Probing the Response of Two-Dimensional Crystals by Optical Spectroscopy (eBook)

Yilei Li (Autor)

eBook Download: PDF

2015 | 1st ed. 2016
XII, 69 Seiten
Springer International Publishing (Verlag)
978-3-319-25376-3 (ISBN)

Infos

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.

Inhalt

Supervisor’s Foreword 6
Preface 8
Acknowledgments 10
Contents 12
Chapter 1: Introduction and Background 14
1.1 Introduction 14
1.2 Overview of Optical Spectroscopy Methods 15
1.3 Optics of Graphene 16
1.4 Optics of Monolayer Transition Metal Dichalcogenides 17
References 19
Chapter 2: Intrinsic Doping Dependence of Raman 2D Mode in Graphene: Signatures of Electron–Electron Interaction 22
2.1 Introduction 22
2.2 Experimental Details for Raman Measurement of Ultraclean Graphene on h-BN 23
2.3 Intrinsic Doping Dependence of the Raman G Mode: Signatures of e–p Interactions 24
2.4 Intrinsic Doping Dependence of the Raman 2D Mode: Signatures of e–e Interactions 25
2.5 Conclusion 28
References 29
Chapter 3: Coupling of Strongly Localized Graphene Plasmons to Molecular Vibrations 32
3.1 Introduction 32
3.2 Sample Preparation and Experiment Setup for Mid-IR Transmission Spectroscopy 33
3.3 Determination of the Out-of-Plane Confinement of Graphene Plasmon 34
3.4 Hybridized Plasmon–Phonon Mode and Enhanced IR Sensing 35
3.5 Finite Difference Time Domain Simulation and a Phenomenological Model 36
3.6 Conclusion 39
References 40
Chapter 4: Dielectric Response of a Thin Sheet 42
4.1 Introduction to the Dielectric Response of a Material 42
4.2 Linear Dielectric Response 42
4.3 Nonlinear Dielectric Response 43
4.4 Models for the Dielectric Response of a Thin Film 43
References 45
Chapter 5: Measurement of the Optical Dielectric Function of Monolayer Transition Metal Dichalcogenides: MoS2, MoSe2, WS2, and WSe2 46
5.1 Introduction 46
5.2 Sample Preparation for Reflectance Measurement 47
5.3 Measurement of Reflectance of the Monolayer TMDCs 47
5.4 Determination of the Dielectric Function from Reflectance Spectrum Using Kramers–Kronig Constrained Analysis 49
5.5 Surface Conductivity and Absorbance 50
5.6 Extraction of the A and B Peaks Splitting 50
5.7 Comparison of the Monolayer and Bulk Dielectric Function 52
5.8 Conclusion 54
References 54
Chapter 6: Measurement of the Second-Order Nonlinear Susceptibility and Probing Symmetry Properties of Few-Layer MoS2 and h-BN by Optical Second-Harmonic Generation 57
6.1 Introduction 57
6.2 Experimental Setup for Optical SHG Measurement 59
6.3 Probing the Absence of Inversion Symmetry and the Crystal Rotational Symmetry by Polarization Resolved SHG 59
6.4 Measurement of the Second-Order Nonlinear Susceptibility 61
6.5 Probing Inversion Symmetry Breaking by SHG Intensity 62
6.6 SHG as an Optical Tool for the Characterization of Atomically Thin Layers 64
6.7 Conclusion 64
References 65
Chapter 7: Valley Splitting and Polarization by Zeeman Effect in Monolayer MoSe2 67
7.1 Introduction 67
7.2 Experimental Setup for Valley Selective Magneto-PL Spectroscopy 68
7.3 Demonstration of Valleys Splitting and Polarization 68
7.4 Determination of the Trion Configuration 71
7.5 Zeeman Effect in the High Doping Regime 72
7.6 Conclusion 74
References 74
Chapter 8: Conclusion and Prospect 77
Curriculum Vitae 78

Produkt-Details

• Erscheint lt. Verlag: 9.11.2015
• Reihe/Serie: Springer Theses
• Reihe/Serie: Springer Theses
• Zusatzinfo: XII, 69 p.
• Verlagsort: Cham
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie
• Themenwelt: Technik ► Elektrotechnik / Energietechnik
• Themenwelt: Technik ► Maschinenbau
• Schlagworte: 2D materials in opto-electronic devices • Atomically thin 2D materials • Atomically thin transition metal dichalcogenides • Graphene plasmon enhanced vibrational sensing • Optical spectroscopy of dichalcogenides • Optics of monolayer transition metal dichalcogenides • Raman 2D mode in Graphene • Transition metal dichalcogenides • Valley physics • Valleytronics using 2D materials
• ISBN-10: 3-319-25376-X / 331925376X
• ISBN-13: 978-3-319-25376-3 / 9783319253763