One-dimensional and hierarchical nanostructures have acquired tremendous attention in the past decades due to their possible application. In spite of the rapid emergence of new morphologies, the underlying growth mechanism is still not well understood. The lack of effective p-type or n-type doping is another obstacle for many semiconducting nanomaterials. A deeper investigation into these structures and new methods to fabricate devices are of significant impact for nanoscience and nanotechnology. Motivated by a desire to understand the growth mechanism of nanostructures and investigate novel device fabrication method, the research described in this thesis carried out on the synthesis, characterization, and device fabrication of semiconducting nanostructures. The main focus of the research was on ZnO, SnO2, and Zn3P2 for their great capability for fundamental phenomena studying, promising applications in sensors and optoelectronics, and the potential generalization of results to other materials. Within this study the following goals have been achieved: 1) Improved understanding of polar-surface-induced growth mechanism in wurtzite-structured ZnO and generalization of this growth mechanism with the discovery and analysis of rutile ¨Cstructured SnO2, 2) observation of the significance of the transversal growth, which is usually ignored, in interpenetrative ZnO nanowires, 3) rational design and growth control over versatile nanostructures of ZnO and Zn3P2, and 4) conjunction of p-type Zn3P2 and n-type ZnO semiconducting nanostructures for device fabrications. The framework for the research is reviewed first in chapter 1. Chapter 2 gives the detailed experimental setup, synthesis procedure, and common growth mechanism for nanostructure growth. A detailed discussion on the growth of ZnO nanostructures in chapter 3 provides more insight into the polar-surface-induced growth, transversal growth, vapor-solid growth, and vapor-liquid-solid growth during the formation of nanostructures. Polar-surface-induced growth is also confirmed in the growth of SnO2 nanostructures, which is also included in chapter 2. Chapter 3 presents Zn3P2 nanostructures from the newly designed experiment setup and the device fabrication from ZnO and Zn3P2 crossed nanowires.

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Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (leaves 185-191). Also available via World Wide Web.

Thesis (Ph.D.)--McMaster University (Canada), 1995. / Source: Dissertation Abstracts International, Volume: 57-03, Section: B, page: 1870. Adviser: D. A. Thompson.

Thesis (Ph.D.)--McMaster University (Canada), 1996. / Source: Dissertation Abstracts International, Volume: 57-10, Section: B, page: 6325. Adviser: D. A. Thompson.

Thesis (Ph.D.)--McMaster University (Canada), 1996. / Source: Dissertation Abstracts International, Volume: 58-06, Section: B, page: 3263. Adviser: G. C. Weatherly.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 178-188).

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. / 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. / Committee in charge: Stephen Kevan, Chairperson, Physics; Heiner Linke, Member, Physics; Roger Haydock, Member, Physics; Stephen Hsu, Member, Physics; David Johnson, Outside Member, Chemistry