AbstractFollowing the isolation of graphene in 2004, scientists quickly showed that it possesses remarkable properties. However, as the scientific understanding of graphene matured, it became clear that it also has limitations: for example, graphene does not have a bandgap, making it poorly suited for use in digital logic. This motivated exploration of monolayer materials “beyond graphene”, which could embody functionalities that graphene lacks. In recent years there has been an increased interest in layered materials such as semiconducting Metal Dichalcogenides (MDs). When isolated in their monolayer form, they are essentially a 2D material, with unique properties. The implementation of 2D materials into future electronic devices could be desirable for industry; as their potential applications include cheap, fast and flexible electronic devices. Furthermore, to fully exploit the unique electrical properties of these materials, such as high electron mobility, new synthesis, manipulation, integration and characterization techniques must be developed.
In this thesis, the synthesis of high quality and crystallinity vertical aligned multilayer MDs by the Chemical Vapor Deposition (CVD) technique is reported. The morphology and the structure, as well as the optical properties, of the so-produced material have been studied using electron microscopies (SEM and TEM), X-ray photoelectron spectroscopy (XPS), Photoluminescence (PL), UV–visible and Raman spectroscopies and X-ray diffraction (XRD). The so-synthesized materials are potentially interesting in various applications where edge accessibility or directionality of the nanosheets play a major role such as gas sensing. For that, the performance of these materials as a gas sensor to detect toxic gases, for example NO2 and NH3, were investigated and discussed in this thesis work.
|Date of Award||19 Oct 2021|
|Sponsors||University of Namur & ICHEC Brussels Management School|
|Supervisor||Jean François Colomer (Supervisor), Carla Bittencourt (Co-Supervisor), Carmela APRILE (President), Luc Henrard (Jury), Marc Debliquy (Jury) & Eduard Llobet Valero (Jury)|