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Home > Thèses et HDR > Thèses en 2018

07/12/2018 - Arbi MAALAOUI

by Laurent Krähenbühl - published on , updated on


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M. Arbi Maalaoui soutient sa thèse le 07/12/2018 à 14h00.
Lieu : Ecole Centrale de Lyon, bâtiment W1, amphithéâtre 203

Titre :
Study and characterization of directed carbon nanotube assembly by dielectrophoresis for chemical sensor applications

Jury :

  • Rapporteurs : Pr. Jérémie GRISOLIA (INSA Toulouse); Pr. France LE BIHAN (Univ. de Rennes 1).
  • Encadrement : Pr. Jean-Pierre CLOAREC (ECL, INL), Pr. Dominique DROUIN et Pr. Paul CHARETTE (Univ. de Sherbrooke), Dr. Marie FRENEA ROBIN (UCB Lyon 1, Ampère)
  • Invités : Pr. Maxime DARNON (Sherbrooke, UMI-LN2) et Dr. Jonathan GENEST (Sherbrooke)

Contexte :
Thèse préparée en cotutelle entre l’Ecole Centrale de Lyon et l’Université de Sherbrooke, à l’Institut des Nanotechnologies de Lyon (UMR 5270), au laboratoire Ampère (UMR 5005) et au laboratoire Nanotechnologies et Nanosystèmes (LN2, UMI 3462)

Abstract :
Due to their remarkable electrical properties, Single-Walled Carbon Nanotubes (SWNTs) are attracting increasing interest in the development of chemical sensors in liquid medium. However, controlling of their position on micro or nano-structured surfaces, in order to allow their integration in transistors or chemiresistor structures, remains a challenge.
The work described here, deals with the addressing of SWNTs by dielectrophoresis (DEP) between metal electrodes and their application to pH measurement in chemiresistor configuration. Firstly, we studied the influence of the DEP’s parameters (field application time, frequency, intensity, etc.) on the structure of the SWNTs assemblies. To explain these experimental results, the respective contributions of the different forces involved were studied using finite element modeling under Comsol. Then, the structures based on SWNTs obtained were characterized by Scanning Electron Microscopy as well as by air resistance measurements, in order to establish a first link between elaboration conditions and obtained characteristics.
The suitability of the devices for pH measurement was then evaluated. Current-voltage measurements in a liquid medium showed that the SWNTs based sensors assembled between gold electrodes, were sensitive to the variation of the pH of the solution. Further measurements, performed at constant pH and variable conductivity, showed that the sensor was also sensitive to change in conductivity. Finally, the study of the sensor impedance indicates that a selectivity to the pH can be favored by a judicious choice of the frequency range.

Keywords :
Dielectrophoresis, single walled carbon nanotubes, sensor in liquid medium, chemiresistor, pH measurement.