Low-Voltage p- and n-Type Organic Self-Assembled Monolayer Field Effect Transistors

Abstract

We report on p- and n-type organic self-assembled monolayer field effect transistors. On the base of quaterthiophene and fullerene units, multifunctional molecules were synthesized, which have the ability to self-assemble and provide multifunctional monolayers. The self-assembly approach, based on phosphonic acids, is very robust and allows the fabrication of functional devices even on larger areas. The p- and n-type transistor devices with only one molecular active layer were demonstrated for transistor channel lengths up to 10 μm. The monolayer composition is proven by electrical experiments and by high-resolution transmission electron microscopy, electron energy loss spectroscopy, XPS, and AFM experiments. Because of the molecular design and the contribution of isolating alkyl chains to the hybrid dielectric, our devices operate at low supply voltages (-4 V to +4 V), which is a key requirement for practical use and simplifies the integration in standard applications. The monolayer devices operate in ambient air and show hole and electron mobilities of 10(-5) cm(2)/(V s) and 10(-4) cm(2)/(V s) respectively. In particular the n-type operation of self-assembled monolayer transistors has not been reported before. Hereby, structure-property relations of the SAMs have been studied. Furthermore an approach to protect the sensitive C(60) from immediate degradation within the molecular design is provided.

N‐Type Self‐Assembled Monolayer Field‐Effect Transistors and Complementary Inverters

“…[ 12 , 13 ] Progress on fabricating n-type SAMFETs has been reported. [ 14 ] A semiconducting fullerene based monolayer molecules compared to the chlorosilanes previously reported [ 9 ] are easier handling, storage and device fabrication as they are environmentally stable.…”

Tuning the molecular order of C60-based self-assembled monolayers in field-effect transistors

“…These films can be incorporated as active layers in thin film transistors, so called self-assembled monolayer field-effect transistors (SAMFETs). [15][16][17][18][19][20] In these devices with real 2D-confined channels, the morphology is of particular interest, as small perturbations in the packing of the molecules, immediately strongly influence the transport properties in the transistor. This, on the other hand means that SAMFETs are an ideal tool to investigate thin film morphologies on the sub-nanometre scale in functionalized self-assembled monolayers.…”

A Toolbox for Controlling the Energetics and Localization of Electronic States in Self‐Assembled Organic Monolayers

“…In many instances, a convenient way for tuning the characteristics of such interfaces is by using molecular (mono)layers. These can even adopt the role of functional elements in devices, for example, in highly efficient organic monolayer transistors1, 2 or as self‐assembled monolayer (SAM) based devices in the field of molecular electronics 3, 4, 5, 6, 7, 8, 9, 10, 11. The spatial localization and energetics of the electronic states in these layers play a crucial role, as the states serve as “channels” for the electrical current 12, 13.…”