Preparation of Nanostructures from Directionally Solidified Eutectics

The production of nanostructured materials is possible by directional solidification. Metals as well as semiconductors can be employed in the eutectics. An appropriate etching allows either the production of short standing wires or of longer wires organised in domains. Furthermore the preparation of isolated nanowires becomes possible by a complete dissolution of the matrix. The system shows a remarkable high degree of order and a uniform crystallographic orientation. Anodic polarisation in a neutral buffer allows a simultaneous passivation of the host phase and selective oxidising dissolution of the wires. Other metals such as gold can be deposited in the so formed cavities. The different strategies for a structuring of these materials and their applications as nanostructured materials and in sensors are discussed.