Solution processed low-voltage organic transistors based on self-assembled monolayer gate dielectrics

Abstract

ABSTRACT Reduction in the operating voltage of organic field-effect transistors (OFETs) is sought for their successful implementation into future portable and low-power electronic applications. Here we demonstrate OFETs with operation below 2 V enabled by the use of self-assembled monolayer (SAM) gate dielectrics with high geometrical capacitances. A high surface energy monolayer is chosen to allow processing of small molecule semiconductors from solution. Impedance spectroscopy measurements of metal-insulator-semiconductor devices suggest the geometrical capacitance of the alumina-SAM dielectric can reach ~1 P F/cm 2 when accumulating charge at the semiconductor-insulator interface. Atomic force microscopy images reveal that the glass substrates and the SAM-functionalized aluminum gate electrode display significant roughness. Despite this, mobilities of 0.02 cm 2 /Vs are demonstrated. These results represent an important step towards low-power solution processable electronics. Keywords: organic semiconductor, organic field-effect transistor, organic thin-film transistor, self-assembled monolayer, low-voltage, metal-insulator-semiconductor, atomic force microscopy,