Probing the Response of Two-Dimensional Crystals by Optical Spectroscopy

Probing the Response of Two-Dimensional Crystals by Optical Spectroscopy

Author: Yilei Li

Publisher: Springer

Published: 2015-11-09

Total Pages: 80

ISBN-13: 331925376X

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This thesis focuses on the study of the optical response of new atomically thin two-dimensional crystals, principally the family of transition metal dichalcogenides like MoS2. One central theme of the thesis is the precise treatment of the linear and second-order nonlinear optical susceptibilities of atomically thin transition metal dichalcogenides. In addition to their significant scientific interest as fundamental material responses, these studies provide essential knowledge and convenient characterization tools for the application of these 2D materials in opto-electronic devices. Another important theme of the thesis is the valley physics of atomically thin transition metal dichalcogenides. It is shown that the degeneracy in the valley degree of freedom can be lifted and a valley polarization can be created using a magnetic field, which breaks time reversal symmetry in these materials. These findings enhance our basic understanding of the valley electronic states and open up new opportunities for valleytronic applications using two-dimensional materials.


Book Synopsis Probing the Response of Two-Dimensional Crystals by Optical Spectroscopy by : Yilei Li

Download or read book Probing the Response of Two-Dimensional Crystals by Optical Spectroscopy written by Yilei Li and published by Springer. This book was released on 2015-11-09 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the study of the optical response of new atomically thin two-dimensional crystals, principally the family of transition metal dichalcogenides like MoS2. One central theme of the thesis is the precise treatment of the linear and second-order nonlinear optical susceptibilities of atomically thin transition metal dichalcogenides. In addition to their significant scientific interest as fundamental material responses, these studies provide essential knowledge and convenient characterization tools for the application of these 2D materials in opto-electronic devices. Another important theme of the thesis is the valley physics of atomically thin transition metal dichalcogenides. It is shown that the degeneracy in the valley degree of freedom can be lifted and a valley polarization can be created using a magnetic field, which breaks time reversal symmetry in these materials. These findings enhance our basic understanding of the valley electronic states and open up new opportunities for valleytronic applications using two-dimensional materials.

Probing the Response of 2D Crystals by Optical Spectroscopy

Probing the Response of 2D Crystals by Optical Spectroscopy

Author: Yilei Li

Publisher:

Published: 2014

Total Pages:

ISBN-13:

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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.


Book Synopsis Probing the Response of 2D Crystals by Optical Spectroscopy by : Yilei Li

Download or read book Probing the Response of 2D Crystals by Optical Spectroscopy written by Yilei Li and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Optical Properties of Two-dimemsional Van Der Waals Crystals

Optical Properties of Two-dimemsional Van Der Waals Crystals

Author: Liang Zhao

Publisher:

Published: 2015

Total Pages: 0

ISBN-13:

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Van der Waals (vdW) materials are layered structures bonded by the weak vdW force. As such, stable single atomic layers can be isolated either by mechanical exfoliation or chemical methods as chemical vapor deposition. Atomically thin vdW materials have emerged as new types of two-dimensional (2D) systems with unique electronic and optical properties that are distinct from that of their bulk counterparts. Studies of this new class of material are not only interesting fundamentally; they can potentially also lead to applications in next-generation electronics and optoelectronics devices. In this thesis, we investigate two prototypes of 2D vdW materials, graphene (a semimetal) and semiconducting transition metal dichalcogenides (TMD) based on optical spectroscopy. Electro-magnetic radiation ranging from the far-infrared (or terahertz (THz)) to the visible has been utilized to investigate two questions: (1) the excitonic effects in Mo/W dichalcogenides; and, (2) the free carrier response in graphene. For the first topic, exciton series in monolayer WSe2 and the effect of electric field on the excitons is studied. A exciton series of WSe2 is observed by a complimentary measurement of linear absorption and two-photon photoluminescense excitation (2PPLE). Strong exciton binding energy ($\sim$ 0.4 eV) and non-Rydberg series are observed arising from 2D screening of Coulomb interactions. Using field-effect transistor structures we apply electrostatic doping and/or perpendicular electric field to WSe2 monolayer through the gates. Trion peak is observed under doping, which further splits under high electric fields. This phenomenon can be explained by Rashba spin-orbit interaction induced spin sub-bands hybridization. For the second topic, the free carrier response in monolayer graphene is investigated using the Fourier transform infrared (FTIR) spectroscopy in steady state conditions and the optical pump-THz probe spectroscopy under non-equilibrium conditions. We observe the Drude response under both conditions. For the steady states study, we find the Drude scattering rate strongly dependent on the doping density, revealing different scattering mechanisms. Under low power photo excitation, we observe that mobilities remain in relatively high values and carrier multiplication is achievable.


Book Synopsis Optical Properties of Two-dimemsional Van Der Waals Crystals by : Liang Zhao

Download or read book Optical Properties of Two-dimemsional Van Der Waals Crystals written by Liang Zhao and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Van der Waals (vdW) materials are layered structures bonded by the weak vdW force. As such, stable single atomic layers can be isolated either by mechanical exfoliation or chemical methods as chemical vapor deposition. Atomically thin vdW materials have emerged as new types of two-dimensional (2D) systems with unique electronic and optical properties that are distinct from that of their bulk counterparts. Studies of this new class of material are not only interesting fundamentally; they can potentially also lead to applications in next-generation electronics and optoelectronics devices. In this thesis, we investigate two prototypes of 2D vdW materials, graphene (a semimetal) and semiconducting transition metal dichalcogenides (TMD) based on optical spectroscopy. Electro-magnetic radiation ranging from the far-infrared (or terahertz (THz)) to the visible has been utilized to investigate two questions: (1) the excitonic effects in Mo/W dichalcogenides; and, (2) the free carrier response in graphene. For the first topic, exciton series in monolayer WSe2 and the effect of electric field on the excitons is studied. A exciton series of WSe2 is observed by a complimentary measurement of linear absorption and two-photon photoluminescense excitation (2PPLE). Strong exciton binding energy ($\sim$ 0.4 eV) and non-Rydberg series are observed arising from 2D screening of Coulomb interactions. Using field-effect transistor structures we apply electrostatic doping and/or perpendicular electric field to WSe2 monolayer through the gates. Trion peak is observed under doping, which further splits under high electric fields. This phenomenon can be explained by Rashba spin-orbit interaction induced spin sub-bands hybridization. For the second topic, the free carrier response in monolayer graphene is investigated using the Fourier transform infrared (FTIR) spectroscopy in steady state conditions and the optical pump-THz probe spectroscopy under non-equilibrium conditions. We observe the Drude response under both conditions. For the steady states study, we find the Drude scattering rate strongly dependent on the doping density, revealing different scattering mechanisms. Under low power photo excitation, we observe that mobilities remain in relatively high values and carrier multiplication is achievable.

Two-Dimensional Crystals

Two-Dimensional Crystals

Author: A. G. Naumovets

Publisher: Elsevier

Published: 2012-12-02

Total Pages: 438

ISBN-13: 0080924395

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This is a self-contained, tutorial introduction to two-dimensional crystal science and technology. Including concise descriptions of experimental methods and results from fundamental theoretical concepts, this book covers a broad range of two-dimensional structures--from overlayers to freestanding films. All those with an active interest in surface science and statistical physics will find this book to be an essential reference work. Presents a coherent overview of experimental methods and theoretical background of two-dimensional crystal physics Provides a tutorial overview of continuous melting of two-dimensional crystals, roughening transitions, wetting phenomena, and commensurate-incommensurate transitions


Book Synopsis Two-Dimensional Crystals by : A. G. Naumovets

Download or read book Two-Dimensional Crystals written by A. G. Naumovets and published by Elsevier. This book was released on 2012-12-02 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a self-contained, tutorial introduction to two-dimensional crystal science and technology. Including concise descriptions of experimental methods and results from fundamental theoretical concepts, this book covers a broad range of two-dimensional structures--from overlayers to freestanding films. All those with an active interest in surface science and statistical physics will find this book to be an essential reference work. Presents a coherent overview of experimental methods and theoretical background of two-dimensional crystal physics Provides a tutorial overview of continuous melting of two-dimensional crystals, roughening transitions, wetting phenomena, and commensurate-incommensurate transitions

Two-Dimensional Materials for Nonlinear Optics

Two-Dimensional Materials for Nonlinear Optics

Author: Qiang Wang

Publisher: John Wiley & Sons

Published: 2024-01-03

Total Pages: 373

ISBN-13: 3527350594

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Comprehensive resource covering concepts, perspectives, and skills required to understand the preparation, nonlinear optics, and applications of two-dimensional (2D) materials Bringing together many interdisciplinary experts in the field of 2D materials with their applications in nonlinear optics, Two-Dimensional Materials for Nonlinear Optics covers preparation methods for various novel 2D materials, such as transition metal dichalcogenides (TMDs) and single elemental 2D materials, excited-state dynamics of 2D materials behind their outstanding performance in photonic devices, instrumentation for exploring the photoinduced excited-state dynamics of the 2D materials spanning a wide time scale from ultrafast to slow, and future trends of 2D materials on a series of issues like fabrications, dynamic investigations, and photonic/optoelectronic applications. Powerful nonlinear optical characterization techniques, such as Z-scan measurement, femtosecond transient absorption spectroscopy, and microscopy are also introduced. Edited by two highly qualified academics with extensive experience in the field, Two-Dimensional Materials for Nonlinear Optics covers sample topics such as: Foundational knowledge on nonlinear optical properties, and fundamentals and preparation methods of 2D materials with nonlinear optical properties Modulation and enhancement of optical nonlinearity in 2D materials, and nonlinear optical characterization techniques for 2D materials and their applications in a specific field Novel nonlinear optical imaging systems, ultrafast time-resolved spectroscopy for investigating carrier dynamics in emerging 2D materials, and transient terahertz spectroscopy 2D materials for optical limiting, saturable absorber, second and third harmonic generation, nanolasers, and space use With collective insight from researchers in many different interdisciplinary fields, Two-Dimensional Materials for Nonlinear Optics is an essential resource for materials scientists, solid state chemists and physicists, photochemists, and professionals in the semiconductor industry who are interested in understanding the state of the art in the field.


Book Synopsis Two-Dimensional Materials for Nonlinear Optics by : Qiang Wang

Download or read book Two-Dimensional Materials for Nonlinear Optics written by Qiang Wang and published by John Wiley & Sons. This book was released on 2024-01-03 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive resource covering concepts, perspectives, and skills required to understand the preparation, nonlinear optics, and applications of two-dimensional (2D) materials Bringing together many interdisciplinary experts in the field of 2D materials with their applications in nonlinear optics, Two-Dimensional Materials for Nonlinear Optics covers preparation methods for various novel 2D materials, such as transition metal dichalcogenides (TMDs) and single elemental 2D materials, excited-state dynamics of 2D materials behind their outstanding performance in photonic devices, instrumentation for exploring the photoinduced excited-state dynamics of the 2D materials spanning a wide time scale from ultrafast to slow, and future trends of 2D materials on a series of issues like fabrications, dynamic investigations, and photonic/optoelectronic applications. Powerful nonlinear optical characterization techniques, such as Z-scan measurement, femtosecond transient absorption spectroscopy, and microscopy are also introduced. Edited by two highly qualified academics with extensive experience in the field, Two-Dimensional Materials for Nonlinear Optics covers sample topics such as: Foundational knowledge on nonlinear optical properties, and fundamentals and preparation methods of 2D materials with nonlinear optical properties Modulation and enhancement of optical nonlinearity in 2D materials, and nonlinear optical characterization techniques for 2D materials and their applications in a specific field Novel nonlinear optical imaging systems, ultrafast time-resolved spectroscopy for investigating carrier dynamics in emerging 2D materials, and transient terahertz spectroscopy 2D materials for optical limiting, saturable absorber, second and third harmonic generation, nanolasers, and space use With collective insight from researchers in many different interdisciplinary fields, Two-Dimensional Materials for Nonlinear Optics is an essential resource for materials scientists, solid state chemists and physicists, photochemists, and professionals in the semiconductor industry who are interested in understanding the state of the art in the field.

Multidimensional Time-Resolved Spectroscopy

Multidimensional Time-Resolved Spectroscopy

Author: Tiago Buckup

Publisher: Springer

Published: 2018-12-07

Total Pages: 320

ISBN-13: 3030024784

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The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.


Book Synopsis Multidimensional Time-Resolved Spectroscopy by : Tiago Buckup

Download or read book Multidimensional Time-Resolved Spectroscopy written by Tiago Buckup and published by Springer. This book was released on 2018-12-07 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.

Probing Electronic and Phononic Processes with Femtosecond Lasers

Probing Electronic and Phononic Processes with Femtosecond Lasers

Author: Yongqian Liu

Publisher:

Published: 1995

Total Pages: 354

ISBN-13:

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Book Synopsis Probing Electronic and Phononic Processes with Femtosecond Lasers by : Yongqian Liu

Download or read book Probing Electronic and Phononic Processes with Femtosecond Lasers written by Yongqian Liu and published by . This book was released on 1995 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

26th Annual Conference of the German Crystallographic Society, March 5-8, 2018, Essen, Germany

26th Annual Conference of the German Crystallographic Society, March 5-8, 2018, Essen, Germany

Author:

Publisher: Walter de Gruyter GmbH & Co KG

Published: 2018-03-05

Total Pages: 141

ISBN-13: 3110595990

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Zeitschrift für Kristallographie. Supplement Volume 38 presents the complete Abstracts of all contributions to the 26th Annual Conference of the German Crystallographic Society in Essen (Germany) 2018:- Plenary Talks- Microsymposia- Poster Session Supplement Series of Zeitschrift für Kristallographie publishes Abstracts of international conferences on the interdisciplinary field of crystallography.


Book Synopsis 26th Annual Conference of the German Crystallographic Society, March 5-8, 2018, Essen, Germany by :

Download or read book 26th Annual Conference of the German Crystallographic Society, March 5-8, 2018, Essen, Germany written by and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-03-05 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zeitschrift für Kristallographie. Supplement Volume 38 presents the complete Abstracts of all contributions to the 26th Annual Conference of the German Crystallographic Society in Essen (Germany) 2018:- Plenary Talks- Microsymposia- Poster Session Supplement Series of Zeitschrift für Kristallographie publishes Abstracts of international conferences on the interdisciplinary field of crystallography.

Femtochemistry

Femtochemistry

Author: Ahmed H. Zewail

Publisher: World Scientific

Published: 1994

Total Pages: 605

ISBN-13: 9814287601

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Volume II continues with reaction rates, the concept of elementary intramolecular vibrational-energy redistribution (IVR) and the phenomena of rotational coherence which has become a powerful tool for the determination of molecular structure via time resolution. The second volume ends with an extensive list of references, according to topics, based on work by Professor Zewail and his group at Caltech. These collected works by Professor Zewail will certainly be indispensable to both experts and beginners in the field. The author is known for his clarity and for his creative and systematic contributions. These volumes will be of interest and should prove useful to chemists, biologists and physicists. As noted by Professor J. Manz (Berlin) and Professor A.W. Castleman, Jr.


Book Synopsis Femtochemistry by : Ahmed H. Zewail

Download or read book Femtochemistry written by Ahmed H. Zewail and published by World Scientific. This book was released on 1994 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume II continues with reaction rates, the concept of elementary intramolecular vibrational-energy redistribution (IVR) and the phenomena of rotational coherence which has become a powerful tool for the determination of molecular structure via time resolution. The second volume ends with an extensive list of references, according to topics, based on work by Professor Zewail and his group at Caltech. These collected works by Professor Zewail will certainly be indispensable to both experts and beginners in the field. The author is known for his clarity and for his creative and systematic contributions. These volumes will be of interest and should prove useful to chemists, biologists and physicists. As noted by Professor J. Manz (Berlin) and Professor A.W. Castleman, Jr.

Encyclopedia of Modern Optics

Encyclopedia of Modern Optics

Author: Bob D. Guenther

Publisher: Academic Press

Published: 2018-02-14

Total Pages: 2253

ISBN-13: 0128149825

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The Encyclopedia of Modern Optics, Second Edition, Five Volume Set provides a wide-ranging overview of the field, comprising authoritative reference articles for undergraduate and postgraduate students and those researching outside their area of expertise. Topics covered include classical and quantum optics, lasers, optical fibers and optical fiber systems, optical materials and light-emitting diodes (LEDs). Articles cover all subfields of optical physics and engineering, such as electro-optical design of modulators and detectors. This update contains contributions from international experts who discuss topics such as nano-photonics and plasmonics, optical interconnects, photonic crystals and 2D materials, such as graphene or holy fibers. Other topics of note include solar energy, high efficiency LED’s and their use in illumination, orbital angular momentum, quantum optics and information, metamaterials and transformation optics, high power fiber and UV fiber lasers, random lasers and bio-imaging. Addresses recent developments in the field and integrates concepts from fundamental physics with applications for manufacturing and engineering/design Provides a broad and interdisciplinary coverage of specialist areas Ensures that the material is appropriate for new researchers and those working in a new sub-field, as well as those in industry Thematically arranged and alphabetically indexed, with cross-references added to facilitate ease-of-use


Book Synopsis Encyclopedia of Modern Optics by : Bob D. Guenther

Download or read book Encyclopedia of Modern Optics written by Bob D. Guenther and published by Academic Press. This book was released on 2018-02-14 with total page 2253 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Encyclopedia of Modern Optics, Second Edition, Five Volume Set provides a wide-ranging overview of the field, comprising authoritative reference articles for undergraduate and postgraduate students and those researching outside their area of expertise. Topics covered include classical and quantum optics, lasers, optical fibers and optical fiber systems, optical materials and light-emitting diodes (LEDs). Articles cover all subfields of optical physics and engineering, such as electro-optical design of modulators and detectors. This update contains contributions from international experts who discuss topics such as nano-photonics and plasmonics, optical interconnects, photonic crystals and 2D materials, such as graphene or holy fibers. Other topics of note include solar energy, high efficiency LED’s and their use in illumination, orbital angular momentum, quantum optics and information, metamaterials and transformation optics, high power fiber and UV fiber lasers, random lasers and bio-imaging. Addresses recent developments in the field and integrates concepts from fundamental physics with applications for manufacturing and engineering/design Provides a broad and interdisciplinary coverage of specialist areas Ensures that the material is appropriate for new researchers and those working in a new sub-field, as well as those in industry Thematically arranged and alphabetically indexed, with cross-references added to facilitate ease-of-use