Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006. / Dr. C. J. Summers, Committee Member ; Dr. H. M. Zhou, Committee Member ; Dr. P. Paul Ruden, Committee Co-Chair ; Dr. W. R. Callen, Committee Chair ; Dr. D. S. Citrin, Committee Member ; Dr. A.B. Frazier, Committee Member.

Thesis (Ph.D.)--Ohio University, November, 2004. / Title from PDF t.p. Includes bibliographical references (p. 202-211)

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2006. / Includes bibliographical references (leaves 69-73). Also available in electronic version.

Thesis (Ph. D.)--University of Canterbury, 2006. / Typescript (photocopy). "1st of February 2006." Includes bibliographical references (p. [217]-230). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Washington State University, May 2007. / Includes bibliographical references (p. 130-136).

<p> This thesis describes the mechanisms by which organic surfactants, particularly thiophenols and phenyldithiocarbamates, reduce the confinement potential experienced by the exciton of semiconductor quantum dots (QDs). The reduction of the confinement potential is enabled by the creation of interfacial electronic states near the band edge of the QD upon ligand adsorption. In the case of thiophenols, we find that this ligand adsorbs in two distinct binding modes, (i) a tightly bound mode capable of exciton delocalization, and (ii) a more weakly bound mode that has no discernable effect on exciton confinement. Both the adsorption constant and reduction in confinement potential are tunable by para substitution and are generally anticorrelated. For tightly bound thiophenols and other moderately delocalizing ligands, the degree of delocalization induced in the QD is approximately linearly proportional to the fractional surface area occupied by the ligand for all sizes of QDs. In the case of phenyldithiocarbamates, the reduction in the confinement potential is much greater, and ligand adjacency must be accounted for to model exciton delocalization. We find that at high surface coverages, exciton delocalization by phenyldithiocarbamates and other highly delocalizing ligands is dominated by ligand packing effects. Finally, we construct a database of electronic structure calculations on organic molecules and propose an algorithm that combines experimental and computational screening to find novel delocalizing ligands.</p>

abstract: In this project, a novel method is presented for measuring the resistivity of nanoscale metallic conductors (nanowires) using a variable-spacing 2-point method with a modified ultrahigh vacuum scanning tunneling microscope. An auxiliary field emission imaging method that allows for scanning insulating surfaces using a large gap distance (20nm) is also presented. Using these methods, the resistivity of self-assembled endotaxial FeSi2 nanowires (NWs) on Si(110) was measured. The resistivity was found to vary inversely with NW width, being rhoNW = 200 uOhm cm at 12 nm and 300 uOhm cm at 2 nm. The increase at small w is attributed to boundary scattering, and is fit to the Fuchs-Sondheimer model, yielding values of rho0 = 150 uOhm cm and lambda = 2.4 nm, for specularity parameter p = 0.5. These results are attributed to a high concentration of point defects in the FeSi2 structure, with a correspondingly short inelastic electron scattering length. It is remarkable that the defect concentration persists in very small structures, and is not changed by surface oxidation. / Dissertation/Thesis / Ph.D. Physics 2011

Phase change phenomena have been of interest mainly due to large latent heats associated with the phase transition and independency on external energy to drive the phase change process. When combined with micro/nano structures, phase change systems become a promising approach to address challenges in high heat flux thermal management. The objective of this thesis is to implement micro and nano structured surfaces for better understanding the underlying fundamentals of evaporation and boiling phase change heat transfer and enhancing the heat transfer performance. First, we study single bubble dynamics on superheated superhydrophobic (SHB) surfaces and the corresponding heat transfer mechanism of water pool boiling. Because of the large contact angle, such surfaces are ideal for correlating pool boiling with single bubble dynamics by accurately controlling the number of nucleation sites in a defined area. The fundamental parameters of single bubble dynamics are collected and put into the heat flux partitioning model. We find that latent heat transport and bulk liquid water convection contribute together to the heat removal on superhydrophobic surfaces. Next, we present a novel method to fabricate silicon nanowires by one-step metal assisted chemical etching (MACE) on micro-structured surfaces with desired morphologies. Patterned vertically aligned silicon nanowires are fabricated on dense cavity/pillar arrays due to trapped hydrogen bubbles serving as an etching mask. Uniformly grown silicon nanowires on structured surfaces can be fabricated if extra energy is introduced to remove the trapped bubbles. An enhanced pool boiling heat transfer performance on such structured surfaces is demonstrated. Finally, we study the ultimate limits of water evaporation in single 2D nanochannels and 1D nanopores. These ultimate transport limits are determined by the maximum evaporation fluxes that liquid/vapor interfaces can provide regardless of liquid supply or vapor removal rates. A hybrid nanochannel design is utilized to provide sufficient liquid supply to the evaporating meniscus and evaporated vapor is efficiently removed by air jet impingement or a vacuum pump. The effect of nanoscale confinement on evaporation flux has been investigated, with feature size ranging from 16 nm to 310 nm. An ultra-high heat flux of 8500 W/cm2 is demonstrated in a single 16-nm nanochannel at 40 °C. / 2017-09-09T00:00:00Z