What is the derivation of built in voltage for a P-n junction?

In summary, the P-n junction built in voltage is the voltage generated when a P-type and N-type semiconductor material are brought into contact, creating a potential barrier between them. It is determined by the difference in energy levels between the materials and can be affected by factors such as dopants, temperature, and physical properties. The built in voltage determines the behavior of a diode and cannot be changed once the junction is created, but can be adjusted through doping and material selection.
  • #1
mertcan
344
6
hi, I am looking a derivation of built in voltage, but the only thing I could find is a statement: built in voltage can be derived from band diagram with the Fermi energy constant throughout the device, or from equating the drift current through the junction equal to the diffusion current. I need some mathematical demonstrations, I tried what the statement had said, but I really lack the mathematical demonstrations for derivation. Could you provide me with proof of it ? Thanks in advance...
 
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  • #2
Perhaps see second half of this vid..
 

1. What is a P-n junction built in voltage?

The P-n junction built in voltage is the voltage that is generated when a P-type and an N-type semiconductor material are brought into contact with each other. This voltage is a result of the diffusion of charge carriers across the junction, creating a potential barrier between the two materials.

2. How is the P-n junction built in voltage determined?

The P-n junction built in voltage is determined by the difference in energy levels between the valence band of the P-type material and the conduction band of the N-type material. This difference in energy levels creates the potential barrier and the resulting built in voltage.

3. What factors can affect the P-n junction built in voltage?

The P-n junction built in voltage can be affected by the type and concentration of dopants used in the P and N-type materials, the temperature, and the physical properties of the materials such as their band gap and crystal structure.

4. How does the P-n junction built in voltage affect the behavior of a diode?

The P-n junction built in voltage determines the direction of current flow in a diode. When the applied voltage is less than the built in voltage, the diode is in the "off" state and only a small leakage current flows. When the applied voltage is greater than the built in voltage, the diode is in the "on" state and a large current can flow through it.

5. Can the P-n junction built in voltage be changed?

The P-n junction built in voltage is a characteristic of the materials used and cannot be changed once the P-n junction is created. However, by varying the doping levels and the materials used, the built in voltage can be adjusted to meet specific device requirements.

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