Patterned Graphene as Source/Drain Electrodes for Bottom-Contact Organic Field-Effect Transistors

摘要

Organic field-effect transistors (OFETs) have attracted much attention in the past decades because of their potential applications in large-area, flexible, and low-cost electronics. The device performance is not only governed by the intrinsic electrical characteristics of the organic semiconductors, but also dependent on the work function of the source/ drain (S/D) electrodes and the interface contact between the organic semiconductors and the S/D electrodes. Metal S/D electrodes are widely used to fabricate OFETs, although a large contact resistance exists between the organic semiconductor and the metal S/D electrodes, especially for devices with bottom-contact geometry. The selection of S/D electrodes with high carrier injection efficiency and excellent interface properties with organic semiconductors is a current challenge in the quest for improving the performance of OFETs and decreasing the device cost. Graphene is a basic building block of graphite, fullerene, and carbon nanotubes. According to the layer number, graphenes can be distinguished as three types: single-, double-, and few-(3-10) layer graphene. Two-dimensional graphene was obtained only very recently, and it has been the focus of great interest because it could provide an excellent subject for study in condensed-matter physics and material sciences. The unusual and stable structure of this new material makes it a promising candidate for future electronic applications. To date, only three methods - mechanical exfoliation of graphite on SiO_2/Si, thermal decomposition of SiC, and oxidation of graphite - have been used to obtain graphene.