MEASURING THE THERMOELECTRIC PROPERTIES OF NANOMATERIALS WITH A MICROMACHINED WORKBENCH

Open Access
Author:
Chang, Matthew
Area of Honors:
Electrical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Srinivas A Tadigadapa, Thesis Supervisor
  • John Douglas Mitchell, Honors Advisor
Keywords:
  • Thermoelectric
  • Nanomaterials
  • Workbench
Abstract:
<p>Thermoelectric devices, which can convert thermal energy into electrical energy or provide a method for solid state cooling, have not been used as a widespread source of renewable energy because of their unmarketably low efficiencies. Recently, however, the development of certain nanomaterials and nanostructures, and a demonstration of their enhanced thermoelectric efficiencies, have reignited the search for an efficient thermoelectric material. Investigating these enhanced thermoelectric effects has not been easy for the scientific community because studying the physics of nanomaterials is a complex and sensitive task. As such, widely accepted, conformal, or statistical data has not been gathered. </p> <p>This honors thesis presents a micromachined workbench designed specifically to study the thermoelectric properties of nanomaterials in an easy and accurate way. Two generations of the workbench, consisting of different material compositions, are characterized and tested both thermally and electrically. Thermally speaking, the thermal crosstalk, thermocouple performance, and thermal time constant are measured on all tested workbenches. On the electrical side, DC I-V measurements are performed along with DC electrical crosstalk (leakage) measurements. A test system is created to perform all these measurements and is automated with LabVIEW code. The measurement system and associated code will be shown and described briefly. </p> <p>The thermopower of 70 nm diameter gold nanowires are measured using both workbenches. The results of the gold nanowire thermopower measurements and the workbench characterization measurements are presented here. An evaluation of both workbench structures, including their benefits and flaws, are also presented along with suggested improvements for future work.</p>