MAT science Week

Metallic nanowires have various applications in the fields of sensorics, electronic or energy harvesting. These applications are based on the excitation of collective electronic oscillations in the nanowires called surface plasmons that are generated by the electric field of light. Whereas the resonant plasmonic wavelength of a spherical Au particle is located in the visible light range, for Au nanowires the resonant wavelength can be tuned precisely and shifted to the infrared by varying the wire dimensions. At the resonant wavelength, very high nearfield enhancements are generated on the wire surface that allow for example to enhance the infrared vibrational modes of an analyte present in the wire proximity. Not only individual nanowires, but also coupling of nanowires is attracting great interest since higher nearfield enhancements and new plasmonic modes are generated. Ion track technology combined with electrodeposition is a powerful technique to synthesize nanowires with well-defined parameters. In this talk, we give an overview of the different Au and Au-Ag nanostructures that we have created with this technique, such as smooth and porous AuAg nanowires as well as two wires separated by very small gaps or small conducting bridges. Their plasmonic properties were studied dependent on the different nanowire parameters such as length, diameter, porosity, or gap sizes by electron energy loss spectroscopy in a TEM as well as by infrared microscopy.