Customizing the Polarity of Single‐Walled Carbon‐Nanotube Field‐Effect Transistors Using Solution‐Based Additives

Abstract

AbstractPolarity control in semiconducting single‐walled carbon‐nanotube field‐effect transistors (s‐SWNT FETs) is important to promote their application in logic devices. The methods to turn the intrinsically ambipolar s‐SWNT FETs into unipolar devices that have been proposed until now require extra fabrication steps that make preparation longer and more complex. It is demonstrated that by starting from a highly purified ink of semiconducting single‐walled carbon nanotubes sorted by a conjugated polymer, and mixing them with additives, it is possible to achieve unipolar charge transport. The three additives used are benzyl viologen (BV), 4‐(2,3‐dihydro‐1,3‐dimethyl‐1H‐benzimidazol‐2‐yl)‐N,N‐dimethylbenzenamine (N‐DMBI), which give rise to n‐type field‐effect transistors, and 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4‐TCNQ) which gives rise to p‐type transistors. BV and N‐DMBI transform the s‐SWNTs transistors from ambipolar with mobility of the order of 0.7 cm2 V−1 s−1 to n‐type with mobility up to 5 cm2 V−1 s−1. F4‐TCNQ transform the ambipolar transistors in p‐type with mobility up to 16 cm2 V−1 s−1.