Metal-Free Fully Solution-Processable Flexible Electrolyte-Gated Carbon Nanotube Field Effect Transistor

Carbon nanotube-based field effect transistors (CNTFETs) are an interesting alternative to organic FETs in the growing field of printed electronics. Solution processed CNTFETs can be fabricated at low temperatures, are compatible with roll to roll processes and with flexible substrates. Usually metal electrodes for CNTFETs are deposited using standard techniques (e.g., evaporation or sputtering) which require expensive equipment and a high thermal budget. The elimination of such deposition step would allow a fully solution-based process for the CNTFETs fabrication. In this paper, we demonstrate an all carbon nanotube (CNT) transistor which is entirely solution processable without sacrificing the device performance. Performed detailed contact resistance analysis shows that CNT electrodes make better contacts to semiconducting CNTs channel than gold electrodes. The device performance is shown for an electrolyte-gated CNTFET fabricated on a flexible substrate. Such transistors are used as low cost biosensors for vivo implants by exploiting better interaction of flexible substrates to cells.