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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Colloidal and Nanoparticles

CPP 13.10: Vortrag

Dienstag, 26. Februar 2008, 17:30–17:45, C 264

X-ray investigations for determining the aspect ratio in CdSe nanorods — Ullrich Pietsch and •Özgül Kurtulus — Festkörperphysik , Universität Siegen, Siegen, Germany

Semiconductor based 1D nanostructures are of high technological interest due to potential application in 1D conductivity measurements and optical devices. Catalyst assisted solution-liquid-solid synthesis is a new method where nanocrystal catalysts are used to grow CdSe nanorods (NR) from solution. The aim of this study is to investigate CdSe samples prepared with this new method by means of x-ray diffraction. The measurements have been performed at DELTA synchrotron using a beam of wavelength 1.127 Å and an image plate system. It is found that the CdSe NRs have a crystal structure of wurtzite with an aspect ratio changing between 2 and 10. This is in contradiction with the results obtained from TEM measurements, according to which the lengths of the NRs are in the order of 1μ and the widths are around 20nm. Presently the results are interpreted by the appearance of stacking faults which separate uniformly stacked AB, AB layers from each other. It is planned to measure an individual NR using a nanofocused x-ray beam. Once an individual NR could be observed, the next step is to measure the powder spectrum using a CCD as a function of the position of the beam spot along the nanorod. Depending on this information, the parameters affecting the structure of the NRs would be clear by making experiments with samples prepared in different conditions.