UMBC logo
UMBC Department of Physics
News & Events

About

This page contains a single entry from the blog posted on November 18, 2008 8:27 AM.

The previous post in this blog was PhD Proposal Defense - Hao You.

The next post in this blog is PhD Defense - Jeff Warner.

Many more can be found on the main index page or by looking through the archives.

Powered by
Movable Type 3.34

« PhD Proposal Defense - Hao You | Main | PhD Defense - Jeff Warner »

PhD Defense - Andrew Bunch

Andrew successfully defended his dissertation on November 18, 2008.

TITLE:
Step Dynamics and the Morphological Evolution of Nanostructures

ABSTRACT:
Surface diffusion of atoms plays a significant role in the evolution of the shape of a material in the nanoscale regime because it becomes the dominant mechanism for mass transport as the surface area to volume ratio increases. In this dissertation, I present a theoretical study of the shape evolution of a particular nanostructure: the nanowire. At non-zero temperatures, atomic steps are always present on the surface of a nanostructure and their growth and motion causes a change of shape and can cause the wire to break.

I have studied the morphological evolution of nanowires before and after a break develops, the resulting segments of a broken nanowire whose tips are nanoneedles. My approach is to develop and compare a step motion model and atomistic simulations and test them against available experimental data and classical continuum theory. My approach also allowed me to derive the scaling relations and exponents describing the morphological evolution of nanowires and study the microscopic nature of the instability that causes them to break.

UMBC's Department of Physics   |   410-455-2513 or 1-877-707-1969 (toll free)   |   physics@umbc.edu  |  Site Info