Semiconductors are classified into two major types: Intrinsic Semiconductors and Extrinsic Semiconductors. This classification is based on their purity and the presence of impurities in the material. These different types of semiconductors are different properties and uses in the industry. Let us deep dive into their applications in real life.
Definition
Intrinsic Semiconductors: All these semiconductor substances occur in a pure form such as silicon or germanium, having electrical properties and, rather, those properties are intrinsic to the structure. The number of charge carriers is few, which can easily be excited with heat or electric field and can sit atop the conduction band and conduct electricity thereafter.
Extrinsic Semiconductors: Their properties can be changed through the toxicity, increasing impressive conductivity. By adding such specific atoms, phosphorus, or boron into the crystal lattice of the material of semiconductor, it could increase the number of charge carriers in such a way as to modify its electrical property. Examples are n type and p type semiconductors.
Types of Extrinsic Semiconductors
N-type: Such typing of doping is the carrying out the addition of elements’ such as phosphorous or arsenic under some semiconductor material such as silicon. These have one more electron than silicon atoms, thus making these elements donate electrons. Therefore, the introduction of these donor atoms in a crystal lattice of semiconductor will eventually release the free electrons into it and, thus, increase its electron concentration. This excess of negative charges makes the material an N-type semiconductor producing high conductivity through electrons.
P-type: Doping the surface with elements such as boron or gallium, which have one less electron than silicon, creates holes in the crystal lattice structure due to missing electrons. These acceptor atoms attract electrons from the neighborhood and create vacancies for fresh electrons who can come and replace them. Hence, there are now more sites available for the movement of electrons. This gives rise to a P-type semiconductor that will exhibit a greater overall concentration of holes. Therefore, it will have much greater hole conductance.
Applications
The different types of semiconductors have different applications. As intrinsic semiconductor is a pure one hence it is much less significant in the industrial process while extrinsic ones are important.
Solar cells: These devices work as semiconductors converting light energy into electrical energy through the photovoltaic effect.
Diodes: The p-n junction is formed when n-type and p-type semiconductors are connected. It is also called a rectifier because it allows current to pass in one direction only.
LEDs: These are light-emitting diodes that emit light from semiconductors when current flows through them.
Transistors: This is the basic building block of any digital circuit. The capability of this device to amplify or switch electronic signals is based on the semiconductor’s behavior.
Integrated Circuits (IC): These are made out of semiconductors and applied to virtually every modern electric appliance – be it a computer, smartphone, or medical device.
This line of learning will help you in the understanding of modern electronics and branches related to it. The study of intrinsic semiconductors exhibits the basic feature of semiconductors. While extrinsic semiconductors significantly improve electrical conductivity through doping, and the application serves to create hitherto highly efficient electronic devices like transistors, diodes, and LEDs.
