Probing Valley and Magnetic Photoexcitations in 2D Crystals and Their Heterostructures PDF Download

Author: Kyle Lee Seyler
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Layered materials are excellent systems for investigating physics in two dimensions. Understanding the optical response of 2D layered materials and their heterostructures at the atomically thin limit is an important aspect of this field. Photoexcitations, such as excitons, critically impact future optoelectronic technologies, such as next-generation solar cells, light-emitting diodes, lasers, and single-photon sources. Moreover, they can provide deep insights into the rich electronic properties of the host crystals, especially in two dimensions, where stronger electron confinement, symmetry changes, and interfacial effects are often very influential. The 2D semiconducting transition metal dichalcogenides, for example, have garnered tremendous excitement for their strong light-matter interactions, which involve tightly bound excitons with intriguing spin-valley physics. Furthermore, newly discovered 2D magnets are unlocking new opportunities to explore magnetic photoexcitations in the atomically thin limit. This dissertation presents optical spectroscopy experiments that probe the fundamental photoexcitations within 2D semiconducting transition metal dichalcogenides, magnetic chromium triiodide (CrI3), and their van der Waals heterostructures. First, we show how second-harmonic generation spectroscopy serves as a powerful probe of excitons and trions in monolayer WSe2 and demonstrate an electrical exciton-based second-harmonic generation switch. We then add MoSe2 to the picture, forming MoSe2/WSe2 heterobilayers in which we reveal the valley-contrasting physics of long-lived free and trapped interlayer excitons. Next, we introduce atomically thin CrI3 and describe our observation of spontaneous circularly polarized photoluminescence. We also unravel its ligand-field and charge-transfer-dominated photoresponse, which broadens the landscape of 2D material photoexcitations beyond excitons. Finally, we combine ultrathin layers of CrI3 with monolayer WSe2, where we discover unprecedented control of valley excitons in monolayer WSe2 by magnetic proximity to CrI3.

Author: Yilei Li
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
In the magneto-optic study of transition metal dichalcogenide monolayers, we demonstrate the induction of valley splitting and polarization by the application of an external magnetic field. The interaction of the valleys with the magnetic field reflects their non-zero magnetic moments, which are compared to theoretical models. We further clarify the electronic configuration of the charged excitons and important many-body corrections to the trion binding energy through the control of valley polarization achieved by the external magnetic field.

Author: Phaedon Avouris
Publisher: Cambridge University Press
ISBN: 1107163714
Category : Science
Languages : en
Pages : 521

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

Author: Felipe A. La Porta
Publisher: Springer Nature
ISBN: 3030622266
Category : Technology & Engineering
Languages : en
Pages : 778

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Book Description
This book shows how a small toolbox of experimental techniques, physical chemistry concepts as well as quantum/classical mechanics and statistical methods can be used to understand, explain and even predict extraordinary applications of these advanced engineering materials and biomolecules. It highlights how improving the material foresight by design, including the fundamental understanding of their physical and chemical properties, can provide new technological levels in the future.

Author: Xin Tong
Publisher: Springer Nature
ISBN: 3030742709
Category : Technology & Engineering
Languages : en
Pages : 319

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Book Description
This book presents a comprehensive overview of state-of-the-art quantum dot photodetectors, including device fabrication technologies, optical engineering/manipulation strategies, and emerging photodetectors with building blocks of novel quantum dots (e.g. perovskite) as well as their hybrid structured (e.g. 0D/2D) materials. Semiconductor quantum dots have attracted much attention due to their unique quantum confinement effect, which allows for the facile tuning of optical properties that are promising for next-generation optoelectronic applications. Among these remarkable properties are large absorption coefficient, high photosensitivity, and tunable optical spectrum from ultraviolet/visible to infrared region, all of which are very attractive and favorable for photodetection applications. The book covers both fundamental and frontier research in order to stimulate readers' interests in developing novel ideas for semiconductor photodetectors at the center of future developments in materials science, nanofabrication technology and device commercialization. The book provides a knowledge sharing platform and can be used as a reference for researchers working in the fields of photonics, materials science, and nanodevices.

Author: A. Miller
Publisher: CRC Press
ISBN: 0429524935
Category : Science
Languages : en
Pages : 325

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Book Description
Ultrafast photonics has become an interdisciplinary topic of high international research interest because of the spectacular development of compact and efficient lasers producing optical pulses with durations in the femtosecond time domain. Present day long-haul telecommunications systems are almost entirely based on the transmission of short burst

Author: Alexander V. Kolobov
Publisher: Springer
ISBN: 3319314505
Category : Technology & Engineering
Languages : en
Pages : 545

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Book Description
This book summarizes the current status of theoretical and experimental progress in 2 dimensional graphene-like monolayers and few-layers of transition metal dichalcogenides (TMDCs). Semiconducting monolayer TMDCs, due to the presence of a direct gap, significantly extend the potential of low-dimensional nanomaterials for applications in nanoelectronics and nano-optoelectronics as well as flexible nano-electronics with unprecedented possibilities to control the gap by external stimuli. Strong quantum confinement results in extremely high exciton binding energies which forms an interesting platform for both fundamental studies and device applications. Breaking of spatial inversion symmetry in monolayers results in strong spin-valley coupling potentially leading to their use in valleytronics. Starting with the basic chemistry of transition metals, the reader is introduced to the rich field of transition metal dichalcogenides. After a chapter on three dimensional crystals and a description of top-down and bottom-up fabrication methods of few-layer and single layer structures, the fascinating world of two-dimensional TMDCs structures is presented with their unique atomic, electronic, and magnetic properties. The book covers in detail particular features associated with decreased dimensionality such as stability and phase-transitions in monolayers, the appearance of a direct gap, large binding energy of 2D excitons and trions and their dynamics, Raman scattering associated with decreased dimensionality, extraordinarily strong light-matter interaction, layer-dependent photoluminescence properties, new physics associated with the destruction of the spatial inversion symmetry of the bulk phase, spin-orbit and spin-valley couplings. The book concludes with chapters on engineered heterostructures and device applications such as a monolayer MoS2 transistor. Considering the explosive interest in physics and applications of two-dimensional materials, this book is a valuable source of information for material scientists and engineers working in the field as well as for the graduate students majoring in materials science.

Author: Rafik Addou
Publisher: Elsevier
ISBN: 032390310X
Category : Technology & Engineering
Languages : en
Pages : 434

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Book Description
Defects in Two-Dimensional Materials addresses the fundamental physics and chemistry of defects in 2D materials and their effects on physical, electrical and optical properties. The book explores 2D materials such as graphene, hexagonal boron nitride (h-BN) and transition metal dichalcogenides (TMD). This knowledge will enable scientists and engineers to tune 2D materials properties to meet specific application requirements. The book reviews the techniques to characterize 2D material defects and compares the defects present in the various 2D materials (e.g. graphene, h-BN, TMDs, phosphorene, silicene, etc.). As two-dimensional materials research and development is a fast-growing field that could lead to many industrial applications, the primary objective of this book is to review, discuss and present opportunities in controlling defects in these materials to improve device performance in general or use the defects in a controlled way for novel applications. Presents the theory, physics and chemistry of 2D materials Catalogues defects of 2D materials and their impacts on materials properties and performance Reviews methods to characterize, control and engineer defects in 2D materials

Author: Narayanasamy Sabari Arul
Publisher: Springer
ISBN: 9811390452
Category : Technology & Engineering
Languages : en
Pages : 355

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Book Description
This book presents advanced synthesis techniques adopted to fabricate two-dimensional (2D) transition metal dichalcogenides (TMDs) materials with its enhanced properties towards their utilization in various applications such as, energy storage devices, photovoltaics, electrocatalysis, electronic devices, photocatalysts, sensing and biomedical applications. It provides detailed coverage on everything from the synthesis and properties to the applications and future prospects of research in 2D TMD nanomaterials.

Author: Rolf Binder
Publisher: World Scientific
ISBN: 9813148764
Category : Science
Languages : en
Pages : 517

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Book Description
This book provides a comprehensive state-of-the-art overview of the optical properties of graphene. During the past decade, graphene, the most ideal and thinnest of all two-dimensional materials, has become one of the most widely studied materials. Its unique properties hold great promise to revolutionize many electronic, optical and opto-electronic devices. The book contains an introductory tutorial and 13 chapters written by experts in areas ranging from fundamental quantum mechanical properties to opto-electronic device applications of graphene.