Wagner, Michael Florian Peter (2018)
Bi and Sb Nanowire Assemblies for Thermoelectric Applications.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication
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Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | Bi and Sb Nanowire Assemblies for Thermoelectric Applications | ||||
Language: | English | ||||
Referees: | Trautmann, Prof. Dr. Christina ; Ensinger, Prof. Dr. Wolfgang | ||||
Date: | 30 May 2018 | ||||
Place of Publication: | Darmstadt | ||||
Date of oral examination: | 24 August 2018 | ||||
Abstract: | This thesis presents the fabrication and characterization of Bi(1-x)Sb(x) nanowire assemblies with wellcontrolled and systematically adjusted wire diameter, composition, and vertical or tilted geometrical alignment. The nanowire assemblies were fabricated by means of ion-track technology combining chemical etching of ion-irradiated polymer membranes with electrodeposition of Bi and Sb into track-etched nanochannels. By systematic variation of the etching and deposition conditions, including pulsed potential parameters and surfactant concentration in the electrolyte, the fabrication process was optimized yielding homogeneously grown, uniform nanowire assemblies and networks. The influence of the deposition parameters on morphology and crystalline structure of the resulting Bi, Sb and Bi(1-x)Sb(x) nanowires and networks was investigated by means of X-ray diffraction, high resolution transmission and scanning electron microscopy. Seebeck coefficient and electrical resistance of the nanowire assemblies were investigated in detail as a function of nanowire diameter and temperature. The results confirm the p- and n-type behavior of the Sb and Bi nanowires and provide evidence of the influence of size effects on the thermoelectric transport properties. In addition, a method to measure all relevant thermoelectrical cross-plane properties to deduce the thermoelectric efficiency of a given nanowire assembly was developed. This includes the measurement of the electrical and thermal conductivity as well as the Seebeck coefficient of a nanowire assembly. Finally, more complex nanowire systems were fabricated by combining ion-track nanotechnology and microtechnology to prepare thermocouples formed by Sb and Bi nanowire arrays. These three-dimensional nanowire assemblies of parallel or interconnected nanowires with adjustable diameter and density, embedded in polymer templates, are of great interest for future implementation as e.g. flexible infrared sensors. |
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URN: | urn:nbn:de:tuda-tuprints-80631 | ||||
Classification DDC: | 500 Science and mathematics > 500 Science 500 Science and mathematics > 530 Physics 500 Science and mathematics > 540 Chemistry 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering |
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Divisions: | 11 Department of Materials and Earth Sciences > Material Science 11 Department of Materials and Earth Sciences > Material Science > Ion-Beam-Modified Materials |
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Date Deposited: | 10 Oct 2018 06:54 | ||||
Last Modified: | 09 Jul 2020 02:21 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/8063 | ||||
PPN: | 43742524X | ||||
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