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You searched for +publisher:"Michigan State University" +contributor:("Zhang, Pengpeng"). Showing records 1 – 3 of 3 total matches.

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Michigan State University

1. Zhu, Zhen, Ph. D. Electronic properties of complex nanostructures.

Degree: 2015, Michigan State University

Thesis Ph. D. Michigan State University. Physics 2015

Nanostructured materials have brought an unprecedented opportunity for advancement in many fields of human endeavor and in applications. Nanostructures are a new research field which may revolutionize people's everyday life. In the Thesis, I have usedtheoretical methods including density functional theory (DFT), molecular dynamic simulations (MD) and tight-binding methods to explore the structural, mechanical and electronic properties of various nanomaterials. In all this, I also paid attention topotential applications of these findings.First, I will briefly introduce the scientific background of this Thesis, including the motivation for the study of a boron enriched aluminum surface, novel carbon foam structures and my research interest in 2D electronics. Then I will review the computational techniques I used in the study, mostly DFT methods.In Chapter 3, I introduce an effective way to enhance surface hardness of aluminum by boron nanoparticle implantation. Using boron dimers to represent the nanoparticles, the process of boron implantation is modeled in a molecular dynamics simulation ofbombarding the aluminum surface by energetic B2 molecules. Possible metastable structures of boron-coated aluminum surface are identified. Within these structures, I find that boron atoms prefer to stay in the subsurface region of aluminum. By modeling the Rockwell indentation process, boron enriched aluminum surface is found to be harder than the pristine aluminum surface by at least 15%.In Chapter 4, I discuss novel carbon structures, including 3D carbon foam and related 2D slab structures. Carbon foam contains both sp2 and sp3 hybridized carbon atoms. It forms a 3D honeycomb lattice with a comparable stability to fullerenes, suggesting possible existence of such carbon foam structures. Although the bulk 3D foam structure is semiconducting, an sp2 terminated carbon surface could maintain a conducting channel even when passivated by hydrogen. To promote the experimental realization of this novel foam structure, I also propose a growth model. I postulate that preferred growth should occur near the grain boundary of a carbon saturated polycrystal of transition metal. These findings are supported by a calculation of carbon diffusion in the solid.2D semiconductors of group V elements are discussed in Chapters 5, 6, 7, and 8, including different phosphorus and arsenic structural phases. Structural and electronicproperties of bulk and few-layer black phosphorus, so-called phosphorene, are studiedin Chapter 5. In Chapter 6, I propose a new 2D structural phase of phosphorus,with the name blue phosphorus related to its wide predicted fundamental band gap. Then I move down in the periodic table and investigate the properties of grey arsenic in Chapter 7. Finally, I propose a tiling model to identify and categorize these structural phases in Chapter 8.

Description based on online resource;

Advisors/Committee Members: Tomanek, David, Zhang, Pengpeng, Piecuch, Piotr, Ruan, Chong-Yu, Pratt, Scott.

Subjects/Keywords: Nanostructured materials – Electric properties; Nanostructures – Electric properties; Physics; Condensed matter physics; Theoretical physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zhu, Zhen, P. D. (2015). Electronic properties of complex nanostructures. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:2570

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Zhu, Zhen, Ph D. “Electronic properties of complex nanostructures.” 2015. Thesis, Michigan State University. Accessed February 18, 2019. http://etd.lib.msu.edu/islandora/object/etd:2570.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Zhu, Zhen, Ph D. “Electronic properties of complex nanostructures.” 2015. Web. 18 Feb 2019.

Vancouver:

Zhu, Zhen PD. Electronic properties of complex nanostructures. [Internet] [Thesis]. Michigan State University; 2015. [cited 2019 Feb 18]. Available from: http://etd.lib.msu.edu/islandora/object/etd:2570.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhu, Zhen PD. Electronic properties of complex nanostructures. [Thesis]. Michigan State University; 2015. Available from: http://etd.lib.msu.edu/islandora/object/etd:2570

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Michigan State University

2. Wagner, Sean Robert. Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures.

Degree: 2015, Michigan State University

Thesis Ph. D. Michigan State University. Physics 2015.

As the electronics industry continues to evolve and move towards functional electronic devices with increasing complexity and functionality, it becomes important to explore materials outside the regime of conventional semiconductors. Organic semiconducting small molecules have received a large amount of attention due to their high degree of flexibility, the option to perform molecular synthesis to modify their electronic and magnetic properties, and their ability to organize into highly-ordered functionalized nanostructures and thin films. Being able to form complex nanostructures and thin films with molecular precision, while maintaining the ability to tune properties through modifications in the molecular chemistry could result in vast improvements in conventional device architectures. However, before this is realized, there still remains a significant lack of understanding regarding how these molecules interact with various substrate surfaces as well as their intermolecular interactions. The interplay between these interactions can produce drastic changes in the molecular orientation and ordering at the hetero-interface, which can affect the transport properties of the molecular thin film and ultimately modify the performance of the organic electronic device.This study first focuses on the growth dynamics, molecular ordering, and molecular orientation of metal phthalocyanine (MPc) molecules, particularly on Si, a substrate which is notoriously difficult to form an organized organic thin film on due to the surface dangling bonds. By deactivating these bonds, the formation of a highly ordered organic molecular thin film becomes possible. Combining scanning tunneling microscopy, scanning tunneling spectroscopy, low-energy electron diffraction, and density functional theory calculations, the growth evolution of MPc molecules (M = Zn, Cu, Co) from the single molecule level to multilayered films on the deactivated Si(111)-B surface is investigated.Initial tests are centered around thermally evaporated ZnPc. These molecules display a highly-ordered, close-packed, tilted configuration which differs from any known bulk packing motif. The ZnPc molecules are able to diffuse rapidly on the Si surface and preferentially nucleate at Si step-edges. This is followed by the formation of highly-ordered anisotropic stripe structures which grow across the Si terraces, i.e. anisotropic step-flow growth. The step-flow growth mode further impacts the growth by reducing the allowed symmetry of the molecular domains such that thin films with an exclusive in-plane molecular ordering are formed. Additionally, the ZnPc tilted packing motif stabilizes the molecular film, allowing it to maintain this packing for multilayered films, despite the decreasing substrate influence. The strength of the MPc-substrate interaction can be modified by changing the central transition-metal ion within the molecule. Through selective p-d orbital coupling between MPc molecules and the substrate, the…

Advisors/Committee Members: Zhang, Pengpeng, Duxbury, Phillip, Schmidt, Carl, Tessmer, Stuart, Tollefson, Kirsten.

Subjects/Keywords: Heterostructures; Nanostructures; Organic semiconductors; Semiconductors; Biotechnology; Condensed matter physics; Molecular physics; Nanoscience

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wagner, S. R. (2015). Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:3616

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Wagner, Sean Robert. “Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures.” 2015. Thesis, Michigan State University. Accessed February 18, 2019. http://etd.lib.msu.edu/islandora/object/etd:3616.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Wagner, Sean Robert. “Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures.” 2015. Web. 18 Feb 2019.

Vancouver:

Wagner SR. Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures. [Internet] [Thesis]. Michigan State University; 2015. [cited 2019 Feb 18]. Available from: http://etd.lib.msu.edu/islandora/object/etd:3616.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wagner SR. Study of organic-inorganic hetero-interfaces and electrical transport in semiconducting nanostructures. [Thesis]. Michigan State University; 2015. Available from: http://etd.lib.msu.edu/islandora/object/etd:3616

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Michigan State University

3. Showalter, Rachel Hodges. Determination of density and momentum dependence of nuclear symmetry potentials with asymmetric heavy ion reactions.

Degree: 2015, Michigan State University

Thesis Ph. D. Michigan State University. Physics 2015.

The nuclear symmetry energy, which is important for asymmetric nuclear systems including rare isotopes and neutron stars, has been studied through both experimental and theoretical approaches, spanning a range of densities from below and above normal nuclear matter density. In the past decade, significant constraints on the density dependence have been obtained in the subsaturation density region, from Heavy Ion Collision (HIC) experiments as well as experiments probing nuclear structure. On the other hand, very little has been determined about the symmetry energy at suprasaturation densities; experimentally, this density region is only accessible in HICs. It is therefore important to understand how to extract nuclear symmetry energy information from HIC at high energies where high density nuclear matter is created in a very brief instant.Symmetry energy constraints from HICs are determined by comparing experimental observables with those calculated using transport models. The goals of this dissertation are to identify the observables most sensitive to the symmetry energy strength, the effective mass splitting, and the in-medium nucleon-nucleon cross sections, σNN, at the region just above saturation density which can be created with heavy ion beams available at NSCL. With better constraints in place, the predictive power of transport models will improve. Recent constraints from HIC experiments have relied on symmetric systems, which are predicted to be sensitive to both the density- and the momentum-dependence of the symmetry potentials. In the study of the nuclear equation of state, asymmetric systems have proven to be more effective at low energy in exploring sensitivities to nucleon-nucleon collisions, which is an important input to any transport model.In this work, particles that were emitted from Ca+Sn systems, with a 48Ca beam impinging on 112Sn or 124Sn targets are measured. The experimental data were compared to predictions from the Improved Molecular Dynamics model with Skyrme interactions (ImQMD-Sky). Four Skyrme parameter sets were chosen that span current constraints on the density dependence of the symmetry energy and on the nucleon effective mass splitting, m^*n \neq m^*p, which results from the momentum dependent interaction potentials. ImQMD-Sky calculations were repeated using an alternate form for σNN.The yields and ratios of both free and coalescence invariant experimental spectra, constructed as a function of the transverse momentum, were contrasted to those simulated by ImQMD-Sky. To select the overlap region between beam and target nuclei, a mid-rapidity cut was taken in the analysis. The parameter sets included in this analysis did not show a significant sensitivity to the symmetry energy strength, but do suggest that the neutron-to-proton ratio bears a large sensitivity both to the nucleon effective mass splitting and the σNN forms used in the calculations.Comparison to the measured…

Advisors/Committee Members: Tsang, ManYee Betty, Brown, Edward, Lynch, William G, Pratt, Scott, Zhang, Pengpeng.

Subjects/Keywords: Heavy ion collisions; Symmetry (Physics); Nuclear physics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Showalter, R. H. (2015). Determination of density and momentum dependence of nuclear symmetry potentials with asymmetric heavy ion reactions. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:2687

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Showalter, Rachel Hodges. “Determination of density and momentum dependence of nuclear symmetry potentials with asymmetric heavy ion reactions.” 2015. Thesis, Michigan State University. Accessed February 18, 2019. http://etd.lib.msu.edu/islandora/object/etd:2687.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Showalter, Rachel Hodges. “Determination of density and momentum dependence of nuclear symmetry potentials with asymmetric heavy ion reactions.” 2015. Web. 18 Feb 2019.

Vancouver:

Showalter RH. Determination of density and momentum dependence of nuclear symmetry potentials with asymmetric heavy ion reactions. [Internet] [Thesis]. Michigan State University; 2015. [cited 2019 Feb 18]. Available from: http://etd.lib.msu.edu/islandora/object/etd:2687.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Showalter RH. Determination of density and momentum dependence of nuclear symmetry potentials with asymmetric heavy ion reactions. [Thesis]. Michigan State University; 2015. Available from: http://etd.lib.msu.edu/islandora/object/etd:2687

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.