Nanoscale materials are demonstrating new properties and promising applications with each passing day. The fabrication of ever more complex and precise nanomaterials represents a continuing drive in the fields of physics, chemistry, and biology. Template-based approaches provide an attractive method of producing new inaccessible materials by modifying and confining older techniques, but most of the templates available today function only in a narrow range of chemical parameters. In this work, new thermally and chemically robust 'nanowell' templates were built to study confined precipitation as a method to fabricate nanomaterials. These templates consisted of two-dimensional arrays of 50 to 100-nm diameter (50-500 zL) hemispherical impressions in silicon and tantalum oxide. We found that after loading these nanowells by discontinuous dewetting the solvent rapidly evaporated, and the solute within each well crystallized into a single nanocrystal. The size of that nanocrystal depended on the size of the well and the concentration of the solution. We reduced metal salt precursor nanoparticles in a high temperature hydrogen atmosphere to fabricate metallic and metal oxide nanoparticles, and experiments were carried out to determine the nature and limits of nanoscale precipitation to generate novel nanomaterials. We found that in the presence of an existing nanoparticle, any new material loaded into the well would preferentially precipitate in contact with the existing nanoparticle. This phenomenon was applied to fabricate intermetallic nanocrystals.

Last modified

• 09/10/2018

Creator

• Jeremy Barton

DOI

• https://doi.org/10.21985/N2PB05

Subject

• Chemistry

Keyword

• Nanotechnology
• Nanoparticles
• Nanowells
• Tantalum Oxide

Date created

• 2008-05-12

Resource type

• Dissertation

Rights statement

• In Copyright