Controlling charge injection in organic field-effect transistors using self-assembled monolayers

TL;DR

This paper investigates how self-assembled monolayers (SAMs) modify gold electrodes to control charge injection in organic field-effect transistors, leading to improved hole injection and reduced contact resistance.

Contribution

It demonstrates that SAMs can effectively tune the electrode work function, enhancing charge injection in P3HT transistors, a novel approach for interface engineering.

Findings

SAM modification increases gold work function

Enhanced hole injection with SAM-treated electrodes

Reduced contact resistivity in P3HT transistors

Abstract

We have studied charge injection across the metal/organic semiconductor interface in bottom-contact poly(3-hexylthiophene) (P3HT) field-effect transistors, with Au source and drain electrodes modified by self-assembled monolayers (SAMs) prior to active polymer deposition. By using the SAM to engineer the effective Au work function, we markedly affect the charge injection process. We systematically examine the contact resistivity and intrinsic channel mobility, and show that chemically increasing the injecting electrode work function significantly improves hole injection relative to untreated Au electrodes.