Generalization of Nyquist-Einstein relationship to conditions far from equilibrium in nondegenerate semiconductors

Abstract
We present for the first time an exact decomposition procedure for the current spectral density in the presence of generation-recombination mechanisms. The correct microscopic analysis shows that the cross correlation between velocity and number fluctuations plays an essential role in the noise properties of semiconductors. This, in turn, yields a generalization of the Nyquist-Einstein relationship in the presence of an applied electric field when statistical generation and recombination mechanisms are active.