The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires
| dc.contributor.author | Hoffmann, Eric A., 1982- | |
| dc.date.accessioned | 2010-07-28T23:32:25Z | |
| dc.date.available | 2010-07-28T23:32:25Z | |
| dc.date.issued | 2009-12 | |
| dc.description | xi, 193 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. | en_US |
| dc.description.abstract | State of the art semiconductor materials engineering provides the possibility to fabricate devices on the lower end of the mesoscopic scale and confine only a handful of electrons to a region of space. When the thermal energy is reduced below the energetic quantum level spacing, the confined electrons assume energy levels akin to the core-shell structure of natural atoms. Such "artificial atoms", also known as quantum dots, can be loaded with electrons, one-by-one, and subsequently unloaded using source and drain electrical contacts. As such, quantum dots are uniquely tunable platforms for performing quantum transport and quantum control experiments. Voltage-biased electron transport through quantum dots has been studied extensively. Far less attention has been given to thermoelectric effects in quantum dots, that is, electron transport induced by a temperature gradient. This dissertation focuses on the efficiency of direct thermal-to-electric energy conversion in InAs/InP quantum dots embedded in nanowires. The efficiency of thermoelectric heat engines is bounded by the same maximum efficiency as cyclic heat engines; namely, by Carnot efficiency. The efficiency of bulk thermoelectric materials suffers from their inability to transport charge carriers selectively based on energy. Owing to their three-dimensional momentum quantization, quantum dots operate as electron energy filters--a property which can be harnessed to minimize entropy production and therefore maximize efficiency. This research was motivated by the possibility to realize experimentally a thermodynamic heat engine operating with near-Carnot efficiency using the unique behavior of quantum dots. To this end, a microscopic heating scheme for the application of a temperature difference across a quantum dot was developed in conjunction with a novel quantum-dot thermometry technique used for quantifying the magnitude of the applied temperature difference. While pursuing high-efficiency thermoelectric performance, many mesoscopic thermoelectric effects were observed and studied, including Coulomb-blockade thermovoltage oscillations, thermoelectric power generation, and strong nonlinear behavior. In the end, a quantum-dot-based thermoelectric heat engine was achieved and demonstrated an electronic efficiency of up to 95% Carnot efficiency. | en_US |
| dc.description.sponsorship | Committee in charge: Stephen Kevan, Chairperson, Physics; Heiner Linke, Member, Physics; Roger Haydock, Member, Physics; Stephen Hsu, Member, Physics; David Johnson, Outside Member, Chemistry | en_US |
| dc.identifier.uri | https://hdl.handle.net/1794/10552 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | University of Oregon | en_US |
| dc.relation.ispartofseries | University of Oregon theses, Dept. of Physics, Ph. D., 2009; | |
| dc.subject | Thermoelectric efficiency | en_US |
| dc.subject | Quantum dots | en_US |
| dc.subject | Nanowires | en_US |
| dc.subject | Indium arsenide | en_US |
| dc.subject | Indium phosphide | en_US |
| dc.subject | Solid state physics | en_US |
| dc.subject | Materials science | en_US |
| dc.title | The thermoelectric efficiency of quantum dots in indium arsenide/indium phosphide nanowires | en_US |
| dc.type | Thesis | en_US |
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