As per the observations of band theory, the distinctions between conductors, insulators, and semiconductors give a better idea of the energy and electrons that are present with a material. The conduction band is one such important concept to be covered concerning this theory. Conduction band can be defined as the band of electron orbitals that can skip from a level with low energy to a high energy level upon getting excited. When electrons are present in these orbitals, they possess enough energy to navigate freely. This shift of electrons gives rise to electric current to form a conduction band in semiconductors.
In this article, we will discuss similar aspects and answer one fundamental question – What is a conduction band?
Meaning of conduction band
Let us now focus on our question – What is a Conduction Band?
Conduction band refers to the energy band that is composed of free electrons that are meant to make the process of conduction possible. Due to the role of electrons, it would not be wrong to say that the same purpose is the reason why it has been named as a conduction band in the first place.
Electrons that shift from the valence band as they experience external force attend higher energy bands to support conduction. The conduction band is usually located above the higher energy state level, which makes it important for electrons to need a large amount of excitation energy to stay in the conduction band.
Similar to the case of conductors, the conduction band and valence band overlap, which makes electrons present in the lower energy band initiate easy movement to the conduction band. However, in the case of semiconductors, there is a sufficient energy gap between conduction bands and valence bands, which requires the external energy forces to leave valence electrons free.
Difference between the conduction band and valence band
Conduction band and valence band are two significant yet different classes of energy levels that differ based on the amount of energy.
Below are several important differences between valence and conduction band –
- On the energy level, the conduction band is located above the Fermi level in the energy band, while the valence band is present right below the level.
- The valence band moves out of the electrons when external excitement is provided. However, electrons usually proceed towards the conduction band due to the force of external energy.
- In the case of the valence band, the electron density is comparatively higher than the conduction band.
- Normally, the valence band is typically either completely or partially filled at a given room temperature. On the other hand, the conduction band is likely to be empty or partially repeated at the same room temperature.
- The conduction band has a comparatively higher energy level when compared to the valence band, which has a relatively lower energy state.
- In the case of the conduction band, the nucleus of an atom usually exerts little to know force on the electrons, which is not the case with the valence band. In the case of the valence band, the nucleus of an atom exerts immense pressure on the electrons.
Conduction band in semiconductors
Have you ever wondered, when it comes to semiconductors, what is the significance of a conduction band? The examples illustrated below may help!
In the case of semiconductors, both the valence band and conduction band remain close to the Fermi level. It helps identify the electrical conductivity level of a given solid material.
In addition to this, the conduction band is probably at the lowest range of empty electronics states in the case of semiconductors and electrical insulators. If this situation is presented on a graph of the electronic band structure of the given material, the variance band would be probably located below the Fermi level while the conduction band will be on the opposite side.
For instance, if we ionise radiation, the material will probably possess a higher potential as an electronic device material. On the other hand, materials such as diamond and germanium will probably have a major difference in their band gap energy, which requires the setup to operate at different temperatures.
With reference to the discussion we had above, it can be concluded that the conduction band is an important topic to be covered. It not only helps us to understand the importance of various aspects and concepts related to it but also its relevance in terms of applicability in semiconductors, conductors, and insulators.
As a classification of energy levels that are determined by a certain amount of energy, electrons held by conduction bands are the major factors behind several materials that facilitate conduction. This presents a scenario where the two things are related and depend on each other.