Coupled Langevin equations for hot-carrier transport in semiconductors
Using the results of a Monte Carlo simulation, a set of coupled Langevin equations for the relevant variables (the fraction of free carriers, their velocity and their energy) is constructed and applied to the case of p-type Si at 77 K under hot-carrier conditions. The relaxation and generalized-diffusion matrices, describing dissipation and fluctuations respectively, are evaluated. From these results, the authors derive a model spectral density of current fluctuations which is applied to interpret experimental noise spectra.