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Quantum Confined Excitons in 2-Dimensional Materials

Author : Carmen Palacios-Berraquero

Publisher : Springer

Page : 125 pages

File Size : 38,84 MB

Release : 2018-11-02

Category : Computers

ISBN : 3030014827

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Book Description

This book presents the first established experimental results of an emergent field: 2-dimensional materials as platforms for quantum technologies, specifically through the optics of quantum-confined excitons. It also provides an extensive review of the literature from a number of disciplines that informed the research, and introduces the materials of focus – 2d Transition Metal Dichalcogenides (2d-TMDs) – in detail, discussing electronic and chemical structure, excitonic behaviour and response to strain. This is followed by a brief overview of quantum information technologies, including concepts such as single-photon sources and quantum networks. The methods chapter addresses quantum optics techniques and 2d-material processing, while the results section shows the development of a method to deterministically create quantum dots (QDs) in the 2d-TMDs, which can trap single-excitons; the fabrication of atomically thin quantum light-emitting diodes to induce all-electrical single-photon emission from the QDs, and lastly, the use of devices to controllably trap single-spins in the QDs –the first step towards their use as optically-addressable matter qubits.



Ultrafast Dynamics of Magnetically Confined Excitons in GaAs Quantum Wells

Author : J. B. Stark

Publisher :

Page : 4 pages

File Size : 20,44 MB

Release : 1992

Category :

ISBN :

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Book Description

Spatial confinement along one dimension, using the methods of epitaxial crystal growth, has demonstrated that linear and nonlinear optical properties depend strongly on dimensionality. Confinement along the remaining directions, however, continues to present formidable technological obstacles. Difficulties in the control of the surface properties and size distribution of quantum dots and semiconductor microcrystallites results in materials with unsatisfactory optical quality. Confinement along all three dimensions can be achieved, in materials of excellent optical quality, by placing a quantum well material in a perpendicular magnetic field. As the field is increased, the extension of the resulting electronic orbitals decreases, so that the dimensionality of the states may be tuned from two to zero dimensions. Using femtosecond excite-and-probe optical techniques in fields as large as 12 Tesla, we measure the time resolved dynamics of zero dimensional magneto-excitons.



Electronic Transport of a 2D Quantum Material WTe2

Author : Wenjin Zhao

Publisher :

Page : 101 pages

File Size : 30,6 MB

Release : 2020

Category :

ISBN :

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Book Description

Quantum materials, such as superconductors, topological insulators, magnets, and Weyl semimetals, are materials whose properties cannot be explained without quantum mechanics. Strong correlation and band topology play very important roles in quantum materials. The study of two-dimensional (2D) quantum materials was triggered by the discovery of graphene, the first atomically thin crystal wherein electrons are confined in a single 2D sheet. In this regime, critical material parameters such as carrier density, electron correlation strength and topology can be modified by electrostatic gate, screening effect and magnetic field, respectively. Moreover, the stacking of different 2D quantum materials enables creation of novel structures which can host new electronic phenomena and realize new device functionalities. All of these make 2D quantum materials a perfect platform to study the physics of strong correlation, magnetism, and topology. This thesis focuses on electronic properties of a 2D quantum material WTe2. In the first part, I will discuss the discovery of the first ferroelectric metal in few-layer WTe2. As WTe2 is thinned down to trilayer and bilayer, it exhibits coexistence of ferroelectric and metallic phases. Then, I will discuss the quantum spin Hall (QSH) edge state of a monolayer WTe2 in three aspects. The spin axis is first established by study of the anisotropy of conductance in an external magnetic field. Then I will show the magnetic proximity effect between the QSH edge and a 2D magnet CrI3. Finally, I will summarize the experiment of spin current injection into the QSH edge.



Advances in Condensed-Matter and Materials Physics

Author : Jagannathan Thirumalai

Publisher : BoD – Books on Demand

Page : 202 pages

File Size : 27,82 MB

Release : 2020-05-06

Category : Science

ISBN : 1838805540

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Book Description

This book, Condensed Matter and Material Physics, incorporates the work of multiple authors to enhance the theoretical as well as experimental knowledge of materials. The investigation of crystalline solids is a growing need in the electronics industry. Micro and nano transistors require an in-depth understanding of semiconductors of different groups. Amorphous materials, on the other hand, as non-equilibrium materials are widely applied in sensors and other medical and industrial applications. Superconducting magnets, composite materials, lasers, and many more applications are integral parts of our daily lives. Superfluids, liquid crystals, and polymers are undergoing active research throughout the world. Hence profound information on the nature and application of various materials is in demand. This book bestows on the reader a deep knowledge of physics behind the concepts, perspectives, characteristic properties, and prospects. The book was constructed using 10 contributions from experts in diversified fields of condensed matter and material physics and its technology from over 15 research institutes across the globe.



Materials for Optoelectronics

Author : Maurice Quillec

Publisher : Springer Science & Business Media

Page : 404 pages

File Size : 11,30 MB

Release : 1996-01-31

Category : Technology & Engineering

ISBN : 9780792396659

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Book Description

Optoelectronics ranks one of the highest increasing rates among the different industrial branches. This activity is closely related to devices which are themselves extremely dependent on materials. Indeed, the history of optoelectronic devices has been following closely that of the materials. KLUWER Academic Publishers has thus rightly identified "Materials for Optoelectronics" as a good opportunity for a book in the series entitled "Electronic Materials; Science and Technology". Although a sound background in solid state physics is recommended, the authors have confined their contribution to a graduate student level, and tried to define any concept they use, to render the book as a whole as self-consistent as possible. In the first section the basic aspects are developed. Here, three chapters consider semiconductor materials for optoelectronics under various aspects. Prof. G. E. Stillman begins with an introduction to the field from the point of view of the optoelectronic market. Then he describes how III-V materials, especially the Multi Quantum Structures meet the requirements of optoelectronic functions, including the support of microelectronics for optoelectronic integrated circuits. In chapter 2, Prof.



Semiconductor Quantum Dots

Author : Ladislaus Alexander Banyai

Publisher : World Scientific

Page : 264 pages

File Size : 40,56 MB

Release : 1993-05-28

Category : Science

ISBN : 9814504238

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Book Description

Semiconductor Quantum Dots presents an overview of the background and recent developments in the rapidly growing field of ultrasmall semiconductor microcrystallites, in which the carrier confinement is sufficiently strong to allow only quantized states of the electrons and holes. The main emphasis of this book is the theoretical analysis of the confinement induced modifications of the optical and electronic properties of quantum dots in comparison with extended materials. The book develops the theoretical background material for the analysis of carrier quantum-confinement effects, introduces the different confinement regimes for relative or center-of-mass motion quantization of the electron-hole-pairs, and gives an overview of the best approximation schemes for each regime. A detailed discussion of the carrier states in quantum dots is presented and surface polarization instabilities are analyzed, leading to the self-trapping of carriers near the surface of the dots. The influence of spin-orbit coupling on the quantum-confined carrier states is discussed. The linear and nonlinear optical properties of small and large quantum dots are studied in detail and the influence of the quantum-dot size distribution in many realistic samples is outlined. Phonons in quantum dots as well as the influence of external electric or magnetic fields are also discussed. Last but not least the recent developments dealing with regular systems of quantum dots are also reviewed. All things included, this is an important piece of work on semiconductor quantum dots not to be dismissed by serious researchers and physicists.



Optical Properties of Low-dimensional Materials

Author : Tetsuo Ogawa

Publisher : World Scientific

Page : 478 pages

File Size : 47,52 MB

Release : 1998

Category : Science

ISBN : 9789810230487

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Book Description

This book surveys recent theoretical and experimental studies of optical properties of low-dimensional materials. As an extended version of Optical Properties of Low-Dimensional Materials (Volume 1, published in 1995 by World Scientific), Volume 2 covers a wide range of interesting low-dimensional materials including both inorganic and organic systems, such as disordered polymers, deformable molecular crystals, dilute magnetic semiconductors, SiGe/Si short-period superlattices, GaAs quantum wires, semiconductor microcavities, and photonic crystals. There are excellent review articles by promising researchers in each field. All the materials introduced in this book yield new optical phenomena originating from their mesoscopic and low-dimensional electronic characters and electron-lattice couplings, which offer a new research field of materials science as well as condensed-matter and optical physics. Volumes 1 and 2 are interrelated but can be read independently. They are pitched at the level of graduate students and are useful to both students and scientists.



Exciton Dynamics in Lead Halide Perovskite Nanocrystals

Author : Bernhard Johann Bohn

Publisher : Springer Nature

Page : 169 pages

File Size : 16,72 MB

Release : 2021-05-18

Category : Science

ISBN : 303070940X

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Book Description

Less than a decade ago, lead halide perovskite semiconductors caused a sensation: Solar cells exhibiting astonishingly high levels of efficiency. Recently, it became possible to synthesize nanocrystals of this material as well. Interestingly; simply by controlling the size and shape of these crystals, new aspects of this material literally came to light. These nanocrystals have proven to be interesting candidates for light emission. In this thesis, the recombination, dephasing and diffusion of excitons in perovskite nanocrystals is investigated using time-resolved spectroscopy. All these dynamic processes have a direct impact on the light-emitting device performance from a technology point of view. However, most importantly, the insights gained from the measurements allowed the author to modify the nanocrystals such that they emitted with an unprecedented quantum yield in the blue spectral range, resulting in the successful implementation of this material as the active layer in an LED. This represents a technological breakthrough, because efficient perovskite light emitters in this wavelength range did not exist before.



Synthesis and Applications of Nanocarbons

Author : Jean-Charles Arnault

Publisher : John Wiley & Sons

Page : 320 pages

File Size : 33,47 MB

Release : 2020-09-21

Category : Technology & Engineering

ISBN : 1119429382

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Book Description

A crucial overview of the cutting-edge in nanocarbon research and applications In Synthesis and Applications of Nanocarbons, the distinguished authors have set out to discuss fundamental topics, synthetic approaches, materials challenges, and various applications of this rapidly developing technology. Nanocarbons have recently emerged as a promising material for chemical, energy, environmental, and medical applications because of their unique chemical properties and their rich surface chemistries. This book is the latest entry in the Wiley book series Nanocarbon Chemistry and Interfaces and seeks to comprehensively address many of the newly surfacing areas of controversy and development in the field. This book introduces foundational concepts in nanocarbon technology, hybrids, and applications, while also covering the most recent and cutting-edge developments in this area of study. Synthesis and Applications of Nanocarbons addresses new discoveries in the field, including: · Nanodiamonds · Onion-like carbons · Carbon nanotubes · Fullerenes · Carbon dots · Carbon fibers · Graphene · Aerographite This book provides a transversal view of the various nanocarbon materials and hybrids and helps to share knowledge between the communities of each material and hybrid type.



2D Monoelemental Materials (Xenes) and Related Technologies

Author : Zongyu Huang

Publisher : CRC Press

Page : 166 pages

File Size : 21,48 MB

Release : 2022-04-19

Category : Science

ISBN : 1000562840

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Book Description

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.