Current shot noise characteristics in resonant tunneling step-barrier structures

Abstract

The current shot noise behavior in resonant tunneling step-barrier structures is investigated based on the standard scattering approach. The relations between the shot noise and the applied bias, the Fermi energies, as well as the structural parameters are revealed. By making a comparison of resonant tunneling among single square-barrier structures, step-barrier structures, and double-barrier structures, the distinct curve shape and extremely large suppression of the shot noise are revealed in the step-barrier structures. It is shown that in the step-barrier structures, a valley of the shot noise occurs at the bias where the current peak locates and the Fano factor drops down to minimum at the valley bottom. It is also found that the shot noise suppression is larger for larger chemical potentials and maximal suppression with the Fano factor close to 0.05 appears at a particular structure configuration. These results are helpful to improve the signal-to-noise ratio of quantum devices based on resonant-tunneling structures.