Authors: M.M. Yazdanpanah, V.V. Dobrokhotov, A. Safir, S. Pabba, D. Rojas, R.W. Cohn
Affilation: University of Louisville, United States
Pages: 896 - 899
Keywords: Intermetallics, crystallization, directed self assembly, selective growth
It is possible to grow single crystals directly on nanoprobes, such as atomic force microscope (AFM) probes, tungsten needles and nanotapered glass pipettes. We have grown single Ag2Ga nanoneedles and PtGa6 nanoplates/blades from supersaturated melts of Ga on AFM tips. These nanomaterials are identified by first placing melted drops of Ga directly on foils of elemental metals to identify the morphology, structure and composition of the crystals formed. Then, an AFM cantilever is coated with the metal of interest and immersed in a Ga droplet. The meniscus formed between the support and the Ga appears to direct the growth of single nanocrystals. On thin films we have observed the formation of nanoscale hexagonal rod (Ag2Ga, CoGa3), square bars (FeGa3), 10 thick plates (Ga6Pt, FeGa3), cubooctahedrons and icosahedrons (Ga5Pd). The growth of single crystals of several of these alloys onto AFM probes starts by sputtering metal films from 30-150 nm onto AFM probes. The probes inserted into a Ga droplet while observing the crystal formation under a scanning electron microscope. In mechanical tests we have observed that the nanostructures are very strongly attached to the AFM probe.