April 14, 2010 Wednesday 15:30
Özgül Kurtuluş, Doğuş University
Structural parameters of CdSe nanowires via micro-focused x-ray diffraction

Abstract: The morphology of CdSe nanowires (NW) can easily be controlled by various growth methods. In this study, CdSe NWs are prepared by solution-liquid-solid (SLS) approach providing needle-shaped wires of about tens of nm in diameter and several microns in length. To make x-ray single NW inspection possible, the NWs were dispersed in toluen and hexadecylamine, homogenized by centrifugation and finally spincoated on silicon substrate. SEM images revealed that the NWs are randomly oriented with length axis parallel to the substrate. However, at selected areas, the distance between neighboured NWs is in the order of one micron. These samples were investigated by x-ray diffraction using a 300nm x 600nm micro-focus at beamline ID1 of ESRF. Diffraction from 110W/2-20ZB basal plane was selected for single nanowire inspection. In order to measure various single objects subsequently, the sample was laterally scanned through the beam keeping the diffraction angle fixed. It was observed that the individual NWs differ slightly in peak position and peak width. From powder diffraction, it is known that NWs consist of an admixture of a wurtzite (W) and zinc-blende (ZB) structure units and the coherent illumination of sample by the micro-focus enables to visualize these zinc-blende and wurzite units seperated by stacking faults.