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Milekhin I, Anikin K, Kurus NN, Mansurov VG, Malin TV, Zhuravlev KS, Milekhin AG, Latyshev AV, Zahn DRT. Local phonon imaging of AlN nanostructures with nanoscale spatial resolution. NANOSCALE ADVANCES 2023; 5:2820-2830. [PMID: 37205283 PMCID: PMC10187024 DOI: 10.1039/d3na00054k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/13/2023] [Indexed: 05/21/2023]
Abstract
We demonstrate local phonon analysis of single AlN nanocrystals by two complementary imaging spectroscopic techniques: tip-enhanced Raman scattering (TERS) and nano-Fourier transform infrared (nano-FTIR) spectroscopy. Strong surface optical (SO) phonon modes appear in the TERS spectra with their intensities revealing a weak polarization dependence. The local electric field enhancement stemming from the plasmon mode of the TERS tip modifies the phonon response of the sample, making the SO mode dominate over other phonon modes. The TERS imaging allows the spatial localization of the SO mode to be visualized. We were able to probe the angle anisotropy on the SO phonon modes in AlN nanocrystals with nanoscale spatial resolution. The excitation geometry and the local nanostructure surface profile determine the frequency position of SO modes in nano-FTIR spectra. An analytical calculation explains the behaviour of SO mode frequencies vs. tip position with respect to the sample.
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Affiliation(s)
- Ilya Milekhin
- Semiconductor Physics, Chemnitz University of Technology D-09107 Chemnitz Germany
- Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), Chemnitz University of Technology Chemnitz Germany
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
- Novosibirsk State University Pirogov, 1 630090 Novosibirsk Russia
| | - Kirill Anikin
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
| | - Nina N Kurus
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
| | - Vladimir G Mansurov
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
| | - Timur V Malin
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
| | - Konstantin S Zhuravlev
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
| | - Alexander G Milekhin
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
- Novosibirsk State University Pirogov, 1 630090 Novosibirsk Russia
| | - Alexander V Latyshev
- A.V. Rzhanov Institute of Semiconductor Physics pr. Lavrentieva, 13 630090 Novosibirsk Russia
- Novosibirsk State University Pirogov, 1 630090 Novosibirsk Russia
| | - Dietrich R T Zahn
- Semiconductor Physics, Chemnitz University of Technology D-09107 Chemnitz Germany
- Center for Materials, Architectures, and Integration of Nanomembranes (MAIN), Chemnitz University of Technology Chemnitz Germany
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2
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Jeon N, Ruhstorfer D, Döblinger M, Matich S, Loitsch B, Koblmüller G, Lauhon L. Connecting Composition-Driven Faceting with Facet-Driven Composition Modulation in GaAs-AlGaAs Core-Shell Nanowires. NANO LETTERS 2018; 18:5179-5185. [PMID: 29995425 DOI: 10.1021/acs.nanolett.8b02104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ternary III-V alloys of tunable bandgap are a foundation for engineering advanced optoelectronic devices based on quantum-confined structures including quantum wells, nanowires, and dots. In this context, core-shell nanowires provide useful geometric degrees of freedom in heterostructure design, but alloy segregation is frequently observed in epitaxial shells even in the absence of interface strain. High-resolution scanning transmission electron microscopy and laser-assisted atom probe tomography were used to investigate the driving forces of segregation in nonplanar GaAs-AlGaAs core-shell nanowires. Growth-temperature-dependent studies of Al-rich regions growing on radial {112} nanofacets suggest that facet-dependent bonding preferences drive the enrichment, rather than kinetically limited diffusion. Observations of the distinct interface faceting when pure AlAs is grown on GaAs confirm the preferential bonding of Al on {112} facets over {110} facets, explaining the decomposition behavior. Furthermore, three-dimensional composition profiles generated by atom probe tomography reveal the presence of Al-rich nanorings perpendicular to the growth direction; correlated electron microscopy shows that short zincblende insertions in a nanowire segment with predominantly wurtzite structure are enriched in Al, demonstrating that crystal phase engineering can be used to modulate composition. The findings suggest strategies to limit alloy decomposition and promote new geometries of quantum confined structures.
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Affiliation(s)
- Nari Jeon
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Daniel Ruhstorfer
- Walter Schottky Institut, Physik Department, and Center for Nanotechnology and Nanomaterials , Technische Universität München , Garching 85748 , Germany
| | - Markus Döblinger
- Department of Chemistry , Ludwig-Maximilians-Universität München , Munich 81377 , Germany
| | - Sonja Matich
- Walter Schottky Institut, Physik Department, and Center for Nanotechnology and Nanomaterials , Technische Universität München , Garching 85748 , Germany
| | - Bernhard Loitsch
- Walter Schottky Institut, Physik Department, and Center for Nanotechnology and Nanomaterials , Technische Universität München , Garching 85748 , Germany
| | - Gregor Koblmüller
- Walter Schottky Institut, Physik Department, and Center for Nanotechnology and Nanomaterials , Technische Universität München , Garching 85748 , Germany
| | - Lincoln Lauhon
- Department of Materials Science and Engineering , Northwestern University , Evanston , Illinois 60208 , United States
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3
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Deckert-Gaudig T, Taguchi A, Kawata S, Deckert V. Tip-enhanced Raman spectroscopy - from early developments to recent advances. Chem Soc Rev 2018. [PMID: 28640306 DOI: 10.1039/c7cs00209b] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An analytical technique operating at the nanoscale must be flexible regarding variable experimental conditions while ideally also being highly specific, extremely sensitive, and spatially confined. In this respect, tip-enhanced Raman scattering (TERS) has been demonstrated to be ideally suited to, e.g., elucidating chemical reaction mechanisms, determining the distribution of components and identifying and localizing specific molecular structures at the nanometre scale. TERS combines the specificity of Raman spectroscopy with the high spatial resolution of scanning probe microscopies by utilizing plasmonic nanostructures to confine the incident electromagnetic field and increase it by many orders of magnitude. Consequently, molecular structure information in the optical near field that is inaccessible to other optical microscopy methods can be obtained. In this general review, the development of this still-young technique, from early experiments to recent achievements concerning inorganic, organic, and biological materials, is addressed. Accordingly, the technical developments necessary for stable and reliable AFM- and STM-based TERS experiments, together with the specific properties of the instruments under different conditions, are reviewed. The review also highlights selected experiments illustrating the capabilities of this emerging technique, the number of users of which has steadily increased since its inception in 2000. Finally, an assessment of the frontiers and new concepts of TERS, which aim towards rendering it a general and widely applicable technique that combines the highest possible lateral resolution and extreme sensitivity, is provided.
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Poliani E, Wagner MR, Vierck A, Herziger F, Nenstiel C, Gannott F, Schweiger M, Fritze S, Dadgar A, Zaumseil J, Krost A, Hoffmann A, Maultzsch J. Breakdown of Far-Field Raman Selection Rules by Light-Plasmon Coupling Demonstrated by Tip-Enhanced Raman Scattering. J Phys Chem Lett 2017; 8:5462-5471. [PMID: 29064705 DOI: 10.1021/acs.jpclett.7b02505] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present an experimental study on the near-field light-matter interaction by tip-enhanced Raman scattering (TERS) with polarized light in three different materials: germanium-doped gallium nitride (GaN), graphene, and carbon nanotubes. We investigate the dependence of the TERS signal on the incoming light polarization and on the sample carrier concentration, as well as the Raman selection rules in the near-field. We explain the experimental data with a tentative quantum mechanical interpretation, which takes into account the role of plasmon polaritons, and the associated evanescent field. The driving force for the breakdown of the classical Raman selection rules in TERS is caused by photon tunneling through the perturbation of the evanescent field, with the consequent polariton annihilation. Predictions based on this quantum mechanical approach are in good agreement with the experimental data, which are shown to be independent of incoming light polarization, leading to new Raman selection rules for TERS.
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Affiliation(s)
- Emanuele Poliani
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Markus R Wagner
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Asmus Vierck
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Felix Herziger
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Christian Nenstiel
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Florentina Gannott
- Nanomaterials for Optoelectronics Group, Institute of Polymer Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
| | - Manuel Schweiger
- Nanomaterials for Optoelectronics Group, Institute of Polymer Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
| | - Stephanie Fritze
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg , 39106 Magdeburg, Germany
| | - Armin Dadgar
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg , 39106 Magdeburg, Germany
| | - Jana Zaumseil
- Physikalisch-Chemisches Institut Lehrstuhl für Angewandte Physikalische Chemie, Ruprecht-Karls-Universität Heidelberg , 69117 Heidelberg, Germany
| | - Alois Krost
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg , 39106 Magdeburg, Germany
| | - Axel Hoffmann
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
| | - Janina Maultzsch
- Institut für Festkörperphysik, Technische Universität Berlin , 10623 Berlin, Germany
- Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
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Gruber J, Zhou XW, Jones RE, Lee SR, Tucker GJ. Molecular dynamics studies of defect formation during heteroepitaxial growth of InGaN alloys on (0001) GaN surfaces. JOURNAL OF APPLIED PHYSICS 2017; 121:195301. [PMID: 28611488 PMCID: PMC5432374 DOI: 10.1063/1.4983066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/20/2017] [Indexed: 05/14/2023]
Abstract
We investigate the formation of extended defects during molecular-dynamics (MD) simulations of GaN and InGaN growth on (0001) and ([Formula: see text]) wurtzite-GaN surfaces. The simulated growths are conducted on an atypically large scale by sequentially injecting nearly a million individual vapor-phase atoms towards a fixed GaN surface; we apply time-and-position-dependent boundary constraints that vary the ensemble treatments of the vapor-phase, the near-surface solid-phase, and the bulk-like regions of the growing layer. The simulations employ newly optimized Stillinger-Weber In-Ga-N-system potentials, wherein multiple binary and ternary structures are included in the underlying density-functional-theory training sets, allowing improved treatment of In-Ga-related atomic interactions. To examine the effect of growth conditions, we study a matrix of >30 different MD-growth simulations for a range of In x Ga 1-x N-alloy compositions (0 ≤ x ≤ 0.4) and homologous growth temperatures [0.50 ≤ T/T*m (x) ≤ 0.90], where T*m (x) is the simulated melting point. Growths conducted on polar (0001) GaN substrates exhibit the formation of various extended defects including stacking faults/polymorphism, associated domain boundaries, surface roughness, dislocations, and voids. In contrast, selected growths conducted on semi-polar ([Formula: see text]) GaN, where the wurtzite-phase stacking sequence is revealed at the surface, exhibit the formation of far fewer stacking faults. We discuss variations in the defect formation with the MD growth conditions, and we compare the resulting simulated films to existing experimental observations in InGaN/GaN. While the palette of defects observed by MD closely resembles those observed in the past experiments, further work is needed to achieve truly predictive large-scale simulations of InGaN/GaN crystal growth using MD methodologies.
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Affiliation(s)
| | - X W Zhou
- Mechanics of Materials Department, Sandia National Laboratories, Livermore, California 94550, USA
| | - R E Jones
- Mechanics of Materials Department, Sandia National Laboratories, Livermore, California 94550, USA
| | - S R Lee
- Advanced Materials Sciences Department, Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | - G J Tucker
- Materials Science and Engineering Department, Drexel University, Philadelphia, Pennsylvania 19104, USA
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6
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Kawata S, Ichimura T, Taguchi A, Kumamoto Y. Nano-Raman Scattering Microscopy: Resolution and Enhancement. Chem Rev 2017; 117:4983-5001. [PMID: 28337915 DOI: 10.1021/acs.chemrev.6b00560] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Raman scattering microscopy is becoming one of the hot topics in analytical microscopy as a tool for analyzing advanced nanomaterials, such as biomolecules in a live cell for the study of cellular dynamics, semiconductor devices for characterizing strain distribution and contamination, and nanocarbons and nano-2D materials. In this paper, we review the recent progress in the development of Raman scattering microscopy from the viewpoint of spatial resolution and scattering efficiency. To overcome the extremely small cross section of Raman scattering, we discuss three approaches for the enhancement of scattering efficiency and show that the scattering enhancement synergistically increases the spatial resolution. We discuss the mechanisms of tip-enhanced Raman scattering, deep-UV resonant Raman scattering, and coherent nonlinear Raman scattering for micro- and nanoscope applications. The combinations of these three approaches are also shown as nanometer-resolution Raman scattering microscopy. The critical issues of the structures, materials, and reproducibility of tips and three-dimensionality for TERS; photodegradation for resonant Raman scattering; and laser availability for coherent nonlinear Raman scattering are also discussed.
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Affiliation(s)
- Satoshi Kawata
- Department of Applied Physics, Osaka University , Osaka 565-0871, Japan
| | - Taro Ichimura
- Quantitative Biology Center, RIKEN , Osaka 565-0874, Japan
| | - Atsushi Taguchi
- Department of Applied Physics, Osaka University , Osaka 565-0871, Japan
| | - Yasuaki Kumamoto
- Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine , Kyoto 602-8566, Japan
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7
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Abstract
Tip-enhanced Raman spectroscopy (TERS), a combination of Raman spectroscopy and apertureless near-field scanning optical microscopy using a metallic tip which resonates with the local mode of the surface plasmon, can provide a high-sensitive and high-spatial-resolution optical analytical approach. The basic principle of TERS, common experimental setups, various SPM technologies, and excitation/collection configurations are introduced as well as recent research progress with respect to TERS.
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Affiliation(s)
- Zhenglong Zhang
- School of Mathematics and Physics, University of Science and Technology Beijing , Beijing, 100083, People's Republic of China.,School of Physics and Information Technology, Shaanxi Normal University , Xi'an, 710062, People's Republic of China.,Leibniz Institute of Photonic Technology , Albert-Einstein-Strasse 9, 07745 Jena, Germany
| | - Shaoxiang Sheng
- Beijing National Laboratory for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
| | - Rongming Wang
- School of Mathematics and Physics, University of Science and Technology Beijing , Beijing, 100083, People's Republic of China
| | - Mengtao Sun
- School of Mathematics and Physics, University of Science and Technology Beijing , Beijing, 100083, People's Republic of China.,Beijing National Laboratory for Condensed Matter Physics, Beijing Key Laboratory for Nanomaterials and Nanodevices, Institute of Physics, Chinese Academy of Sciences , Beijing, 100190, People's Republic of China
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8
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Langelüddecke L, Singh P, Deckert V. Exploring the Nanoscale: Fifteen Years of Tip-Enhanced Raman Spectroscopy. APPLIED SPECTROSCOPY 2015; 69:1357-71. [PMID: 26554759 DOI: 10.1366/15-08014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Spectroscopic methods with high spatial resolution are essential to understand the physical and chemical properties of nanoscale materials including biological and chemical materials. Tip-enhanced Raman spectroscopy (TERS) is a combination of surface-enhanced Raman spectroscopy (SERS) and scanning probe microscopy (SPM), which can provide high-resolution topographic and spectral information simultaneously below the diffraction limit of light. Even examples of sub-nanometer resolution have been demonstrated. This review intends to give an introduction to TERS, focusing on its basic principle and the experimental setup, the strengths followed by recent applications, developments, and perspectives in this field.
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Affiliation(s)
- Lucas Langelüddecke
- Institute of Physical Chemistry and Abbe Center of Photonics, University of Jena, Helmholtzweg 4, D-07743 Jena, Germany
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9
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Boujday S, de la Chapelle ML, Srajer J, Knoll W. Enhanced Vibrational Spectroscopies as Tools for Small Molecule Biosensing. SENSORS 2015; 15:21239-64. [PMID: 26343666 PMCID: PMC4610423 DOI: 10.3390/s150921239] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 08/06/2015] [Accepted: 08/10/2015] [Indexed: 12/28/2022]
Abstract
In this short summary we summarize some of the latest developments in vibrational spectroscopic tools applied for the sensing of (small) molecules and biomolecules in a label-free mode of operation. We first introduce various concepts for the enhancement of InfraRed spectroscopic techniques, including the principles of Attenuated Total Reflection InfraRed (ATR-IR), (phase-modulated) InfraRed Reflection Absorption Spectroscopy (IRRAS/PM-IRRAS), and Surface Enhanced Infrared Reflection Absorption Spectroscopy (SEIRAS). Particular attention is put on the use of novel nanostructured substrates that allow for the excitation of propagating and localized surface plasmon modes aimed at operating additional enhancement mechanisms. This is then be complemented by the description of the latest development in Surface- and Tip-Enhanced Raman Spectroscopies, again with an emphasis on the detection of small molecules or bioanalytes.
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Affiliation(s)
- Souhir Boujday
- UPMC Univ Paris 6, UMR CNRS 7197, Laboratoire de Réactivité de Surface, 4 Place Jussieu, F-75005 Paris, France.
- CNRS, UMR 7197, Laboratoire de Réactivité de Surface, F-75005 Paris, France.
- Center for Biomimetic Sensor Science, 50 Nanyang Drive, Singapore 637553, Singapore.
| | - Marc Lamy de la Chapelle
- Université Paris 13, Sorbonne Paris Cité, Laboratoire CSPBAT, CNRS, (UMR 7244), 74 rue Marcel Cachin, F-93017 Bobigny, France.
| | - Johannes Srajer
- AIT Austrian Institute of Technology, Donau City Strasse 1, A-1220 Vienna, Austria.
| | - Wolfgang Knoll
- Center for Biomimetic Sensor Science, 50 Nanyang Drive, Singapore 637553, Singapore.
- AIT Austrian Institute of Technology, Donau City Strasse 1, A-1220 Vienna, Austria.
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10
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Sharma G, Deckert-Gaudig T, Deckert V. Tip-enhanced Raman scattering--Targeting structure-specific surface characterization for biomedical samples. Adv Drug Deliv Rev 2015; 89:42-56. [PMID: 26130490 DOI: 10.1016/j.addr.2015.06.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/11/2015] [Accepted: 06/19/2015] [Indexed: 11/16/2022]
Abstract
Tip-enhanced Raman scattering (TERS) has become a powerful tool for nanoscale structural analysis for several branches of organic, inorganic, and biological chemistry. This highly sensitive technique enables molecular characterization with a lateral resolution far beyond Abbe's diffraction limit and correlates structural and topographic information on a nanometer scale. In this review, the current experimental concepts with respect to their strengths and obstacles are introduced and discussed. A further focus was set to biochemistry comprising applications like nucleic acids, proteins, and microorganisms, thus demonstrating the potential use towards the pharmaceutically relevant challenges where nanometer resolution is required.
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Affiliation(s)
- Gaurav Sharma
- Institute for Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, Friedrich Schiller-University Jena, D-07743 Jena, Germany
| | - Tanja Deckert-Gaudig
- Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745 Jena, Germany
| | - Volker Deckert
- Institute for Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, Friedrich Schiller-University Jena, D-07743 Jena, Germany; Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, D-07745 Jena, Germany.
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11
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Hallam T, Shakouri A, Poliani E, Rooney AP, Ivanov I, Potie A, Taylor HK, Bonn M, Turchinovich D, Haigh SJ, Maultzsch J, Duesberg GS. Controlled folding of graphene: GraFold printing. NANO LETTERS 2015; 15:857-863. [PMID: 25539448 DOI: 10.1021/nl503460p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We have used elastomeric stamps with periodically varying adhesive properties to introduce structure and print folded graphene films. The structure of the induced folds is investigated with scanning probe techniques, high-resolution electron-microscopy, and tip-enhanced Raman spectroscopy. Furthermore, a finite element model is developed to show the fold formation process. Terahertz spectroscopy reveals induced anisotropy of carrier mobility along, and perpendicular to, the graphene folds. Graphene fold printing is a new technique which allows for significant modification of the properties of 2D materials without damaging or chemically modifying them.
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Affiliation(s)
- Toby Hallam
- Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN) and Advanced Materials BioEngineering Research Centre (AMBER), and ∇School of Chemistry, Trinity College , Dublin 2, Ireland
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12
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Poyser CL, Akimov AV, Campion RP, Kent AJ. Coherent phonon optics in a chip with an electrically controlled active device. Sci Rep 2015; 5:8279. [PMID: 25652241 PMCID: PMC4317685 DOI: 10.1038/srep08279] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 01/06/2015] [Indexed: 11/10/2022] Open
Abstract
Phonon optics concerns operations with high-frequency acoustic waves in solid media in a similar way to how traditional optics operates with the light beams (i.e. photons). Phonon optics experiments with coherent terahertz and sub-terahertz phonons promise a revolution in various technical applications related to high-frequency acoustics, imaging, and heat transport. Previously, phonon optics used passive methods for manipulations with propagating phonon beams that did not enable their external control. Here we fabricate a phononic chip, which includes a generator of coherent monochromatic phonons with frequency 378 GHz, a sensitive coherent phonon detector, and an active layer: a doped semiconductor superlattice, with electrical contacts, inserted into the phonon propagation path. In the experiments, we demonstrate the modulation of the coherent phonon flux by an external electrical bias applied to the active layer. Phonon optics using external control broadens the spectrum of prospective applications of phononics on the nanometer scale.
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Affiliation(s)
- Caroline L Poyser
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Andrey V Akimov
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Richard P Campion
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Anthony J Kent
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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13
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Sarau G, Heilmann M, Latzel M, Christiansen S. Disentangling the effects of nanoscale structural variations on the light emission wavelength of single nano-emitters: InGaN/GaN multiquantum well nano-LEDs for a case study. NANOSCALE 2014; 6:11953-11962. [PMID: 25178052 DOI: 10.1039/c4nr02939a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The scattering in the light emission wavelength of semiconductor nano-emitters assigned to nanoscale variations in strain, thickness, and composition is critical in current and novel nanotechnologies from highly efficient light sources to photovoltaics. Here, we present a correlated experimental and theoretical study of single nanorod light emitting diodes (nano-LEDs) based on InGaN/GaN multiquantum wells to separate the contributions of these intrinsic fluctuations. Cathodoluminescence measurements show that nano-LEDs with identical strain states probed by non-resonant micro-Raman spectroscopy can radiate light at different wavelengths. The deviations in the measured optical transitions agree very well with band profile calculations for quantum well thicknesses of 2.07-2.72 nm and In fractions of 17.5-19.5% tightly enclosing the growth values. The nanorod surface roughness controls the appearance of surface optical phonon modes with direct implications on the design of phonon assisted nano-LED devices. This work establishes a new, simple, and powerful methodology for fundamental understanding as well as quantitative analysis of the strain - light emission relationship and surface-related phenomena in the emerging field of nano-emitters.
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Affiliation(s)
- George Sarau
- Max Planck Institute for the Science of Light, Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
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14
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Lavenus P, Messanvi A, Rigutti L, De Luna Bugallo A, Zhang H, Bayle F, Julien FH, Eymery J, Durand C, Tchernycheva M. Experimental and theoretical analysis of transport properties of core-shell wire light emitting diodes probed by electron beam induced current microscopy. NANOTECHNOLOGY 2014; 25:255201. [PMID: 24897006 DOI: 10.1088/0957-4484/25/25/255201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We report a systematic experimental and theoretical investigation of core-shell InGaN/GaN single wire light-emitting diodes (LEDs) using electron beam induced current (EBIC) microscopy. The wires were grown by catalyst-free MOVPE and processed into single wire LEDs using electron beam lithography on dispersed wires. The influence of the acceleration voltage and of the applied bias on the EBIC maps was investigated. We show that the EBIC maps provide information both on the minority carrier effects (i.e. on the local p-n junction collection efficiency) and on the majority carrier effects (i.e. the transport efficiency from the excited region toward the contacts). Because of a finite core and shell resistance a non-negligible current redistribution into the p-n junction takes place during the majority carrier transport. A theoretical model for transport in a core-shell wire is developed, allowing to explain the dependence of the EBIC profiles on the experimental parameters (the electron beam acceleration voltage and the bias applied on the device) and on the structural parameters of the wire (core and shell resistance, shunt resistance, etc). Comparison between simulated and experimental profiles provides valuable information concerning the structure inhomogeneities and gives insight into the wire electrical parameters.
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Affiliation(s)
- P Lavenus
- Institut d'Electronique Fondamentale, UMR 8622 CNRS, Université Paris Sud XI, 91405 Orsay cedex, France
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Rigutti L, Blum I, Shinde D, Hernández-Maldonado D, Lefebvre W, Houard J, Vurpillot F, Vella A, Tchernycheva M, Durand C, Eymery J, Deconihout B. Correlation of microphotoluminescence spectroscopy, scanning transmission electron microscopy, and atom probe tomography on a single nano-object containing an InGaN/GaN multiquantum well system. NANO LETTERS 2014; 14:107-114. [PMID: 24397602 DOI: 10.1021/nl4034768] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A single nanoscale object containing a set of InGaN/GaN nonpolar multiple-quantum wells has been analyzed by microphotoluminescence spectroscopy (μPL), high-resolution scanning transmission electron microscopy (HR-STEM) and atom probe tomography (APT). The correlated measurements constitute a rich and coherent set of data supporting the interpretation that the observed μPL narrow emission lines, polarized perpendicularly to the crystal c-axis and with energies in the interval 2.9-3.3 eV, are related to exciton states localized in potential minima induced by the irregular 3D In distribution within the quantum well (QW) planes. This novel method opens up interesting perspectives, as it will be possible to apply it on a wide class of quantum confining emitters and nano-objects.
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Affiliation(s)
- Lorenzo Rigutti
- Groupe de Physique des Matériaux, UMR CNRS 6634, Normandie University, University of Rouen and INSA Rouen , 76801 St. Etienne du Rouvray, France
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