Coupled Atomic Force and Raman Microscope

点击翻译按钮获取中文摘要

For many nanoscale samples an analysis of the topographic as well as the chemical structure is extremely valuable to reveal their composition und functions. A coupled atomic force – Raman microscope is ideally suited to record chemical, topographic as well as mechanical information in a correlative, i.e. colocalized, or even simultaneous way under atmospheric or liquid conditions. A detailed structural information with a spatial resolution in the nanometer range is obtained using atomic force microscopy. However, the spatial resolution of Raman spectroscopy is typically restricted by the diffraction limit, i.e. chemical information is obtained for several hundred nanometers. Through the use of plasmonic nanoparticles or AFM tips functionalized with plasmonic materials, the Raman signal intensity and the spatial resolution can be significantly enhanced. Through excitation of the localized surface plasmon resonance a signal enhancement of many orders of magnitude can be achieved, which even allows for the detection of single molecules by Raman spectroscopy. For example, the instrument will be used to monitor chemical reactions of individual molecules taking place in close vicinity to metallic nanoparticles. By measuring simultaneously the topography of nanostructures and the Raman signal, relationships between nanostructure and signal enhancement can be revealed, and chemical reactions can be studied in detail under a variety of conditions. At the University of Potsdam, both atomic force microscopy and (spatially resolved) Raman spectroscopy are extensively used, however, there is no instrument yet that allows for correlation of both methods. The requested instrument is supposed to provide the working ability of the new professorship for hybrid nanostructures at the University of Potsdam and to enable a variety of new, partly cooperative, research projects.