Conductive AFM measurements on Twisted Bilayer Graphene

Twisted bilayer graphene at a magic angle might be used to increase our understanding of high temperature superconductivity. Studying 2D-materials with an Atomic Force Microscope (AFM) yields information on its surface properties, such as its topography or its conductivity. In this thesis, AFM work has been done on different samples, with the final goal of identifying moiré patterns. AFM tapping mode shows clear roughness decline of a silicon/silicon oxide wafer after annealing 500 degrees for 24 hours. AC mode on layered graphene placed on an identical substrate was able to identify different atomic layers clearly. Sputtered gold, graphite and evaporated gold have been analyzed with current sensing AFM. Finally, I/V-curves have been acquired with AFM contact mode on sputtered gold, corresponding to theoretical expectations. All initial work has been done to measure I/V curves and start conductive AFM measurements on twisted bilayer graphene, in hopes of identifying moiré patterns...Show moreTwisted bilayer graphene at a magic angle might be used to increase our understanding of high temperature superconductivity. Studying 2D-materials with an Atomic Force Microscope (AFM) yields information on its surface properties, such as its topography or its conductivity. In this thesis, AFM work has been done on different samples, with the final goal of identifying moiré patterns. AFM tapping mode shows clear roughness decline of a silicon/silicon oxide wafer after annealing 500 degrees for 24 hours. AC mode on layered graphene placed on an identical substrate was able to identify different atomic layers clearly. Sputtered gold, graphite and evaporated gold have been analyzed with current sensing AFM. Finally, I/V-curves have been acquired with AFM contact mode on sputtered gold, corresponding to theoretical expectations. All initial work has been done to measure I/V curves and start conductive AFM measurements on twisted bilayer graphene, in hopes of identifying moiré patterns in the current map.Show less

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Conductive AFM measurements on Twisted Bilayer Graphene