Near-field optical imaging and spectroscopy of 2D-TMDs

Abstract Two-dimensional transition metal dichalcogenides (2D-TMDs) are atomically thin semiconductors with a direct bandgap in monolayer thickness, providing ideal platforms for the development of exciton-based optoelectronic devices. Extensive studies on the spectral characteristics of exciton emission have been performed, but spatially resolved optical studies of 2D-TMDs are also critically important because of large variations in the spatial profiles of exciton emissions due to local defects and charge distributions that are intrinsically nonuniform. Because the spatial resolution of conventional optical microscopy and spectroscopy is fundamentally limited by diffraction, near-field optical imaging using apertured or metallic probes has been used to spectrally map the nanoscale profiles of exciton emissions and to study the effects of nanosize local defects and carrier distribution. While these unique approaches have been frequently used, revealing information on the exciton dynamics of 2D-TMDs that is not normally accessible by conventional far-field spectroscopy, a dedicated review of near-field imaging and spectroscopy studies on 2D-TMDs is not available. This review is intended to provide an overview of the current status of near-field optical research on 2D-TMDs and the future direction with regard to developing nanoscale optical imaging and spectroscopy to investigate the exciton characteristics of 2D-TMDs.

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Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics

10.21203/rs.3.rs-97117/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Georgy Ermolaev ◽

D. Grudinin ◽

Y. Stebunov ◽

K. Voronin ◽

Vasyl Kravets ◽

...

Keyword(s):

Transition Metal ◽

Optical Anisotropy ◽

Near Infrared ◽

Near Field ◽

Transition Metal Dichalcogenides ◽

Next Generation ◽

Infrared Wavelength ◽

Infrared Spectral ◽

Metal Dichalcogenides ◽

On Chip

Abstract Large optical anisotropy observed in a broad spectral range is of paramount importance for efficient light manipulation in countless devices. Although a giant anisotropy was recently observed in the mid-infrared wavelength range, for visible and near-infrared spectral intervals, the problem remains acute with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN crystals. This inspired an intensive search for giant optical anisotropy among natural and artificial materials. Here, we demonstrate that layered transition metal dichalcogenides (TMDCs) provide an answer to this quest owing to their fundamental differences between intralayer strong covalent bonding and weak interlayer van der Walls interaction. To do this, we carried out a correlative far- and near-field characterization validated by first-principle calculations that reveals an unprecedented birefringence of 1.5 in the infrared and 3 in the visible light for MoS2. Our findings demonstrate that this outstanding anisotropy allows for tackling the diffraction limit enabling an avenue for on-chip next-generation photonics.

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Deep subwavelength control of valley polarized cathodoluminescence in h-BN/WSe2/h-BN heterostructure

Nature Communications ◽

10.1038/s41467-020-20545-x ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Liheng Zheng ◽

Zhixin Liu ◽

Donglin Liu ◽

Xingguo Wang ◽

Yu Li ◽

...

Keyword(s):

Information Technologies ◽

Optical Pumping ◽

Near Field ◽

Transition Metal Dichalcogenides ◽

Hybrid Structure ◽

Effective Control ◽

Polarization Degree ◽

Valley Polarization ◽

Metal Dichalcogenides ◽

Field Excitation

AbstractValley pseudospin in transition metal dichalcogenides monolayers intrinsically provides additional possibility to control valley carriers, raising a great impact on valleytronics in following years. The spin-valley locking directly contributes to optical selection rules which allow for valley-dependent addressability of excitons by helical optical pumping. As a binary photonic addressable route, manipulation of valley polarization states is indispensable while effective control methods at deep-subwavelength scale are still limited. Here, we report the excitation and control of valley polarization in h-BN/WSe2/h-BN and Au nanoantenna hybrid structure by electron beam. Near-field circularly polarized dipole modes can be excited via precise stimulation and generate the valley polarized cathodoluminescence via near-field interaction. Effective manipulation of valley polarization degree can be realized by variation of excitation position. This report provides a near-field excitation methodology of valley polarization, which offers exciting opportunities for deep-subwavelength valleytronics investigation, optoelectronic circuits integration and future quantum information technologies.

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Giant optical anisotropy in transition metal dichalcogenides for next-generation photonics

Nature Communications ◽

10.1038/s41467-021-21139-x ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

G. A. Ermolaev ◽

D. V. Grudinin ◽

Y. V. Stebunov ◽

K. V. Voronin ◽

V. G. Kravets ◽

...

Keyword(s):

Transition Metal ◽

Optical Anisotropy ◽

Near Infrared ◽

Near Field ◽

Transition Metal Dichalcogenides ◽

Next Generation ◽

Infrared Wavelength ◽

Infrared Spectral ◽

Metal Dichalcogenides ◽

On Chip

AbstractLarge optical anisotropy observed in a broad spectral range is of paramount importance for efficient light manipulation in countless devices. Although a giant anisotropy has been recently observed in the mid-infrared wavelength range, for visible and near-infrared spectral intervals, the problem remains acute with the highest reported birefringence values of 0.8 in BaTiS3 and h-BN crystals. This issue inspired an intensive search for giant optical anisotropy among natural and artificial materials. Here, we demonstrate that layered transition metal dichalcogenides (TMDCs) provide an answer to this quest owing to their fundamental differences between intralayer strong covalent bonding and weak interlayer van der Waals interaction. To do this, we made correlative far- and near-field characterizations validated by first-principle calculations that reveal a huge birefringence of 1.5 in the infrared and 3 in the visible light for MoS2. Our findings demonstrate that this remarkable anisotropy allows for tackling the diffraction limit enabling an avenue for on-chip next-generation photonics.

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A Perspective on the Application of Spatially Resolved ARPES for 2D Materials

10.20944/preprints201804.0150.v1 ◽

2018 ◽

Author(s):

Mattia Cattelan ◽

Neil Fox

Keyword(s):

Electronic Band Structure ◽

2D Materials ◽

Transition Metal Dichalcogenides ◽

Electronic Band ◽

Preparation Methods ◽

2D Material ◽

Angle Resolved Photoemission Spectroscopy ◽

Spatially Resolved ◽

Metal Dichalcogenides ◽

Future Direction

In this paper a perspective on the application of spatially- and Angle- Resolved PhotoEmission Spectroscopy (ARPES) for the study of two-dimensional (2D) materials is presented. ARPES allows the direct measurement of the electronic band structure of materials generating extremely useful insights into their electronic properties. The possibility to apply this technique to 2D materials is of paramount importance because these ultrathin layers are considered fundamental for future electronic, photonic and spintronic devices. In this review an overview of the technical aspects of spatially localized ARPES is given along with a description of the most advanced setups for laboratory and synchrotron-based equipment. This technique is sensitive to the lateral dimensions of the sample, therefore a discussion on the preparation methods of 2D material is presented. Some of the most interesting results obtained by ARPES are reported in three sections including: graphene, transition metal dichalcogenides (TMDCs) and 2D heterostructures. Graphene has played a key role in ARPES studies because it inspired the use of this technique with other 2D materials. TMDCs are presented for their peculiar transport, optical and spin properties. Finally, the section featuring heterostructures highlights a future direction for research into 2D material structures.

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Near-Field Optical Imaging and Spectroscopy of Single Molecules

Single-Molecule Optical Detection, Imaging and Spectroscopy ◽

10.1002/9783527614714.ch7 ◽

2007 ◽

pp. 191-222

Keyword(s):

Optical Imaging ◽

Near Field ◽

Single Molecules ◽

Imaging And Spectroscopy

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Photoresponse of Optical Sensors Based on Transition Metal Dichalcogenides: Influence of Thickness on Spectral Characteristics

Technical Physics Letters ◽

10.1134/s106378501906018x ◽

2019 ◽

Vol 45 (6) ◽

pp. 625-627 ◽

Cited By ~ 1

Author(s):

A. Yu. Avdizhiyan ◽

S. D. Lavrov ◽

A. V. Kudryavtsev ◽

A. P. Shestakova ◽

M. V. Vasina

Keyword(s):

Transition Metal ◽

Optical Sensors ◽

Spectral Characteristics ◽

Transition Metal Dichalcogenides ◽

Metal Dichalcogenides

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Spatially Resolved Photogenerated Exciton and Charge Transport in Emerging Semiconductors

Annual Review of Physical Chemistry ◽

10.1146/annurev-physchem-052516-050703 ◽

2020 ◽

Vol 71 (1) ◽

pp. 1-30 ◽

Cited By ~ 12

Author(s):

Naomi S. Ginsberg ◽

William A. Tisdale

Keyword(s):

Organic Semiconductors ◽

Energy Transport ◽

Transition Metal Dichalcogenides ◽

Electronic Energy ◽

Time Resolved ◽

Spatially Resolved ◽

New Family ◽

Dependent Rate ◽

Metal Dichalcogenides ◽

Colloidal Quantum Dot

We review recent advances in the characterization of electronic forms of energy transport in emerging semiconductors. The approaches described all temporally and spatially resolve the evolution of initially localized populations of photogenerated excitons or charge carriers. We first provide a comprehensive background for describing the physical origin and nature of electronic energy transport both microscopically and from the perspective of the observer. We introduce the new family of far-field, time-resolved optical microscopies developed to directly resolve not only the extent of this transport but also its potentially temporally and spatially dependent rate. We review a representation of examples from the recent literature, including investigation of energy flow in colloidal quantum dot solids, organic semiconductors, organic-inorganic metal halide perovskites, and 2D transition metal dichalcogenides. These examples illustrate how traditional parameters like diffusivity are applicable only within limited spatiotemporal ranges and how the techniques at the core of this review,especially when taken together, are revealing a more complete picture of the spatiotemporal evolution of energy transport in complex semiconductors, even as a function of their structural heterogeneities.

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Фоточувствительность оптических сенсоров на основе дихалькогенидов переходных металлов: влияние толщины на их спектральные характеристики

Письма в журнал технической физики ◽

10.21883/pjtf.2019.12.47918.17773 ◽

2019 ◽

Vol 45 (12) ◽

pp. 42

Author(s):

А.Ю. Авдижиян ◽

С.Д. Лавров ◽

А.В. Кудрявцев ◽

А.П. Шестакова ◽

М.В. Васина

Keyword(s):

Transition Metal ◽

Optical Sensors ◽

Field Effect Transistors ◽

Spectral Characteristics ◽

Theoretical Estimate ◽

Transition Metal Dichalcogenides ◽

Photocurrent Spectroscopy ◽

Photosensitive Layer ◽

Metal Dichalcogenides ◽

Work Samples

In this work, samples of field-effect transistors were fabricated based on solid solutions of transition metal dichalcogenides and their spectral characteristics were studied using photocurrent spectroscopy. The results of a theoretical estimate of the total optical absorption of two-dimensional semiconductors at different thicknesses of the sample and for different wavelengths of optical radiation with allowance for multibeam interference are presented. It is shown that interference effects make a significant contribution to the change in the shape of the spectral characteristics of optical sensors with a change in the thickness of the photosensitive layer of transition metal dichalcogenides.

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