Single-walled carbon nanotube sensor concepts

Abstract

Carbon nanotubes are excellent nanocomponents that offer unique properties that can be exploited in next-generation devices. Sensing applications is perhaps the class that has most to gain from single-walled carbon nanotubes (SWNTsingle-walled (carbon) nanotube (SWNT)carbon nanotube (CNT)single-wall (SWNT)s); virtually any property of SWNTs, such as electronic, electrical, mechanical and optical, can result or has already resulted in sensor concept demonstrators. The basic questions this chapter will attempt to address are, why use SWNTs? and how can SWNTs be used? in sensing applications. A tour through the gallery of basic nanotube properties is given in order to reveal the richness and uniqueness of this material's intrinsic properties. Together with examples from the literature, showing performance of SWNT-based sensors at least comparable to – but oftentimes surpassing – state-of-the-art micro- or macrodevices, nanotube properties should explain why there is so much effort currently being invested in this field. As nanotubes, like any other nano-object, are not easy to probe, a versatile strategy for accessing their properties, via the carbon nanotube field-effect transistor (CNFETcarbon nanotube (CNT)field-effect transistor (CNFET)) concept, will be described in this chapter. Furthermore, descriptions of CNFET device fabrication together with examples of SWNT sensor demonstrators utilizing the CNFET principle will be followed by proposals of how nanotubes can be utilized in sensors.