Upconversion of intergroup hot-carrier noise in semiconductors operating under periodic large-signal conditions

By means of Monte Carlo simulations of carrier transport in bulk semi conductors operating under periodic large-signal regime, we show the existence of upconversion of low-frequency hot-carrier noise associated with velocity fluctuations into a high-frequency region centered around the fundamental frequency of the large-signal. It is found that the upconverted noise corresponds to long-time fluctuations of relative populations of two groups of carriers characterized by different dynamical properties in momentum space. The appearance of the upconversion process is related to kinks of the static velocity-field characteristic when the dynamics of carrier motion in momentum space undergoes drastic changes.