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 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: A comprehensive and accessible introduction to 2D materials, covering basic physics, electronic and optical properties, and potential applications.

Download or read book 2D Materials for Photonic and Optoelectronic Applications written by Qiaoliang Bao and published by Woodhead Publishing. This book was released on 2019-10-19 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2D Materials for Photonic and Optoelectronic Applications introduces readers to two-dimensional materials and their properties (optical, electronic, spin and plasmonic), various methods of synthesis, and possible applications, with a strong focus on novel findings and technological challenges. The two-dimensional materials reviewed include hexagonal boron nitride, silicene, germanene, topological insulators, transition metal dichalcogenides, black phosphorous and other novel materials. This book will be ideal for students and researchers in materials science, photonics, electronics, nanotechnology and condensed matter physics and chemistry, providing background for both junior investigators and timely reviews for seasoned researchers. Provides an in-depth look at boron nitride, silicene, germanene, topological insulators, transition metal dichalcogenides, and more Reviews key applications for photonics and optoelectronics, including photodetectors, optical signal processing, light-emitting diodes and photovoltaics Addresses key technological challenges for the realization of optoelectronic applications and comments on future solutions

Download or read book 2D Materials for Electronics Sensors and Devices written by Saptarshi Das and published by Elsevier. This book was released on 2022-09-14 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2D Materials for Electronics, Sensors and Devices: Synthesis, Characterization, Fabrication and Application provides an overview of various top-down and bottom-up synthesis techniques, along with stitching, stacking and stoichiometric control methods for different 2D materials and their heterostructures. The book focuses on the widespread applications of various 2D materials in high-performance and low-power sensors, field effect devices, flexible electronics, straintronics, spintronics, brain-inspired electronics, energy harvesting and energy storage devices. This is an important reference for materials scientists and engineers looking to gain a greater understanding on how 2D materials are being used to create a range of low cost, sustainable products and devices. Discusses the major synthesis and preparation methods of a range of emerging 2D electronic materials Provides state-of–the-art information on the most recent advances, including theoretical and experimental studies and new applications Discusses the major challenges of the mass application of 2D materials in industry

Download or read book Engineering Epitaxial Graphene based 2D Heterojunctions for Electronic and Optoelectronic Applications written by Shruti Subramanian and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-dimensional (2D) materials have exhibited great promise for several electronic and optoelectronic applications. Depending on the complexity of the technology, they lie on various sections of the Gartner Hype cycle. With the famous pencil and scotch tape success story, graphene was the first of this family of van der Waals materials to open up a forte of either 2D-based or 2D-enabled technologies. The combination of different 2D materials allows the construction of vertical and lateral 2D heterostructures. The work presented in this dissertation focuses on epitaxial graphene-based heterostructures for electronic and optoelectronic applications. Chapter 1 presents the motivation of the dissertation study from the key technology drivers identified from the United States Grand Challenges. Before delving into the discussion of the results presented in this dissertation, Chapter 2 lays down the necessary basics of 2D materials and devices. It ranges from explaining graphene, its physics, synthesis and intercalation to transition metal dichalcogenides (TMDs), their physics and synthesis. An introduction to the electronic devices used in this dissertation follows next along with the basics of device fabrication and ends with the fundamentals of ellipsometry. Chapter 3 gets more specific and outlines all the experimental procedures used during the course of this dissertation including the microscopy and spectroscopy techniques used to understand the complex heterostructure systems synthesized. 2D materials are finding a niche spot in high-performance and energy-efficient computing, but fundamental problems arise due to contacts, which are connections between the 2D material and the 3D world. Chapter 4 of this dissertation focuses on developing a technique to synthesize seed-free selected-area lateral heterostructures with an as-grown graphene contact to TMDs like MoS2. 2D-only or 2D-enabled architectures are finding a place in the development of photovoltaics for economical solar energy. Chapter 5 of this dissertation focuses on understanding the photocurrent generation and subsequent dissociation of charge carriers at heterostructure interfaces in large-area scalable graphene/MoS2 architectures. The in-depth understanding of optoelectronic properties of heterostructure interfaces allows for expansion to application-specific engineering of heterostructure interfaces with improved contacts and extraction of photogenerated current. Atomically thin electronic materials are finding niche applications in electronics, sensors, and transmitters, and coatings among several other technologies, furthering the next technology driver - the Internet of Things. Chapter 6 of this dissertation focuses on as-grown graphene contacts to MoS2 and utilizes a unique property of enabling electrostatic modulation of the intrinsic doping of epitaxially grown graphene on SiC from n- to p-type, providing an additional knob for tuning 2D heterojunctions. Intercalation of metals between the graphene and SiC is yet another route for tuning and an excellent platform for biosensing applications; it further allows for the exploration of novel 2D metals. Chapter 7 of this dissertation is focused on understanding the optical properties of these novel 2D metals to integrate them into functional heterostructures. An outlook is presented in Chapter 8 along with future directions that can be explored within the realm of the work presented in this dissertation. The future directions are presented in the same format as the motivation, tying the two ends of this dissertation together. The works of this dissertation were primarily funded by National Science Foundation's CAREER (Award: 1453924). The findings and conclusions of this dissertation work does not necessarily reflect the view of the National Science Foundation.

Download or read book Two Dimensional Transition Metal Dichalcogenides written by Chi Sin Tang and published by John Wiley & Sons. This book was released on 2023-11-14 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Preparation and Properties of 2D Materials written by Byungjin Cho and published by MDPI. This book was released on 2020-12-10 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the great success of graphene, atomically thin-layered nanomaterials, called two dimensional (2D) materials, have attracted tremendous attention due to their extraordinary physical properties. Specifically, van der Waals heterostructured architectures based on a few 2D materials, named atomic-scale Lego, have been proposed as unprecedented platforms for the implementation of versatile devices with a completely novel function or extremely high-performance, shifting the research paradigm in materials science and engineering. Thus, diverse 2D materials beyond existing bulk materials have been widely studied for promising electronic, optoelectronic, mechanical, and thermoelectric applications. Especially, this Special Issue included the recent advances in the unique preparation methods such as exfoliation-based synthesis and vacuum-based deposition of diverse 2D materials and also their device applications based on interesting physical properties. Specifically, this Editorial consists of the following two parts: Preparation methods of 2D materials and Properties of 2D materials

Download or read book 2D Materials and Van der Waals Heterostructures written by Antonio Di Bartolomeo and published by MDPI. This book was released on 2020-06-23 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of graphene and, more recently, two-dimensional materials has opened new perspectives in electronics, optoelectronics, energy harvesting, and sensing applications. This book, based on a Special Issue published in Nanomaterials – MDPI covers experimental, simulation, and theoretical research on 2D materials and their van der Waals heterojunctions. The emphasis is the physical properties and the applications of 2D materials in state-of-the-art sensors and electronic or optoelectronic devices.

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 Defects in Two Dimensional Materials written by Rafik Addou and published by Elsevier. This book was released on 2022-02-14 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book 2D Semiconductors for Environmental Remediation written by Honey John and published by CRC Press. This book was released on 2024-10-02 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a comprehensive description of various aspects of 2D semiconductors including their synthesis, surface science, characterizations, and their allied application in environmental remediation including air and water purification, oil-water separation, hydrogen production, and CO2 removal. The electronic and optoelectronic enhancement properties of these semiconductors with bandgap engineering, doping, and chemical functionalization for various applications are exemplified. Features: Provides focus on the application of 2D semiconductors for environmental applications. Covers the fundamental understanding of material design, fabrication, defect engineering, physical and chemical properties of 2D semiconductors, and their advantages for environmental applications. Focuses on the reliable future perspectives and developments that lead to advanced research in utilizing 2D materials for large-scale exploration and commercial deployment. Explores an in-depth insight into various aspects and processes for environmental remediation. Details the importance of 2D semiconductors over other 0D, 1D, or 3D semiconductors. This book is aimed at researchers and graduate students in materials science and environmental engineering.

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 Two Dimensional Electronics and Optoelectronics written by Yoke Khin Yap and published by MDPI. This book was released on 2018-04-03 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Two-Dimensional Electronics and Optoelectronics" that was published in Electronics

Download or read book 2D Semiconducting Materials for Electronic Photonic and Optoelectronic Devices written by Anuj Kumar and published by CRC Press. This book was released on 2024-11-07 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-dimensional semiconducting materials (2D-SCMs) are the subject of intensive study in the fields of photonics and optoelectronics because of their unusual optical, electrical, thermal, and mechanical properties. The main objective of 2D Semiconducting Materials for Electronic, Photonic, and Optoelectronic Devices is to provide current, state-of-the-art knowledge of two-dimensional semiconducting materials for various applications. Two-dimensional semiconducting materials are the basic building blocks for making photodiodes, light-emitting diodes, light-detecting devices, data storage, telecommunications, and energy-storage devices. When it comes to two-dimensional semiconducting materials, electronic, photonic, and optoelectronic applications, as well as future plans for improving performance, no modern book covers as much ground. The planned book will fill such gaps by offering a comprehensive analysis of two-dimensional semiconducting materials. This book covers a range of advanced 2D materials, their fundamentals, and the chemistry for many emerging applications. All the chapters are covered by experts in these areas around the world, making this a suitable textbook for students and providing new guidelines to researchers and industries. • Covers topics such as fundamentals and advanced knowledge of two-dimensional semiconducting materials • Provides details about the recent methods used for the synthesis, characterization, and applications of two-dimensional semiconducting materials • Covers the state-of-the-art development in two-dimensional semiconducting materials and their emerging applications This book provides directions to students, scientists, and researchers in semiconductors and related disciplines to help them better understand the physics, characteristics, and applications of 2D semiconductors.

Download or read book 2D Nanoscale Heterostructured Materials written by Satyabrata Jit and published by Elsevier. This book was released on 2020-05-22 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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

Download or read book Ultrathin Two Dimensional Semiconductors for Novel Electronic Applications written by Mohammad Karbalaei Akbari and published by CRC Press. This book was released on 2020-07-30 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offering perspective on both the scientific and engineering aspects of 2D semiconductors, Ultrathin Two-Dimensional Semiconductors for Novel Electronic Applications discusses how to successfully engineer 2D materials for practical applications. It also covers several novel topics regarding 2D semiconductors which have not yet been discussed in any other publications. Features: Provides comprehensive information and data about wafer-scale deposition of 2D semiconductors, ranging from scientific discussions up to the planning of experiments and reliability testing of the fabricated samples Precisely discusses wafer-scale ALD and CVD of 2D semiconductors and investigates various aspects of deposition techniques Covers the new group of 2D materials synthesized from surface oxide of liquid metals and also explains the device fabrication and post-treatment of these 2D nanostructures Addresses a wide range of scientific and practical applications of 2D semiconductors and electronic and optoelectronic devices based on these nanostructures Offers novel coverage of 2D heterostructures and heterointerfaces and provides practical information about fabrication and application of these heterostructures Introduces the latest advancement in fabrication of novel memristors, artificial synapses and sensorimotor devices based on 2D semiconductors This work offers practical information valuable for engineering applications that will appeal to researchers, academics, and scientists working with and interested in developing an array of semiconductor electronic devices.

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.