Charge transport in monolayers of metal nanoparticles

TL;DR

This paper develops an analytical and simulation-based theory to understand charge transport mechanisms and temperature effects in monolayer nanoparticle films, which are crucial for nanoelectronic applications.

Contribution

It introduces a new analytical model backed by Monte-Carlo simulations to analyze charge transport in 2D nanoparticle arrays with different morphologies and disorder levels.

Findings

Charge transport is influenced by array morphology and temperature.

Ordered arrays exhibit non-linear, symmetric I-V characteristics.

The model predicts temperature-dependent electron dynamics.

Abstract

Two-dimensional (2D) nanoparticle films are a new class of materials with interesting physical properties and applications ranging from nanoelectronics to sensing and photonics. The importance of conducting nanoparticle films makes the fundamental understanding of their charge transport extremely important for materials and process design. Various hopping and transport mechanisms have been proposed and the nanoparticle monolayer is consistent with the electrical equivalent RC circuit, but their theoretical methods are limited to the model of the single electron tunneling between capacitively coupled nanoparticles with a characteristic time constant RC and the conductivity of thin film is the experimental conductivity, which cannot be deduced from these theoretical models. It is also unclear that how the specific process of electron transpot is affected by temperature. So, nowadays the electron dynamics of thin film cannot be understood fundamentally. Here, we develop an analytical theory based on the model of Sommerfeld, backed up by Monte-Carlo simulations, that predicts the process of charge transport and the effect of temperature on the electron transport in the thin film. In this paper two different nanoparticle models were built to cope with different types of morphology: triangular array and rectangular array. The transport properties of these different kinds of arrays including 2D ordered nanoparticle arrays with/without local structural disorder and 2D gradient nanoparticle arrays were investigated at different temperatures. For 2D well-ordered nanoparticle array without local structural disorder, the I-V curves are non-linear and highly symmetric.