Download or read book Atomic and Electronic Properties of 2D Moir Interfaces written by Astrid Weston and published by Springer Nature. This book was released on 2022-10-06 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis provides the first atomic length-scale observation of the structural transformation (referred to as lattice reconstruction) that occurs in moiré superlattices of twisted bilayer transition metal dichalcogenides (TMDs) at low (θ 2 ̊) twist angles. Such information is essential for the fundamental understanding of how manipulating the rotational twist-angle between two adjacent 2-dimensional crystals subsequently affects their optical and electrical properties./ppStudies using Scanning transmission electron microscopy (STEM), a powerful tool for atomic-scale imaging, were limited due to the complexity of the (atomically-thin) sample fabrication requirements. This work developed a unique way to selectively cut and re-stack monolayers of TMDs with a controlled rotational twist angle which could then be easily suspended on a TEM grid to meet the needs of the atomically thin sample requirements. The fabrication technique enabled the study of the two common stacking-polytypes including 3R and 2H (using MoS2 and WS2 as the example) as well as their structural evolution with decreasing twist-angle./ppAtomic-scale studies were followed by a comprehensive investigation of their electronic properties using scanning probe microscopy and electrical transport measurements of the artificially-engineered structures. The electronic structure of two common stacking-polytypes (3R and 2H) were strikingly different, as revealed by conductive atomic force microscopy. Further studies focused on the 3R-stacking polytype to reveal room-temperature out-of-plane ferroelectricity using tools such as kelvin probe force microscopy, scanning electron microscopy and electrical transport measurements. This work highlights that the unique intrinsic properties of TMDs (i.e. semiconductors with strongly light-matter interaction) combined with the additional twisted degree-of-freedom has great potential to create atomically thin transistors/LEDs with built-in memory storage functions and will further aid in the development of the next generation of optoelectronics.

Download or read book Effects of Interfaces on Electronic Properties in Solids written by Yan-Ten Lu and published by . This book was released on 1989 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding and Engineering Electronic and Optoelectronic Properties of 2D Materials and Their Interfaces written by Youngwoo Son (Ph. D.) and published by . This book was released on 2016 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the pursuit of further miniaturization beyond Moore's law, tremendous effort has been dedicated to exploring the potential of two-dimensional (2D) materials for nanoscale electronic devices. 2D materials are a group of solid state materials that possess strong in-plane covalent bonds while individual atomic layers are held together by weak van der Waals (vdW) interactions. Hence, their bulk crystals can be exfoliated into few-layer or even atomically thin single-layers via micro-mechanical exfoliation techniques. These materials possess unique and exotic properties due to quantum confinement of importance to future electronics. However, many technical problems need to be solved to realize this goal. For example, as 2D material based devices become smaller down to the nanometer scale, the electrical contacts must also be reduced in scale which creates different characteristics from those of macroscopic counterparts. In addition, there are issues of reliability and stability with devices comprised of such materials. There is a need to understand the electronic and chemical properties of several interfaces that arise in such materials: metal-2D and 2D-2D junctions, for example. To this end, this thesis focuses on understanding nanoscale metal-2D semiconductor (SC) and 2D SC-2D SC junctions exploring: (1) electronic and optoelectronic behavior at the nanoscale junction of metal-MoS2 and dependence on the layer number (thickness), (2) realization of voltage selectable photodiodes based on a lateral in-plane MoS2-WSe2 heterojunctions, and (3) interfacial properties and (opto)electronic characteristics of a phosphorene-MoS2 vertical vdW p-n junction. The first part of this thesis explores the layer number dependent electrical characteristics of the MoS2-metal nanoscale junction using current imaging of MoS2 nanosheets consisting of regions of varying different thicknesses using conductive and photoconductive spectral atomic force microscopy (C- and PCS-AFM). The layer number dependence of the effective barrier was measured, by obtaining consecutive current images while changing bias voltages, showing it to be linear. At the same time, spatially resolved two-dimensional (2D) maps of local electrical properties are generated from simultaneously recorded local current-voltage (IV) data. Furthermore, the layer number dependent spectral photoresponse of MoS2 is investigated, which shows the highest response in single layer (1L) region. The photoresponse decreases for increasing layer number, but increases again between 4L and 1 OL due to increased light absorption. The photoresponse is also strongly dependent on the wavelength of the incident light, showing much higher currents for photon energies that are above the optical bandgap. The photoresponse in forward and reverse biases shows barrier symmetry for 1 L but asymmetry for 2, 3, and 4L, which further indicates a dominant role of the barrier on carrier transport at the junction. The second part of this thesis investigates the spatially resolved transverse electrical properties of the monolayer WSe2 -MoS2 lateral p-n heterostructures at their nanoscale junctions with metals both in the dark and under laser illumination. As in the first part of the thesis, C- and PCS-AFM, versatile tools to conveniently and efficiently interrogate layer-dependent electronic and optoelectronic characteristics in a MoS2 crystal containing regions of different thicknesses, which enables direct characterization and comparison of the different layer regions without the complexities associated with fabricating and testing of different individual field-effect transistor devices, are used for measurements. By performing current imaging using a PtIr-coated conductive tip on an ultrathin nanosheet that includes homogeneous crystals of WSe2 and MoS2 and a lateral junction region in between, many thousands of WSe2/MoS2/the junction-metal contact points form during imaging and directly compare their local properties at the same time under identical experimental conditions with the nanoscale spatial resolution. The third part of this thesis explores a new type of 2D vertical heterostructures that simultaneously possess desirable properties of constituent materials, paving the path for overcoming intrinsic shortcomings of each component material to be used as an active material in nanoelectronic devices. As a first example, a MoS 2-graphene vertical heterostructure is constructed and its charge transfer and photoluminescence (PL) at the interface are investigated. C-AFM and Raman spectroscopy show that there is a significant charge transfer between the two component materials. The PL intensity of monolayer MoS2 is noticeably quenched when in contact with a single layered graphene in comparison to that of a bare monolayer MoS2 crystal. Then, with the acquired understanding of the underlying physics at the 2D vdW heterointerfaces, the possibility of a black phosphorus (BP)-MoS2 vertical heterostructure as an ultrathin channel material for high-performance 2D (opto)electronic devices is studied. CVD-synthesized MoS2 and micromechanically exfoliated BP crystals are stacked together to form a vertical p-n heterostructure. Optical microscopy, AFM images, and Raman spectroscopy data show that the MoS2 thin films can be used as a passivation layer, protecting BP from deteriorating in ambient conditions for extended period of time or under an elevated temperature in an Ar environment. The IV characteristics of FET devices based on the vertical heterostuctures exhibit that the MoS2 layer has limited impact on superior carrier transport properties of the BP in the dark. Upon light illumination, photoconductivity of the BP-MoS2 heterostructure region increased compared to that of the bare BP region of the same flake, mainly due to the fact that a built-in electric field formed at the BP-MoS2 interface facilitates the dissociation of electron-hole pairs generated by light absorption.

Download or read book Two dimensional Devices and Interfaces written by Saurabh Vinayak Suryavanshi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Atomic and Electronic Structure of Interfaces in Materials Systems for Future Semiconductor Devices written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of the intrinsic limits of the Si/SiO2 based industry, there is a great trend towards the monolithic integration of new materials into already well developed silicon technology. Having lasted for several decades now, downscaling reaches the limit, in which a critical device dimension approaches the size of one atom. At this level of the miniaturization, it is not the bulk material, but the interface between the two materials that what controls the properties of the resulting optoelectronic device. Thus, the characterization of precise atomic arrangements at different interfaces and the influence of these arrangements on the optoelectronic properties of interfaces is required. Therefore, in this study, a combination of scanning transmission electron microscopy (STEM) techniques and density functional theory calculations was used as a research tool for the characterization of interfaces. The STEM instruments used for the study were equipped with prototypes of spherical aberration correctors, enabling to achieve the highest resolution currently available both in space and energy. The combination of experimental and theoretical methods was applied to study interfaces between Si/GaAs, Si/Ge, Ge/SiO2, Si/HfO2 and Si/Al2O3. As the result of the present research, a new dislocation configuration at the Si/GaAs interface was reported for the first time. The influence of this dislocation structure on the electrical properties of the Si/GaAs interface was analyzed. Also, the transition from Si to GaAs and from Si to Ge at corresponding interfaces was described with atomic precision. For the first time, the interface between Ge and SiO2 was shown to have 'ideal' characteristics (chemical abruptness and sharpness). This indicates the potential, both for a more successful use of Ge in high-speed devices and for advances in interface engineering to enhance performance in electronic devices. The features of Si/HfO2 and Si/Al2O &

Download or read book 2D Materials written by and published by Academic Press. This book was released on 2016-06-24 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2D Materials contains the latest information on the current frontier of nanotechnology, the thinnest form of materials to ever occur in nature. A little over 10 years ago, this was a completely unknown area, not thought to exist. However, since then, graphene has been isolated and acclaimed, and a whole other class of atomically thin materials, dominated by surface effects and showing completely unexpected and extraordinary properties has been created. This book is ideal for a variety of readers, including those seeking a high-level overview or a very detailed and critical analysis. No nanotechnologist can currently overlook this new class of materials. Presents one of the first detailed books on this subject of nanotechnology Contains contributions from a great line-up of authoritative contributors that bring together theory and experiments Ideal for a variety of readers, including those seeking a high-level overview or a very detailed and critical analysis

Download or read book Monatomic Two Dimensional Layers written by Iwao Matsuda and published by Elsevier. This book was released on 2018-08-22 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Modeling Characterization and Production of Nanomaterials written by Vinod Tewary and published by Woodhead Publishing. This book was released on 2022-11-09 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nano-scale materials have unique electronic, optical, and chemical properties that make them attractive for a new generation of devices. In the second edition of Modeling, Characterization, and Production of Nanomaterials: Electronics, Photonics, and Energy Applications, leading experts review the latest advances in research in the understanding, prediction, and methods of production of current and emerging nanomaterials for key applications. The chapters in the first half of the book cover applications of different modeling techniques, such as Green’s function-based multiscale modeling and density functional theory, to simulate nanomaterials and their structures, properties, and devices. The chapters in the second half describe the characterization of nanomaterials using advanced material characterization techniques, such as high-resolution electron microscopy, near-field scanning microwave microscopy, confocal micro-Raman spectroscopy, thermal analysis of nanoparticles, and applications of nanomaterials in areas such as electronics, solar energy, catalysis, and sensing. The second edition includes emerging relevant nanomaterials, applications, and updated modeling and characterization techniques and new understanding of nanomaterials. Covers the close connection between modeling and experimental methods for studying a wide range of nanomaterials and nanostructures Focuses on practical applications and industry needs through a solid outlining of the theoretical background Includes emerging nanomaterials and their applications in spintronics and sensing

Download or read book Van der Waals Heterostructures written by Zheng Zhang and published by John Wiley & Sons. This book was released on 2022-10-31 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Van der Waals Heterostructures A comprehensive resource systematically detailing the developments and applications of van der Waals heterostructures and devices Van der Waals Heterostructures is essential reading to understand the developments made in van der Waals heterostructures and devices in all aspects, from basic synthesis to physical analysis and heterostructures assembling to devices applications, including demonstrated applications of van der Waals heterostructure on electronics, optoelectronics, and energy conversion, such as solar energy, hydrogen energy, batteries, catalysts, biotechnology, and more. This book starts from an in-depth introduction of van der Waals interactions in layered materials and the forming of mixed-dimensional heterostructures via van der Waals force. It then comprehensively summarizes the synthetic methods, devices building processes and physical mechanism of 2D van der Waals heterostructures, and devices including 2D-2D electronics, 2D-2D optoelectronics, and mixed dimensional van der Waals heterostructures. In Van der Waals Heterostructures, readers can expect to find specific information on: The current library of 2D semiconductors and the current synthesis and performances of 2D semiconductors Controllable synthesis and assemble van der Waals heterostructures, physics of the van der Waals interface, and multi-field coupling effects 2D-2D electronics, 2D-2D optoelectronics, mixed dimensional van der Waals heterostructures, and van der Waals heterostructure applications on energy conversion Insight into future perspectives of the van der Waals heterostructures and devices with the detailed effective role of 2D materials for integrated electrical and electronic equipment

Download or read book Optoelectronic Properties of Graphene Based van der Waals Hybrids written by Kallol Roy and published by Springer Nature. This book was released on 2020-10-21 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis deals with the development and in-depth study of a new class of optoelectronic material platform comprising graphene and MoS_2, in which MoS_2 is used essentially to sensitize graphene and lead to unprecedently high gain and novel opto-electronic memory effects. The results presented here open up the possibility of designing a new class of photosensitive devices which can be utilized in various optoelectronic applications including biomedical sensing, astronomical sensing, optical communications, optical quantum information processing and in applications requiring low intensity photodetection and number resolved single photon detection.

Download or read book X ray Standing Wave Technique The Principles And Applications written by Jorg Zegenhagen and published by World Scientific. This book was released on 2013-01-30 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: The X-ray standing wave (XSW) technique is an X-ray interferometric method combining diffraction with a multitude of spectroscopic techniques. It is extremely powerful for obtaining information about virtually all properties of surfaces and interfaces on the atomic scale. However, as with any other technique, it has strengths and limitations. The proper use and necessary understanding of this method requires knowledge in quite different fields of physics and technology. This volume presents comprehensively the theoretical background, technical requirements and distinguished experimental highlights of the technique. Containing contributions from the most prominent experts of the technique, such as Andre Authier, Boris Batterman, Michael J Bedzyk, Jene Golovchenko, Victor Kohn, Michail Kovalchuk, Gerhard Materlik and D Phil Woodruff, the book equips scientists with all the necessary information and knowledge to understand and use the XSW technique in practically all applications.

Download or read book Modeling Characterization and Production of Nanomaterials written by and published by Elsevier. This book was released on 2015-03-17 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nano-scale materials have unique electronic, optical, and chemical properties which make them attractive for a new generation of devices. Part one of Modeling, Characterization, and Production of Nanomaterials: Electronics, Photonics and Energy Applications covers modeling techniques incorporating quantum mechanical effects to simulate nanomaterials and devices, such as multiscale modeling and density functional theory. Part two describes the characterization of nanomaterials using diffraction techniques and Raman spectroscopy. Part three looks at the structure and properties of nanomaterials, including their optical properties and atomic behaviour. Part four explores nanofabrication and nanodevices, including the growth of graphene, GaN-based nanorod heterostructures and colloidal quantum dots for applications in nanophotonics and metallic nanoparticles for catalysis applications. Comprehensive coverage of the close connection between modeling and experimental methods for studying a wide range of nanomaterials and nanostructures Focus on practical applications and industry needs, supported by a solid outlining of theoretical background Draws on the expertise of leading researchers in the field of nanomaterials from around the world

Download or read book Molecular Beam Epitaxy written by Mohamed Henini and published by Elsevier. This book was released on 2018-06-27 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular Beam Epitaxy (MBE): From Research to Mass Production, Second Edition, provides a comprehensive overview of the latest MBE research and applications in epitaxial growth, along with a detailed discussion and ‘how to’ on processing molecular or atomic beams that occur on the surface of a heated crystalline substrate in a vacuum. The techniques addressed in the book can be deployed wherever precise thin-film devices with enhanced and unique properties for computing, optics or photonics are required. It includes new semiconductor materials, new device structures that are commercially available, and many that are at the advanced research stage. This second edition covers the advances made by MBE, both in research and in the mass production of electronic and optoelectronic devices. Enhancements include new chapters on MBE growth of 2D materials, Si-Ge materials, AIN and GaN materials, and hybrid ferromagnet and semiconductor structures. Condenses the fundamental science of MBE into a modern reference, speeding up literature review Discusses new materials, novel applications and new device structures, grounding current commercial applications with modern understanding in industry and research Includes coverage of MBE as mass production epitaxial technology and how it enhances processing efficiency and throughput for the semiconductor industry and nanostructured semiconductor materials research community

Download or read book 2D Monoelemental Materials Xenes and Related Technologies written by Zongyu Huang and published by CRC Press. This book was released on 2022-04-19 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monoelemental 2D materials called Xenes have a graphene-like structure, intra-layer covalent bond, and weak van der Waals forces between layers. Materials composed of different groups of elements have different structures and rich properties, making Xenes materials a potential candidate for the next generation of 2D materials. 2D Monoelemental Materials (Xenes) and Related Technologies: Beyond Graphene describes the structure, properties, and applications of Xenes by classification and section. The first section covers the structure and classification of single-element 2D materials, according to the different main groups of monoelemental materials of different components and includes the properties and applications with detailed description. The second section discusses the structure, properties, and applications of advanced 2D Xenes materials, which are composed of heterogeneous structures, produced by defects, and regulated by the field. Features include: Systematically detailed single element materials according to the main groups of the constituent elements Classification of the most effective and widely studied 2D Xenes materials Expounding upon changes in properties and improvements in applications by different regulation mechanisms Discussion of the significance of 2D single-element materials where structural characteristics are closely combined with different preparation methods and the relevant theoretical properties complement each other with practical applications Aimed at researchers and advanced students in materials science and engineering, this book offers a broad view of current knowledge in the emerging and promising field of 2D monoelemental materials.

Download or read book Fundamentals of Friction and Wear on the Nanoscale written by Enrico Gnecco and published by Springer Nature. This book was released on with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 2D Materials written by Phaedon Avouris and published by Cambridge University Press. This book was released on 2017-06-29 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn about the most recent advances in 2D materials with this comprehensive and accessible text. Providing all the necessary materials science and physics background, leading experts discuss the fundamental properties of a wide range of 2D materials, and their potential applications in electronic, optoelectronic and photonic devices. Several important classes of materials are covered, from more established ones such as graphene, hexagonal boron nitride, and transition metal dichalcogenides, to new and emerging materials such as black phosphorus, silicene, and germanene. Readers will gain an in-depth understanding of the electronic structure and optical, thermal, mechanical, vibrational, spin and plasmonic properties of each material, as well as the different techniques that can be used for their synthesis. Presenting a unified perspective on 2D materials, this is an excellent resource for graduate students, researchers and practitioners working in nanotechnology, nanoelectronics, nanophotonics, condensed matter physics, and chemistry.