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Optical Properties of metallized DNA

Diplomarbeit 2007 112 Seiten

Physik - Angewandte Physik


Modern technologies cannot be imagined without electronic devices, as e.g. the success stories of transistors and diodes illustrate. The performance of these electronic devices has tremendously increased during the last decades through a process known as downscaling: Minimizing structural units allows for extremely high densities of electronic modules. This entails an increase of speed as well as an enhanced performance. Today’s photonic devices, however, are still rather large. The reason therefore can be found in the nature of light: Diffraction sets a lower limit for the scales of photonic devices and therefore prevents densely packed photonic components. The diffraction limit can be, however, overcome by so called ’Surface Plasmon Polaritons’ (SPPs): These are oscillations of the conducting electrons in a metallic nanoparticle induced by an incoming electromagnetic field with a suitable frequency. By this conversion of the optical mode to surface plasmons, the electromagnetic energy can be localized to regions of merely several tens of nanometers. This property is highly desirable for the construction of future optoelectronic devices: Chains of metallic nanoparticles, for example, are promising waveguides with lateral confinements below the diffraction limit.
DNA is a potential pattern material for constructing nanostructures as it can be synthesized in almost arbitrary lengths in the nanometer scale and also allows for modifications that make site-specific reactions possible. Its inherent scaling limit is determined by the distance of two neighbored basepairs: This length is only 0.34nm and therefore much below the diffraction limit. Moreover, it seems very appealing to exploit the self-recognition properties of DNA to build functional nanostructures by self-assembly processes. Among all possible template-directed material syntheses, metallization of DNA is particularly interesting for photonic devices as it makes a controlled growth of metal nanoparticles with defined size and shape along the DNA template possible. Furthermore the use of DNA as a pattern promises to achieve a defined arrangement of the particles relative to each other.
Experiments concerning metallization of DNA have been done for approximately a decade now. Most experiments, however, have concentrated on investigating the electrical conductance of the DNA. Absorption spectra have merely been recorded for verifying the existence of metallized DNA […]


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Institution / Hochschule
Technische Universität München – Physik Department, Walter Schottky Institut
optical properties dynamic light scattering silver nanoparticles uv/vis



Titel: Optical Properties of metallized DNA