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Most common types of semiconductors

When an electrician is going to do an electrical installation, he usually uses cables and conductive wires. These conducting wires are so called because they are good conductors of electricity: they have free electrons. Most of the time, these cables are made of copper, which is a great conductor of electricity and a non-expensive material. Other materials are classified as insulating because they do not have free electrons. So they are not meant to be used to conduct electricity. We have several examples of materials with these characteristics: Styrofoam, wood and rubber. For more information kindly visit this link 

Conductors and insulators are well known. Just remember that we put on shoes and slippers with rubber soles, which provide insulation from the floor. What many may not know is that there is a third category of materials. They are those who are in an intermediate situation (in one situation they are insulating and in another they are conductors). These materials are classified as semiconductors.

The most used semiconductors

Silicon and germanium are the most used semiconductors on the market. Let’s take silicon as an example. In a solid state, it is always bound to four other silicon atoms. In each bond, two electrons are shared. Silicon is an insulator, as there are no free electrons left. This state can be modified by increasing the temperature of the silicon. This causes some electrons to escape from these bonds, resulting in a decrease in resistivity. The higher the temperature is, the greater the amount of free electrons will be, and, therefore, the lower the resistivity.

Contamination or doping process

Another way to decrease the resistance of the silicon crystal is to uniformly introduce impurities, which can be arsenic or boron atoms. When we introduce arsenic, the semiconductor is called an n-type semiconductor. When boron is introduced, it is called a p-type semiconductor. In the predefined proportion of an atom in a million, arsenic atoms are uniformly introduced into the silicon crystal. Arsenic tends to make five bonds with neighboring atoms, while silicon makes four bonds. The result is that we will have a free electron that can move through the crystal. This means that we will have negative charge carriers. That’s why it’s called an n-type.

Semiconductor type p 

Instead of arsenic, boron atoms will now be introduced in the same proportion as before. This element tends to establish three bonds with neighboring atoms and, when it is introduced into the silicon crystal, an electron is missing. If this crystal is subjected to a potential difference, the electron that is the most in the silicon atom will move to the side with the greatest potential, while the gap will move to the side with the least potential. In short: this gap behaves as if it were a positive charge, and so this semiconductor is called a p-type semiconductor. The great advantage of using semiconductors is that with them we can control the number of positive and negative charges per unit of volume. These materials are widely used in a component present in electronic devices, such as television and radio.

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