Fabrication and Characterization of Mesoscopic Plasmonic Structures

点击翻译按钮获取中文摘要

The focus of this project is the defined preparation and optical as well as structural characterization of regular and disordered metallic and dielectric nanostructures. The preparation will include the following strategies: (A) Wet chemical preparation of monodisperse nanosized particles with a diameter of 2 to 50 nm and their deposition on various substrates for the creation of flat 2-D nanostructures as well as hollow sphere structures based an nanoparticles (NP). On the one hand the metallic 2-D and 3-D particle arrays can establish a polaritonic electronic structure, and they can therefore provide supreme optical filter properties. On the other hand, disorder and defect states can lead to optical confinement. Optical resonators and input/output couplers could be based an these structures. Within these systems we will study the plasmon dephasing of Au and Ag nanostructures. An important aspect is the direct study of the dephasing time for metal particles with strong interactions (2-D order) and their coupling properties with respect to local energetic field enhancements of the stored light energy. Special attention will be drawn to the investigation of single defects as well as non-periodic (disordered) and quasi-periodic particle arrangements. (B) Nanosphere lithography (NSL) using periodic and quasiperiodic self assembly of spherical objects like polystyrene or silica particles with a diameter in the range of 200 to 2000 nm is another project goal; the two and three-dimensional (2-D, 3-D) ordered particles will be used as a mask for the subsequent deposition of various amounts of different metals. Light confinement in hexagonal and cubic arrangements compared to disordered nanostructures will be studied. (C) Direct writing of arbitrary structures by electron beam lithography using standard resist techniques will be carried out. (D) Furthermore, self-assembled organic monolayer methods will be utilized. Defect structures with well defined geometry, symmetry, and shape variations within periodic 2-D nanodots and with defined degrees of disorder will be carried out using evaporation and galvanic deposition. It is of fundamental interest to study the induced correlated disorder in such mesoscopic resonant structures and whether, similar to electronic crystals, extremely narrow band gap states can be achieved.