- Tim Verhagen: Topographic states of graphene and its consequences on charge and strain phenomena
- 4. 4. 2018, 14:30
- lecture room F2, first floor Ke Karlovu 5
- more information
Abstract:
The transfer of either exfoliated or chemical vapour deposition (CVD) grown graphene to another substrate is one of the key steps during the fabrication of graphene based devices. The creation of rugae, a single state of a corrugated material configuration during the transfer is generally seen as unwanted, as these topographic features deteriorate the properties of graphene.
In recent years, graphene research has partly shifted their focus from the investigation of as ‘perfect as possible’ graphene to explore these ‘imperfections’. Those topographic features can be very suitable to further explore graphene's potential. One of the more significant changes due to the these rugae is a change in the pyramidalization angle, which is a measure for the chemical reactivity of graphene.
The chemical reactivity can be further controlled via the doping level. Van der Waals heterostructures (vdWh) consisting of combinations of transition metal dichalgonides (TMDs) and graphene are considered as a promising candidate for novel optoelectronic devices. However, not much is known yet about energy and charge transfer between monolayer TMDs and graphene, and the possibilities of using the energy or charge transferred to graphene to change locally, optically the doping level of graphene.
In this presentation, I will discuss how we can modify locally the topographical and/or doping landscape of graphene. Using Raman spectroscopy and atomic force microscopy, the created topographic and doping landscape in graphene is studied. Using a careful analysis of the measured data of these different graphene based systems, a correlation between the topography and locally induced strain and doping in graphene can be found. Using this knowledge, we will be able in the future to control spatially the functionalization of graphene.