FLUCTUATIONS AND ULTRAFAST PROCESSES IN VOLTAGE-BIASED TWO-DIMENSIONAL CHANNELS

Hot-electron fluctuation techniques were developed for experimental investigation of picosecond and subpicosecond electronic and phononic processes in voltage-biased 2DEG channels of interest for microwave low-noise and high-power transistors. Examples illustrate real-space transfer, hot-electron energy relaxation, and occupancy relaxation of hot-phonon modes. The pioneering results on hot-electron energy relaxation and hot-phonon lifetime are confirmed by time-resolved response experiments. The fluctuation technique for measuring the hot-phonon lifetime as a function of the hot-phonon temperature is unique, no datum has been reported for comparison as yet.