# Why the mass action law is not valid for very low temperatures?

1. ### Ger3

2
why the mass action law is not valid for very low temperatures??

Hi,
In the context of semiconductors, I was asked why the mass action law is not valid for very low temperatures. I thought that it was valid, since for very low temperature it holds the non-degeneracy condition $$E_g >> k_B T$$ (I think so...). But maybe for some other reason it breaks. Does someone know why??? Thanks!

Last edited: Dec 5, 2013
2. ### hjelmgart

127
I am not sure, but perhaps it is related to the behavior of electrons in the lattice, which becomes more prominent at lower temperatures (or low energies)?