solar cells, which are technological miracles of today’s era. Transistors, other controlling devices made of semiconductor materials, create the microprocessor, which is used to power the operation of various space ships, trains, robots, and other devices.

Conclusion 

 From computers, mobile phones, and tablets to self-driving cars, we and our future are surrounded by semiconductors and their applications. A semiconductor with a narrow energy gap possesses rare properties that open up wide varieties of applications in the practical field of science. The usefulness of these materials rests on the extremely high sensitivity of their band structure to external influences like- magnetic field, electromagnetic radiation, pressure temperature, and impurities. In summary, we have represented p-type and n-type semiconductor, p-type semiconductor examples, their manufacturing, their application in everyday life, industry, etc., which will help us develop in the semiconductor field.