Download or read book Electronic Band Engineering in Epitaxial Graphene written by Hansika Iroshini Sirikumara and published by . This book was released on 2014 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research work, we have investigated the band engineering of epitaxial graphene using first principles calculations. Epitaxial graphene on SiC (0001) surface is modified by using different methods such as intercalation, doping, passivation and oxidation. The calculations are done using Density functional theory which is implemented in quantum espresso package. In the presence of H intercalation, epitaxial graphene is shown to have p type behavior with monolayer graphene. However this behavior is different for multilayer epitaxial graphene systems, and it depended on the concentration of the H atoms. When epitaxial graphene is intercalated with Ge atoms, the Ge atoms make clusters and these clusters are responsible for the electronic properties of the epitaxial graphene systems. As a result of oxidation of epitaxial SiC surface, the graphene layer is mostly stable on the surface for both silicates and oxynitrides structures. For silicate/SiC configurations, the epitaxial graphene is shown to be less n type. For oxynitrides/ SiC configurations, epitaxial graphene is shown to be neutral. In the presence of oxygen intercalation with silicate/SiC, epitaxial graphene is shown to have p type behavior. These systematic studies of epitaxial graphene will opens up great potential for electronic applications. Additionally the resultant models can be used to guide further studies.
Download or read book Electronic Band Engineering in Epitaxial Graphene b First Principles Calculations written by Hansika Iroshini Sirikumara (‡e author) and published by . This book was released on 2014 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this research work, we have investigated the band engineering of epitaxial graphene using first principles calculations. Epitaxial graphene on SiC (0001) surface is modified by using different methods such as intercalation, doping, passivation and oxidation. The calculations are done using Density functional theory which is implemented in quantum espresso package. In the presence of H intercalation, epitaxial graphene is shown to have p type behavior with monolayer graphene. However this behavior is different for multilayer epitaxial graphene systems, and it depended on the concentration of the H atoms. When epitaxial graphene is intercalated with Ge atoms, the Ge atoms make clusters and these clusters are responsible for the electronic properties of the epitaxial graphene systems. As a result of oxidation of epitaxial SiC surface, the graphene layer is mostly stable on the surface for both silicates and oxynitrides structures. For silicate/SiC configurations, the epitaxial graphene is shown to be less n type. For oxynitrides/ SiC configurations, epitaxial graphene is shown to be neutral. In the presence of oxygen intercalation with silicate/SiC, epitaxial graphene is shown to have p type behavior. These systematic studies of epitaxial graphene will opens up great potential for electronic applications. Additionally the resultant models can be used to guide further studies.
Download or read book Substrate induced Band Gap Opening in Epitaxial Graphene written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene has shown great application potential as the hostmaterial for next-generation electronic devices. However, despite itsintriguing properties, one of the biggest hurdles for graphene to beuseful as an electronic material is the lack of an energy gap in itselectronic spectra. This, for example, prevents the use of graphene inmaking transistors. Although several proposals have been made to open agap in graphene's electronic spectra, they all require complexengineering of the graphene layer. Here, we show that when graphene isepitaxially grown on SiC substrate, a gap of ~;0.26 eV is produced. Thisgap decreases as the sample thickness increases and eventually approacheszero when the number of layers exceeds four. We propose that the originof this gap is the breaking of sublattice symmetry owing to thegraphene-substrate interaction. We believe that our results highlight apromising direction for band gap engineering of graphene.
Download or read book Epitaxial Graphene on Silicon Carbide written by Gemma Rius and published by CRC Press. This book was released on 2018-01-19 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book dedicated exclusively to epitaxial graphene on silicon carbide (EG-SiC). It comprehensively addresses all fundamental aspects relevant for the study and technology development of EG materials and their applications, using quantum Hall effect studies and probe techniques such as scanning tunneling microscopy and atomic resolution imaging based on transmission electron microscopy. It presents the state of the art of the synthesis of EG-SiC and profusely explains it as a function of SiC substrate characteristics such as polytype, polarity, and wafer cut as well as the in situ and ex situ conditioning techniques, including H2 pre-deposition annealing and chemical mechanical polishing. It also describes growth studies, including the most popular characterization techniques, such as ultrahigh-vacuum, partial-pressure, or graphite-cap sublimation techniques, for high-quality controlled deposition. The book includes relevant examples on synthesis and characterization techniques as well as device fabrication processing and performance and complements them with theoretical modeling and simulation studies, which are helpful in the fundamental comprehension of EG-SiC substrates and their potential use in electronic applications. It addresses the fundamental aspects of EG-SiC using quantum Hall effect studies as well as probe techniques, such as scanning tunneling microscopy or atomic resolution imaging based on transmission electron microscopy. It comprises chapters that present reviews and vision on the current state of the art of experts in physics, electronic engineering, materials science, and nanotechnology from Europe and Asia.
Download or read book Growing Graphene on Semiconductors written by Nunzio Motta and published by CRC Press. This book was released on 2017-09-08 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene, the wonder material of the 21st century, is expected to play an important role in future nanoelectronic applications, but the only way to achieve this goal is to grow graphene directly on a semiconductor, integrating it in the chain for the production of electronic circuits and devices. This book summarizes the latest achievements in this field, with particular attention to the graphitization of SiC. Through high-temperature annealing in a controlled environment, it is possible to decompose the topmost SiC layers, obtaining quasi-ideal graphene by Si sublimation with record electronic mobilities, while selective growth on patterned structures makes possible the opening of a gap by quantum confinement. The book starts with a review chapter on the significance and challenges of graphene growth on semiconductors, followed by three chapters dedicated to an up-to-date analysis of the synthesis of graphene in ultrahigh vacuum, and concludes with two chapters discussing possible ways of tailoring the electronic band structure of epitaxial graphene by atomic intercalation and of creating a gap by the growth of templated graphene nanostructures.
Download or read book Electronic Band Structure Engineering and Ultrafast Dynamics of Dirac Semimetals written by Changhua Bao and published by Springer Nature. This book was released on with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Graphene Nanoelectronics written by Raghu Murali and published by Springer Science & Business Media. This book was released on 2012-03-09 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene has emerged as a potential candidate to replace traditional CMOS for a number of electronic applications; this book presents the latest advances in graphene nanoelectronics and the potential benefits of using graphene in a wide variety of electronic applications. The book also provides details on various methods to grow graphene, including epitaxial, CVD, and chemical methods. This book serves as a spring-board for anyone trying to start working on graphene. The book is also suitable to experts who wish to update themselves with the latest findings in the field.
Download or read book Controlled Synthesis and Scanning Tunneling Microscopy Study of Graphene and Graphene Based Heterostructures written by Mengxi Liu and published by Springer. This book was released on 2017-10-10 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the energy band engineering of graphene. It presents pioneering findings on the controlled growth of graphene and graphene-based heterostructures, as well as scanning tunneling microscopy/scanning tunneling spectroscopy (STM/STS) studies on their electronic structures. The thesis primarily investigates two classes of graphene-based systems: (i) twisted bilayer graphene, which was synthesized on Rh substrates and manifests van Hove singularities near Fermi Level, and (ii) in-plane h-BN-G heterostructures, which were controllably synthesized in an ultrahigh vacuum chamber and demonstrate intriguing electronic properties on the interface. In short, the thesis offers revealing insights into the energy band engineering of graphene-based nanomaterials, which will greatly facilitate future graphene applications.
Download or read book Handbook of Graphene Volume 2 written by Tobias Stauber and published by John Wiley & Sons. This book was released on 2019-06-28 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second volume in a series of handbooks on graphene research and applications Graphene is a valuable nanomaterial used in technology. This handbook features graphene topics related to Physics, Chemistry, and Biology. The Handbook of Graphene, Volume 2 delivers an overview on the numerous and diverse graphene research directions and innovations. The handbook covers a range of areas including graphene in optoelectronic devices and as a detector of biomolecules.
Download or read book Epitaxial Graphene Films on SiC written by Xuebin Li and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene is a single sheet of graphite. While bulk graphite is semimetal, graphene is a zero bandgap semiconductor. Band structure calculations show graphene has a linear energy dispersion relation in the low energy region close to the Dirac points where the conduction band and the valence band touch. Carriers in graphene are described as massless Dirac fermions in contrast to massive carriers in normal metals and semiconductors that obey a parabolic energy dispersion relation. The uniqueness of graphene band structure indicates its peculiar electronic transport properties.
Download or read book Graphene Photonics written by Jia-Ming Liu and published by Cambridge University Press. This book was released on 2018-12-13 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene is a single-layer crystal of carbon, the thinnest two-dimensional material. It has unique electronic and photonic properties.
Download or read book Handbook of Graphene written by Tobias Stauber and published by John Wiley & Sons. This book was released on 2019-06-12 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second volume in a series of handbooks on graphene research and applications Graphene is a valuable nanomaterial used in technology. This handbook features graphene topics related to Physics, Chemistry, and Biology. The Handbook of Graphene, Volume 2 delivers an overview on the numerous and diverse graphene research directions and innovations. The handbook covers a range of areas including graphene in optoelectronic devices and as a detector of biomolecules.
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 Structured Epitaxial Graphene for Electronics written by Ming Ruan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: After the pioneering investigations into graphene-based electronics at Georgia Tech, great strides have been made developing epitaxial graphene on silicon carbide (EG) as a new electronic material. EG has not only demonstrated its potential for large scale applications, it also has become an important material for fundamental two-dimensional electron gas physics. Graphene is generally considered to be a strong candidate to succeed silicon as an electronic material. However, to date, it actually has not yet demonstrated capabilities that exceed standard semiconducting materials. One disadvantage of conventionally fabricated graphene devices is that nanoscopically patterned graphene tends to have disordered edges that severely reduce mobilities thereby obviating its advantage over other materials. The other disadvantage is that pristine graphene does not contain a band gap, which is critical for standard field effect transistor to operate. This thesis will show that graphene grown on structured silicon carbide surfaces overcomes the edge roughness and promises to provide an inroad into nanoscale patterning of graphene. High-quality ribbons and rings can be made using this technique.
Download or read book The Physics of Graphene written by Mikhail I. Katsnelson and published by Cambridge University Press. This book was released on 2020-03-19 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading graphene research theorist Mikhail I. Katsnelson systematically presents the basic concepts of graphene physics in this fully revised second edition. The author illustrates and explains basic concepts such as Berry phase, scaling, Zitterbewegung, Kubo, Landauer and Mori formalisms in quantum kinetics, chirality, plasmons, commensurate-incommensurate transitions and many others. Open issues and unsolved problems introduce the reader to the latest developments in the field. New achievements and topics presented include the basic concepts of Van der Waals heterostructures, many-body physics of graphene, electronic optics of Dirac electrons, hydrodynamics of electron liquid and the mechanical properties of one atom-thick membranes. Building on an undergraduate-level knowledge of quantum and statistical physics and solid-state theory, this is an important graduate textbook for students in nanoscience, nanotechnology and condensed matter. For physicists and material scientists working in related areas, this is an excellent introduction to the fast-growing field of graphene science.
Download or read book Graphene written by Wonbong Choi and published by CRC Press. This book was released on 2016-04-19 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the late 20th century, graphene-a one-atom-thick planar sheet of sp2-bonded carbon atoms densely packed in a honeycomb crystal lattice-has garnered appreciable attention as a potential next-generation electronic material due to its exceptional properties. These properties include high current density, ballistic transport, chemical inertness,
Download or read book GraphITA 2011 written by Luca Ottaviano and published by Springer Science & Business Media. This book was released on 2012-03-06 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, graphene based research has witnessed a tremendous explosion. This two dimensional "dream" material has come into the main spotlight of fundamental and applied research in diverse nano-science fields, but surprisingly rapidly, it has also attracted the interest of major stakeholders in the private sector (especially industries in the ICT sector). The technological exploitation of graphene can be considered to be based on four fundamental interconnected wide topics: growth and synthesis methods, nano-structuring and tailoring of graphene properties, structural and physical characterization, and device design and applications. This proceedings book presents the results highlighted at GraphITA 2011, a multidisciplinary and intersectorial European Workshop on Synthesis, Characterization and Technological Exploitation of Graphene. The workshop realised on 15-18 May at Gran Sasso National Laboratories (Assegi-L'Aquila, Italy) has brought together scientists and engineers working on different technological uses of graphene in a multidisciplinary and multisectorial (academia/industry) environment.
