Transition from valence band to conduction at T above 0K + procedure

[itsbiprangshu]

we know that at temperature above 0K, in semiconductor some electron collecting sufficient energy fron surroundings to cross the band gap, placed in the conduction band. But what's the actual procedure to make the transition. I mean to say is it direct absorption of IR photons or by some other means. If it is direct absorption of IR photons, then how the transition occurs in the semiconductors having band gap energy higher than IR photons. what's the actual procedure.

 

[Defennder]

It should be by absorption of phonons.

 

[charng]

The transition from the valence band to the conduction band in semiconductors at temperatures above 0K occurs through a process known as thermal excitation. This means that as the temperature increases, some electrons in the valence band gain enough thermal energy to overcome the band gap and move into the conduction band.

This process can also occur through the absorption of photons, including infrared (IR) photons. When an electron absorbs a photon, it gains energy and can move from the valence band to the conduction band. However, this process is not limited to just IR photons. Electrons can also absorb photons with higher energies, such as visible or ultraviolet light, depending on the band gap energy of the semiconductor.

In semiconductors with band gap energies higher than IR photons, the transition can still occur through the absorption of these photons. This is because the electrons in the valence band only need to gain enough energy to overcome the band gap, not necessarily exactly the energy of the photon being absorbed. The excess energy is then dissipated as heat.

Overall, the actual procedure for the transition from the valence band to the conduction band at temperatures above 0K involves a combination of thermal excitation and photon absorption. The specific proportions of each process may vary depending on the temperature and the band gap energy of the semiconductor.