Show simple item record

dc.contributor.advisorMildred S. Dresselhaus.en_US
dc.contributor.authorRabin, Oded, 1974-en_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Chemistry.en_US
dc.date.accessioned2005-06-02T18:27:22Z
dc.date.available2005-06-02T18:27:22Z
dc.date.copyright2004en_US
dc.date.issued2004en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/17738
dc.descriptionThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2004.en_US
dc.descriptionVita.en_US
dc.descriptionIncludes bibliographical references (p. 187-200).en_US
dc.description.abstractPorous anodic alumina (PAA) films were utilized to template the fabrication of nanostructures of bismuth, antimony and bismuth-antimony alloys. The cylindrical template pores were used to synthesize nanowires by electrochemical methods. The porous surface of the template was used as a substrate for the e-beam deposition of antidot array thin films. Electrical transport measurements in bismuth nanowire arrays embedded in the templates were demonstrated to be highly sensitive to structural imperfections. Thin film studies compared the weak anti-localization effect in bismuth films with antidot array morphology versus continuous films. It is shown that the antidot array makes the weak anti-localization effect more pronounced in magnetoresistance measurements, and allows for a more detailed study of carrier scattering mechanisms in thin films. A new process is presented for the fabrication of PAA templates on rigid substrates. The substrate provides mechanical support for the generation of crack-free PAA films over areas of tens of cm2, while electrically-conducting substrates can serve as back-electrodes for the electrochemical growth of nanowires and for their electrical characterization. Various processing challenges were solved, including the deposition of thick aluminum films, the control over the adhesion between the layers of the structure, and the removal of the alumina barrier-layer at the interface between the porous film and the substrate. The use of the substrate to achieve non-planar and patterned PAA films is demonstrated.en_US
dc.description.abstract(cont.) A model is constructed to calculate the thermoelectric figure-of-merit Z of bismuth- antimony alloy nanowires as a function of diameter, composition, and carrier density. In this model, the band structure of the alloy in bulk form is modified by the quantization of k-space in the two dimensions perpendicular to the nanowire main-axis. Boltzmann's transport equations are solved with this one-dimensional band structure. The model predicts an enhancement in Z in alloy nanowires compared to the alloys in bulk form and to bismuth nanowires. The enhancement, which was found to be non- monotonic i diameter-composition space, was related to shifts in the populations and energies of the different carrier pockets.en_US
dc.description.statementofresponsibilityby Oded Rabin.en_US
dc.format.extent200, [2] p.en_US
dc.format.extent8382985 bytes
dc.format.extent8382791 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectChemistry.en_US
dc.titleBismuth nanowire and antidot array studies motivated by thermoelectricityen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Dept. of Chemistry.en_US
dc.identifier.oclc56481081en_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record