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Rasheed T, Sorour AA. Unveiling the power of MXenes: Solid lubrication perspectives and future directions. Adv Colloid Interface Sci 2024; 329:103186. [PMID: 38763047 DOI: 10.1016/j.cis.2024.103186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 03/13/2024] [Accepted: 05/11/2024] [Indexed: 05/21/2024]
Abstract
The interaction between two surfaces leads to the generation of friction and wear of material. Friction and wear are some of the major challenges that may readily be overcome by the third part of tribology called lubrication. Utilizing solid lubricants including polymers, carbon-based materials, soft metals, transition metal dichalcogenides, along with their potential benefits and drawbacks in dry environments can reduce friction. Recently, an emerging class of two-dimensional (2D) transition metal nitrides, carbides or carbonitrides commonly known as MXenes have emerged as an attractive alternative for solid lubrication because of their ability to establish wear-resistant tribo layers and well as low friction and shear strength. Furthermore, the inherent hydrophilic nature of these substances has led to limited dispersion stability and phase compatibility when combined with pure base oils. As a result, their potential use as solid lubricants and lubricant additives has been impeded. To address this issue and enhance the applicability of MXenes as solid lubricants, their surface modification can be an attractive tool. Therefore, this review provides a succinct summary of the current state-of-the-art in surface functionalization of MXenes, a subject that has not yet been thoroughly addressed. Further, the mechanical behavior of MXenes and composites has been discussed, followed by the potential of MXenes as a solid lubricant at micro- and macro-scale. Finally, the existing opportunities and challenges of the research area have been discussed with possible future research directions. We believe, this article will be a valuable resource for MXenes and opens the door to improve the chemical, physical and mechanical properties of MXenes in various applications, such as solid lubrication.
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Affiliation(s)
- Tahir Rasheed
- Interdisciplinary Research Center for Advanced Materials, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
| | - A A Sorour
- Interdisciplinary Research Center for Advanced Materials, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia; Department of Mechanical Engineering, King Fahd University of Petroleum & Minerals (KFUPM), Dhahran 31261, Saudi Arabia
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2
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Ağırcan H, Convertino D, Rossi A, Martini L, Pace S, Mishra N, Küster K, Starke U, Kartal Şireli G, Coletti C, Forti S. Determination and investigation of defect domains in multi-shape monolayer tungsten disulfide. NANOSCALE ADVANCES 2024; 6:2850-2859. [PMID: 38817435 PMCID: PMC11134227 DOI: 10.1039/d4na00125g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/15/2024] [Indexed: 06/01/2024]
Abstract
Single-layer tungsten disulfide (WS2) is among the most widely investigated two-dimensional materials. Synthesizing it over large areas would enable the exploitation of its appealing optical and electronic properties in industrial applications. However, defects of different nature, concentration and distribution profoundly affect the optical as well as the electronic properties of this crystal. Controlling the defect density distribution can be an effective way to tailor the local dielectric environment and therefore the electronic properties of the system. In this work we investigate the defects in single-layer WS2, grown in different shapes by liquid phase chemical vapor deposition, where the concentration of certain defect species can be controlled by the growth conditions. The properties of the material are surveyed by means of optical spectroscopy, photoelectron spectroscopy and Kelvin probe force microscopy. We determine the chemical nature of the defects and study their influence on the optical and electronic properties of WS2. This work contributes to the understanding of the microscopic nature of the intrinsic defects in WS2, helping the development of defect-based technologies which rely on the control and engineering of defects in dielectric 2D crystals.
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Affiliation(s)
- H Ağırcan
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Department of Metallurgical & Materials Engineering Istanbul Technical University 34469 Maslak Istanbul Turkey
| | - D Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
| | - A Rossi
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - L Martini
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
| | - S Pace
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - N Mishra
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - K Küster
- Max-Planck-Institut für Festkörperforschung Heisenbergstr. 1 70569 Stuttgart Germany
| | - U Starke
- Max-Planck-Institut für Festkörperforschung Heisenbergstr. 1 70569 Stuttgart Germany
| | - G Kartal Şireli
- Department of Metallurgical & Materials Engineering Istanbul Technical University 34469 Maslak Istanbul Turkey
| | - C Coletti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
- Graphene Labs, Istituto Italiano di Tecnologia Via Morego 30 16163 Genova Italy
| | - S Forti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia Piazza San Silvestro 12 I-56127 Pisa Italy
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3
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Potočnik T, Burton O, Reutzel M, Schmitt D, Bange JP, Mathias S, Geisenhof FR, Weitz RT, Xin L, Joyce HJ, Hofmann S, Alexander-Webber JA. Fast Twist Angle Mapping of Bilayer Graphene Using Spectroscopic Ellipsometric Contrast Microscopy. NANO LETTERS 2023. [PMID: 37289669 DOI: 10.1021/acs.nanolett.3c00619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Twisted bilayer graphene provides an ideal solid-state model to explore correlated material properties and opportunities for a variety of optoelectronic applications, but reliable, fast characterization of the twist angle remains a challenge. Here we introduce spectroscopic ellipsometric contrast microscopy (SECM) as a tool for mapping twist angle disorder in optically resonant twisted bilayer graphene. We optimize the ellipsometric angles to enhance the image contrast based on measured and calculated reflection coefficients of incident light. The optical resonances associated with van Hove singularities correlate well to Raman and angle-resolved photoelectron emission spectroscopy, confirming the accuracy of SECM. The results highlight the advantages of SECM, which proves to be a fast, nondestructive method for characterization of twisted bilayer graphene over large areas, unlocking process, material, and device screening and cross-correlative measurement potential for bilayer and multilayer materials.
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Affiliation(s)
- Teja Potočnik
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Oliver Burton
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Marcel Reutzel
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - David Schmitt
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Jan Philipp Bange
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Stefan Mathias
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
| | - Fabian R Geisenhof
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
| | - R Thomas Weitz
- I. Physikalisches Institut, Georg-August-Universität Göttingen, 37077 Göttingen, Germany
- Physics of Nanosystems, Department of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, Munich 80539, Germany
| | - Linyuan Xin
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Hannah J Joyce
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Stephan Hofmann
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
| | - Jack A Alexander-Webber
- Department of Engineering, University of Cambridge, 9 JJ Thompson Avenue, Cambridge CB3 0FA, United Kingdom
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4
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Ferrera M, Sharma A, Milekhin I, Pan Y, Convertino D, Pace S, Orlandini G, Peci E, Ramò L, Magnozzi M, Coletti C, Salvan G, Zahn DRT, Canepa M, Bisio F. Local dielectric function of hBN-encapsulated WS 2flakes grown by chemical vapor deposition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:274001. [PMID: 36996840 DOI: 10.1088/1361-648x/acc918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 03/30/2023] [Indexed: 06/19/2023]
Abstract
Hexagonal boron nitride (hBN), sometimes referred to as white graphene, receives growing interest in the scientific community, especially when combined into van der Waals (vdW) homo- and heterostacks, in which novel and interesting phenomena may arise. hBN is also commonly used in combination with two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs). The realization of hBN-encapsulated TMDC homo- and heterostacks can indeed offer opportunities to investigate and compare TMDC excitonic properties in various stacking configurations. In this work, we investigate the optical response at the micrometric scale of mono- and homo-bilayer WS2grown by chemical vapor deposition and encapsulated between two single layers of hBN. Imaging spectroscopic ellipsometry is exploited to extract the local dielectric functions across one single WS2flake and detect the evolution of excitonic spectral features from monolayer to bilayer regions. Exciton energies undergo a redshift by passing from hBN-encapsulated single layer to homo-bilayer WS2, as also confirmed by photoluminescence spectra. Our results can provide a reference for the study of the dielectric properties of more complex systems where hBN is combined with other 2D vdW materials into heterostructures and are stimulating towards the investigation of the optical response of other technologically-relevant heterostacks.
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Affiliation(s)
- Marzia Ferrera
- OptMatLab, Physics Department, Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
- Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Apoorva Sharma
- Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
| | - Ilya Milekhin
- Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, D-09107 Chemnitz, Germany
| | - Yang Pan
- Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, D-09107 Chemnitz, Germany
| | - Domenica Convertino
- Center for Nanotechnology Innovation IIT@NEST, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Simona Pace
- Center for Nanotechnology Innovation IIT@NEST, Piazza San Silvestro 12, 56127 Pisa, Italy
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Giorgio Orlandini
- Center for Nanotechnology Innovation IIT@NEST, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Ermes Peci
- OptMatLab, Physics Department, Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
| | - Lorenzo Ramò
- OptMatLab, Physics Department, Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
| | - Michele Magnozzi
- OptMatLab, Physics Department, Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
- INFN, Sezione di Genova, via Dodecaneso 33, 16146 Genova, Italy
| | - Camilla Coletti
- Center for Nanotechnology Innovation IIT@NEST, Piazza San Silvestro 12, 56127 Pisa, Italy
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Georgeta Salvan
- Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
| | - Dietrich R T Zahn
- Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany
- Center for Materials, Architectures and Integration of Nanomembranes (MAIN), Chemnitz University of Technology, D-09107 Chemnitz, Germany
| | - Maurizio Canepa
- OptMatLab, Physics Department, Università di Genova, via Dodecaneso 33, 16146 Genova, Italy
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Thakur D, Sato Y, Balakrishnan V. Heteroatomic stitching of broken WS 2 monolayer with enhanced surface potential. NANOSCALE 2023; 15:5274-5283. [PMID: 36804718 DOI: 10.1039/d2nr06288g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Sub-nanometre thick two-dimensional (2D) materials suffer from severe cracking during the high temperature chemical vapour deposition growth process. The cracking can be utilised to generate more active edges. These active edges can be stitched with a homo- or hetero-material. While the direct growth of 2D-heterostructures is mostly limited to a small fraction of outer edges of monolayer flakes, the cracked monolayers can be utilised to produce a large fraction of heterostructures. Heterostructures are important for developing multifunctional components for nanoscale electronics and optoelectronics. In this work, we demonstrate the formation of WS2-MoS2 heterostructures in large fractions by atomic stitching of cracked WS2 monolayers with the sequential growth of MoS2. Aberration-corrected scanning transmission electron microscopy and Raman spectroscopy have been utillised to probe fine details on the stitched interface between WS2 and MoS2. Growth of MoS2 domains were observed to take place at the terminating edge of cracked WS2, which then merged to form MoS2 multilayers at the cracked site. Growth of MoS2 at the opposite edges of WS2 eventually results in a MoS2-MoS2 junction with a Σ = 7 tilt boundary. Kelvin probe force microscope (KPFM) measurement from the stitched region revealed that the work function of WS2 is ∼32.46 meV higher than that of MoS2, which also closely matches with the Fermi energy difference between these two materials. With the aid of an atomic force microscope and KPFM, the surface potential width at the stitched region was found to be ∼5 times higher than the actual width of the interface, confirming the modulation of properties near the interface.
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Affiliation(s)
- Deepa Thakur
- School of Mechanical and Materials Engineering, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, India-175075.
| | - Yukio Sato
- Department of Materials Science and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395 Japan
| | - Viswanath Balakrishnan
- School of Mechanical and Materials Engineering, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, India-175075.
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6
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Nguyen V, Li W, Ager J, Xu K, Taylor H. Optical reflectance imaging reveals interlayer coupling in mechanically stacked MoS 2 and WS 2 bilayers. OPTICS EXPRESS 2023; 31:3291-3303. [PMID: 36785325 DOI: 10.1364/oe.473397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
Optical reflectance imaging is a popular technique for characterizing 2D materials, thanks to its simplicity and speed of data acquisition. The use of this method for studying interlayer phenomena in stacked 2D layers has, however, remained limited. Here we demonstrate that optical imaging can reveal the nature of interlayer coupling in stacked MoS2 and WS2 bilayers through their observed reflectance contrast versus the substrate. Successful determination of interlayer coupling requires co-optimization of the illumination wavelength and the thickness of an underlying SiO2 film. Our observations are supported by multilayer optical calculations together with an analysis of the effect of any interlayer gap. This approach promises quick characterization of constructed 2D material systems.
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7
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Al Qaydi M, Kotbi A, Rajput NS, Bouchalkha A, El Marssi M, Matras G, Kasmi C, Jouiad M. Photodetection Properties of MoS 2, WS 2 and Mo xW 1-xS 2 Heterostructure: A Comparative Study. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 13:24. [PMID: 36615933 PMCID: PMC9824100 DOI: 10.3390/nano13010024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 12/04/2022] [Accepted: 12/16/2022] [Indexed: 06/17/2023]
Abstract
Layered transition metals dichalcogenides such as MoS2 and WS2 have shown a tunable bandgap, making them highly desirable for optoelectronic applications. Here, we report on one-step chemical vapor deposited MoS2, WS2 and MoxW1-xS2 heterostructures incorporated into photoconductive devices to be examined and compared in view of their use as potential photodetectors. Vertically aligned MoS2 nanosheets and horizontally stacked WS2 layers, and their heterostructure form MoxW1-xS2, exhibit direct and indirect bandgap, respectively. To analyze these structures, various characterization methods were used to elucidate their properties including Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectrometry and high-resolution transmission electron microscopy. While all the investigated samples show a photoresponse in a broad wavelength range between 400 nm and 700 nm, the vertical MoS2 nanosheets sample exhibits the highest performances at a low bias voltage of 5 V. Our findings demonstrate a responsivity and a specific detectivity of 47.4 mA W-1 and 1.4 × 1011 Jones, respectively, achieved by MoxW1-xS2. This study offers insights into the use of a facile elaboration technique for tuning the performance of MoxW1-xS2 heterostructure-based photodetectors.
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Affiliation(s)
- Maryam Al Qaydi
- Laboratory of Physics of Condensed Mater, University of Picardie Jules Verne, 80039 Amiens, France
- Technology Innovation Institute, Abu Dhabi P.O. Box 9639, United Arab Emirates
| | - Ahmed Kotbi
- Laboratory of Physics of Condensed Mater, University of Picardie Jules Verne, 80039 Amiens, France
| | - Nitul S. Rajput
- Technology Innovation Institute, Abu Dhabi P.O. Box 9639, United Arab Emirates
| | | | - Mimoun El Marssi
- Laboratory of Physics of Condensed Mater, University of Picardie Jules Verne, 80039 Amiens, France
| | - Guillaume Matras
- Technology Innovation Institute, Abu Dhabi P.O. Box 9639, United Arab Emirates
| | - Chaouki Kasmi
- Technology Innovation Institute, Abu Dhabi P.O. Box 9639, United Arab Emirates
| | - Mustapha Jouiad
- Laboratory of Physics of Condensed Mater, University of Picardie Jules Verne, 80039 Amiens, France
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8
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Tang PW, Shiau SY, Chou HC, Zhang XQ, Yu JR, Sung CT, Lee YH, Chen C. Visualization of Band Shifting and Interlayer Coupling in W xMo 1-xS 2 Alloys Using Near-Field Broadband Absorption Microscopy. ACS NANO 2022; 16:7503-7511. [PMID: 35486895 DOI: 10.1021/acsnano.1c10593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Beyond-diffraction-limit optical absorption spectroscopy provides in-depth information on the graded band structures of composition-spread and stacked two-dimensional materials, in which direct/indirect bandgap, interlayer coupling, and defects significantly modify their optoelectronic functionalities such as photoluminescence efficiency. We here visualize the spatially varying band structure of monolayer and bilayer transition metal dichalcogenide alloys by using near-field broadband absorption microscopy. The near-field spectral and spatial information manifests the excitonic band shift that results from the interplay of composition spreading and interlayer coupling. These results enable us to identify, notably, the top layer of the bilayer alloy as pure WS2. We also use the aberration-free near-field transmission images to demarcate the exact boundaries of alloyed and pure transition metal dichalcogenides. This technology can offer valuable insights on various layered structures in the era of "stacking science" in the quest of quantum optoelectronic devices.
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Affiliation(s)
- Po-Wen Tang
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Shiue-Yuan Shiau
- Physics Division, National Center for Theoretical Sciences, Taipei 106, Taiwan
| | - He-Chun Chou
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Xin-Quan Zhang
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan
| | - Jia-Ru Yu
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Chun-Te Sung
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan
| | - Yi-Hsien Lee
- Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan
| | - Chi Chen
- Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan
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9
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Optical Response of CVD-Grown ML-WS2 Flakes on an Ultra-Dense Au NP Plasmonic Array. CHEMOSENSORS 2022. [DOI: 10.3390/chemosensors10030120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The combination of metallic nanostructures with two-dimensional transition metal dichalcogenides is an efficient way to make the optical properties of the latter more appealing for opto-electronic applications. In this work, we investigate the optical properties of monolayer WS2 flakes grown by chemical vapour deposition and transferred onto a densely-packed array of plasmonic Au nanoparticles (NPs). The optical response was measured as a function of the thickness of a dielectric spacer intercalated between the two materials and of the system temperature, in the 75–350 K range. We show that a weak interaction is established between WS2 and Au NPs, leading to temperature- and spacer-thickness-dependent coupling between the localized surface plasmon resonance of Au NPs and the WS2 exciton. We suggest that the closely-packed morphology of the plasmonic array promotes a high confinement of the electromagnetic field in regions inaccessible by the WS2 deposited on top. This allows the achievement of direct contact between WS2 and Au while preserving a strong connotation of the properties of the two materials also in the hybrid system.
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Negri M, Francaviglia L, Kaplan D, Swaminathan V, Salviati G, Fontcuberta I Morral A, Fabbri F. Excitonic absorption and defect-related emission in three-dimensional MoS 2 pyramids. NANOSCALE 2022; 14:1179-1186. [PMID: 34918727 PMCID: PMC8793919 DOI: 10.1039/d1nr06041d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/27/2021] [Indexed: 06/14/2023]
Abstract
MoS2 micro-pyramids have demonstrated interesting properties in the fields of photonics and non-linear optics. In this work, we show the excitonic absorption and cathodoluminescence (CL) emission of MoS2 micro-pyramids grown by chemical vapor deposition (CVD) on SiO2 substrates. The excitonic absorption was obtained at room and cryogenic temperatures by taking advantage of the cathodoluminescence emission of the SiO2 substrate. We detected the CL emission related to defect intra-gap states, localized at the pyramid edges and with an enhanced intensity at the pyramid basal vertices. The photoluminescence and absorption analysis provided the Stokes shift of both the A and B excitons in the MoS2 pyramids. This analysis provides new insights into the optical functionality of MoS2 pyramids. This method can be applied to other 3D structures within the 2D materials family.
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Affiliation(s)
- M Negri
- Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
- Institute for Materials for Electronics and Magnetism (IMEM-CNR), Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - L Francaviglia
- Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
| | - D Kaplan
- U.S. Army RDECOM-ARDEC, Fuze Precision Armaments and Technology Directorate, Picatinny Arsenal, NJ 07806, USA
| | - V Swaminathan
- U.S. Army RDECOM-ARDEC, Fuze Precision Armaments and Technology Directorate, Picatinny Arsenal, NJ 07806, USA
- Department of Physics, Penn State University, USA
| | - G Salviati
- Institute for Materials for Electronics and Magnetism (IMEM-CNR), Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - A Fontcuberta I Morral
- Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
- Institute of Physics, Faculty of Basic Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - F Fabbri
- NEST, Istituto Nanoscienze - CNR, Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
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