Generation-recombination and thermal noise coupling in the drift-diffusion model

In the framework of the drift-diffusion approximation in semiconductors, an expression for the autocorrelation of the current noise is derived that self-consistently leads to the well-known expression for thermal noise without the need of adding a proper stochastic term to the current density. The autocorrelation is derived on the basis of a single-particle model of the carrier motion. In the presence of generation-recombination processes, an interaction white noise term appears in the power spectral density of the current noise due to the coupling between thermal and generation-recombination noise. The proposed model is also applicable to the study of the contribution of diffusion to noise in nonstationary processes.