Percolating through networks of random thresholds: Finite temperature electron tunneling in metal nanocrystal arrays

TL;DR

This paper studies how temperature influences electron tunneling in networks of gold nanocrystals, revealing a crossover temperature where conduction behavior shifts from nonlinear to linear with increasing temperature.

Contribution

It introduces a model explaining temperature-dependent tunneling thresholds and predicts the crossover temperature in nanocrystal arrays.

Findings

Threshold voltage decreases linearly with temperature below T*

Above T*, the threshold vanishes and conductance increases rapidly

The model accurately predicts the crossover temperature T*

Abstract

We investigate how temperature affects transport through large networks of nonlinear conductances with distributed thresholds. In monolayers of weakly-coupled gold nanocrystals, quenched charge disorder produces a range of local thresholds for the onset of electron tunneling. Our measurements delineate two regimes separated by a cross-over temperature $T^*$. Up to $T^*$ the nonlinear zero-temperature shape of the current-voltage curves survives, but with a threshold voltage for conduction that decreases linearly with temperature. Above $T^*$ the threshold vanishes and the low-bias conductance increases rapidly with temperature. We develop a model that accounts for these findings and predicts $T^*$.