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Full-Text Articles in Physical Sciences and Mathematics

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki Oct 2019

Laser-Spark Multicharged Ion Implantation System ‒ Application In Ion Implantation And Neural Deposition Of Carbon In Nickel (111), Oguzhan Balki

Electrical & Computer Engineering Theses & Dissertations

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J/cm2) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C4+ are observed. When no acceleration voltage is applied between …


Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon May 2019

Exploring The Electrical Properties Of Twisted Bilayer Graphene, William Shannon

Senior Theses

Two-dimensional materials exhibit properties unlike anything else seen in conventional substances. Electrons in these materials are confined to move only in the plane. In order to explore the effects of these materials, we have built apparatus and refined procedures with which to create two-dimensional structures. Two-dimensional devices have been made using exfoliated graphene and placed on gold contacts. Their topography has been observed using Atomic Force Microscopy (AFM) confirming samples with monolayer, bilayer, and twisted bilayer structure. Relative work functions of each have been measured using Kelvin Probe Force Microscopy (KPFM) showing that twisted bilayer graphene has a surface potential …


Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse Jan 2019

Electron Transport In One And Two Dimensional Materials, Samuel William Lagasse

Legacy Theses & Dissertations (2009 - 2024)

This dissertation presents theoretical and experimental studies in carbon nanotubes (CNTs), graphene, and van der Waals heterostructures. The first half of the dissertation focuses on cutting edge tight-binding-based quantum transport models which are used to study proton irradiation-induced single-event effects in carbon nanotubes [1], total ionizing dose effects in graphene [2], quantum hall effect in graded graphene p-n junctions [3], and ballistic electron focusing in graphene p-n junctions [4]. In each study, tight-binding models are developed, with heavy emphasis on tying to experimental data. Once benchmarked against experiment, properties of each system which are difficult to access in the laboratory, …


Electrostatically Assembled Construction Of Ternary Tio2-Cu@C Hybrid With Enhanced Solar-To-Hydrogen Evolution Employing Amorphous Carbon Dots As Electronic Mediator, Jiaxin Zhu, Mengmeng Zhang, Jinyan Xiong, Yinan Yan, Weijie Li, Gang Cheng Jan 2019

Electrostatically Assembled Construction Of Ternary Tio2-Cu@C Hybrid With Enhanced Solar-To-Hydrogen Evolution Employing Amorphous Carbon Dots As Electronic Mediator, Jiaxin Zhu, Mengmeng Zhang, Jinyan Xiong, Yinan Yan, Weijie Li, Gang Cheng

Australian Institute for Innovative Materials - Papers

The huge demand for renewable hydrogen produced by water splitting has prompted people to conduct in-depth research on the hydrogen evolution reaction for the development of earth-abundant, non-precious, and multi-functional metal catalysts. Herein, a noble-metal-free ternary composite of TiO2-Cu@C was prepared by electrostatic self-assembly loaded copper nanoparticles and amorphous carbon dots (CDs) on porous TiO2 microrods. The good conductivity of the CDs was beneficial to promoting the charge transfer and separation, generating an enhanced solar-to-hydrogen performance on TiO2-Cu@C. The optimized TiO2-Cu@C reveals a stable and notable hydrogen evolution rate of 3911 μmol g−1h−1, which is 1.6 times that of TiO2-Cu …


Bio‑Derived Hierarchical Multicore-Shell Fe2n‑Nanoparticle‑Impregnated N‑Doped Carbon Nanofiber Bundles: A Host Material For Lithium‑/Potassium‑Ion Storage, Hongjun Jiang, Ling Huang, Yunhong Wei, Boya Wang, Hao Wu, Yun Zhang, Hua-Kun Liu, Shi Xue Dou Jan 2019

Bio‑Derived Hierarchical Multicore-Shell Fe2n‑Nanoparticle‑Impregnated N‑Doped Carbon Nanofiber Bundles: A Host Material For Lithium‑/Potassium‑Ion Storage, Hongjun Jiang, Ling Huang, Yunhong Wei, Boya Wang, Hao Wu, Yun Zhang, Hua-Kun Liu, Shi Xue Dou

Australian Institute for Innovative Materials - Papers

Despite the significant progress in the fabrication of advanced electrode materials, complex control strategies and tedious processing are often involved for most targeted materials to tailor their compositions, morphologies, and chemistries. Inspired by the unique geometric structures of natural biomacromolecules together with their high affinities for metal species, we propose the use of skin collagen fibers for the template crafting of a novel multicore-shell Fe2N-carbon framework anode configuration, composed of hierarchical N-doped carbon nanofiber bundles firmly embedded with Fe2N nanoparticles (Fe2N@N-CFBs). In the resultant heterostructure, the Fe2N nanoparticles firmly confined inside the carbon shells are spatially isolated but electronically well …


Synthesis Of Cose2-Snse2 Nanocube-Coated Nitrogen-Doped Carbon (Nc) As Anode For Lithium And Sodium Ion Batteries, Jin Bai, Huimin Wu, Shiquan Wang, Guangxue Zhang, Chuanqi Feng, Hua-Kun Liu Jan 2019

Synthesis Of Cose2-Snse2 Nanocube-Coated Nitrogen-Doped Carbon (Nc) As Anode For Lithium And Sodium Ion Batteries, Jin Bai, Huimin Wu, Shiquan Wang, Guangxue Zhang, Chuanqi Feng, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

CoSe2-SnSe2/NC nanocubes (CSNC@NC) coated by nitrogen-doped carbon (NC) were synthesized successfully by an ordinary pyrazole polymerization and carbonization process. In comparison with bare CSNC, the CSNC@NC composite exhibited good structural stability and improved electrical conductivity when used as anode. The CSNC@NC electrode showed a stable Li storage capacity (730.41 mAh g−1 over 100 cycles at 0.2 A g−1) and excellent rate performance (402.10 mAh g−1 at 2 A g−1). For Na storage, the discharge capacity could be maintained 279.3 mAh g−1 over 100 cycles at 0.2 A g−1; the lower capacity than that for Li storage maybe caused by the …


Constructing Coo/Co3s4 Heterostructures Embedded In N-Doped Carbon Frameworks For High-Performance Sodium-Ion Batteries, Can Guo, Wenchao Zhang, Yi Liu, Jiapeng He, Shun Yang, Mingkai Liu, Qinghong Wang, Zaiping Guo Jan 2019

Constructing Coo/Co3s4 Heterostructures Embedded In N-Doped Carbon Frameworks For High-Performance Sodium-Ion Batteries, Can Guo, Wenchao Zhang, Yi Liu, Jiapeng He, Shun Yang, Mingkai Liu, Qinghong Wang, Zaiping Guo

Australian Institute for Innovative Materials - Papers

Heterostructures are attractive for advanced energy storage devices due to their rapid charge transfer kinetics, which is of benefit to the rate performance. The rational and facile construction of heterostructures with satisfactory electrochemical performance, however, is still a great challenge. Herein, ultrafine hetero-CoO/Co3S4 nanoparticles embedded in N-doped carbon frameworks (CoO/Co3S4@N-C) are successfully obtained by employing metal-organic frameworks as precursors. As anodes for sodium ion batteries, the CoO/Co3S4@N-C electrodes exhibit high specific capacity (1029.5 mA h g−1 at 100 mA g−1) and excellent rate capability (428.0 mA h g−1 at 5 A g−1), which may be attributed to their enhanced electric …


Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji Jan 2019

Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji

Electrical & Computer Engineering Faculty Publications

Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg-1 at 2 mVs-1), higher surface capacitive contribution (75%), better stability and rate …