Author: Yiling YuPublisher:
ISBN:
Category :
Languages : en
Pages : 109
Book Description
Engineering Light Matter Interaction of Atomically Thin Transition Metal Dichalcogenide Materials
Author: Yiling YuTwo-Dimensional Transition-Metal Dichalcogenides
Author: Alexander V. KolobovPublisher: Springer
ISBN: 3319314505
Category : Technology & Engineering
Languages : en
Pages : 545
Book Description
This book summarizes the current status of theoretical and experimental progress in 2 dimensional graphene-like monolayers and few-layers of transition metal dichalcogenides (TMDCs). Semiconducting monolayer TMDCs, due to the presence of a direct gap, significantly extend the potential of low-dimensional nanomaterials for applications in nanoelectronics and nano-optoelectronics as well as flexible nano-electronics with unprecedented possibilities to control the gap by external stimuli. Strong quantum confinement results in extremely high exciton binding energies which forms an interesting platform for both fundamental studies and device applications. Breaking of spatial inversion symmetry in monolayers results in strong spin-valley coupling potentially leading to their use in valleytronics. Starting with the basic chemistry of transition metals, the reader is introduced to the rich field of transition metal dichalcogenides. After a chapter on three dimensional crystals and a description of top-down and bottom-up fabrication methods of few-layer and single layer structures, the fascinating world of two-dimensional TMDCs structures is presented with their unique atomic, electronic, and magnetic properties. The book covers in detail particular features associated with decreased dimensionality such as stability and phase-transitions in monolayers, the appearance of a direct gap, large binding energy of 2D excitons and trions and their dynamics, Raman scattering associated with decreased dimensionality, extraordinarily strong light-matter interaction, layer-dependent photoluminescence properties, new physics associated with the destruction of the spatial inversion symmetry of the bulk phase, spin-orbit and spin-valley couplings. The book concludes with chapters on engineered heterostructures and device applications such as a monolayer MoS2 transistor. Considering the explosive interest in physics and applications of two-dimensional materials, this book is a valuable source of information for material scientists and engineers working in the field as well as for the graduate students majoring in materials science.
Two-Dimensional Transition-Metal Dichalcogenides
Author: Chi Sin TangPublisher: John Wiley & Sons
ISBN: 3527350640
Category : Technology & Engineering
Languages : en
Pages : 357
Book Description
Two-Dimensional Transition-Metal Dichalcogenides Comprehensive resource covering rapid scientific and technological development of polymorphic two-dimensional transition-metal dichalcogenides (2D-TMDs) over a range of disciplines and applications Two-Dimensional Transition-Metal Dichalcogenides: Phase Engineering and Applications in Electronics and Optoelectronics provides a discussion on the history of phase engineering in 2D-TMDs as well as an in-depth treatment on the structural and electronic properties of 2D-TMDs in their respective polymorphic structures. The text addresses different forms of in-situ synthesis, phase transformation, and characterization methods for 2D-TMD materials and provides a comprehensive treatment of both the theoretical and experimental studies that have been conducted on 2D-TMDs in their respective phases. Two-Dimensional Transition-Metal Dichalcogenides includes further information on: Thermoelectric, fundamental spin-orbit structures, Weyl semi-metallic, and superconductive and related ferromagnetic properties that 2D-TMD materials possess Existing and prospective applications of 2D-TMDs in the field of electronics and optoelectronics as well as clean energy, catalysis, and memristors Magnetism and spin structures of polymorphic 2D-TMDs and further considerations on the challenges confronting the utilization of TMD-based systems Recent progress of mechanical exfoliation and the application in the study of 2D materials and other modern opportunities for progress in the field Two-Dimensional Transition-Metal Dichalcogenides provides in-depth review introducing the electronic properties of two-dimensional transition-metal dichalcogenides with updates to the phase engineering transition strategies and a diverse range of arising applications, making it an essential resource for scientists, chemists, physicists, and engineers across a wide range of disciplines.
Plasmonics: Fundamentals and Applications
Author: Stefan Alexander MaierPublisher: Springer Science & Business Media
ISBN: 0387378251
Category : Technology & Engineering
Languages : en
Pages : 234
Book Description
Considered a major field of photonics, plasmonics offers the potential to confine and guide light below the diffraction limit and promises a new generation of highly miniaturized photonic devices. This book combines a comprehensive introduction with an extensive overview of the current state of the art. Coverage includes plasmon waveguides, cavities for field-enhancement, nonlinear processes and the emerging field of active plasmonics studying interactions of surface plasmons with active media.
Valleytronics In 2d Materials
Author: Kuan Eng Johnson GohPublisher: World Scientific
ISBN: 9811229112
Category : Technology & Engineering
Languages : en
Pages : 360
Book Description
Driven by the advent of two-dimensional materials, valleytronics is emerging as the next hot field of research in materials science. While the use of charge or spin degrees of freedom in electronic materials as information carriers is familiar and well-appreciated, employment of the valley degree of freedom as an information carrier has remained elusive for many decades. Shortly following the discovery of isolated graphene, 2D semiconductors such as transition metal dichalcogenides were also isolated and investigated. We now understand that these materials can have separately addressable valleys because each valley can be uniquely coupled to a spin state. This imparts the ability to address different valleys (like pseudospins) with electric field, magnetic field, or light, and there is now a real possibility to engineer practical devices based on using valley as the information carrier.Valleytronics in 2D Materials is the first book in the world on the topic of valleytronics. The reader is introduced to the concept via a brief history emphasizing the challenges that impeded its development for so long. We then dive into the valley physics of 2D semiconductors to explain the recent excitement in 2D valleytronics, the scientific investigations to confirm the addressable valleys, and the attempts to engineer valley devices for practical purposes. The text takes on a decidedly practical approach towards the subject, seeking to bring the reader quickly into the field by presenting the minimum theoretical basis for understanding the use of the valley degree of freedom in devices. A selection of key works establishing the scientific underpinnings of valley addressability and control are described to help the reader grasp the current stage of understanding, the technical foundations established, and the open questions. The renewal in valleytronics is yet unfinished, but with more than a decade of research and engineering efforts devoted in recent times, this book seeks to provide a timely reference for students, scientists and engineers to join this exciting journey and perhaps help to create the next disruption in information technology.
Defects in Two-Dimensional Materials
Author: Rafik AddouPublisher: Elsevier
ISBN: 032390310X
Category : Technology & Engineering
Languages : en
Pages : 434
Book Description
Defects in Two-Dimensional Materials addresses the fundamental physics and chemistry of defects in 2D materials and their effects on physical, electrical and optical properties. The book explores 2D materials such as graphene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMD). This knowledge will enable scientists and engineers to tune 2D materials properties to meet specific application requirements. The book reviews the techniques to characterize 2D material defects and compares the defects present in the various 2D materials (e.g. graphene, h-BN, TMDs, phosphorene, silicene, etc.). As two-dimensional materials research and development is a fast-growing field that could lead to many industrial applications, the primary objective of this book is to review, discuss and present opportunities in controlling defects in these materials to improve device performance in general or use the defects in a controlled way for novel applications. Presents the theory, physics and chemistry of 2D materials Catalogues defects of 2D materials and their impacts on materials properties and performance Reviews methods to characterize, control and engineer defects in 2D materials
Probing Excitonic Mechanics in Suspended and Strained Transition Metal Dichalcogenides Monolayers
Author: Hongchao XiePublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Over the past decade, the interest in two-dimensional (2D) materials, especially for atomically thin transition metal dichalcogenide (TMD) semiconductors, had dramatically thrived for both fundamental science and practical applications. The reduced dielectric screening in 2D mainly attributes to the strong excitonic effect in atomically thin TMD semiconductors. This pronounced exciton feature can maintain at room temperature, which indicates strong light-matter interaction and possible optoelectronic application using monolayer semiconductors. Meanwhile, the absence of inversion symmetry and out-of-plane mirror symmetry jointly endows carriers in monolayer TMDs with a new valley degree of freedom (DOF). Namely, in hexagonally-arranged lattice of 2D materials, electrons that residing at band edges of K and K valleys can carry opposite valley magnetic moments and Berry curvatures, which allows the further control of valley-indexed carriers with polarized light, electrical and magnetic fields. Besides, the large strain sustainability of monolayer TMDs gives rise to mechanically tunable band gap with 70 meV redshift per 1% strain up to recorded 10% applied strain. Thus, the interaction of macroscopic mechanical means with valley electrons makes monolayer TMD semiconductor a promising platform to implement novel valley-controlled mechanical devices. This motivates the experimental studies demonstrated in this dissertation.In this dissertation, we investigate the valley contrasting coupling between optoelectronic carriers (exciton & flowing electrons) and mechanics in a monolayer TMD semiconductor. In the first parts (Chapter 1&2), I will present emerging properties of TMD monolayers and discuss interesting physics that can study after suspending or straining these atomically thin materials. The fabrication and measurement of typical TMD suspended devices will also be demonstrated in details. In the secondary part (Chapter 3), we demonstrate robust exciton bistability by continuous-wave optical excitation in a suspended monolayer WSe2 at a much lower intensity level of 103 W/cm2. The observed bistability is originated from a photothermal mechanism, which can provide both optical nonlinearity and internal passive feedback in a simple cavity-less structure. This is supported by detailed excitation wavelength and power dependence studies of the sample reflectance, as well as by numerical simulation including the temperature-dependent optical response of monolayer WSe2. Furthermore, under a finite magnetic field, the bistability becomes valley dependent and controllable not only by light intensity but also by light helicity due to the exciton valley Zeeman effect, which open up an exciting opportunity in controlling light with light using monolayer materials.In the following part (Chapter 4), we report the observation of exciton-optomechanical coupling in a suspended monolayer MoSe2 mechanical resonator. In particular, we have observed light-induced damping and anti-damping of mechanical vibrations and modulation of the mechanical spring constant by moderate optical pumping near the exciton resonance with variable detuning. The observed exciton-optomechanical coupling strength is also highly gate-tunable. Our observations can be fully explained by a model based on photothermal backaction and gate-induced mirror symmetry breaking in the device structure. The observation of gate-tunable exciton-optomechanical coupling in a monolayer semiconductor may find novel applications in nanoelectromechanical systems (NEMS) and in exciton-optomechanics.In the last part of this dissertation (Chapter 5), we present the study of magnetization purely originated from the valley DOF in strained MoS2 monolayers. By breaking the three-fold rotational symmetry in single-layer MoS2 via a uniaxial stress, we have demonstrated the pure electrical generation of valley magnetization in this material, and its direct imaging by Kerr rotation microscopy. The observed out-of-plane magnetization is independent of in-plane magnetic field, linearly proportional to the in-plane current density, and optimized when the current is orthogonal to the strain-induced piezoelectric field. These results are fully consistent with a theoretical model of valley magnetoelectricity driven by Berry curvature effects. Furthermore, the effect persists at room temperature, opening possibilities for practical valleytronic devices.
Plasmonic Materials and Metastructures
Author: Shangjr GwoPublisher: Elsevier
ISBN: 0323860184
Category : Technology & Engineering
Languages : en
Pages : 347
Book Description
Plasmonic Materials and Metastructures: Fundamentals, Current Status, and Perspectives reviews the current status and emerging trends in the development of conventional and alternative plasmonic materials. Sections cover fundamentals and emerging trends of plasmonic materials development, including synthesis strategies (chemical and physical) and optical characterization techniques. Next, the book addresses fundamentals, properties, remaining barriers for commercial translation, and the latest advances and opportunities for conventional noble metal plasmonic materials. Fundamentals and advances for alternative plasmonic materials are also reviewed, including two-dimensional hybrid materials composed of graphene, monolayer transition metal dichalcogenides, boron nitride, etc. In addition, other sections cover applications of plasmonic metastructures enabled by plasmonic materials with improved material properties and newly discovered functionalities. Applications reviewed include quantum plasmonics, topological plasmonics, chiral plasmonics, nanolasers, imaging (metalens), active, and integrated technologies. Provides an overview of materials properties, characterization and fabrication techniques for plasmonic metastructured materials Includes key concepts and advances for a wide range of metastructured materials, including metamaterials, metasurfaces and epsilon-near-zero plasmonic metastructures Discusses emerging applications and barriers to commercial translation for quantum plasmonics, topological plasmonics, nanolasers, imaging and integrated technologies
Two Dimensional Transition Metal Dichalcogenides Grown by Chemical Vapor Deposition
Author: Ka-Yi TsangPublisher: Open Dissertation Press
ISBN: 9781361380963
Category :
Languages : en
Pages :
Book Description
This dissertation, "Two Dimensional Transition Metal Dichalcogenides Grown by Chemical Vapor Deposition" by Ka-yi, Tsang, 曾家懿, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: An atomically thin film of semiconducting transition metal dichalcogenides (TMDCs) is emerging as a class of key materials in chemistry and physics due to their remarkable chemical and electronic properties. The TMDCs are layered materials with weak out-of-plane van der Waals (vdW) interaction and strong in-plane covalent bonding enabling scalable exfoliation into two-dimensional (2D) layers of atomic thickness. The growth techniques to prepare these 2D TMDC materials in high yield and large scale with high crystallinity have attracted intensive attention recently because of the new properties and potentials in nano-elctronic, optoelectronic, spintronic and valleytronic applications. In this thesis, I develop methods for the chemical synthesis of 2D TMDCs films. The relevant growth mechanism and material characteristics of these films are also investigated. Molybdenum disulfide (MoS2) is synthesized by using molybdenum trioxide (MoO3) and sulfur (S) powder as the precursor. The films are formed on substrate pre-treated with reduced graphene oxide as the catalyst. However, this method cannot be extended to other TMDC materials such as molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) because reduced graphene oxide (rGO) reacts with selenium to form alloy materials rather than TMDC films. At the same time, the conversion of MoO3 to MoSe2 or that of tungsten trioxide (WO3) to WSe2 without the assistance of hydrogen in the chemical reaction is not thermodynamically feasible because the oxygen in the metal oxide cannot be replaced by selenium due to lower reactivity of the latter. On the other hand, I demonstrate that MoSe2 film can be synthesized directly by using MoSe2 and Se powder. Furthermore, the method of sulfurization or selenization of pre-deposited metal film can be promising due to precise thickness/size controls. Finally, some perspectives on the engineering challenges and fabrication methods of this family of materials will be given. Subjects: Transition metal compounds - Synthesis Chalcogenides - Synthesis
Metasurfaces: Physics and Applications
Author: Sergey I. BozhevolnyiPublisher: MDPI
ISBN: 3038973440
Category : Electronic books
Languages : en
Pages : 167
Book Description
This book is a printed edition of the Special Issue "Metasurfaces: Physics and Applications" that was published in Applied Sciences