• Hoffmann, B.; Bashouti, M.Y.; Feichtner, T.; Mackovic, M.; Dieker, C.; Salaheldin, A.M.; Richter, P.; Gordan, O.D.; Zahn, D.R.T.; Spiecker, E.; Christiansen, S.: New insights into colloidal gold flakes: structural investigation, micro-ellipsometry and thinning procedure towards ultrathin monocrystalline layers. Nanoscale 8 (2016), p. 4529-4536

10.1039/C5NR04439A
Open Access Version (externer Anbieter)

Abstract:
High-quality fabrication of plasmonic devices often relies on wet-chemically grown ultraflat, presumably single-crystalline gold flakes due to their superior materials properties. However, important details about their intrinsic structure are not well understood yet. In this study, we present a new synthesis routine for large flakes with diameters of up to 100 µm and an in- depth investigation of their structural and optical properties. The flakes were precisely analyzed by transmission electron microscopy, electron backscatter diffraction and micro-ellipsometry. We found new evidence for the existence of multiple planar twin defects inside the flakes parallel to their surface in contrast to earlier studies. Micro-Ellipsometry was carried out to determine the complex dielectric function and to compare it to previous measurements of bulk single crystalline gold. Finally, we used focused ion beam milling to prepare smooth crystalline layers and high-quality nanostructures with desired thicknessdown to 10 nm. Our findings support the plasmonics and nano optics, community with a better understanding of this material which is ideally suited for superior plasmonic nano-structures.