Year of Publication

2008

Document Type

Dissertation

College

Engineering

Department

Mechanical Engineering

First Advisor

M. Pinar Mengüç

Abstract

The ability to pattern in the nanoscale to drill holes, to draw lines, to make circles, or more complicated shapes that span a few atoms in width is the main driver behind current efforts in the rapidly growing area of nanomanufacturing. In applications ranging from the microprocessor industry to biomedical science, there is a constant need to develop new tools and processes that enable the shrinking of devices. For this and more applications, nanomanufacturing using electron beams offers a window of opportunity as a top-down approach since electrons, unlike light, have a wavelength that is in the order of the atomic distance. Though the technology based on electron beams has been available for more than twenty years, new concepts are constantly being explored and developed based on fundamental approaches. As such, a tool that utilizes electron field-emission from carbon nanotubes was proposed to accomplish such feats. A full numerical analysis of electron field-emission from carbon nanotubes for nanomachining applications is presented. The different aspects that govern the process of electron field-emission from carbon nanotubes using the finite element method are analyzed. Extensive modeling is carried here to determine what the effect of different carbon nanotube geometries have on their emission profiles, what energy transport processes they are subject to, and establish what the potential experimental parameters are for nanomachining. This dissertation builds on previous efforts based on Monte Carlo simulations to determine electron deposition profiles inside metals, but takes them to next level by considering realistic emission scenarios. A hybrid numerical approach is used that combines the two-temperature model with Molecular Dynamics to study phase change and material removal in depth. The use of this method, allows the determination of the relationship between the amount of energy required to remove a given number of atoms from a metallic workpiece and the number of carbon nanotubes and their required settings in order to achieve nanomachining. Finally, the grounds for future work in this area are provided, including the need for novel electron focusing systems, as well as the extension of the hybrid numerical approach to study different materials.

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