Regensburg 2010 – wissenschaftliches Programm

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KR: Fachverband Kristallographie

KR 2: Crystallography in nanoscience

KR 2.2: Vortrag

Dienstag, 23. März 2010, 10:15–10:30, H9

X-ray characterisation of single GaAs nanorods grown on Si — •Andreas Biermanns¹, Anton Davydok¹, Steffen Breuer², Lutz Geelhaar², and Ullrich Pietsch¹ — ¹Universität Siegen, Festkörperphysik, Germany — ²Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany

Semiconductor nanorods are of particular interest for new semiconductor devices. The nanorod approach can be used to form radial or axial heterostructures of materials with a large lattice mismatch. For the inspection of average structural parameters of the nanorods, typically x-ray or electron diffraction techniques are used. Alternatively, transmission electron microscopy can be used to inspect few individual nanorods after respective sample preparation. Complementary, recent developments in x-ray optics allow to focus a synchrotron beam down to the nanometer scale and to perform nondestructive diffraction studies at several individual nano-objects grown the same substrate. In this contribution we report on x-ray diffraction studies at individual GaAs nanorods grown Au seed-free on a Si[111] substrate. Due to the nanometer-sized x-ray beam, size and lattice parameters of individual nanorods could be measured and compared to the value obtained from the whole ensemble. Using the coherence properties of the focused beam we could observe speckle-like interference fringes in the surrounding of particular sensitive Bragg reflections which are a measure for the appearance of stacking faults within the nanorods. The separation of the speckles could be used to estimate the number of stacking faults and the size of the coherently scattering nanorod-segments.