Transport and noise in organic field effect devices

TL;DR

This paper investigates transport and noise in organic field-effect devices using surface Green functions, revealing conductance staggering, anomalous thermal behavior at certain voltages, and high thermoelectric efficiency.

Contribution

It introduces a first-principles based method to analyze nonlinear transport and thermoelectric properties in organic molecular devices.

Findings

Conductance exhibits staggering depending on the number of molecules.

Thermal properties show anomalous behavior at specific voltages.

Thermoelectric figure of merit exceeds one at resonance.

Abstract

The transport and fluctuation properties of organic molecules ordered parallel between two Au contact leads are investigated by the method of surface Green function. From first-principles simulation the relevant hopping parameters are extracted and used to calculate nonlinear transport coefficients with respect to an external bias voltage. A staggering of conductance is found in dependence on the number of molecules squeezed in between the contacts. The thermal properties show an anomalous behavior whenever the voltage reaches the values of the molecular energy levels active for transport. The thermoelectric figure of merit shows a resonance allowing to reach values even larger than one.