Subbands in semiconductor band structure

In summary, the band structure of a semiconductor is a graphical representation of the energy levels of electrons in the material, consisting of conduction and valence bands separated by an energy gap, as well as forbidden bands that affect the material's properties and can be altered by external factors.
  • #1
guedman
4
1
i would like to know all the details about the band structure in a semiconductor and in particular
what we call :
upload_2015-3-27_17-26-14.png

yours sincerly

guedman
 
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  • #2
The band structure of a semiconductor is a description of the energy levels of electrons in the material. It is generally represented graphically, with the vertical axis being energy and the horizontal axis being wavevector. The band structure consists of regions known as conduction and valence bands, separated by an energy gap. In the conduction band, electrons can move freely and are responsible for electrical conductivity. In the valence band, electrons are bound to atoms and are responsible for the material’s insulating properties.The band structure also contains regions known as forbidden bands, which are areas where electrons cannot exist. These bands play an important role in the operation of semiconductor devices such as transistors and diodes. The band structure of a semiconductor is determined by its composition and structure, and can be modified by applying a voltage or temperature.
 

1. What are subbands in semiconductor band structure?

Subbands in semiconductor band structure refer to the quantized energy states that exist within the conduction and valence bands of a semiconductor material. These subbands are formed due to the periodic potential created by the crystal lattice of the material.

2. How are subbands formed in semiconductor band structure?

Subbands are formed through the process of quantum confinement, where the electrons in the material are confined to a smaller space due to the presence of a potential barrier. This results in the energy levels of the electrons becoming discrete, creating subbands within the conduction and valence bands.

3. What is the significance of subbands in semiconductor band structure?

The presence of subbands in semiconductor band structure plays a crucial role in determining the electronic properties of the material. The number and distribution of subbands can affect the conductivity, carrier mobility, and other important characteristics of the material.

4. How are subbands affected by external factors?

External factors such as temperature, strain, and electric fields can influence the formation and behavior of subbands in semiconductor band structure. For example, an increase in temperature can lead to thermal excitation of electrons into higher subbands, while the application of strain can shift the energy levels of the subbands.

5. Can subbands be engineered in semiconductor materials?

Yes, subbands can be engineered in semiconductor materials through various techniques such as quantum well structures, quantum dots, and strained layers. These methods involve controlling the dimensions and composition of the material to manipulate the formation and energy levels of the subbands for specific applications.

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