Scanning electron microscopy image of IDQD-SET device (left) and SET only device (right). Light regions are the oxidized active silicon while dark regions are the etched portions of the device. The IDQD is above, with no direct connections, while the single dot SET is below, connected to source and drain leads. was used for the IDQD control gate, and for the SET.
Stability diagram of SET response, differentiated with respect to , as control gates are varied. Experimental data with IDQD present (bottom left), with no IDQD (top left), simulated (bottom right), and simulated with no IDQD (top right), all plotted with the same gate scaling, although SET only measurement is offset. Results are representative of measurements performed on multiple devices. Grey scale is differentiated conductance, plotted to an arbitrary scale.
Device response to sweeping for a range of values of . Experimental (left) and simulated (right) data. Plots are offset for clarity. Note the rotation of axis in comparison to previous stability plots (Fig. 2). One SET oscillation is observed coming across the three IDQD oscillations. Fine oscillations are also observed in the experiment data.
Stability diagrams of the SET only with source potential on the vertical axis and gate on the horizontal. Experimental results are shown on the left and simulation of two quantum dots in series on the right. The top two plots are differentiated along the axis to more clearly show the larger Coulomb diamonds, while the bottom two plots are the same data sets differentiated along the axis to more clearly show the fine oscillations. Grey scale is differentiated conductance, plotted to an arbitrary scale.
Conduction response of the SET to sweeping IDQD gate from experiment (thin black) and simulation with cotunneling (thick red). Peaks have approximately the same form and width and correspond in gate potential as the experimental sweep is free from most other undesirable effects. Commonly the amplitude of the experimental response varies as tunnel barriers are tuned and other semiconductor SET effects become apparent reducing the accuracy of the fit.
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