Carbon Nanotube Sensors for Gas and Organic Vapor Detection

Abstract

A gas sensor, fabricated by the simple casting of single-walled carbon nanotubes (SWNTs) on an interdigitated electrode (IDE), is presented for gas and organic vapor detection at room temperature. The sensor responses are linear for concentrations of sub ppm to hundreds of ppm with detection limits of 44 ppb for NO2 and 262 ppb for nitrotoluene. The time is on the order of seconds for the detection response and minutes for the recovery. The variation of the sensitivity is less than 6% for all of the tested devices, comparable with commercial metal oxide or polymer microfilm sensors while retaining the room-temperature high sensitivity of the SWNT transistor sensors and manufacturability of the commercial sensors. The extended detection capability from gas to organic vapors is attributed to direct charge transfer on individual semiconducting SWNT conductivity with additional electron hopping effects on intertube conductivity through physically adsorbed molecules between SWNTs.

Carbon Nanotubes for Electronic and Electrochemical Detection of Biomolecules

“…[7,8] In particular, metallic (met-) nanotubes are highly suited for nanoscale circuits, [9] ultrathin, flexible, and transparent conductors, [10] supercapacitors, [11] field emitters, [12] actuators, [13] and nanosized electrochemical probes. [14] Semiconducting (sem-) CNTs on the other hand, are applicable for nanoscale sensors, [15,16] transistors, [17,18] and photovoltaic devices. [19] With diameters similar to or smaller than those of individual proteins, CNTs are expected to serve as high-performance electrical conduits for interfacing with biological systems.…”

Parallel arrays of individually addressable single-walled carbon nanotube field-effect transistors

“…Some recent developments toward an industrially favorable SWNT transistor fabrication process include prepatterned catalysts where SWNTs selectively grow at the device sites, [20][21][22][23][24] and dispersing SWNTs over a surface in order to produce an entangled network. 25,26 In this paper, we report a three-step procedure that yields individually addressable arrays of high-throughput SWNT FETs. The simple approach described here could be easily integrated in the existing commercial processing of silicon electronics.…”

“…Recently, there have also been reports 25,26,28 of high output current CNT FETs that take advantage of multiple parallel nanotube channels between metal source and drain contacts. However, in these experiments, the channel-forming CNTs often appear in the form of an entangled network of junctions.…”

Carbon nanotube‐sensor‐integrated microfluidic platform for real‐time chemical concentration detection

“…With the rapid progress and improvement of nanotechnology, sensors fabricated by using carbon nanotubes (CNTs) as the sensing element were reported to give electrical response to different chemicals, such as NO 2 , NH 3 , CO, H 2 , and O 3 for gas detection [4][5][6][7][8][9]. CNT sensors provide high sensitivity, low power, and portable tools for in situ chemical analysis.…”