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ASU Electronic Theses and Dissertations


This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.




A theoretical study of a three-dimensional (3D) N/S interface with arbitrary spin polarization and interface geometry is presented. The 3D model gives the same intrinsic spin polarization and superconducting gap dependence as the 1D model. This demonstrates that the 1D model can be use to t 3D data. Using this model, a Heusler alloy is investigated. Andreev reflection measurements show that the spin polarization is 80% in samples sputtered on unheated MgO(100) substrates and annealed at high temperatures. However, the spin polarization is considerably smaller in samples deposited on heated substrates. Ferromagnetic FexSi􀀀x alloys have been proposed as potential spin …

Contributors
Gifford, Jessica Anna, Chen, Tingyong, Bennett, Peter, et al.
Created Date
2015

Cubic boron nitride (c-BN) has potential for electronic applications as an electron emitter and serving as a base material for diodes, transistors, etc. However, there has been limited research on c-BN reported, and many of the electronic properties of c-BN and c-BN interfaces have yet to be reported. This dissertation focused on probing thin film c-BN deposited via plasma enhanced chemical vapor deposition (PECVD) with in situ photoelectron spectroscopy (PES). PES measurements were used to characterize the electronic properties of c-BN films and interfaces with vacuum and diamond. First, the interface between c-BN and vacuum were characterized with ultraviolet PES …

Contributors
Shammas, Joseph, Nemanich, Robert J, Ponce, Fernando, et al.
Created Date
2016

In this dissertation, the interface chemistry and electronic structure of plasma-enhanced atomic layer deposited (PEALD) dielectrics on GaN are investigated with x-ray and ultraviolet photoemission spectroscopy (XPS and UPS). Three interrelated issues are discussed in this study: (1) PEALD dielectric growth process optimization, (2) interface electronic structure of comparative PEALD dielectrics on GaN, and (3) interface electronic structure of PEALD dielectrics on Ga- and N-face GaN. The first study involved an in-depth case study of PEALD Al2O3 growth using dimethylaluminum isopropoxide, with a special focus on oxygen plasma effects. Saturated and self-limiting growth of Al2O3 films were obtained with an …

Contributors
Yang, Jialing, Nemanich, Robert J, Chen, Tingyong, et al.
Created Date
2014

One dimensional (1D) and quasi-one dimensional quantum wires have been a subject of both theoretical and experimental interest since 1990s and before. Phenomena such as the "0.7 structure" in the conductance leave many open questions. In this dissertation, I study the properties and the internal electron states of semiconductor quantum wires with the path integral Monte Carlo (PIMC) method. PIMC is a tool for simulating many-body quantum systems at finite temperature. Its ability to calculate thermodynamic properties and various correlation functions makes it an ideal tool in bridging experiments with theories. A general study of the features interpreted by the …

Contributors
Liu, Jianheng, Shumway, John B, Schmidt, Kevin E, et al.
Created Date
2012

This dissertation presents research findings regarding the exploitation of localized surface plasmon (LSP) of epitaxial Ag islands as a means to enhance the photoluminescence (PL) of Germanium (Ge) quantum dots (QDs). The first step of this project was to investigate the growth of Ag islands on Si(100). Two distinct families of Ag islands have been observed. “Big islands” are clearly faceted and have basal dimensions in the few hundred nm to μm range with a variety of basal shapes. “Small islands” are not clearly faceted and have basal diameters in the 10s of nm range. Big islands form via a …

Contributors
Kong, Dexin, Drucker, Jeffery, Chen, Tingyong, et al.
Created Date
2015

In this dissertation, remote plasma interactions with the surfaces of low-k interlayer dielectric (ILD), Cu and Cu adhesion layers are investigated. The first part of the study focuses on the simultaneous plasma treatment of ILD and chemical mechanical polishing (CMP) Cu surfaces using N2/H2 plasma processes. H atoms and radicals in the plasma react with the carbon groups leading to carbon removal for the ILD films. Results indicate that an N2 plasma forms an amide-like layer on the surface which apparently leads to reduced carbon abstraction from an H2 plasma process. In addition, FTIR spectra indicate the formation of hydroxyl …

Contributors
Liu, Xin, Nemanich, Robert, Chamberlin, Ralph, et al.
Created Date
2012

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 …

Contributors
Tobler, Samuel, Bennett, Peter, Mccartney, Martha, et al.
Created Date
2011

An electrical current with high spin polarization is desirable for the performance of novel spintronics devices, such as magnetic tunnel junction and giant magnetoresistance devices. The generation of spin polarized current can be from ferromagnetic materials or triplet superconductors. Anomalous Hall effect (AHE) is an effective way to study the properties of magnetic structures. The scattering of electrons by the magnetic moments affects the change of resistance, which can be used to detect the magnetization. In this dissertation, AHE is used to study the perpendicular magnetic anisotropy (PMA) structures, including Co/Pt and Ta/CoFeB/MgO. Domain walls exist in all ferromagnetic materials. …

Contributors
Zhao, Gejian, Chen, Tingyong, Bennett, Peter, et al.
Created Date
2018

High electron mobility transistors (HEMTs) based on Group III-nitride heterostructures have been characterized by advanced electron microscopy methods including off-axis electron holography, nanoscale chemical analysis, and electrical measurements, as well as other techniques. The dissertation was organized primarily into three topical areas: (1) characterization of near-gate defects in electrically stressed AlGaN/GaN HEMTs, (2) microstructural and chemical analysis of the gate/buffer interface of AlN/GaN HEMTs, and (3) studies of the impact of laser-liftoff processing on AlGaN/GaN HEMTs. The electrical performance of stressed AlGaN/GaN HEMTs was measured and the devices binned accordingly. Source- and drain-side degraded, undegraded, and unstressed devices were then …

Contributors
Johnson, Michael Ray, Mccartney, Martha R, Smith, David J, et al.
Created Date
2012