S. Perlt

Plasmonic Activity of Large-Area Gold Nanodot Arrays on Arbitrary Substrates

Highly efficient fabrication of well-ordered, embedded gold nanodot matrices using diffraction mask projection laser ablation is demonstrated. These gold nanodot arrays are ideally generated onto sapphire substrates but do also form onto AlO(x) thin films, enabling the application to arbitrary bulk substrates. Well-ordered gold dots become embedded into the Al(2)O(3) substrate during the process, thus improving their mechanical stability, chemical inertness, and technological compliance. Such substrates may be useful, for example, to enhance solar-cell efficiency by surface plasmons or as convenient, biocompatible focusing elements in nearfield optical tweezers.

Gold nanostructure matrices by diffraction mask-projection laser ablation: extension to previously inaccessible substrates

Gold nanodot matrices made by diffraction mask-projection laser ablation (DiMPLA) are presented. The nanodots are well ordered and can be synthesized on so far not accessible substrates by virtue of intermediate thin AlO(x) layers deposited by pulsed-laser deposition (PLD). Investigations were made on the influence of layer thickness, roughness and type of substrate on the nanodots and their fabrication. It is shown that all of these parameters are crucial for the generation of nanodots on thin AlO(x) layers. The roughness of the layer and the substrate material determine whether the layer cracks upon laser patterning. The layer thickness, on the other hand, influences the size of gold nanodots on top. Extinction spectra show that the particle size is the dominant contribution that shifts the plasmon resonance peak.

Correlation between microstructure and thermoelectric properties of AgPb18SbTe20 (LAST-18)

This study reports microstructure investigations at AgPbmSbTe2+m (m = 18) (Lead-Antimony-Silver-Tellurium, LAST-18). Two different length scales were explored. The micrometer scale was evaluated by SEM to analyze volume fraction and number of secondary phases as well as the impact of processing parameters on the homogeneity of bulk samples. Site-specific liftout of TEM lamellae from thermoelectrically characterised samples was made to investigate the structure on the nanometer scale. High-resolution TEM and energy-filtered TEM were performed to reveal shape and size distribution of nanoprecipitates, respectively. An attempt is made to derive a structure-property relationship.