Transport and noise behavior of cascaded realistic tunnel barriers

We present a numerical investigation of the conductance and shot noise behavior of a cascade of realistic tunnel barriers, defined in a GaAs/AlGaAs heterostructure using negatively biased depletion gates. We show that, even in the presence of irregularities in the gate boundaries, strong localization dominates the transport through the device and consequently the shot noise suppression factor does not approach, increasing the number of barriers, the 1/3 limit characteristic of diffusive conductors