Nanotube Synthesis

Currently, we are investigating creative ways to catalyze the production of nanotubes from carbon as well as other elements. Ideally, we seek to produce high-yield, uniformly-shaped nanotubes (specifically carbon nanotubes and boron-nitride tubes) by simply finding the optimum operating parameters and catalysts. We presently use various techniques including both direct current arc plasma and laser ablation to synthesize materials. Using methods such as Transmission Electron Microscopy (TEM), it is possible to view the lattices of tubes. Other analytical methods include Mass Spectrometry to obtain the molecular weight distribution for determining the presence of various fullerenes such as C₆₀, elemental combustion analysis, and Electron Energy Loss Spectrometry (EELS) to determine the elemental composition of a sample. In this type of work, it is also natural to generate new types of materials and structures. Simply by varying the parameters of our synthesis, we have been able to form a number of unusual nanostructured materials. Sometimes the results are difficult to characterize, as in the case of the new C₃₆ fullerene. At other times, the TEM immediately shows that something unusual has been formed.

Here is a TEM micrograph of a "pearl necklace," a string of metallic tungsten clusters connected by a few layers of BN. The electrically insulating nature of the BN sheets suggests this structure may have interesting properties as a chain of quantum dots.

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