Control of Graphene Field-Effect Transistors by Interfacial Hydrophobic Self-Assembled Monolayers

Hydrophobic self-assembled monolayers (SAMs) with alkyl chains of various lengths were inserted between CVD-grown graphene layers and their SiO(2) substrates (figure). As the SAM alkyl chain length increased, substrate-induced doping was suppressed by the ordered close-packed structure of SAMs with long alkyl chains. Accordingly, graphene transistors constructed on SAMs with long alkyl chains exhibited higher electron/hole mobilities with lower Dirac point voltages.X119287sciescopu

Transparent Flexible Organic Transistors Based on Monolayer Graphene Electrodes on Plastic

Transparent, flexible carbon-based pentacene field-effect transistors (FETs) were successfully fabricated from monolayer graphene electrodes on plastic substrates. One-atom-thick monolayer graphene provides an ideal material for source/drain electrodes for efficient charge injection and transport, resulting in low contact resistance between the electrodes and the pentacene films. Thus, pentacene FETs with patterned graphene electrodes exhibit significantly higher performances than those of common metal electrodes.X11151137sciescopu

Work-Function Engineering of Graphene Electrodes by Self-Assembled Monolayers for High-Performance Organic Field-Effect Transistors

We have devised a method to optimize the performance of organic field-effect transistors (OFETs) by controlling the work functions of graphene electrodes by functionalizing the surface of SiO(2) substrates with self-assembled monolayers (SAMs). The electron-donating NH(2)-terminated SAMs induce strong n-doping in graphene, whereas the CH(3)-terminated SAMs neutralize the p-doping induced by SiO(2) substrates, resulting in considerable changes in the work functions of graphene electrodes. This approach was successfully utilized to optimize electrical properties of graphene field-effect transistors and organic electronic devices using graphene electrodes. Considering the patternability and robustness of SAMs, this method would find numerous applications in graphene-based organic electronics and optoelectronic devices such as organic light-emitting diodes and organic photovoltaic devices.X11144134sciescopu