Quantitative analysis of electronic transport through weakly-coupled metal/organic interfaces

TL;DR

This study investigates electronic transport at weak metal/organic interfaces using single-crystal transistors, demonstrating that thermionic emission theory, including barrier lowering, accurately models the observed behavior.

Contribution

It provides a quantitative analysis of electron transport through oxidized copper/rubrene interfaces, highlighting the impact of weak metal-molecule coupling and barrier effects.

Findings

Transport behavior aligns with thermionic emission theory

Barrier lowering significantly influences current flow

Weak coupling due to oxide layer affects device performance

Abstract

Using single-crystal transistors, we have performed a systematic experimental study of electronic transport through oxidized copper/rubrene interfaces as a function of temperature and bias. We find that the measurements can be reproduced quantitatively in terms of the thermionic emission theory for Schottky diodes, if the effect of the bias-induced barrier lowering is included. Our analysis emphasizes the role of the coupling between metal and molecules, which in our devices is weak due to the presence of an oxide layer at the surface of the copper electrodes.