46498-G10
Exploring Improved Petroleum Utilization Via Nanoscale Thermal Engineering of Thermoelectric Materials
The first year of our program of fundamental research focused on investigating high efficiency thermoelectrics based on nonequilibrium materials has been extremely productive and puts our group in a strong position for the final year of PRF funding. The bulk of our first year has been focused on designing and implementing the unique measurements required to simultaneously determine all parameters in the dimensionless figure-of-merit for thin films and nanostructures. We have been very successful in developing a micromachined thermal isolation structure that allows measurements of thermopower, electrical conductivity, and in-plane thermal conductivity for a single deposited thin film sample, and have conducted preliminary tests of the platform on deposited metallic films. Results indicate that our measurements will be ideal for exploring the nonequilbrium semiconductor alloys that are the main focus of our project.
The main area of work in year two will focus on the growth and detailed characterization of these amorphous silicon (and germanium) alloy films, and their investigation as potential thermoelectric materials. We are currently completing assembly of a UHV deposition chamber (partially supported by this PRF Type G award), and will soon begin a systematic study of these materials. The physics of the thermal, electric, and thermoelectric transport properties of this system will not only be of fundamental interest, but could also lead either directly to a promising thin-film thermoelectric, or to key insights that will guide future searches for both bulk or thin film solid-state energy conversion or cooling technologies.
Additional efforts in year two will center on the improvements to our measurement techniques that are necessary to study small arrays of wires with widths in the deep sub-micron regime. Though measurements these nanoscale systems require highly sensitive instruments to measure, we are confident that our approach to understanding thermal and thermoelectric transport in these systems will be fruitful and will shed additional light on both the fundamental physics of heat and charge flow in nanoscale systems and on ways to exploit the resulting effects for functional systems such as thermoelectric generators and coolers.
As detailed in the supporting documents, funding from PRF has supported research staff, (including graduate and undergraduate researchers), travel to conferences, laboratory equipment and supplies. Results from our first year of support have enabled one publication in a peer-reviewed journal (Journal of Applied Physics, in press), contributed presentations at the APS March Meeting in 2008 and 2009 (two talks will be presented), two contributed posters at the joint meeting of the APS Four Corners and Texas Section meeting in 2008, an invited talk at the joint meeting of the APS 4CS and Texas Sections in 2008, and invited seminar or colloquium presentations at Colorado State University, the University of Colorado at Boulder, the University of Wyoming, and the State University of New York at Stony Brook.
