Exploring the Mechanisms of Electron-Hole Recombination

[Goodver]

I understand that electron-hole produced when certain energy in form of a photons applied to atom that electron can escape.

But, why would free electron fall back to the hole if it has more energy than energy on valence band? How recombination happens? Or it is because it collides with other electrons in this atom, than why don't they escape then?

thanks

 

[Simon Bridge]

Everything seeks the lower energy state - if one is available.

 

[Goodver]

Thanks Simon. Is there a mathematical or physical proof of this phenomena?

 

[DrDu]

It is all a question of entropy maximization. The energy will finally get distributed over a continuum of photon states due to the coupling of electric dipole moment to the electric field. The large number of photon states have a higher entropy.