Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 18: Poster Monday: 2D Materials 1
O 18.5: Poster
Monday, September 5, 2022, 18:00–20:00, P4
On the Way to Twisted Bilayer Graphene: Formation and Decoupling of 0°-Rotated Epitaxial Graphene — •Hao Yin1,2, Miriam Raths1,2, Mark Hutter1,2, François C. Bocquet1, and Christian Kumpf1,2 — 1Peter Grünberg Institute (PGI-3), Forschungszentrum Jülich and Jülich-Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, Jülich, Germany — 2Experimentalphysik IV A, RWTH Aachen University, Aachen, Germany
On the way to twisted bilayer graphene with a twisting angle of 30°, we investigated the graphene growth on 6H-SiC(0001) using an unconventional epitaxial growth method named 'surfactant-mediated growth', which is based on annealing the SiC surface in borazine atmosphere. Here, we report a LEEM-based study on two different samples, on which we observed different surface morphologies with varying numbers of stacked graphene layers. A large-scale uniform graphene R0° monolayer is found on the first sample that was annealed to 1330°C. This sample is a promising candidate for producing 30° TBG. Interestingly, some regions of the graphene R0° layer exhibit different brightness contrasts at specific start voltages, without showing significant differences in their LEEM-IV curves. The second sample was annealed 50°C higher, causing the formation of graphene multilayer domains. We utilized LEEM and LEEM-IV in order to determine the number of layers as well as the distribution of multilayer graphene domains. Furthermore, we discuss the influence of the annealing temperatures in terms of the formation and decoupling of the epitaxial graphene layers.