AbstractThe chemical vapour deposition (CVD) of graphene is the most promising route for the production of large-area high-quality graphene films. This work is devoted to the investigation of the CVD processes of graphene on transition metals, and to study the mechanisms of graphene growth on metals having different carbon solubility and, thus, different affinity to carbon. In this work, three transition metals, copper, tantalum, and rhenium, were explored as growth substrates for graphene CVD. The last two metals are of interest for further investigation with the collaborators in the European Organization for Nuclear Research (CERN). The copper foil was chosen as a test metal since it is widely investigated object in the field of graphene production. Several growth factors have been modified to improve the graphene quality such as growth temperature, gas feeding ratio, and position of the substrate in the reaction tube. In addition to gas precursors used in this work, the formation of graphene from a liquid precursor of a biological origin was also studied. The growth of graphene on tantalum was investigated using the isothermal-isobaric (at constant temperature and pressure) approach. The role of surface oxygen was found to be important for graphene formation on tantalum foil. In the case of rhenium, it was found that there is only a narrow window of growth temperatures for the deposition of graphene. Tantalum and rhenium are both refractory metals, but they have a drastically different affinity to carbon â low for tantalum and high for rhenium. Therefore, the mechanism of graphene formation on these two metals differs significantly. In order to check the protective properties of deposited graphene, both metals were exposed to corrosive liquids and high-temperature oxidation. The obtained results confirmed the protective role of graphene and graphene-carbide surface layers.
|Date of Award||1 Aug 2019|
|Supervisor||Konstantin Novoselov (Supervisor) & Roman Gorbachev (Supervisor)|
- transition metals