Conductance noise in nano-patterned PbS quantum dot arrays

TL;DR

This study investigates large conductance noise in nanopatterned PbS quantum dot arrays, revealing temperature-dependent spectral behavior and linking noise characteristics to Levy statistics and percolation models.

Contribution

It introduces a novel analysis of conductance fluctuations in PbS quantum dot films, connecting noise behavior to Levy statistics and percolation theory.

Findings

Noise proportional to current under various conditions

Transition from power-law to telegraph noise at lower temperatures

Conductance fluctuations explained by Levy statistics and percolation models

Abstract

We report unexpectedly large noise in the current from nanopatterned PbS quantum dot films. The noise is proportional to the current when the latter is varied by changing the source-drain bias, gate voltage or temperature. The spectral density of the noise is given by a power law in frequency at room temperature, but remarkably, we observe a transition to telegraph noise at lower temperatures. The probability distribution of the off-times follows a power law, reminiscent of fluorescence blinking in colloidal quantum dot systems. Our results are understood simply in terms of conductance fluctuations in a quasi-one dimensional percolation path, and more rigorously in terms of a model in which charge through the film is transmitted in discrete time intervals, with the distribution of intervals completely described by Levy statistics.