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

 P: 2 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!