The electrical properties of granular systems display many interesting features, including the metal-insulator transition. A number of studies have approached the metal-insulator transition by measuring idealized samples ranging from highly ordered to slightly disordered, though, in practical reality, nanoscale systems are often highly disordered. This dissertation is based on measurements of the electrical transport properties of gold nanoparticle wires produced by a new method called Vertical Colloidal Deposition (VCD), which has been used to synthesize highly disordered films and wires from gold nanoparticles in a colloidal suspension. Measurements of the temperature dependent transport properties of conductance, thermopower, and magnetoresistance, between 20K and 260K are reported. The conductance measurements show that a metal-insulator transition occurs in the gold nanoparticle wires upon varying the size of the gold nanoparticles. The thermopower measurements give us information about the electron-phonon interaction within the wires. The magnetoresistance measurements enlighten the different scattering mechanisms in the gold nanoparticle wires, and give us information about the quantum interference within the wires. The study helps us to understand the transport mechanism of electrons in self-assembled, highly disordered systems.
My contribution to the experiment includes: (1) synthesizing and characterizing the samples, (2) taking and analyzing conductance and thermopower data, (3) analyzing magnetoresistance data, and (4) developing a self-consistent picture for understanding these three different types of measurements.
|Advisor:||Reeves, Mark E.|
|Commitee:||Goodrich, Roy, Griesshammer, Harald W., Parke, William, Qiu, Xiangyun, Tessema, Guebre X.|
|School:||The George Washington University|
|School Location:||United States -- District of Columbia|
|Source:||DAI-B 72/11, Dissertation Abstracts International|
|Subjects:||Nanoscience, Electromagnetics, Nanotechnology, Materials science|
|Keywords:||Gold nanoparticle wires, Granular materials, Magnetoresistance, Phonon confinement, Phonon drag, Thermopower, Transport measurements, Weak localization|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be