Fabrication of organic field effect transistors using directed assembled and transfer printed carbon nanotube source/drain electrodes

Abstract

Printing processes are increasingly used in the fabrication of organic field effect transistors (OFETs) owing to their merits of low cost, low processing temperature, vacuum-free nature, and compatibility with various substrates. Among various printing processes, transfer printing is preferable because of its high resolution and pattern fidelity. Here, we fabricate OFETs using directed assembled and transfer printed carbon nanotube (CNT) source/drain electrodes. The CNT electrodes are selectively assembled on a Damascene template using an electrophoretic directed assembly based inking process and then transferred onto a polyurethane film on a silicon substrate with a high pattern fidelity. Selective inking and direct transfer without sacrificial layers or intermediate transfer steps enable a high material efficiency and a low cost of our fabrication process. The fabricated OFETs with a spin-coated 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene semiconducting film show typical p-type behavior with an on/off ratio of approximately 105, implying great potential to use our method for practical OFET fabrication.