Schottky-type response of carbon nanotube NO2 gas sensor fabricated onto aluminum electrodes by dielectrophoresis

Single-walled carbon nanotube (CNT) gas sensors were fabricated by dielectrophoresis onto microelectrodes made of Cr, Pd or Al. The Al/CNT sensor response to NO2 (nitrogen dioxide) gas was characterized by fast and large resistance increase at the moment of NO2 exposure, whereas the resistance of the other metal/CNT sensors monotonously decreased. It was suggested that the adsorbed NO2 molecules might alter the Schottky barrier at the Al/CNT interface as well as the positive hole density in the p-type semiconducting CNT. The Al/CNT sensor response could be interpreted as a superposition of the Schottky contact resistance and the CNT resistance, which were differently influenced by the NO2 adsorption and contributed to the overall sensor response. The Schottky response of the Al/CNT sensor was approximately one order of magnitude faster than the CNT response obtained using the other metal electrodes. © 2005 Elsevier B.V. All rights reserved.

[1]  I. Eisele,et al.  Iridium oxide as low temperature NO/sub 2/-sensitive material for work function-based gas sensors , 2004, IEEE Sensors Journal.

[2]  Kong,et al.  Nanotube molecular wires as chemical sensors , 2000, Science.

[3]  S. Wind,et al.  Field-modulated carrier transport in carbon nanotube transistors. , 2002, Physical review letters.

[4]  Qian Wang,et al.  Toward Large Arrays of Multiplex Functionalized Carbon Nanotube Sensors for Highly Sensitive and Selective Molecular Detection. , 2003, Nano letters.

[5]  Craig A. Grimes,et al.  Gas sensing characteristics of multi-wall carbon nanotubes , 2001 .

[6]  J. L. Davidson,et al.  A novel microelectronic gas sensor utilizing carbon nanotubes for hydrogen gas detection , 2003 .

[7]  O. Velev,et al.  Dielectrophoretic Assembly of Electrically Functional Microwires from Nanoparticle Suspensions , 2001, Science.

[8]  B. Flietner,et al.  Dipole- and charge transfer contributions to the work function change of semiconducting thin films: experiment and theory , 1996 .

[9]  W. Mike Arnold,et al.  Electric-field oriented carbon nanotubes in different dielectric solvents , 2004 .

[10]  Junya Suehiro,et al.  Controlled fabrication of carbon nanotube NO2 gas sensor using dielectrophoretic impedance measurement , 2005 .

[11]  Franco Cacialli,et al.  Work Functions and Surface Functional Groups of Multiwall Carbon Nanotubes , 1999 .

[12]  M. Meyyappan,et al.  Room temperature methane detection using palladium loaded single-walled carbon nanotube sensors , 2004 .

[13]  Jose Maria Kenny,et al.  Sensitivity to NO2 and cross-sensitivity analysis to NH3, ethanol and humidity of carbon nanotubes thin film prepared by PECVD , 2003 .

[14]  Qian Wang,et al.  An investigation of the mechanisms of electronic sensing of protein adsorption on carbon nanotube devices. , 2004, Journal of the American Chemical Society.

[15]  Satoru Suzuki,et al.  Work functions and valence band states of pristine and Cs-intercalated single-walled carbon nanotube bundles , 2000 .

[16]  M. Meyyappan,et al.  Carbon Nanotube Sensors for Gas and Organic Vapor Detection , 2003 .

[17]  H. B. Weber,et al.  Contacting single bundles of carbon nanotubes with alternating electric fields , 2002 .

[18]  Junya Suehiro,et al.  Fabrication of a carbon nanotube-based gas sensor using dielectrophoresis and its application for ammonia detection by impedance spectroscopy , 2003 .

[19]  Yu Huang,et al.  Indium phosphide nanowires as building blocks for nanoscale electronic and optoelectronic devices , 2001, Nature.

[20]  J. Suehiro,et al.  DETECTION OF PARTIAL DISCHARGE IN SF6 GAS USING A CARBON NANOTUBE-BASED GAS SENSOR , 2005 .

[21]  S. Iijima.  Helical microtubules of graphitic carbon , 1991, Nature.

[22]  R Martel,et al.  Carbon nanotubes as schottky barrier transistors. , 2002, Physical review letters.

[23]  J. Suehiro,et al.  Calibration methods of carbon nanotube gas sensor for partial discharge detection in SF/sub 6/ , 2006, IEEE Transactions on Dielectrics and Electrical Insulation.

[24]  M. Washizu,et al.  Electrostatic manipulation of DNA in microfabricated structures , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[25]  Xinqi Chen,et al.  Aligning single-wall carbon nanotubes with an alternating-current electric field , 2001 .

[26]  Junya Suehiro,et al.  Quantitative estimation of biological cell concentration suspended in aqueous medium by using dielectrophoretic impedance measurement method , 1999 .

[27]  Seiji Akita,et al.  Orientation of Carbon Nanotubes Using Electrophoresis , 1996 .

[28]  Richard Martel,et al.  Controlling doping and carrier injection in carbon nanotube transistors , 2002 .