Upconversion of partition noise in semiconductors operating under periodic large-signal conditions

International audience; By means of Monte Carlo simulations of bulk semiconductors operating in the periodic large-signal regime, we show the existence of upconversion of hot-carrier partition noise associated with the fluctuations between different groups of carriers in momentum space, characterized by different dynamical properties. The signature of the upconversion phenomenon is predicted by an analytical model and confirmed by the spectral analysis of the instantaneous spectral density of velocity fluctuations. As applications, we investigate the cases in which the two groups of carriers pertain to a single band in the presence of strong low-temperature optical-phonon emission and to lowest- and upper-valley populations in compound semiconductors.