Synthesis and characterization of light-element nanomaterials

One-dimensional (1D) nanostructures are attractive because of their interesting physical, chemical, electrical properties and potential applications in nanoelectronics, nanocomposites and others. Significant research progresses have been made on synthesizing 1 D nanostructures recently.; In this dissertation, we report our recent results on synthesis of carbon-related and boron-related nanostructures. We are interested in using carbon-related nanostructure in nanocomposites application, and using boron-related nanostructure in nanoelectronics application. Vapor phase growth synthetic strategy was adopted in this work.; A template-based synthesis approach was employed to produce carbon-related nanostructures. Using this approach, nanomaterials having uniform geometries and dimensions can be created via appropriate manipulation of the template fabrication and materials deposition processes. In this work, porous anodic alumina films were used as templates and chemical vapor deposition process was used as materials deposition tool. One of our accomplishments was the synthesis of novel dumbbell-shaped carbon nanotubes. The dumbbell-shaped nanomaterials are promising in nanocomposites application, where enhanced load-transfer through mechanical interlocking with the matrix at the widened ends is anticipated.; Motivated by the theoretical prediction of the existence of metallic single-walled boron and metal boride nanotubes, experimental works on synthesis of novel boron-related nanostructures have been carried out. Using a home-built low-pressure chemical vapor deposition system, various boron-related nanostructures have been synthesized. For example, non-catalyst-assisted growth of crystalline boron nanoribbons was achieved by pyrolysis of diborane at relatively low temperature and pressure. Catalyst-assisted growth of calcium boride nanowires was observed by pyrolysis of diborane over calcium oxide powder. Catalyst-assisted growth of boron wire-catalyst-tube hybrid nanostructures was also realized. These novel boron nanostructures could serve as testing units for properties studying, and also have potential application in nanocomposites and nanoelectronics.