Primary thermometry with nanoscale tunnel junctions

We have found current-voltage (I-V) and conductance (dI/dV) characteristics of arrays of nanoscale tunnel junctions between normal metal electrodes to exhibit suitable features for primary thermometry. The current through a uniform array depends on the ratio of the thermal energy k sub(B)T and the electrostatic charging energy E sub(c) of the islands between the junctions and is completely blocked by Coulomb repulsion at T identical with 0 and at small voltages eV/2 less than or equal to E sub(c). In the opposite limit, k sub(B)T > > E sub(c), the width of the conductance minimum scales linearly and universally with T and N, the number of tunnel junctions, and qualifies as a primary thermometer. The zero bias drop in the conductance is proportional to T super(-1) and can be used as a secondary thermometer. We will show with Monte Carlo simulations how background charge and nonuniformities of the array will affect the thermometer.