DC field response of hot carriers under circular polarized intense microwave fields in semiconductors limited to two-dimension

Abstract

Hot carrier dynamics under intense microwave fields is investigated theoretically for the case that the dominant scattering process is optical phonon emission, and the carrier motion limited to two-dimension is intrinsic. When the microwave amplitude is appropriately large, an accumulated distribution of carriers in momentum space appears. The system of this motion is found to cause various peculiar DC fields response, e.g. strong non-linearity, negative differential conductivity, and negative response, under realistic physical conditions [J. Phys. Soc. Jpn 68 (1995) 2994]. In the proper strength of microwave and DC electric fields, especially in the case of circular polarized microwave fields, the carrier motions are converged to some trajectories in momentum space [Proceeding of 25th International Conference on the Physics of Semiconductors, 2001]. Resultantly a new type of accumulated distribution of carriers in momentum space appears. This situation is a sort of population inversion of carriers and causes various phenomena including a negative differential conductivity and/or a negative response appeared in the drift velocity vs. DC field relation not found in the case of linear polarized microwave fields. The carrier motion restricted in two-dimensional band may be essential and effective for these properties.