N-type self-assembled monolayer field-effect transistors

Within this work we present the synthesis and applications of a novel material designed for n-type self-assembled monolayer field-effect transistors (SAMFETs). Our novel perylene bisimide based molecule was obtained in six steps and is functionalized with a phosphonic acid linker which enables a covalent fixation on aluminum oxide dielectrics. The organic field-effect transistors (OFETs) were fabricated by submerging predefined transistor substrates in a dilute solution of the molecule under ambient conditions. Investigations showed a thickness of about 3 nm for the organic layer which is coincides to the molecular length. The transistors showed bulk-like electron mobilities up to 10-3 cm2/Vs. Due to the absence of bulk current high on/off-ratios were achieved. An increase of the electron mobility with the channel length and XPS investigations point to a complete coverage of the dielectric with a dense monolayer. In addition, a p-type SAMFET based on a thiophene derivative and our new n-type SAMFET were combined to the first CMOS bias inverter based solely on SAMFETs.