Influence of the gate dielectric on the mobility of rubrene single-crystal field-effect transistors

TL;DR

This study shows that in rubrene single-crystal FETs, the charge carrier mobility decreases as the dielectric constant of the gate insulator increases, highlighting the interface's intrinsic role.

Contribution

It reveals that the mobility reduction is proportional to the inverse of the dielectric constant, emphasizing the importance of the interface in organic FET performance.

Findings

Mobility decreases with higher dielectric constant

Reproducible device characteristics across materials

Mobility is an intrinsic property of the interface

Abstract

We have performed a comparative study of rubrene single-crystal field-effect transistors fabricated using different materials as gate insulator. For all materials, highly reproducible device characteristics are obtained. The achieved reproducibility permits to observe that the mobility of the charge carriers systematically decreases with increasing the dielectric constant of the gate insulator, the decrease being proportional to (epsilon)-1. This finding demonstrates that the mobility of carriers in organic single-crystal field-effect transistors is an intrinsic property of the crystal/dielectric interface and that it does not only depend on the specific molecule used.