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Bussolotti F, Kawai H, Maddumapatabandi TD, Fu W, Khoo KH, Goh KEJ. Role of S-Vacancy Concentration in Air Oxidation of WS 2 Single Crystals. ACS NANO 2024; 18:8706-8717. [PMID: 38465866 DOI: 10.1021/acsnano.3c10389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Semiconducting transition metal dichalcogenides (TMDs) are a class of two-dimensional materials with potential applications in optoelectronics, spintronics, valleytronics, and quantum information processing. Understanding their stability under ambient conditions is critical for determining their in-air processability during device fabrication and for predicting their long-term device performance stability. While the effects of environmental conditions (i.e., oxygen, moisture, and light) on TMD degradation are well-acknowledged, the role of defects in driving their oxidation remains unclear. We conducted a systematic X-ray photoelectron spectroscopy study on WS2 single crystals with different surface S-vacancy concentrations formed via controlled argon sputtering. Oxidation primarily occurred at defect concentrations ≥ 10%, resulting in stoichiometric WO3 formation, while a stable surface was observed at lower concentrations. Theoretical calculations informed us that single S-vacancies do not spontaneously oxidize, while defect pairing at high vacancy concentrations facilitates O2 dissociation and subsequent oxide formation. Our XPS results also point to vacancy-related structural and electrostatic disorder as the main origin for the p-type characteristics that persists even after oxidation. Despite the complex interplay between defects and TMD oxidation processes, our work unveils scientifically informed guidance for working effectively with TMDs.
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Affiliation(s)
- Fabio Bussolotti
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, #08-03 Innovis, Singapore 138634, Republic of Singapore
| | - Hiroyo Kawai
- Institute of High-Performance Computing (IHPC), Agency for Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Thathsara D Maddumapatabandi
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, #08-03 Innovis, Singapore 138634, Republic of Singapore
| | - Wei Fu
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, #08-03 Innovis, Singapore 138634, Republic of Singapore
| | - Khoong Hong Khoo
- Institute of High-Performance Computing (IHPC), Agency for Science, Technology and Research, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Republic of Singapore
| | - Kuan Eng Johnson Goh
- Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, #08-03 Innovis, Singapore 138634, Republic of Singapore
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2
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Zhou J, Barnard E, Cabrini S, Munechika K, Schwartzberg A, Weber-Bargioni A. Integrating collapsible plasmonic gaps on near-field probes for polarization-resolved mapping of plasmon-enhanced emission in 2D material. OPTICS EXPRESS 2023; 31:20440-20448. [PMID: 37381438 DOI: 10.1364/oe.490112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/16/2023] [Indexed: 06/30/2023]
Abstract
Scanning near-field optical microscopy (SNOM) is an important technique used to study the optical properties of material systems at the nanoscale. In previous work, we reported on the use of nanoimprinting to improve the reproducibility and throughput of near-field probes including complicated optical antenna structures such as the 'campanile' probe. However, precise control over the plasmonic gap size, which determines the near-field enhancement and spatial resolution, remains a challenge. Here, we present a novel approach to fabricating a sub-20 nm plasmonic gap in a near-field plasmonic probe through the controlled collapse of imprinted nanostructures using atomic layer deposition (ALD) coatings to define the gap width. The resulting ultranarrow gap at the apex of the probe provides a strong polarization-sensitive near-field optical response, which results in an enhancement of the optical transmission in a broad wavelength range from 620 to 820 nm, enabling tip-enhanced photoluminescence (TEPL) mapping of 2-dimensional (2D) materials. We demonstrate the potential of this near-field probe by mapping a 2D exciton coupled to a linearly polarized plasmonic resonance with below 30 nm spatial resolution. This work proposes a novel approach for integrating a plasmonic antenna at the apex of the near-field probe, paving the way for the fundamental study of light-matter interactions at the nanoscale.
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3
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Zhou J, Thomas JC, Barre E, Barnard ES, Raja A, Cabrini S, Munechika K, Schwartzberg A, Weber-Bargioni A. Near-Field Coupling with a Nanoimprinted Probe for Dark Exciton Nanoimaging in Monolayer WSe 2. NANO LETTERS 2023. [PMID: 37262350 DOI: 10.1021/acs.nanolett.3c00621] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Tip-enhanced photoluminescence (TRPL) is a powerful technique for spatially and spectrally probing local optical properties of 2-dimensional (2D) materials that are modulated by the local heterogeneities, revealing inaccessible dark states due to bright state overlap in conventional far-field microscopy at room temperature. While scattering-type near-field probes have shown the potential to selectively enhance and reveal dark exciton emission, their technical complexity and sensitivity can pose challenges under certain experimental conditions. Here, we present a highly reproducible and easy-to-fabricate near-field probe based on nanoimprint lithography and fiber-optic excitation and collection. The novel near-field measurement configuration provides an ∼3 orders of magnitude out-of-plane Purcell enhancement, diffraction-limited excitation spot, and subdiffraction hyperspectral imaging resolution (below 50 nm) of dark exciton emission. The effectiveness of this high spatial XD mapping technique was then demonstrated through reproducible hyperspectral mapping of oxidized sites and bubble areas.
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Affiliation(s)
- Junze Zhou
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - John C Thomas
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Elyse Barre
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Edward S Barnard
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Archana Raja
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Stefano Cabrini
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Keiko Munechika
- HighRI Optics, Inc. 5401 Broadway Ter 304, Oakland, California 94618, United States
| | - Adam Schwartzberg
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Alexander Weber-Bargioni
- The Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
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4
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Wang X, Pettes MT, Wang Y, Zhu JX, Dhall R, Song C, Jones AC, Ciston J, Yoo J. Enhanced Exciton-to-Trion Conversion by Proton Irradiation of Atomically Thin WS 2. NANO LETTERS 2023; 23:3754-3761. [PMID: 37094221 DOI: 10.1021/acs.nanolett.2c04987] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Defect engineering of van der Waals semiconductors has been demonstrated as an effective approach to manipulate the structural and functional characteristics toward dynamic device controls, yet correlations between physical properties with defect evolution remain underexplored. Using proton irradiation, we observe an enhanced exciton-to-trion conversion of the atomically thin WS2. The altered excitonic states are closely correlated with nanopore induced atomic displacement, W nanoclusters, and zigzag edge terminations, verified by scanning transmission electron microscopy, photoluminescence, and Raman spectroscopy. Density functional theory calculation suggests that nanopores facilitate formation of in-gap states that act as sinks for free electrons to couple with excitons. The ion energy loss simulation predicts a dominating electron ionization effect upon proton irradiation, providing further evidence on band perturbations and nanopore formation without destroying the overall crystallinity. This study provides a route in tuning the excitonic properties of van der Waals semiconductors using an irradiation-based defect engineering approach.
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Affiliation(s)
- Xuejing Wang
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Michael Thompson Pettes
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Yongqiang Wang
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Materials Science in Radiation and Dynamics Extremes (MST-8), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jian-Xin Zhu
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
- Physics of Condensed Matter and Complex Systems (T-4), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Rohan Dhall
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chengyu Song
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew C Jones
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jim Ciston
- National Center for Electron Microscopy (NCEM), Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jinkyoung Yoo
- Center for Integrated Nanotechnologies (CINT), Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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5
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Jones AJH, Gammelgaard L, Sauer MO, Biswas D, Koch RJ, Jozwiak C, Rotenberg E, Bostwick A, Watanabe K, Taniguchi T, Dean CR, Jauho AP, Bøggild P, Pedersen TG, Jessen BS, Ulstrup S. Nanoscale View of Engineered Massive Dirac Quasiparticles in Lithographic Superstructures. ACS NANO 2022; 16:19354-19362. [PMID: 36321616 DOI: 10.1021/acsnano.2c08929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Massive Dirac fermions are low-energy electronic excitations characterized by a hyperbolic band dispersion. They play a central role in several emerging physical phenomena such as topological phase transitions, anomalous Hall effects, and superconductivity. This work demonstrates that massive Dirac fermions can be controllably induced by lithographically patterning superstructures of nanoscale holes in a graphene device. Their band dispersion is systematically visualized using angle-resolved photoemission spectroscopy with nanoscale spatial resolution. A linear scaling of effective mass with feature sizes is reported, underlining the Dirac nature of the superstructures. In situ electrostatic doping dramatically enhances the effective hole mass and leads to the direct observation of an electronic band gap that results in a peak-to-peak band separation of 0.64 ± 0.03 eV, which is shown via first-principles calculations to be strongly renormalized by carrier-induced screening. The methodology demonstrates band structure engineering guided by directly viewing structurally and electrically tunable massive Dirac quasiparticles in lithographic superstructures at the nanoscale.
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Affiliation(s)
- Alfred J H Jones
- Department of Physics and Astronomy, Aarhus University, 8000Aarhus C, Denmark
| | - Lene Gammelgaard
- DTU Physics, Technical University of Denmark, 2800Kgs. Lyngby, Denmark
- Center for Nanostructured Graphene, Technical University of Denmark, 2800Kgs. Lyngby, Denmark
| | - Mikkel O Sauer
- Department of Materials and Production, Aalborg University, 9220Aalborg Øst, Denmark
- Department of Mathematical Science, Aalborg University, 9220Aalborg Øst, Denmark
- Center for Nanostructured Graphene (CNG), 9220Aalborg Øst, Denmark
| | - Deepnarayan Biswas
- Department of Physics and Astronomy, Aarhus University, 8000Aarhus C, Denmark
| | - Roland J Koch
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Chris Jozwiak
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Eli Rotenberg
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Aaron Bostwick
- Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California94720, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Cory R Dean
- Department of Physics, Columbia University, New York, New York10027, United States
| | - Antti-Pekka Jauho
- DTU Physics, Technical University of Denmark, 2800Kgs. Lyngby, Denmark
- Center for Nanostructured Graphene, Technical University of Denmark, 2800Kgs. Lyngby, Denmark
| | - Peter Bøggild
- DTU Physics, Technical University of Denmark, 2800Kgs. Lyngby, Denmark
- Center for Nanostructured Graphene, Technical University of Denmark, 2800Kgs. Lyngby, Denmark
| | - Thomas G Pedersen
- Department of Materials and Production, Aalborg University, 9220Aalborg Øst, Denmark
- Center for Nanostructured Graphene (CNG), 9220Aalborg Øst, Denmark
| | - Bjarke S Jessen
- Department of Physics, Columbia University, New York, New York10027, United States
| | - Søren Ulstrup
- Department of Physics and Astronomy, Aarhus University, 8000Aarhus C, Denmark
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6
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Bisht P, Kumar A, Ghosh A, Vullum PE, Sunding MF, Belle BD, Mehta BR. Tailoring the Vertical and Planar Growth of 2D WS 2 Thin Films Using Pulsed Laser Deposition for Enhanced Gas Sensing Properties. ACS APPLIED MATERIALS & INTERFACES 2022; 14:36789-36800. [PMID: 35943092 DOI: 10.1021/acsami.2c07759] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this study, pulsed laser deposition has been utilized for the controllable synthesis of WS2 thin films with growth orientation ranging from vertically to horizontally aligned layers, and the effect of growth parameters has been investigated. The growth of thin films on SiO2 substrates at three different pressures (30, 50, and 70 mTorr) and three different temperatures (400, 500, and 600 °C) has been studied. Detailed characterizations carried out on the as-grown layers clearly show the formation of the 2H-WS2 phase and its morphological evolution with deposition conditions. Atomic force microscopy and cross-sectional transmission electron microscopy have been used to deduce the growth mechanism of the vertical and planar films with different deposition parameters. The samples grown with a combination of lower temperatures and higher pressures exhibit a vertical flake-like growth with a flake thickness of ∼2-5 nm. However, at higher temperatures and lower pressures, the film growth is observed to be rather planar. The gas sensing parameters and the underlying mechanism have been observed to be quite different for vertically and horizontally grown layers. The vertical layers showed a selective response toward NO2 gas at room temperature (RT) with a limit of detection less than 50 ppb. In comparison, a very subdued and poor gas sensing response was recorded for the planar film at RT. A large specific area and abundance of active edge sites along with the flat basal plane present in the vertically grown layers seem to be responsible for efficient gas sensing toward NO2.
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Affiliation(s)
- Prashant Bisht
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Arvind Kumar
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Abhishek Ghosh
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Per Erik Vullum
- SINTEF Industry, Høgskoleringen, NO: 57046, Trondheim 7491, Norway
| | | | - Branson D Belle
- SINTEF Industry, Materials Physics, Forskningsveien 1, NO: 0373, Oslo 0314, Norway
| | - Bodh Raj Mehta
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
- Directorate of Research, Innovation and Development, Jaypee Institute of Information Technology, Noida, Uttar Pradesh 201309, India
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7
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Suzuki H, Hashimoto R, Misawa M, Liu Y, Kishibuchi M, Ishimura K, Tsuruta K, Miyata Y, Hayashi Y. Surface Diffusion-Limited Growth of Large and High-Quality Monolayer Transition Metal Dichalcogenides in Confined Space of Microreactor. ACS NANO 2022; 16:11360-11373. [PMID: 35793540 DOI: 10.1021/acsnano.2c05076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Transition metal dichalcogenides (TMDCs), including MoS2 and WS2, are potential candidates for next-generation semiconducting materials owing to their atomically thin structure and strong optoelectrical responses, which allow for flexible optoelectronic applications. Monolayer TMDCs have been grown utilizing chemical vapor deposition (CVD) techniques. Enhancing the domain size with high crystallinity and forming heterostructures are important topics for practical applications. In this study, the size of monolayer WS2 increased via the vapor-liquid-solid growth-based CVD technique utilizing the confined space of the substrate-stacked microreactor. The use of spin-coated metal salts (Na2WO4 and Na2MoO4) and organosulfur vapor allowed us to precisely control the source supply and investigate the growth in a systematic manner. We obtained a relatively low activation energy for growth (1.02 eV), which is consistent with the surface diffusion-limited growth regime observed in the confined space. Through systematic photoluminescence (PL) analysis, we determined that a growth temperature of ∼820 °C is optimal for producing high-quality WS2 with a narrow PL peak width (∼35 meV). By controlling the source balance of W and S, we obtained large-sized fully monolayered WS2 (∼560 μm) and monolayer WS2 with bilayer spots (∼1100 μm). Combining two distinct sources of transition metals, WS2/MoS2 lateral heterostructures were successfully created. In electrical transport measurements, the monolayer WS2 grown under optimal conditions has a high on-current (∼70 μA/μm), on/off ratio (∼5 × 108), and a field-effect mobility of ∼7 cm2/(V s). The field-effect transistor displayed an intrinsic photoresponse with wavelength selectivity that originated from the photoexcited carriers.
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Affiliation(s)
- Hiroo Suzuki
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Ryoki Hashimoto
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Masaaki Misawa
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Yijun Liu
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Misaki Kishibuchi
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Kentaro Ishimura
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Kenji Tsuruta
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Yasumitsu Miyata
- Department of Physics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Yasuhiko Hayashi
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
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8
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Verma D, Kumar P, Mukherjee S, Thakur D, Singh CV, Balakrishnan V. Interplay between Thermal Stress and Interface Binding on Fracture of WS 2 Monolayer with Triangular Voids. ACS APPLIED MATERIALS & INTERFACES 2022; 14:16876-16884. [PMID: 35353490 DOI: 10.1021/acsami.2c00901] [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
The defect engineering of two-dimensional (2D) materials has become a pivotal strategy for tuning the electrical and optical properties of the material. However, the reliable application of these atomically thin materials in practical devices require careful control of structural defects to avoid premature failure. Herein, a systematic investigation is presented to delineate the complex interactions among structural defects, the role of thermal mismatch between WS2 monolayer and different substrates, and their consequent effect on the fracture behavior of the monolayer. Detailed microscopic and Raman/PL spectroscopic observations enabled a direct correlation between thermal mismatch stress and crack patterns originating from the corner of faceted voids in the WS2 monolayer. Aberration-corrected STEM-HAADF imaging reveals the tensile strain localization around the faceted void corners. Density functional theory (DFT) simulations on interfacial interaction between the substrate (Silicon and sapphire -Al2O3) and monolayer WS2 revealed a binding energy between WS2 and Si substrate is 20 times higher than that with a sapphire substrate. This increased interfacial interaction in WS2 and substrate-aided thermal mismatch stress arising due to difference in thermal expansion coefficient to a maximum extent leading to fracture in monolayer WS2. Finite element simulations revealed the stress distribution near the void in the WS2 monolayer, where the maximum stress was concentrated at the void tip.
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Affiliation(s)
- Divya Verma
- School of Engineering, Indian Institute of Technology, Mandi, Himachal Pradesh 175075, India
| | - Pawan Kumar
- School of Engineering, Indian Institute of Technology, Mandi, Himachal Pradesh 175075, India
- Department of Electrical and System Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Sankha Mukherjee
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario M5S 3E4, Canada
- Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302, India
| | - Deepa Thakur
- School of Engineering, Indian Institute of Technology, Mandi, Himachal Pradesh 175075, India
| | - Chandra Veer Singh
- Department of Materials Science and Engineering, University of Toronto, Toronto, Ontario M5S 3E4, Canada
| | - Viswanath Balakrishnan
- School of Engineering, Indian Institute of Technology, Mandi, Himachal Pradesh 175075, India
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9
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Lapkin D, Kirsch C, Hiller J, Andrienko D, Assalauova D, Braun K, Carnis J, Kim YY, Mandal M, Maier A, Meixner AJ, Mukharamova N, Scheele M, Schreiber F, Sprung M, Wahl J, Westendorf S, Zaluzhnyy IA, Vartanyants IA. Spatially resolved fluorescence of caesium lead halide perovskite supercrystals reveals quasi-atomic behavior of nanocrystals. Nat Commun 2022; 13:892. [PMID: 35173165 PMCID: PMC8850480 DOI: 10.1038/s41467-022-28486-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/14/2022] [Indexed: 12/01/2022] Open
Abstract
We correlate spatially resolved fluorescence (-lifetime) measurements with X-ray nanodiffraction to reveal surface defects in supercrystals of self-assembled cesium lead halide perovskite nanocrystals and study their effect on the fluorescence properties. Upon comparison with density functional modeling, we show that a loss in structural coherence, an increasing atomic misalignment between adjacent nanocrystals, and growing compressive strain near the surface of the supercrystal are responsible for the observed fluorescence blueshift and decreased fluorescence lifetimes. Such surface defect-related optical properties extend the frequently assumed analogy between atoms and nanocrystals as so-called quasi-atoms. Our results emphasize the importance of minimizing strain during the self-assembly of perovskite nanocrystals into supercrystals for lighting application such as superfluorescent emitters. By utilizing spatially resolved fluorescence (-lifetime) measurements and high precision X-ray nanodiffraction, the authors correlate the influence of structural misalignment and fluorescence (-lifetime) properties of all-inorganic CsPbX3 (X– = Br–, Cl–) perovskite superlattices.
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Affiliation(s)
- Dmitry Lapkin
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Christopher Kirsch
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Jonas Hiller
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Denis Andrienko
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Dameli Assalauova
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Kai Braun
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Jerome Carnis
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Young Yong Kim
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Mukunda Mandal
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Andre Maier
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.,Center for Light-Matter Interaction, Sensors & Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, 72076, Tübingen, Germany
| | - Alfred J Meixner
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany.,Center for Light-Matter Interaction, Sensors & Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, 72076, Tübingen, Germany
| | | | - Marcus Scheele
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany. .,Center for Light-Matter Interaction, Sensors & Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, 72076, Tübingen, Germany.
| | - Frank Schreiber
- Center for Light-Matter Interaction, Sensors & Analytics LISA+, Universität Tübingen, Auf der Morgenstelle 15, 72076, Tübingen, Germany.,Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Michael Sprung
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany
| | - Jan Wahl
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Sophia Westendorf
- Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
| | - Ivan A Zaluzhnyy
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076, Tübingen, Germany
| | - Ivan A Vartanyants
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607, Hamburg, Germany. .,National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse 31, 115409, Moscow, Russia.
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10
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Yang W, Huang T, He J, Zhang S, Yang Y, Liu W, Ge X, Zhang R, Qiu M, Sang Y, Wang X, Zhou X, Li T, Liu C, Dai N, Chen X, Fan Z, Shen G. Monolayer WS 2 Lateral Homosuperlattices with Two-dimensional Periodic Localized Photoluminescence. ACS NANO 2022; 16:597-603. [PMID: 34919386 DOI: 10.1021/acsnano.1c07803] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Homojunctions and homosuperlattices are essential structures and have been widely explored for use in advanced electronic and optoelectronic devices. However, artificially manipulating crystalline phases in two-dimensional (2D) monolayers is still challenging, especially when attempting to engineer lateral homogeneous junctions in a single monolayer of transition metal dichalcogenides (TMDs). Herein, we demonstrate a lateral homosuperlattice (MLHS) with alternating 1T and 2H domains in a 2D WS2 monolayer plane. In MLHSs, the 2H domains, which are laterally localized and isolated by potential wells, manifest junction interfaces and irradiated photoluminescence (PL) with a lateral periodic distribution in the two-dimensional plane. The studies on MLHSs here can provide further understanding of lateral homojunctions and homosuperlattices in a monolayer plane, providing an alternative route to modulate optical and electronic behaviors in TMD monolayers.
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Affiliation(s)
- Wanli Yang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tiantian Huang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Junbo He
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Shuaijun Zhang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Yan Yang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Weiming Liu
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Xun Ge
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Rui Zhang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Mengxia Qiu
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Yuxiang Sang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Xingjun Wang
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Xiaohao Zhou
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Tianxin Li
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Congfeng Liu
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
| | - Ning Dai
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xin Chen
- National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
- Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyong Fan
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Guozhen Shen
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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11
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Yang X, Zhu Z, Luo F, Wang G, Peng G, Zhu M, Qin S. Strain-Induced Alternating Photoluminescence Segmentation in Hexagonal Monolayer Tungsten Disulfide Grown by Physical Vapor Deposition. ACS APPLIED MATERIALS & INTERFACES 2021; 13:46164-46170. [PMID: 34533939 DOI: 10.1021/acsami.1c13096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Two-dimensional semiconductors exhibit strong light emission under optical or electrical pumping due to quantum confinement and large exciton binding energies. The regulation of the light emission shows great application potential in next-generation optoelectronic devices. Herein, by the physical vapor deposition strategy, we synthesize monolayer hexagonal-shaped WS2, and its photoluminescence intensity mapping show three-fold symmetric patterns with alternating bright and dark regions. Regardless of the length of the edges, all domains with S-terminated edges show lower photoluminescence intensity, while all regions with W-terminated edges exhibit higher photoluminescence intensity. The photoluminescence segmentation mechanism is studied in detail by employing Raman spectroscopy, atomic force microscopy, high-resolution transmission electron microscopy, and Kelvin probe force microscopy, and it is found to originate from different strain distributions in the S-terminated region and the W-terminated region. The optical band gap determined by the photoluminescence in the dark region is ∼2 meV lower than that in the bright region, implying that more strain is stored in the S-terminated region than in the W-terminated region. The photoluminescence segmentation vanishes in transferred hexagonal-shaped WS2 from the initial substrate to a fresh silicon substrate, further confirming the physical mechanism. Our results provide guidance for tuning the optical properties of two-dimensional semiconductors by controllable strain engineering.
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Affiliation(s)
- Xi Yang
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Zhihong Zhu
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Fang Luo
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Guang Wang
- College of Liberal Arts and Sciences & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Gang Peng
- College of Liberal Arts and Sciences & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Mengjian Zhu
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Shiqiao Qin
- College of Advanced Interdisciplinary Studies & Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, Hunan 410073, China
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12
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Akhtaruzzaman M, Shahiduzzaman M, Amin N, Muhammad G, Islam MA, Rafiq KSB, Sopian K. Impact of Ar Flow Rates on Micro-Structural Properties of WS 2 Thin Film by RF Magnetron Sputtering. NANOMATERIALS 2021; 11:nano11071635. [PMID: 34206518 PMCID: PMC8306877 DOI: 10.3390/nano11071635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/12/2021] [Accepted: 06/16/2021] [Indexed: 12/04/2022]
Abstract
Tungsten disulfide (WS2) thin films were deposited on soda-lime glass (SLG) substrates using radio frequency (RF) magnetron sputtering at different Ar flow rates (3 to 7 sccm). The effect of Ar flow rates on the structural, morphology, and electrical properties of the WS2 thin films was investigated thoroughly. Structural analysis exhibited that all the as-grown films showed the highest peak at (101) plane corresponds to rhombohedral phase. The crystalline size of the film ranged from 11.2 to 35.6 nm, while dislocation density ranged from 7.8 × 1014 to 26.29 × 1015 lines/m2. All these findings indicate that as-grown WS2 films are induced with various degrees of defects, which were visible in the FESEM images. FESEM images also identified the distorted crystallographic structure for all the films except the film deposited at 5 sccm of Ar gas flow rate. EDX analysis found that all the films were having a sulfur deficit and suggested that WS2 thin film bears edge defects in its structure. Further, electrical analysis confirms that tailoring of structural defects in WS2 thin film can be possible by the varying Ar gas flow rates. All these findings articulate that Ar gas flow rate is one of the important process parameters in RF magnetron sputtering that could affect the morphology, electrical properties, and structural properties of WS2 thin film. Finally, the simulation study validates the experimental results and encourages the use of WS2 as a buffer layer of CdTe-based solar cells.
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Affiliation(s)
- Md. Akhtaruzzaman
- Solar Energy Research Institute, The National University of Malaysia, Bangi 43600, Malaysia; (M.A.); (K.S.)
| | - Md. Shahiduzzaman
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa 920-1292, Japan
- Correspondence: (M.S.); (N.A.); (K.S.B.R.)
| | - Nowshad Amin
- Institute of Sustainable Energy, Universiti Tenaga Nasional (@The National Energy University), Jalan Ikram-Uniten, Kajang 43000, Malaysia
- Correspondence: (M.S.); (N.A.); (K.S.B.R.)
| | - Ghulam Muhammad
- Department of Computer Engineering, College of Computer and Information Sciences, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Mohammad Aminul Islam
- Department of Electrical Engineering, University of Malaya, Jalan Universiti, Kuala Lumpur 50603, Malaysia;
| | - Khan Sobayel Bin Rafiq
- Solar Energy Research Institute, The National University of Malaysia, Bangi 43600, Malaysia; (M.A.); (K.S.)
- Correspondence: (M.S.); (N.A.); (K.S.B.R.)
| | - Kamaruzzaman Sopian
- Solar Energy Research Institute, The National University of Malaysia, Bangi 43600, Malaysia; (M.A.); (K.S.)
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13
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Mitterreiter E, Schuler B, Micevic A, Hernangómez-Pérez D, Barthelmi K, Cochrane KA, Kiemle J, Sigger F, Klein J, Wong E, Barnard ES, Watanabe K, Taniguchi T, Lorke M, Jahnke F, Finley JJ, Schwartzberg AM, Qiu DY, Refaely-Abramson S, Holleitner AW, Weber-Bargioni A, Kastl C. The role of chalcogen vacancies for atomic defect emission in MoS 2. Nat Commun 2021; 12:3822. [PMID: 34158488 PMCID: PMC8219741 DOI: 10.1038/s41467-021-24102-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 05/28/2021] [Indexed: 11/08/2022] Open
Abstract
For two-dimensional (2D) layered semiconductors, control over atomic defects and understanding of their electronic and optical functionality represent major challenges towards developing a mature semiconductor technology using such materials. Here, we correlate generation, optical spectroscopy, atomic resolution imaging, and ab initio theory of chalcogen vacancies in monolayer MoS2. Chalcogen vacancies are selectively generated by in-vacuo annealing, but also focused ion beam exposure. The defect generation rate, atomic imaging and the optical signatures support this claim. We discriminate the narrow linewidth photoluminescence signatures of vacancies, resulting predominantly from localized defect orbitals, from broad luminescence features in the same spectral range, resulting from adsorbates. Vacancies can be patterned with a precision below 10 nm by ion beams, show single photon emission, and open the possibility for advanced defect engineering of 2D semiconductors at the ultimate scale.
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Grants
- EXC 2089/1-390776260 Deutsche Forschungsgemeinschaft (German Research Foundation)
- RTG 2247 Deutsche Forschungsgemeinschaft (German Research Foundation)
- RTG 2247 Deutsche Forschungsgemeinschaft (German Research Foundation)
- DE-AC02-05CH11231 DOE | Office of Science (SC)
- DE-AC02-05CH11231 DOE | Office of Science (SC)
- DE-AC02-05CH11231 DOE | Office of Science (SC)
- DE-AC02-05CH11231 DOE | Office of Science (SC)
- JPMJCR15F3 MEXT | JST | Core Research for Evolutional Science and Technology (CREST)
- JPMJCR15F3 MEXT | JST | Core Research for Evolutional Science and Technology (CREST)
- JPMXP0112101001 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H00354 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JPMXP0112101001 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- Nanosystems Initiative Munich (NIM) Bavaria California Technology Center (BaCaTeC)
- Alexander von Humboldt-Stiftung (Alexander von Humboldt Foundation)
- INCITE, Contract No. DE-AC05-00OR22725
- Bavaria California Technology Center (BaCaTeC) TUM International Graduate School of Science and Engineering (IGSSE)
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Affiliation(s)
- Elmar Mitterreiter
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - Bruno Schuler
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
| | - Ana Micevic
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - Daniel Hernangómez-Pérez
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Katja Barthelmi
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | | | - Jonas Kiemle
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - Florian Sigger
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | - Julian Klein
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Edward Wong
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Edward S Barnard
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan
| | - Michael Lorke
- Bremen Center for Computational Materials Science, University of Bremen, Bremen, Germany
- Bremen Institute for Theoretical Physics, University of Bremen, Bremen, Germany
| | - Frank Jahnke
- Bremen Institute for Theoretical Physics, University of Bremen, Bremen, Germany
| | - Johnathan J Finley
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), München, Germany
| | | | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, USA
| | - Sivan Refaely-Abramson
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander W Holleitner
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany.
- Munich Center for Quantum Science and Technology (MCQST), München, Germany.
| | | | - Christoph Kastl
- Walter Schottky Institut and Physics Department, Technical University of Munich, Garching, Germany.
- Munich Center for Quantum Science and Technology (MCQST), München, Germany.
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14
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Kolesnichenko PV, Zhang Q, Zheng C, Fuhrer MS, Davis JA. Multidimensional analysis of excitonic spectra of monolayers of tungsten disulphide: toward computer-aided identification of structural and environmental perturbations of 2D materials. MACHINE LEARNING: SCIENCE AND TECHNOLOGY 2021. [DOI: 10.1088/2632-2153/abd87c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Despite 2D materials holding great promise for a broad range of applications, the proliferation of devices and their fulfillment of real-life demands are still far from being realized. Experimentally obtainable samples commonly experience a wide range of perturbations (ripples and wrinkles, point and line defects, grain boundaries, strain field, doping, water intercalation, oxidation, edge reconstructions) significantly deviating the properties from idealistic models. These perturbations, in general, can be entangled or occur in groups with each group forming a complex perturbation making the interpretations of observable physical properties and the disentanglement of simultaneously acting effects a highly non-trivial task even for an experienced researcher. Here we generalise statistical correlation analysis of excitonic spectra of monolayer WS2, acquired by hyperspectral absorption and photoluminescence imaging, to a multidimensional case, and examine multidimensional correlations via unsupervised machine learning algorithms. Using principal component analysis we are able to identify four dominant components that are correlated with tensile strain, disorder induced by adsorption or intercalation of environmental molecules, multi-layer regions and charge doping, respectively. This approach has the potential to determine the local environment of WS2 monolayers or other 2D materials from simple optical measurements, and paves the way toward advanced, machine-aided, characterization of monolayer matter.
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15
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Zhang M, Lihter M, Chen TH, Macha M, Rayabharam A, Banjac K, Zhao Y, Wang Z, Zhang J, Comtet J, Aluru NR, Lingenfelder M, Kis A, Radenovic A. Super-resolved Optical Mapping of Reactive Sulfur-Vacancies in Two-Dimensional Transition Metal Dichalcogenides. ACS NANO 2021; 15:7168-7178. [PMID: 33829760 DOI: 10.1021/acsnano.1c00373] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Transition metal dichalcogenides (TMDs) represent a class of semiconducting two-dimensional (2D) materials with exciting properties. In particular, defects in 2D-TMDs and their molecular interactions with the environment can crucially affect their physical and chemical properties. However, mapping the spatial distribution and chemical reactivity of defects in liquid remains a challenge. Here, we demonstrate large area mapping of reactive sulfur-deficient defects in 2D-TMDs in aqueous solutions by coupling single-molecule localization microscopy with fluorescence labeling using thiol chemistry. Our method, reminiscent of PAINT strategies, relies on the specific binding of fluorescent probes hosting a thiol group to sulfur vacancies, allowing localization of the defects with an uncertainty down to 15 nm. Tuning the distance between the fluorophore and the docking thiol site allows us to control Föster resonance energy transfer (FRET) process and reveal grain boundaries and line defects due to the local irregular lattice structure. We further characterize the binding kinetics over a large range of pH conditions, evidencing the reversible adsorption of the thiol probes to the defects with a subsequent transitioning to irreversible binding in basic conditions. Our methodology provides a simple and fast alternative for large-scale mapping of nonradiative defects in 2D materials and can be used for in situ and spatially resolved monitoring of the interaction between chemical agents and defects in 2D materials that has general implications for defect engineering in aqueous condition.
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Affiliation(s)
- Miao Zhang
- Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Department of Applied Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden
| | - Martina Lihter
- Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Tzu-Heng Chen
- Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Michal Macha
- Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Archith Rayabharam
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, 61801 Illinois United States
| | - Karla Banjac
- Max Planck-EPFL Laboratory for Molecular Nanoscience and Institut de Physique, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Yanfei Zhao
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Zhenyu Wang
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jing Zhang
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Jean Comtet
- Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Narayana R Aluru
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, 61801 Illinois United States
| | - Magalí Lingenfelder
- Max Planck-EPFL Laboratory for Molecular Nanoscience and Institut de Physique, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andras Kis
- Electrical Engineering Institute, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
- Institute of Materials Science and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Aleksandra Radenovic
- Laboratory of Nanoscale Biology, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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16
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Bradford J, Shafiei M, MacLeod J, Motta N. Synthesis and characterization of WS 2/graphene/SiC van der Waals heterostructures via WO 3-x thin film sulfurization. Sci Rep 2020; 10:17334. [PMID: 33060655 PMCID: PMC7567119 DOI: 10.1038/s41598-020-74024-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/15/2020] [Indexed: 11/28/2022] Open
Abstract
Van der Waals heterostructures of monolayer transition metal dichalcogenides (TMDs) and graphene have attracted keen scientific interest due to the complementary properties of the materials, which have wide reaching technological applications. Direct growth of uniform, large area TMDs on graphene substrates by chemical vapor deposition (CVD) is limited by slow lateral growth rates, which result in a tendency for non-uniform multilayer growth. In this work, monolayer and few-layer WS2 was grown on epitaxial graphene on SiC by sulfurization of WO3−x thin films deposited directly onto the substrate. Using this method, WS2 growth was achieved at temperatures as low as 700 °C – significantly less than the temperature required for conventional CVD. Achieving long-range uniformity remains a challenge, but this process could provide a route to synthesize a broad range of TMD/graphene van der Waals heterostructures with novel properties and functionality not accessible by conventional CVD growth.
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Affiliation(s)
- Jonathan Bradford
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,School of Physics and Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Mahnaz Shafiei
- Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, VIC, Australia.,Institute for Future Environments, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Jennifer MacLeod
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Institute for Future Environments, Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Centre for Materials Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Nunzio Motta
- School of Chemistry and Physics, Queensland University of Technology (QUT), Brisbane, QLD, Australia. .,Institute for Future Environments, Queensland University of Technology (QUT), Brisbane, QLD, Australia. .,Centre for Materials Science, Queensland University of Technology (QUT), Brisbane, QLD, Australia.
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17
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Hwang Y, Kang SG, Shin N. Inherent Resistance of Seed-Mediated Grown MoSe 2 Monolayers to Defect Formation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:34297-34305. [PMID: 32618179 DOI: 10.1021/acsami.0c05558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Recent progress in the chemical vapor deposition technique toward growing large-area and single-crystalline two-dimensional (2D) transition metal dichalcogenides (TMDs) has resulted in an electronic/optoelectronic device performance that rivals that of their top-down counterparts, despite the extensive use of hydrogen, a common reducing agent that readily generates defects in TMDs. Herein, we report that 2D MoSe2 domains containing oxide seeds are resistant to hydrogen-induced defect generation. Specifically, we observed that the etching of the edges of seed-containing MoSe2 was significantly less than that of pristine MoSe2, without apparent seed particles, under the same H2 annealing conditions. Our systematic approach for controlling the H2 exposure time indicates that the oxidation of Mo and the edge roughening of seedless MoSe2 coincidentally increase after H2 exposure owing to the formation of Se vacancy followed by Mo oxidation, which is not the case with seed-containing MoSe2. An ab initio calculation indicates that hydrogen preferentially adsorbs more onto O bonded to Mo than onto Se, providing further evidence of the resistance of seeded MoSe2 to hydrogen etching. This finding provides an insight into controlling defect formation in 2D TMDs by employing sacrificial adsorption sites for reactive species (i.e., hydrogen).
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Affiliation(s)
- Yunjeong Hwang
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Sung Gu Kang
- School of Chemical Engineering, University of Ulsan, Ulsan 680-749, Republic of Korea
| | - Naechul Shin
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
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18
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Li R, Taniguchi T, Watanabe K, Xue J. Detecting band profiles of devices with conductive atomic force microscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:073702. [PMID: 32752799 DOI: 10.1063/5.0008412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/24/2020] [Indexed: 06/11/2023]
Abstract
Band profiles of electronic devices are of fundamental importance in determining their properties. A technique that can map the band profile of both the interior and edges of a device at the nanometer scale is highly demanded. Conventional scanning tunneling spectroscopy (STS) can map band structure at the atomic scale but is limited to the interior of large and conductive samples. Here, we develop contact-mode STS based on a conductive atomic force microscope that can remove these constraints. With this technique, we map the band profile of MoS2 transistors with nanometer resolution at room temperature. A band bending of 0.6 eV within 18 nm of the edges of MoS2 on an insulating substrate is discovered. This technique will be of great use for both fundamental and applied studies of various electronic devices.
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Affiliation(s)
- Ranran Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | | | - Kenji Watanabe
- National Institute for Materials Science, Tsukuba 305-0044, Japan
| | - Jiamin Xue
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
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19
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Mitterreiter E, Schuler B, Cochrane KA, Wurstbauer U, Weber-Bargioni A, Kastl C, Holleitner AW. Atomistic Positioning of Defects in Helium Ion Treated Single-Layer MoS 2. NANO LETTERS 2020; 20:4437-4444. [PMID: 32368920 DOI: 10.1021/acs.nanolett.0c01222] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Structuring materials with atomic precision is the ultimate goal of nanotechnology and is becoming increasingly relevant as an enabling technology for quantum electronics/spintronics and quantum photonics. Here, we create atomic defects in monolayer MoS2 by helium ion (He-ion) beam lithography with a spatial fidelity approaching the single-atom limit in all three dimensions. Using low-temperature scanning tunneling microscopy (STM), we confirm the formation of individual point defects in MoS2 upon He-ion bombardment and show that defects are generated within 9 nm of the incident helium ions. Atom-specific sputtering yields are determined by analyzing the type and occurrence of defects observed in high-resolution STM images and compared with Monte Carlo simulations. Both theory and experiment indicate that the He-ion bombardment predominantly generates sulfur vacancies.
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Affiliation(s)
- Elmar Mitterreiter
- Walter Schottky Institut and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
| | - Bruno Schuler
- Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
- nanotech@surfaces Laboratory, Empa - Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Katherine A Cochrane
- Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Ursula Wurstbauer
- Walter Schottky Institut and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Institute of Physics, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Str.10, 48149 Münster, Germany
| | - Alexander Weber-Bargioni
- Molecular Foundry, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Christoph Kastl
- Walter Schottky Institut and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
| | - Alexander W Holleitner
- Walter Schottky Institut and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstrasse 4, 80799 München, Germany
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20
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Koçak Y, Gür E. Growth Control of WS 2: From 2D Layer by Layer to 3D Vertical Standing Nanowalls. ACS APPLIED MATERIALS & INTERFACES 2020; 12:15785-15792. [PMID: 32176470 DOI: 10.1021/acsami.9b18759] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Large area 2D WS2 has been grown successfully by radio frequency magnetron sputtering (RFMS) method. First, in order to investigate the pressure dependence on the grown WS2 samples, WS2 were grown at 5 different growth pressures, 5, 10, 15, 20, and 25 mTorr. It has been observed that the surface morphology changes for the samples grown at higher growth pressures, 15, 20, and 25 mTorr. Vertically standing nanowall (NW)-like structures have been formed at these relatively high growth pressures. It has also been observed that the (002) plane is highly dominant, which means layer by layer growth parallel to the substrate, for the sample grown at 20 mTorr. X-ray photoelectron spectroscopy (XPS) measurements revealed an increasing atomic percentage of the S element to W element, S/W, ratio in thin films, as the growth pressure increases. Growth dynamics of WS2 has been investigated by time-dependent-growth WS2 samples, 5, 10, 20, 40, and 80 s under 20 mTorr pressure. It has been shown by atomic force microscopy, scanning electron microscopy, and transmission electron microscopy that a highly smooth surface has been achieved in the samples grown for the duration of 5 and 10 s. Raman mapping measurements on the sample grown at 5 s have revealed large area homogeneous growth. As the growth time gets longer, the NWs emerge on the surface at some nucleation points. Only the peak that belongs to the (002) plane has been observed for samples grown at 5 and 10 s by the X-ray diffraction (XRD) measurements. XRD measurements have revealed the appearance of turbostratic peaks of (11l) and (10l) as the thickness increases. Photoluminescence measurements have indicated near-band-edge emission centered at 630 nm for only 5 and 10 s samples.
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Affiliation(s)
- Yusuf Koçak
- Department of Physics, Faculty of Science, Ataturk University, 25250 Erzurum, Turkey
| | - Emre Gür
- Department of Physics, Faculty of Science, Ataturk University, 25250 Erzurum, Turkey
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21
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Feng Y, Wu J, Chi Q, Li W, Yu Y, Fei W. Defects and Aliovalent Doping Engineering in Electroceramics. Chem Rev 2020; 120:1710-1787. [DOI: 10.1021/acs.chemrev.9b00507] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Yu Feng
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080, P. R. China
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, P. R. China
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jiagang Wu
- Department of Materials Science, Sichuan University, Chengdu 610064, P. R. China
| | - Qingguo Chi
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080, P. R. China
| | - Weili Li
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Yang Yu
- Key Laboratory of Engineering Dielectrics and Its Application, Ministry of Education, Harbin University of Science and Technology, Harbin 150080, P. R. China
| | - Weidong Fei
- State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, P. R. China
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22
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Ulstrup S, Giusca CE, Miwa JA, Sanders CE, Browning A, Dudin P, Cacho C, Kazakova O, Gaskill DK, Myers-Ward RL, Zhang T, Terrones M, Hofmann P. Nanoscale mapping of quasiparticle band alignment. Nat Commun 2019; 10:3283. [PMID: 31337765 PMCID: PMC6650412 DOI: 10.1038/s41467-019-11253-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 07/02/2019] [Indexed: 11/22/2022] Open
Abstract
Control of atomic-scale interfaces between materials with distinct electronic structures is crucial for the design and fabrication of most electronic devices. In the case of two-dimensional materials, disparate electronic structures can be realized even within a single uniform sheet, merely by locally applying different vertical gate voltages. Here, we utilize the inherently nano-structured single layer and bilayer graphene on silicon carbide to investigate lateral electronic structure variations in an adjacent single layer of tungsten disulfide (WS2). The electronic band alignments are mapped in energy and momentum space using angle-resolved photoemission with a spatial resolution on the order of 500 nm (nanoARPES). We find that the WS2 band offsets track the work function of the underlying single layer and bilayer graphene, and we relate such changes to observed lateral patterns of exciton and trion luminescence from WS2. Sharp atomic interfaces between materials dictate the interface’s electronic properties. The authors use angle-resolved photoemission spectroscopy with a spatial resolution of ~500 nm to investigate the nanoscale electronic band structure and band alignment in a lateral heterostructure composed of WS2 placed on alternating nano-stripes of monolayer and bilayer graphene.
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Affiliation(s)
- Søren Ulstrup
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark.
| | - Cristina E Giusca
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK.
| | - Jill A Miwa
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
| | - Charlotte E Sanders
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK
| | - Alex Browning
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Pavel Dudin
- Diamond Light Source, Division of Science, Didcot, OX11 0DE, UK
| | - Cephise Cacho
- Diamond Light Source, Division of Science, Didcot, OX11 0DE, UK
| | - Olga Kazakova
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - D Kurt Gaskill
- U.S. Naval Research Laboratory, Washington, DC, 20375, USA
| | | | - Tianyi Zhang
- Department of Physics and Center for 2-Dimensional and Layered Materials, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mauricio Terrones
- Department of Physics and Center for 2-Dimensional and Layered Materials, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Philip Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000, Aarhus C, Denmark
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