Density of holes in valence band

In summary, when electrons leave the valence band and jump to the conduction band, the density of remaining holes is equal to the number of electrons that have migrated. This means that if 2.5 electrons/cm^3 leave the valence band, the density of remaining holes will also be 2.5 holes/cm^3. The mass of the electron does not affect this relationship, as the effective mass of electrons and holes does not change the number of particles.
  • #1
Caulfield
11
0
When electrons leave the valence band and jump over the gap to the conduction band, what is the density of the remaining holes?

If 2.5 electrons/cm^3 leave the VB to the CB, will the density of remaining holes be 2.5 electrons/cm^3?

To me it is logical, but I am wondering if mass of electron can change it. In crystal electron has mass mn*, and in CB, that mass is m0.
 
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  • #2
1 electron always leaves one hole. If you did not have holes before and 2.5 electrons/cm^3 migrate, then you'll have 2.5 holes/cm^3. The effective mass of electrons and holes does not matter for their number.
 

Related to Density of holes in valence band

1. What is the definition of density of holes in valence band?

Density of holes in valence band refers to the number of electron vacancies present in the valence band of a material. It is a measure of the number of available energy states for electrons to move into.

2. How is the density of holes in valence band calculated?

The density of holes in valence band can be calculated by using the equation: p = Nv x exp(-Eg/kT), where p is the density of holes, Nv is the effective density of states in the valence band, Eg is the band gap energy, k is Boltzmann's constant, and T is the temperature in Kelvin.

3. What factors affect the density of holes in valence band?

The density of holes in valence band is affected by various factors such as temperature, band gap energy, and the effective density of states in the valence band. It may also be influenced by the type of material, its crystal structure, and any impurities present.

4. How does the density of holes in valence band impact the properties of a material?

The density of holes in valence band plays a crucial role in determining the electrical and optical properties of a material. It affects the conductivity, carrier mobility, and absorption of light in the material. A higher density of holes usually leads to better conductivity and absorption of light.

5. Can the density of holes in valence band be controlled or manipulated?

Yes, the density of holes in valence band can be controlled and manipulated by altering the factors that affect it, such as temperature, band gap energy, and impurity levels. This can be done through various methods such as doping, annealing, and changing the crystal structure of the material.

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