Graphene investigated by dynamic non-contact atomic force microscopy

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The aim of the project is the investigation of mono- and bi-layer graphene flakes with atomic resolution using the method of dynamic non-contact atomic force microscopy (NC-AFM). The three central goals are:1. The determination of the detailed surface and interface structure of graphene with the highest accuracy by means of dynamic NC-AFM imaging and 3D force-field spectroscopy measurements on mesoscopic down to atomic scales. In particular, we aim at a detailed comparison of structural and mechanical properties between mono- and bi-layers of graphene. Furthermore, we would like to study the influence of atomically-localized strain, originating from geometrical defects (e.g. pentagonal rings), atomic vacancies, or single adsorbates, on the nanomechanical properties of graphene. The evaluation of the nanomechanical properties (e.g. effective elastic modulus) will be performed by precise measurements of the mechanical responses to the atomically sharp AFM tip as extracted from 3D force-field spectroscopy with atomic resolution.2. The evaluation of atomic defects and their correlation with soft vibrational modes by means of energy-loss AE measurements with threedimensional spatial resolution, using simultaneous dynamic NC-AFM imaging and 3D force-field spectroscopy measurements. In particular, we will investigate the relationship between types and locations of atomic defects and local excitations of soft vibrational modes.3. The correlation of local electronic and electrostatic properties with electron transport, taking into account the number of carbon layers, the size of two-dimensional crystal domains, the presence of atomically-localized strain due to the presence of defects, and the degree of the electronic coupling of graphene to the substrate.