Nielsen, Simon
[UCL]
Hackens, Benoît
[UCL]
Pardoen, Thomas
[UCL]
Since its discovery in 2004 graphene has quickly become the most studied material mainly because of its incredible properties. Many believe graphene to be the material of the futur that will revolutionize all sorts of technologies. The discovery also started a wide research movement for other two dimensional materials, one of which is hexagonal boron nitride (hBN). This one is of particular interest since it is an ideal substrate for graphene, enhancing its already incredible properties. As any other 2D material neither graphene nor hBN are completely flat because some sorts of corrugations and irregularities simply can not be avoided. To exploit in the best manner possible the potential of these materials it is therefore important to understand the impact of such irregularities. In this thesis we have studied the wrinkling process by thermal treatment of hBN flakes on different substrates. We have tried to to understand how these wrinkles can be linked to thermal strain $\epsilon =\alpha\Delta T$ with $\alpha$ the thermal expansion coefficient (TEC) and $T$ the temperature. By applying thermal treatments with different parameters to the hBN flakes, we have proposed a scenario for the wrinkling process that is plausible with our observations, trying to identify the key parameters in the process. We also created stacks of graphene on hBN and of encapsulated graphene between two hBN flakes to study the effect the thermal treatment would have on these stacks. The different samples were characterized by optical microscopy, Raman spectroscopy and Atomic Force Microscopy.


Bibliographic reference |
Nielsen, Simon. Graphene on wrinkled hexagonal boron nitride. Ecole polytechnique de Louvain, Université catholique de Louvain, 2019. Prom. : Hackens, Benoît ; Pardoen, Thomas. |
Permanent URL |
http://hdl.handle.net/2078.1/thesis:22141 |