Carrier Accumulation in Momentum Space and Related Phenomenaνnder Intense Microwave Fieldsin Semiconductors

Abstract

Hot carrier dynamics under intense microwave fields isinvestigated theoretically for the case that the dominant scatteringprocess is optical phonon emission. When the microwave amplitude isappropriately large, an accumulated distribution of carriers inmomentum space appears. This distribution is a new type of dynamicpopulation inversion and is found to cause various peculiar dc fieldresponses, e.g. strong nonlinearity, negative differentialconductivity, and often negative response, under realistic physicalconditions.