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Bui TA, Leuthner GT, Madsen J, Monazam MRA, Chirita AI, Postl A, Mangler C, Kotakoski J, Susi T. Creation of Single Vacancies in hBN with Electron Irradiation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2301926. [PMID: 37259696 DOI: 10.1002/smll.202301926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/16/2023] [Indexed: 06/02/2023]
Abstract
Understanding electron irradiation effects is vital not only for reliable transmission electron microscopy characterization, but increasingly also for the controlled manipulation of 2D materials. The displacement cross sections of monolayer hexagonal boron nitride (hBN) are measured using aberration-corrected scanning transmission electron microscopy in near ultra-high vacuum at primary beam energies between 50 and 90 keV. Damage rates below 80 keV are up to three orders of magnitude lower than previously measured at edges under poorer residual vacuum conditions, where chemical etching appears to dominate. Notably, it is possible to create single vacancies in hBN using electron irradiation, with boron almost twice as likely as nitrogen to be ejected below 80 keV. Moreover, any damage at such low energies cannot be explained by elastic knock-on, even when accounting for the vibrations of the atoms. A theoretical description is developed to account for the lowering of the displacement threshold due to valence ionization resulting from inelastic scattering of probe electrons, modeled using charge-constrained density functional theory molecular dynamics. Although significant reductions are found depending on the constrained charge, quantitative predictions for realistic ionization states are currently not possible. Nonetheless, there is potential for defect-engineering of hBN at the level of single vacancies using electron irradiation.
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Affiliation(s)
- Thuy An Bui
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Gregor T Leuthner
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Jacob Madsen
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Mohammad R A Monazam
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Alexandru I Chirita
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Andreas Postl
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Clemens Mangler
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Jani Kotakoski
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
| | - Toma Susi
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, Vienna, 1090, Austria
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2
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Jiang N. Electron irradiation effects in transmission electron microscopy: Random displacements and collective migrations. Micron 2023; 171:103482. [PMID: 37167653 DOI: 10.1016/j.micron.2023.103482] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 05/02/2023] [Accepted: 05/02/2023] [Indexed: 05/13/2023]
Abstract
Electron beam damage in transmission electron microscopy (TEM) is complicated because the damage phenomena can be the result of random atomic displacements or collective migrations. The former is categorized as the primary beam effects and the latter is the secondary beam effects. The mechanisms for these two distinguishing atomic processes of damage are different. The primary beam effects can be caused by the mechanisms of knock-on and/or radiolysis, while the secondary effects must be driven by a field that is induced by electron irradiation. One such field has been identified to be the electric field produced by the accumulated charges due to the ejection of secondary and Auger electrons from the irradiated region. One convincing example is the electron irradiation-induced domain switch in ferroelectric materials, in which the collective cation displacements are driven by the induced electric field. A detailed interpretation is given in this review. The sintering of metal NPs under electron irradiation is a secondary beam effect and is most likely also caused by the induced electric fields. The interactions between the charged NP and substrate, and between charged NPs, result in NP motion. Interchanging atoms between NPs during the sintering may also be driven by the electric fields. Although many beam-damage phenomena in C nanotubes and layered materials, such as graphene, BN, and transition metal dichalcogenides, are caused by the primary beam effects and have been well studied experimentally and theoretically in the literature, some phenomena from the secondary beam effects have also been identified in this review. These phenomena are sensitive to electron current density, the shape and orientation of the specimen, and even the illumination mode (i.e., TEM or STEM). Unfortunately, the mechanisms responsible for these phenomena still need to be clarified.
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Affiliation(s)
- Nan Jiang
- Department of Physics, Arizona State University, Tempe, AZ 85281-1504, USA.
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3
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Yoshimura A, Lamparski M, Giedt J, Lingerfelt D, Jakowski J, Ganesh P, Yu T, Sumpter BG, Meunier V. Quantum theory of electronic excitation and sputtering by transmission electron microscopy. NANOSCALE 2023; 15:1053-1067. [PMID: 35703316 DOI: 10.1039/d2nr01018f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Many computational models have been developed to predict the rates of atomic displacements in two-dimensional (2D) materials under electron beam irradiation. However, these models often drastically underestimate the displacement rates in 2D insulators, in which beam-induced electronic excitations can reduce the binding energies of the irradiated atoms. This bond softening leads to a qualitative disagreement between theory and experiment, in that substantial sputtering is experimentally observed at beam energies deemed far too small to drive atomic dislocation by many current models. To address these theoretical shortcomings, this paper develops a first-principles method to calculate the probability of beam-induced electronic excitations by coupling quantum electrodynamics (QED) scattering amplitudes to density functional theory (DFT) single-particle orbitals. The presented theory then explicitly considers the effect of these electronic excitations on the sputtering cross section. Applying this method to 2D hexagonal BN and MoS2 significantly increases their calculated sputtering cross sections and correctly yields appreciable sputtering rates at beam energies previously predicted to leave the crystals intact. The proposed QED-DFT approach can be easily extended to describe a rich variety of beam-driven phenomena in any crystalline material.
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Affiliation(s)
- Anthony Yoshimura
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Michael Lamparski
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Joel Giedt
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - David Lingerfelt
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jacek Jakowski
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Panchapakesan Ganesh
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Tao Yu
- Department of Chemistry, University of North Dakota, Grand Forks, ND 58202, USA
| | - Bobby G Sumpter
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Vincent Meunier
- Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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4
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Valencia L, de la Mata M, Herrera M, Delgado F, Hernández-Saz J, Molina S. Induced damage during STEM-EELS analyses on acrylic-based materials for Stereolithography. Polym Degrad Stab 2022. [DOI: 10.1016/j.polymdegradstab.2022.110044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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de Graaf S, Ahmadi M, Lazić I, Bosch EGT, Kooi BJ. Imaging atomic motion of light elements in 2D materials with 30 kV electron microscopy. NANOSCALE 2021; 13:20683-20691. [PMID: 34878478 DOI: 10.1039/d1nr06614e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Scanning transmission electron microscopy (STEM) is the most widespread adopted tool for atomic scale characterization of two-dimensional (2D) materials. However, damage free imaging of 2D materials with electrons has remained problematic even with powerful low-voltage 60 kV-microscopes. An additional challenge is the observation of light elements in combination with heavy elements, particularly when recording fast dynamical phenomena. Here, we demonstrate that 2D WS2 suffers from electron radiation damage during 30 kV-STEM imaging, and we capture beam-induced defect dynamics in real-time by atomic electrostatic potential imaging using integrated differential phase contrast (iDPC)-STEM. The fast imaging of atomic electrostatic potentials with iDPC-STEM reveals the presence and motion of single sulfur atoms near defects and edges in WS2 that are otherwise invisible at the same imaging dose at 30 kV with conventional annular dark-field STEM, and has a vast speed and data processing advantage over electron detector camera based STEM techniques like electron ptychography.
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Affiliation(s)
- Sytze de Graaf
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Majid Ahmadi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
| | - Ivan Lazić
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - Eric G T Bosch
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - Bart J Kooi
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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6
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Cretu O, Ishizuka A, Yanagisawa K, Ishizuka K, Kimoto K. Atomic-Scale Electrical Field Mapping of Hexagonal Boron Nitride Defects. ACS NANO 2021; 15:5316-5321. [PMID: 33577281 DOI: 10.1021/acsnano.0c10849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The distribution of electric fields in hexagonal boron nitride is mapped down to the atomic level inside a scanning transmission electron microscope by using the recently introduced technique of differential phase contrast imaging. The maps are calculated and displayed in real time, along with conventional annular dark-field images, through the use of custom-developed hardware and software. An increased electric field is observed around boron monovacancies and subsequently mapped and measured relative to the perfect lattice. The edges of extended defects feature enhanced electric fields, which can be used to trap diffusing adatoms. The magnitude of the electric field produced by the different types of edges is compared to monolayer areas, confirming previous predictions regarding their stability. These observations provide insight into the properties of this interesting material, serving as a suitable platform on which to test the limits of this technique, and encourage further work, such as dynamic experiments coupled with in situ techniques.
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Affiliation(s)
- Ovidiu Cretu
- Electron Microscopy Group, National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Akimitsu Ishizuka
- HREM Research, Inc., 14-48 Matsukazedai, Higashimatsuyama, Saitama 355-0055, Japan
| | - Keiichi Yanagisawa
- Electron Microscopy Group, National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
| | - Kazuo Ishizuka
- HREM Research, Inc., 14-48 Matsukazedai, Higashimatsuyama, Saitama 355-0055, Japan
| | - Koji Kimoto
- Electron Microscopy Group, National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan
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7
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Chirita Mihaila AI, Susi T, Kotakoski J. Influence of temperature on the displacement threshold energy in graphene. Sci Rep 2019; 9:12981. [PMID: 31506494 PMCID: PMC6736860 DOI: 10.1038/s41598-019-49565-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 08/24/2019] [Indexed: 11/09/2022] Open
Abstract
The atomic structure of nanomaterials is often studied using transmission electron microscopy. In addition to image formation, the energetic electrons impinging on the sample may also cause damage. In a good conductor such as graphene, the damage is limited to the knock-on process caused by elastic electron-nucleus scattering. This process is determined by the kinetic energy an atom needs to be sputtered, i.e. its displacement threshold energy Ed. This is typically assumed to have a fixed value for all electron impacts on equivalent atoms within a crystal. Here we show using density functional tight-binding simulations that the displacement threshold energy is affected by thermal perturbations of atoms from their equilibrium positions. This effect can be accounted for in the estimation of the displacement cross section by replacing the constant threshold energy value with a distribution. Our refined model better describes previous precision measurements of graphene knock-on damage, and should be considered also for other low-dimensional materials.
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Affiliation(s)
| | - Toma Susi
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090, Vienna, Austria
| | - Jani Kotakoski
- University of Vienna, Faculty of Physics, Boltzmanngasse 5, 1090, Vienna, Austria.
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8
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Zhou X, Tang DM, Mitome M, Bando Y, Sasaki T, Golberg D. Intrinsic and Defect-Related Elastic Moduli of Boron Nitride Nanotubes As Revealed by in Situ Transmission Electron Microscopy. NANO LETTERS 2019; 19:4974-4980. [PMID: 31265300 DOI: 10.1021/acs.nanolett.9b01170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Boron nitride nanotubes (BNNTs) are promising for mechanical applications owing to the high modulus, high strength, and inert chemical nature. However, up to now, precise evaluation of their elastic properties and their relation to defects have not been experimentally established. Herein, the intrinsic elastic modulus of BNNTs and its dependence on intrinsic and deliberately irradiation-induced extrinsic defects have been studied via an electric-field-induced high-order resonance technique inside a high-resolution transmission electron microscope (HRTEM). Resonances up to fourth order for normal modes and third order for parametric modes have been initiated in the cantilevered tubes, and the recorded frequencies are well consistent with the theoretical calculations with a discrepancy of ∼1%. The elastic moduli of the BNNTs measured from high-order resonance is about 906.2 GPa on average, with a standard deviation of 9.3%, which is found to be closely related to the intrinsic defect as cavities in the nanotube walls. Furthermore, electron irradiation in HRTEM has been used to study the effects of defects to elastic moduli and to evaluate the radiation resistance of the BNNTs. Along with an increase in the irradiation dose, the outer diameter has linearly reduced due to the knock-on effects. A defective shell with nearly constant thickness has been formed on the outer surface, and as a result, the elastic modulus decreases gradually to ∼662.9 GPa, which is still 3 times that of steel. Excellent intrinsic elastic properties and decent radiation-resistance prove that BNNTs could be a material of choice for applications in extreme environments, such as those existing in space.
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Affiliation(s)
- Xin Zhou
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
- Graduate School of Pure and Applied Sciences , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8577 , Japan
| | - Dai-Ming Tang
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
| | - Masanori Mitome
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
| | - Yoshio Bando
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
| | - Takayoshi Sasaki
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
- Graduate School of Pure and Applied Sciences , University of Tsukuba , 1-1-1 Tennodai , Tsukuba , Ibaraki 305-8577 , Japan
| | - Dmitri Golberg
- International Center for Materials Nanoarchitectonics (MANA) , National Institute for Materials Science (NIMS) , 1-1 Namiki , Tsukuba , Ibaraki 305-0044 , Japan
- School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty , Queensland University of Technology (QUT) , Second George Street , Brisbane , QLD 4000 , Australia
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9
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Radiation damage to organic and inorganic specimens in the TEM. Micron 2019; 119:72-87. [DOI: 10.1016/j.micron.2019.01.005] [Citation(s) in RCA: 174] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 02/07/2023]
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10
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Pham T, Oh S, Stetz P, Onishi S, Kisielowski C, Cohen ML, Zettl A. Torsional instability in the single-chain limit of a transition metal trichalcogenide. Science 2018; 361:263-266. [DOI: 10.1126/science.aat4749] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/16/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Thang Pham
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute, University of California, Berkeley, CA 94720, USA
| | - Sehoon Oh
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Patrick Stetz
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute, University of California, Berkeley, CA 94720, USA
| | - Seita Onishi
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute, University of California, Berkeley, CA 94720, USA
| | - Christian Kisielowski
- Molecular Foundry and Joint Center for Artificial Photosynthesis, Berkeley, CA 94720, USA
| | - Marvin L. Cohen
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alex Zettl
- Department of Physics, University of California, Berkeley, CA 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Kavli Energy NanoSciences Institute, University of California, Berkeley, CA 94720, USA
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11
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Gilbert SM, Dunn G, Azizi A, Pham T, Shevitski B, Dimitrov E, Liu S, Aloni S, Zettl A. Fabrication of Subnanometer-Precision Nanopores in Hexagonal Boron Nitride. Sci Rep 2017; 7:15096. [PMID: 29118413 PMCID: PMC5678191 DOI: 10.1038/s41598-017-12684-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/14/2017] [Indexed: 01/22/2023] Open
Abstract
We demonstrate the fabrication of individual nanopores in hexagonal boron nitride (h-BN) with atomically precise control of the pore shape and size. Previous methods of pore production in other 2D materials typically create pores with irregular geometry and imprecise diameters. In contrast, other studies have shown that with careful control of electron irradiation, defects in h-BN grow with pristine zig-zag edges at quantized triangular sizes, but they have failed to demonstrate production and control of isolated defects. In this work, we combine these techniques to yield a method in which we can create individual size-quantized triangular nanopores through an h-BN sheet. The pores are created using the electron beam of a conventional transmission electron microscope; which can strip away multiple layers of h-BN exposing single-layer regions, introduce single vacancies, and preferentially grow vacancies only in the single-layer region. We further demonstrate how the geometry of these pores can be altered beyond triangular by changing beam conditions. Precisely size- and geometry-tuned nanopores could find application in molecular sensing, DNA sequencing, water desalination, and molecular separation.
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Affiliation(s)
- S Matt Gilbert
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Gabriel Dunn
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Amin Azizi
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Thang Pham
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Brian Shevitski
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Edgar Dimitrov
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Stanley Liu
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA.,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Shaul Aloni
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alex Zettl
- Department of Physics, University of California at Berkeley, Berkeley, CA, 94720, USA. .,Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Kavli Energy NanoScience Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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12
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13
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Pham T, Gibb AL, Li Z, Gilbert SM, Song C, Louie SG, Zettl A. Formation and Dynamics of Electron-Irradiation-Induced Defects in Hexagonal Boron Nitride at Elevated Temperatures. NANO LETTERS 2016; 16:7142-7147. [PMID: 27685639 DOI: 10.1021/acs.nanolett.6b03442] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The atomic structure, stability, and dynamics of defects in hexagonal boron nitride (h-BN) are investigated using an aberration-corrected transmission electron microscope operated at 80 kV between room temperature and 1000 °C. At temperatures above 700 °C, parallelogram- and hexagon-shaped defects with zigzag edges become prominent, in contrast to the triangular defects typically observed at lower temperatures. The appearance of 120° corners at defect vertices indicates the coexistence of both N- and B-terminated zigzag edges in the same defect. In situ dynamics studies show that the hexagonal holes grow by electron-induced sputtering of B-N chains, and that at high temperatures these chains can migrate from one defect corner to another. We complement the experiments with first-principles calculation which consider the thermal equilibrium formation energy of different defect configurations. It is shown that, below a critical defect size, hexagonal defects have the lowest formation energy and therefore are the more-stable configuration, and triangular defects are energetically metastable but can be "frozen in" under experimental conditions. We also discuss the possible contributions of several dynamic processes to the temperature-dependent defect formation.
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Affiliation(s)
- Thang Pham
- Department of Physics, University of California , Berkeley, California 94720, United States
- Department of Materials Science and Engineering, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
| | - Ashley L Gibb
- Department of Physics, University of California , Berkeley, California 94720, United States
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
| | - Zhenglu Li
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
| | - S Matt Gilbert
- Department of Physics, University of California , Berkeley, California 94720, United States
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
| | - Chengyu Song
- The Molecular Foundry, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
| | - Steven G Louie
- Department of Physics, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
| | - Alex Zettl
- Department of Physics, University of California , Berkeley, California 94720, United States
- Department of Chemistry, University of California , Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
- Kavli Energy NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720 United States
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14
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Chejanovsky N, Rezai M, Paolucci F, Kim Y, Rendler T, Rouabeh W, Fávaro de Oliveira F, Herlinger P, Denisenko A, Yang S, Gerhardt I, Finkler A, Smet JH, Wrachtrup J. Structural Attributes and Photodynamics of Visible Spectrum Quantum Emitters in Hexagonal Boron Nitride. NANO LETTERS 2016; 16:7037-7045. [PMID: 27700104 DOI: 10.1021/acs.nanolett.6b03268] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Newly discovered van der Waals materials like MoS2, WSe2, hexagonal boron nitride (h-BN), and recently C2N have sparked intensive research to unveil the quantum behavior associated with their 2D structure. Of great interest are 2D materials that host single quantum emitters. h-BN, with a band gap of 5.95 eV, has been shown to host single quantum emitters which are stable at room temperature in the UV and visible spectral range. In this paper we investigate correlations between h-BN structural features and emitter location from bulk down to the monolayer at room temperature. We demonstrate that chemical etching and ion irradiation can generate emitters in h-BN. We analyze the emitters' spectral features and show that they are dominated by the interaction of their electronic transition with a single Raman active mode of h-BN. Photodynamics analysis reveals diverse rates between the electronic states of the emitter. The emitters show excellent photo stability even under ambient conditions and in monolayers. Comparing the excitation polarization between different emitters unveils a connection between defect orientation and the h-BN hexagonal structure. The sharp spectral features, color diversity, room-temperature stability, long-lived metastable states, ease of fabrication, proximity of the emitters to the environment, outstanding chemical stability, and biocompatibility of h-BN provide a completely new class of systems that can be used for sensing and quantum photonics applications.
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Affiliation(s)
- Nathan Chejanovsky
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Mohammad Rezai
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Federico Paolucci
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Youngwook Kim
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Torsten Rendler
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Wafa Rouabeh
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | | | - Patrick Herlinger
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Andrej Denisenko
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Sen Yang
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Ilja Gerhardt
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Amit Finkler
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
| | - Jurgen H Smet
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
| | - Jörg Wrachtrup
- 3. Physikalisches Institut, Universität Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart, Germany
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15
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Sutter E, Huang Y, Komsa HP, Ghorbani-Asl M, Krasheninnikov AV, Sutter P. Electron-Beam Induced Transformations of Layered Tin Dichalcogenides. NANO LETTERS 2016; 16:4410-4416. [PMID: 27336595 DOI: 10.1021/acs.nanolett.6b01541] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
By combining high-resolution transmission electron microscopy and associated analytical methods with first-principles calculations, we study the behavior of layered tin dichalcogenides under electron beam irradiation. We demonstrate that the controllable removal of chalcogen atoms due to electron irradiation, at both room and elevated temperatures, gives rise to transformations in the atomic structure of Sn-S and Sn-Se systems so that new phases with different properties can be induced. In particular, rhombohedral layered SnS2 and SnSe2 can be transformed via electron beam induced loss of chalcogen atoms into highly anisotropic orthorhombic layered SnS and SnSe. A striking dependence of the layer orientation of the resulting SnS-parallel to the layers of ultrathin SnS2 starting material, but slanted for transformations of thicker few-layer SnS2-is rationalized by a transformation pathway in which vacancies group into ordered S-vacancy lines, which convert via a Sn2S3 intermediate to SnS. Absence of a stable Sn2Se3 intermediate precludes this pathway for the selenides, hence SnSe2 always transforms into basal plane oriented SnSe. Our results provide microscopic insights into the transformation mechanism and show how irradiation can be used to tune the properties of layered tin chalcogenides for applications in electronics, catalysis, or energy storage.
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Affiliation(s)
- E Sutter
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Y Huang
- Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States
| | - H-P Komsa
- Department of Applied Physics, Aalto University , P.O. Box 11100, FI-00076 Aalto, Finland
| | - M Ghorbani-Asl
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf , 01314 Dresden, Germany
| | - A V Krasheninnikov
- Department of Applied Physics, Aalto University , P.O. Box 11100, FI-00076 Aalto, Finland
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf , 01314 Dresden, Germany
| | - P Sutter
- Department of Electrical and Computer Engineering, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
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16
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Liu Z, Tizei LHG, Sato Y, Lin YC, Yeh CH, Chiu PW, Terauchi M, Iijima S, Suenaga K. Postsynthesis of h-BN/Graphene Heterostructures Inside a STEM. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2016; 12:252-9. [PMID: 26618896 PMCID: PMC4738398 DOI: 10.1002/smll.201502408] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/01/2015] [Indexed: 05/25/2023]
Abstract
Combinations of 2D materials with different physical properties can form heterostructures with modified electrical, mechanical, magnetic, and optical properties. The direct observation of a lateral heterostructure synthesis is reported by epitaxial in-plane graphene growth from the step-edge of hexagonal BN (h-BN) within a scanning transmission electron microscope chamber. Residual hydrocarbon in the chamber is the carbon source. The growth interface between h-BN and graphene is atomically identified as largely N-C bonds. This postgrowth method can form graphene nanoribbons connecting two h-BN domains with different twisting angles, as well as isolated carbon islands with arbitrary shapes embedded in the h-BN layer. The electronic properties of the vertically stacked h-BN/graphene heterostructures are investigated by electron energy-loss spectroscopy (EELS). Low-loss EELS analysis of the dielectric response suggests a robust coupling effect between the graphene and h-BN layers.
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Affiliation(s)
- Zheng Liu
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Luiz H G Tizei
- Laboratoire de Physique des Solides, Université Paris-Sud, CNRS-UMR 8502, Orsay, 91405, France
| | - Yohei Sato
- Division of Electron Crystallography and Spectroscopy, Tohoku University, Sendai, 980-8577, Japan
| | - Yung-Chang Lin
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
| | - Chao-Hui Yeh
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Po-Wen Chiu
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu, 30013, Taiwan
| | - Masami Terauchi
- Division of Electron Crystallography and Spectroscopy, Tohoku University, Sendai, 980-8577, Japan
| | - Sumio Iijima
- Meijo University, Department of Materials Science and Engeering, Nagoya, 468-8502, Japan
| | - Kazu Suenaga
- Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, 305-8565, Japan
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17
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Single-atom electron energy loss spectroscopy of light elements. Nat Commun 2015; 6:7943. [PMID: 26228378 PMCID: PMC4532884 DOI: 10.1038/ncomms8943] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 06/27/2015] [Indexed: 12/28/2022] Open
Abstract
Light elements such as alkali metal (lithium, sodium) or halogen (fluorine, chlorine) are present in various substances and indeed play significant roles in our life. Although atomic behaviours of these elements are often a key to resolve chemical or biological activities, they are hardly visible in transmission electron microscope because of their smaller scattering power and higher knock-on probability. Here we propose a concept for detecting light atoms encaged in a nanospace by means of electron energy loss spectroscopy using inelastically scattered electrons. In this method, we demonstrate the single-atom detection of lithium, fluorine, sodium and chlorine with near-atomic precision, which is limited by the incident probe size, signal delocalization and atomic movement in nanospace. Moreover, chemical shifts of lithium K-edge have been successfully identified with various atomic configurations in one-dimensional lithium compounds. Light atoms are hardly visible through standard microscopy techniques, because of their smaller scattering power and higher knock-on probability. Here, the authors present an approach to probe light atoms by means of electron energy loss spectroscopy, relying on inelastically scattered electrons.
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