PhD Defense of Fanny MORISOT

Nanowires are structures combining a diameter of nanometric dimensions and length of micrometric dimension with interesting features for many fields of application such as electronics, optics and molecular detection. However, their small size makes them difficult and costly to integrate into devices. One way to overcome this issue is to assemble them to form a network of randomly oriented nanowires, also called nanonet, which is of macroscopic scale. This work deals with zinc oxide nanonets, which were successfully integrated into three different types of devices: field-effect transistors, DNA sensors and acetone detectors. First, we present the whole fabrication process, from nanowires synthesis to nanonet fabrication and integration into functional devices. Two integration processes were used. The first one involved direct nanonet integration on micro-hotplates with electrodes, provided by our industrial partner, for gaz sensing applications. The second one was a full microelectronic process, which was developed and tested in this work, for the fabrication of field effect transistors. We then discuss the performance of the different devices developed.  The fabricated field effect transistors demonstrated remarkable properties which had never been achieved before in the literature for similar devices. We successfully detected DNA by fluorescence and showed the influence of nanowires density on such a sensor. Finally, the electrical detection of gaseous acetone was carried out over a wide range of conditions from dry atmosphere at room temperature to very humid atmosphere at 360°C.
This work shows that ZnO nanonets have interesting properties that offer prospects for applications in fields as varied as electronics or the detection of chemical or biological molecules.

Keywords :
ZnO nanowires, ZnO nanonets, DNA biodetection, Acetone electrical detection, Electrical devices, Field Effect transistors
 

• Céline TERNON  : Supervisor
• Yamin LEPRINCE-WANG : Reviewer
• Khalifa AGUIR : Reviewer
• Jumana BOUSSEY : Examiner
• Pierre TEMPLE-BOYER : Examiner
• Thierry LIVACHE : Examiner
• Mireille MOUIS : CoSupervisor