A semiconductor is a material that can act as an insulator and a conductor based on certain conditions.
It acts as a conductor when its temperature is increased. Meanwhile, it functions as an insulator with a decrease in temperature.
Recall when your high school teacher taught you about atoms, the bedrock of elements. Semiconductors are the foundation of electronic components and devices.
The most common examples of semiconductors used today are germanium, silicon, and gallium arsenide. The carriers of the charge in a semiconductor are called the holes and electrons.
Types of Semiconductors
The functionality of a semiconductor depends on whether it is an intrinsic or extrinsic semiconductor.
Intrinsic semiconductor
This is a pure semiconductor. Like an atom existing in its original form, an intrinsic semiconductor stands alone without the presence of any other material. Germanium and silicon are examples of intrinsic semiconductors.
Extrinsic semiconductor
The “ex” in extrinsic semiconductors tells us that external materials have been added to this type of semiconductor.
In this case, impurities are added to this type of semiconductor through a process known as doping. This changes the original properties of the semiconductor.
Extrinsic semiconductors are divided into the P-type and N-type semiconductor.
A P-type semiconductor has more holes (positive charges) present. Here, the majority carriers are the holes while the minority carriers are the electrons (negative charges).
An N-type semiconductor has more electrons (negative charges) present. Here, the electrons are the majority carriers while the holes (positive charges) are the minority carriers.
Characteristics of Semiconductors
Temperature changes have a major role to play in the properties of semiconductors.
- Semiconductors can conduct or restrict the flow of electricity.
- The ability to dissipate and conduct heat is one of the characteristics of semiconductors.
- Semiconductors have a negative temperature coefficient of resistance due to their decrease in resistance when temperature increases.
- Semiconductors have a valence band and conduction band which play roles in the conduction of electricity.
- At absolute temperature (0K) semiconductors have no free electrons.
How a Semiconductor Functions as a Conductor
A semiconductor functions as a conductor when there is an increase in temperature in its surroundings.
Semiconductors have a valence band and a conduction band that determines where electrons and holes will be based on their temperature.
When there is a temperature rise, free electrons are spurred to move from the valence band into the conduction band.
This causes current flow, making the semiconductor a conductor of electricity.
How a Semiconductor Functions as an Insulator
We spoke about the conduction band and the valence band earlier. For a semiconductor to function as an insulator, there is no random movement of free electrons. This is because there is no change in temperature.
The free electrons are left in the valence band which results in no flow of current making the semiconductor an insulator.
Applications of Semiconductors
- Some materials that can emit light, e.g. Light Emitting Diodes (LEDs) are produced with semiconductors.
- Semiconductors are used in the production of electronic components like transistors and diodes.
- They are used in the manufacturing of microcontrollers and microprocessors used in the automation industry.
- Semiconductors are used in producing mobile phones, laptops, and other electrical appliances.
- Semiconductors play a huge role in the banking industry in the production of Automated Teller Machines (ATMs).
- They are also utilised in the making of sophisticated machines in the medical sector.
The benefits and use of semiconductors in the technology space are numerous as this sector cannot experience tremendous growth without its applications.
