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KR: Fachverband Kristallographie

KR 2: Crystallography in nanoscience

KR 2.3: Vortrag

Dienstag, 23. März 2010, 10:30–10:45, H9

Mechanical properties of single nanostructures investigated by in-situ AFM and micro-XRD — •Thomas Cornelius, Thomas Scheler, Rogerio Magalhães-Paniago, and Till Hartmut Metzger — ESRF, 38043 Grenoble Cedex, France

In recent years, nanostructures attracted enormous attention due to size-effects influencing the structural, optical, electrical, and mechanical properties of materials with low dimensions. Concerning the mechanical properties mainly the plastic regime was explored showing a trend that "smaller is stronger". In contrast, studies of the elastic behaviour of nanowires revealed contradictory results concerning the influence of size-effects on the elasticity. To investigate single nanoobjects in the elastic regime, we combined an in-situ AFM with XRD in a microfocused beam. The AFM is used to image the sample surface, to select an individual nanostructure, and to apply pressure on a chosen object. Due to the interaction between the AFM-tip and the compressed object the resonance frequency of the AFM force sensor shifts to larger values enabling us to derive the stiffness of the contact area. Simultaneous to the pressure application, XRD images around a pre-defined Bragg peak are recorded. These images allow for the determination of the elastic lattice parameter change in-situ. From the contact stiffness and the lattice parameter change, the Young modulus of an individual nanoobject is derived. Here, we will present results both for SiGe islands grown by liquid-phase epitaxy on Si wafers and GaAs nanorods created by selective-area metal organic vapor phase epitaxy on GaAs substrates.