Growth Structure And Properties Of Selected Two Dimensional Materials From Density Functional Theory Investigations
DOWNLOAD
Download Growth Structure And Properties Of Selected Two Dimensional Materials From Density Functional Theory Investigations PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Growth Structure And Properties Of Selected Two Dimensional Materials From Density Functional Theory Investigations book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Growth Structure And Properties Of Selected Two Dimensional Materials From Density Functional Theory Investigations
DOWNLOAD
Author : Abdulfattah Ab Abdulslam
language : en
Publisher:
Release Date : 2018
Growth Structure And Properties Of Selected Two Dimensional Materials From Density Functional Theory Investigations written by Abdulfattah Ab Abdulslam and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Density functionals categories.
Theory Of Two Dimensional Materials
DOWNLOAD
Author : Yuanxi Wang
language : en
Publisher:
Release Date : 2016
Theory Of Two Dimensional Materials written by Yuanxi Wang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
In this dissertation, I study the synthesis (and post-synthesis modifications), properties, and structural engineering of two-dimensional materials, using atomistic modeling techniques such as empirical forcefields and density functional theory. The dissertation is divided into four parts. The first part consists of four chapters: in Chapters 1-3 I give an overview on density functional theory and how vibrational properties and optical properties can be calculated within the DFT framework; in Chapter 4 a brief review on two-dimensional materials is given.The second part is devoted to the synthesis and post-synthesis modifications of two-dimensional materials. In Chapter 5 I investigate the intercalation of hexagonal boron nitride and graphite using Bronsted acids such as H3PO4. DFT calculations show that dipolar interactions between acids molecules and the 2D sheets drive the intercalation process.In Chapter 6 I study stripe patterns of W and Mo atoms in triangular monolayers of WxMo1-xS2 alloys. DFT calculations suggest that stripe ordering is kinetically driven, governed by fluctuations in local thermodynamic conditions during growth. In addition, I show that the striped phase alloy is electronically isotropic but vibrationally anisotropic, due to the nearly-identical electronic properties but very different atomic masses of Mo and W.The third part is devoted to computation of vibrational and optical properties of molybdenum and tungsten disulfides. In Chapter 7 we investigate the optical signatures of defect-bound excitons in monolayer WS2. I show that the optical transitions between the highest valence band and mid-gap states introduced by sulfur vacancy defects have finite transition matrix elements. These results agrees with the measured photoluminescence spectra of monolayer WS2 grown by chemical vapor deposition, where spatially resolved photoluminescence at low temperatures revealed two bound excitons. To explain the anomaly in the thermal activation energy of the bound exciton, we propose that excitons are bound to negatively charged defects where two channels of radiative recombinations are allowed.Chapter 8 focuses on intervalley scattering processes in monolayer MoS2, as probed by resonance raman spectroscopy, where the incident laser energy is varied across the A and B excitonic levels. We focus on two Raman peaks that are dispersive, a clear signature of second-order processes involving intervalley scattering. Using group theory and DFT calculations, selection rules are established for intervalley scattering processes mediated by acoustic phonons. In Chapter 9 I investigate Second Harmonic Generation (SHG) in monolayer WS2. Its second order nonlinear susceptibility is nearly three orders of magnitude larger than other common nonlinear crystals. Density functional theory calculations suggest that the origin of the large nonlinear susceptibility lies in resonance enhancement and sharp features in the joint density of states.In the final part, I explore possible methods of manipulating the geometry and grain texture of 2D materials. In Chapter 10 I show that when an atomically thin two-dimensional crystal grows on a substrate of non-zero Gaussian curvature, it can develop finite-length grain boundaries that terminate abruptly within a monocrystalline domain. By properly designing the substrate topography, these grain boundaries can be placed at desired locations and at specified misfit angles, as the thermodynamic ground state of a 2D system bound to a substrate. New properties specific to certain grain boundary geometries, including magnetism and metallicity, can thus be engineered into 2D crystals through topographic design of their substrates.
First Principles Method Development And Design Of Complex 2d Materials For Renewable Energy Applications
DOWNLOAD
Author : Levi Carl Lentz
language : en
Publisher:
Release Date : 2018
First Principles Method Development And Design Of Complex 2d Materials For Renewable Energy Applications written by Levi Carl Lentz and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
Modulation of a material's dimensionality enables novel physics at the atomic scale. Exploiting this effect creates opportunities to design and manufacture highly functional materials for specific engineering applications. As such, 2D materials are an exciting material group due to their unique properties compared to their 3D counterparts. Currently, research is focused on understanding how these low dimensional materials can perform as photovoltaics, catalysts, and high strength materials. The first goal of this thesis is to understand and design the properties of complex 2D materials for novel applications in renewable energy. The second goal is to develop new methods that will enable accurate and efficient investigation of the fundamental electronic structure properties of these and other complex materials. In this thesis, we study the underlying physics of an exciting class of materials broadly referred to as transition metal phosphates (TMPs). These materials are of interest for engineering applications because of their 2D properties, ease of solution processing, and ability to form 2D monolayers. Interestingly, they form crystalline materials composed of alternating layers of TMPs and organic molecules, enabling a wide range of material properties. Additionally, TMPs exist in a variety of compositions including zirconium, titanium, vanadium, zinc, tin, and a number of other metal cations. This range of cations presents an opportunity to study a rich set of properties and potential applications within the framework of TMPs. To study these materials, we employ density functional theory (DFT) computations to investigate the properties of TMPs and TMP-based heterostructures. Using DFT, we develop a framework for the understanding and control of the band gap, band alignment, and other properties within TMP-organic heterojunctions. This work enables new pathways for the realization of cheap and efficient photovoltaic materials as well as applications to broader engineering fields concerned with precise control of band energies. In performing this study, we also address several critical limitations of DFT. While DFT is highly accurate at studying many materials properties, it has significant limitations in studying time variant and excited-state properties. Further, computationally, DFT does not scale linearly with the system size, imposing significant roadblocks to study large systems. To enable the study of these complex material properties, method development represents a significant portion of this work. Artificial neural network (ANN) approaches represent an emergent method in the field of Material Science. Exploiting this trend, we develop ANN methods to reduce the computational complexity and cost of DFT simulations. By combining large datasets of relatively small DFT calculations, we develop high dimensional potentials for large-scale molecular dynamics (MD) calculations. This enables the prediction of DFT-accurate energies in large and time-variant systems for a fraction of the computational cost. Additionally, DFT relies on accurately understanding the relationship between functionals of the charge density even though the explicit form of some functionals are sometimes unknown. To address this shortcoming of DFT, we develop machine-learning methods as a novel way to learn complex functionals. Understanding this process may allow for linear speedup in DFT calculations, possibly opening enabling 'orbital-free' DFT. In concluding this thesis, we deploy our computational framework to learn both analytical potentials as well as functionals of the charge density. We use these developed methods to study a range of material properties of interest to the engineering sciences including the bandgap and mechanical properties of 2D and bulk materials. This method could enable significant advances in the computational material science field by enabling researchers to study systems not possible with classical approaches.
2d Nanoscale Heterostructured Materials
DOWNLOAD
Author : Satyabrata Jit
language : en
Publisher: Elsevier
Release Date : 2020-05-09
2d Nanoscale Heterostructured Materials written by Satyabrata Jit and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-05-09 with Technology & Engineering categories.
2D Nanoscale Heterostructured Materials: Synthesis, Properties, and Applications assesses the current status and future prospects for 2D materials other than graphene (e.g., BN nanosheets, MoS2, NbSe2, WS2, etc.) that have already been contemplated for both low-end and high-end technological applications. The book offers an overview of the different synthesis techniques for 2D materials and their heterostructures, with a detailed explanation of the many potential future applications. It provides an informed overview and fundamentals properties related to the 2D Transition metal dichalcogenide materials and their heterostructures. The book helps researchers to understand the progress of this field and points the way to future research in this area. Explores synthesis techniques of newly evolved 2D materials and their heterostructures with controlled properties Offers detailed analysis of the fundamental properties (via various experimental process and simulations techniques) of 2D heterostructures materials Discusses the applications of 2D heterostructured materials in various high-performance devices
Fundamentals And Sensing Applications Of 2d Materials
DOWNLOAD
Author : Chandra Sekhar Rout
language : en
Publisher: Woodhead Publishing
Release Date : 2019-06-15
Fundamentals And Sensing Applications Of 2d Materials written by Chandra Sekhar Rout and has been published by Woodhead Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-06-15 with Science categories.
Fundamentals and Sensing Applications of 2D Materials provides a comprehensive understanding of a wide range of 2D materials. Examples of fundamental topics include: defect and vacancy engineering, doping and advantages of 2D materials for sensing, 2D materials and composites for sensing, and 2D materials in biosystems. A wide range of applications are addressed, such as gas sensors based on 2D materials, electrochemical glucose sensors, biosensors (enzymatic and non-enzymatic), and printed, stretchable, wearable and flexible biosensors. Due to their sub-nanometer thickness, 2D materials have a high packing density, thus making them suitable for the fabrication of thin film based sensor devices. Benefiting from their unique physical and chemical properties (e.g. strong mechanical strength, high surface area, unparalleled thermal conductivity, remarkable biocompatibility and ease of functionalization), 2D layered nanomaterials have shown great potential in designing high performance sensor devices. Provides a comprehensive overview of 2D materials systems that are relevant to sensing, including transition metal dichalcogenides, metal oxides, graphene and other 2D materials system Includes information on potential applications, such as flexible sensors, biosensors, optical sensors, electrochemical sensors, and more Discusses graphene in terms of the lessons learned from this material for sensing applications and how these lessons can be applied to other 2D materials
Monatomic Two Dimensional Layers
DOWNLOAD
Author : Iwao Matsuda
language : en
Publisher: Elsevier
Release Date : 2018-08-22
Monatomic Two Dimensional Layers written by Iwao Matsuda and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-08-22 with Science categories.
Monatomic Two-Dimensional Layers: Properties, Fabrication and Industrial Applications provides a detailed examination on basic principles and state-of-the-art experimental techniques for monatomic layers on model surfaces, and in operating devices. Both conventional surface science and novel 2D materials science are included. The reader is guided through an introduction to the basic science of the field that is followed by advanced science specific to the system. Characterization techniques, the principles of state-of-the-art instruments for monatomic layers, and topics, including positron diffraction, time-resolved photoemission spectroscopy, surface transport measurements, and operando nanospectroscopy are also covered. Researchers, graduate students and professionals will find this volume invaluable to acquire a deeper knowledge of the basic science, preparation, and experimental characterization techniques for 2D materials. Industrial technicians and operators will find it a useful overview of surface science related methods for fabrication and characterization of 2D materials. Gives comprehensive access to the properties of 2D materials, selected fabrication methods, and advanced characterization tools Discusses structure analysis by diffraction methods and ‘operando’ spectroscopy to provide direct information on device performance for industrial applications Written by authors who developed the techniques and have conducted extensive research on monatomic layers
Design Of Two Dimensional Functional Materials And Nanodevices
DOWNLOAD
Author : Guangzhao Wang
language : en
Publisher: Frontiers Media SA
Release Date : 2022-07-26
Design Of Two Dimensional Functional Materials And Nanodevices written by Guangzhao Wang and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-07-26 with Science categories.
Fundamentals And Supercapacitor Applications Of 2d Materials
DOWNLOAD
Author : Chandra Sekhar Rout
language : en
Publisher: Elsevier
Release Date : 2021-05-10
Fundamentals And Supercapacitor Applications Of 2d Materials written by Chandra Sekhar Rout and has been published by Elsevier this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-05-10 with Technology & Engineering categories.
Fundamentals and Applications of Supercapacitor 2D Materials covers different aspects of supercapacitor 2D materials, including their important properties, synthesis, and recent developments in supercapacitor applications of engineered 2D materials. In addition, theoretical investigations and various types of supercapacitors based on 2D materials such as symmetric, asymmetric, flexible, and micro-supercapacitors are covered. This book is a useful resource for research scientists, engineers, and students in the fields of supercapacitors, 2D nanomaterials, and energy storage devices. Due to their sub-nanometer thickness, 2D materials have a high packing density, which is suitable for the fabrication of highly-packed energy supplier/storage devices with enhanced energy and power density. The flexibility of 2D materials, and their good mechanical properties and high packing densities, make them suitable for the development of thin, flexible, and wearable devices. Explores recent developments and looks at the importance of 2D materials in energy storage technologies Presents both the theoretical and DFT related studies Discusses the impact on performance of various operating conditions Includes a brief overview of the applications of supercapacitors in various industries, including aerospace, defense, biomedical, environmental, energy, and automotive
2d Materials
DOWNLOAD
Author : Phaedon Avouris
language : en
Publisher: Cambridge University Press
Release Date : 2017-06-29
2d Materials written by Phaedon Avouris and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-06-29 with Science categories.
A comprehensive and accessible introduction to 2D materials, covering basic physics, electronic and optical properties, and potential applications.
Two Dimensional Layered Materials
DOWNLOAD
Author : Youjian Tang
language : en
Publisher:
Release Date : 2016
Two Dimensional Layered Materials written by Youjian Tang and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Two-dimensional layered materials have emerged as a fascinating research area due to their unique physical and chemical properties, which differ from those of their bulk counterparts. Some of these unique properties are due to carriers and transport being confined to 2 dimensions, some are due to lattice symmetry, and some arise from their large surface area, gateability, stackability, high mobility, spin transport, or optical accessibility. How to modify the electronic and magnetic properties of two-dimensional layered materials for desirable long-term applications or fundamental physics is the main focus of this thesis. We explored the methods of adsorption, intercalation, and doping as ways to modify two-dimensional layered materials, using density functional theory as the main computational methodology. Chapter 1 gives a brief review of density functional theory. Due to the difficulty of solving the many-particle Schrödinger equation, density functional theory was developed to find the ground-state properties of many-electron systems through an examination of their charge density, rather than their wavefunction. This method has great application throughout the chemical and material sciences, such as modeling nano-scale systems, analyzing electronic, mechanical, thermal, optical and magnetic properties, and predicting reaction mechanisms. Graphene and transition metal dichalcogenides are arguably the two most important two-dimensional layered materials in terms of the scope and interest of their physical properties. Thus they are the main focus of this thesis. In chapter 2, the structure and electronic properties of graphene and transition metal dichalcogenides are described. Alkali adsorption onto the surface of bulk graphite and metal intecalation into transition metal dichalcogenides -- two methods of modifying properties through the introduction of metallic atoms into layered systems -- are described in chapter 2. Chapter 3 presents a new method of tuning the electronic properties of 2D materials: resonant physisorption. An example is given for adsorption of polycyclic aromatic hydrocarbon molecules onto graphene. The energy levels of these molecules were fine tuned to make them resonate with the graphene Fermi level, thus enhancing iiithe strength of their effect on the graphene electronic structure. Chapter 4 develops the idea of coupling two distinct surface adsorption systems across a suspended atomically thin membrane. We examine a system of dual-sided adsorption of potassium onto a graphene membrane. The sequence of adsorption patterns predicted undergoes a striking devil's staircase of intermediate coverage fractions as the difference in adsorbate chemical potential betweeen the two sides of the membrane varies. Chapter 5 is devoted to magnetic and band structure engineering of transition metal dichalcogenides through introduction of magnetic atoms into the lattice. Semiconducting transition metal dichalcogenide systems such as MoS2 and WS2 have band gaps suitable for electronic and optoelectronic applications, but are not magnetic. By intercalating and doping in a carefully designed stoichiometric ratio that precisely controls the occupation and relative placement of the dopant and host levels, we can convert a semiconducting transition metal dichalcogenide system into a half-metal or -- more surprisingly -- a half-semiconductor, where the conduction band is fully spin polarized and the energy scale for magnetism is the band gap.