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Kato R, Moriyama T, Umakoshi T, Yano TA, Verma P. Ultrastable tip-enhanced hyperspectral optical nanoimaging for defect analysis of large-sized WS 2 layers. SCIENCE ADVANCES 2022; 8:eabo4021. [PMID: 35857514 PMCID: PMC9286508 DOI: 10.1126/sciadv.abo4021] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 06/03/2022] [Indexed: 05/25/2023]
Abstract
Optical nanoimaging techniques, such as tip-enhanced Raman spectroscopy (TERS), are nowadays indispensable for chemical and optical characterization in the entire field of nanotechnology and have been extensively used for various applications, such as visualization of nanoscale defects in two-dimensional (2D) materials. However, it is still challenging to investigate micrometer-sized sample with nanoscale spatial resolution because of severe limitation of measurement time due to drift of the experimental system. Here, we achieved long-duration TERS imaging of a micrometer-sized WS2 sample for 6 hours in a reproducible manner. Our ultrastable TERS system enabled to reveal the defect density on the surface of tungsten disulfide layers in large area equivalent to the device scale. It also helped us to detect rare defect-related optical signals from the sample. The present study paves ways to evaluate nanoscale defects of 2D materials in large area and to unveil remarkable optical and chemical properties of large-sized nanostructured materials.
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Affiliation(s)
- Ryo Kato
- Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan
- Institute of Post-LED Photonics, Tokushima University, 2-1 Minamijosanjima, Tokushima, Tokushima 770-8506, Japan
| | - Toki Moriyama
- Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan
| | - Takayuki Umakoshi
- Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, Suita, Osaka 565-0871, Japan
- PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Taka-aki Yano
- Institute of Post-LED Photonics, Tokushima University, 2-1 Minamijosanjima, Tokushima, Tokushima 770-8506, Japan
| | - Prabhat Verma
- Department of Applied Physics, Osaka University, Suita, Osaka 565-0871, Japan
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2
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van den Berg M, Moeinian A, Kobald A, Chen YT, Horneber A, Strehle S, Meixner AJ, Zhang D. Revealing the local crystallinity of single silicon core-shell nanowires using tip-enhanced Raman spectroscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:1147-1156. [PMID: 32802717 PMCID: PMC7404174 DOI: 10.3762/bjnano.11.99] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/16/2020] [Indexed: 05/26/2023]
Abstract
Tip-enhanced Raman spectroscopy is combined with polarization angle-resolved spectroscopy to investigate the nanometer-scale structural properties of core-shell silicon nanowires (crystalline Si core and amorphous Si shell), which were synthesized by platinum-catalyzed vapor-liquid-solid growth and silicon overcoating by thermal chemical vapor deposition. Local changes in the fraction of crystallinity in these silicon nanowires are characterized at an optical resolution of about 300 nm. Furthermore, we are able to resolve the variations in the intensity ratios of the Raman peaks of crystalline Si and amorphous Si by applying tip-enhanced Raman spectroscopy, at sample positions being 8 nm apart. The local crystallinity revealed using confocal Raman spectroscopy and tip-enhanced Raman spectroscopy agrees well with the high-resolution transmission electron microscopy images. Additionally, the polarizations of Raman scattering and the photoluminescence signal from the tip-sample nanogap are explored by combining polarization angle-resolved emission spectroscopy with tip-enhanced optical spectroscopy. Our work demonstrates the significant potential of resolving local structural properties of Si nanomaterials at the sub-10 nanometer scale using tip-enhanced Raman techniques.
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Affiliation(s)
- Marius van den Berg
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
| | - Ardeshir Moeinian
- Institute of Electronic Devices and Circuits, Ulm University, Albert-Einstein-Allee 45, Ulm, Germany
| | - Arne Kobald
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
| | - Yu-Ting Chen
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
| | - Anke Horneber
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
| | - Steffen Strehle
- Institute of Micro- and Nanotechnology, Technische Universität Ilmenau, Max-Planck-Ring 12, Ilmenau, Germany
| | - Alfred J Meixner
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
| | - Dai Zhang
- Institute of Physical and Theoretical Chemistry, Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
- Center for Light-Matter Interaction, Sensors & Analytics (LISA+), Eberhard Karls University of Tübingen, Auf der Morgenstelle 15, Tübingen, Germany
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Abstract
When molecules are assembled into an aggregate, their mutual dipole-dipole interaction leads to electronic eigenstates that are coherently delocalized over many molecules. Knowledge about these states is important to understand the optical and transfer properties of the aggregates. Optical spectroscopy, in principle, allows one to infer information on these eigenstates and about the interactions between the molecules. However, traditional optical techniques using an electromagnetic field which is uniform over the relevant size of the aggregate cannot access most of the excited states because of selection rules. We demonstrate that by using localized fields one can obtain information about these otherwise inaccessible states. As an example, we discuss in detail the case of local excitation via radiation from the apex of a metallic tip, which allows also scanning across the aggregate. The resulting spatially resolved spectra provide extensive information on the eigenenergies and wave functions. Finally we show that the technique will elucidate the anomalous temperature dependence of superradiance found recently for two-dimensional aggregates of the semiconductor PTCDA formed on a KCl surface.
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Affiliation(s)
- Xing Gao
- Max Planck Institute for the Physics of Complex Systems , Nöthnitzer Strasse 38 , D-01187 Dresden , Germany
| | - Alexander Eisfeld
- Max Planck Institute for the Physics of Complex Systems , Nöthnitzer Strasse 38 , D-01187 Dresden , Germany
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Tang X, van den Berg M, Gu E, Horneber A, Matt GJ, Osvet A, Meixner AJ, Zhang D, Brabec CJ. Local Observation of Phase Segregation in Mixed-Halide Perovskite. NANO LETTERS 2018; 18:2172-2178. [PMID: 29498866 DOI: 10.1021/acs.nanolett.8b00505] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mixed-halide perovskites have emerged as promising materials for optoelectronics due to their tunable band gap in the entire visible region. A challenge remains, however, in the photoinduced phase segregation, narrowing the band gap of mixed-halide perovskites under illumination thus restricting applications. Here, we use a combination of spatially resolved and bulk measurements to give an in-depth insight into this important yet unclear phenomenon. We demonstrate that photoinduced phase segregation in mixed-halide perovskites selectively occurs at the grain boundaries rather than within the grain centers by using shear-force scanning probe microscopy in combination with confocal optical spectroscopy. Such difference is further evidenced by light-biased bulk Fourier-transform photocurrent spectroscopy, which shows the iodine-rich domain as a minority phase coexisting with the homogeneously mixed phase during illumination. By mapping the surface potential of mixed-halide perovskites, we evidence the higher concentration of positive space charge near the grain boundary possibly provides the initial driving force for phase segregation, while entropic mixing dominates the reverse process. Our work offers detailed insight into the microscopic processes occurring at the boundary of crystalline perovskite grains and will support the development of better passivation strategies, ultimately allowing the processing of more environmentally stable perovskite films.
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Affiliation(s)
- Xiaofeng Tang
- Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering , Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstrasse 7 , Erlangen 91058 , Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT) , Paul-Gordan-Strasse 6 , Erlangen 91052 , Germany
| | - Marius van den Berg
- Institute of the Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 15 , Tübingen 72074 , Germany
| | - Ening Gu
- Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering , Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstrasse 7 , Erlangen 91058 , Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT) , Paul-Gordan-Strasse 6 , Erlangen 91052 , Germany
| | - Anke Horneber
- Institute of the Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 15 , Tübingen 72074 , Germany
| | - Gebhard J Matt
- Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering , Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstrasse 7 , Erlangen 91058 , Germany
| | - Andres Osvet
- Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering , Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstrasse 7 , Erlangen 91058 , Germany
| | - Alfred J Meixner
- Institute of the Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 15 , Tübingen 72074 , Germany
| | - Dai Zhang
- Institute of the Physical and Theoretical Chemistry , University of Tübingen , Auf der Morgenstelle 15 , Tübingen 72074 , Germany
| | - Christoph J Brabec
- Institute of Materials for Electronics and Energy Technology (I-MEET), Department of Materials Science and Engineering , Friedrich-Alexander-Universität Erlangen-Nürnberg , Martensstrasse 7 , Erlangen 91058 , Germany
- Bavarian Center for Applied Energy Research (ZAE Bayern) , Haberstrasse 2a , Erlangen 91058 , Germany
- Erlangen Graduate School in Advanced Optical Technologies (SAOT) , Paul-Gordan-Strasse 6 , Erlangen 91052 , Germany
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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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Martín Sabanés N, Ohto T, Andrienko D, Nagata Y, Domke KF. Electrochemical TERS Elucidates Potential‐Induced Molecular Reorientation of Adenine/Au(111). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/anie.201704460] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
| | - Tatsuhiko Ohto
- Graduate School of Engineering ScienceOsaka University 1-3 Machikaneyama Toyonaka 560-8531 Japan
| | - Denis Andrienko
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Katrin F. Domke
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
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Neff A, Niefind F, Abel B, Mannsfeld SCB, Siefermann KR. Imaging Nanoscale Morphology of Semiconducting Polymer Films with Photoemission Electron Microscopy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1701012. [PMID: 28513882 DOI: 10.1002/adma.201701012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 03/18/2017] [Indexed: 06/07/2023]
Abstract
Photoemission electron microscopy in combination with polarized laser light is presented as a tool permitting direct imaging of polymer-chain orientation and local degree of order in semicrystalline samples of semiconducting polymers, a promising class of materials for future electronics. The key advantages of this imaging tool are its nondestructive and fast measurements, straightforward data analysis, the low complexity of sample preparation, and the possibility of performing measurements on a broad variety of technologically relevant substrates. The high spatial resolution of the microscope provides insights into the nanoscale morphology, which is relevant for the material's performance in electronic devices.
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Affiliation(s)
- Andreas Neff
- Leibniz-Institut für Oberflächenmodifizierung (IOM), Chemical Department, Permoserstraße 15, 04318, Leipzig, Germany
| | - Falk Niefind
- Leibniz-Institut für Oberflächenmodifizierung (IOM), Chemical Department, Permoserstraße 15, 04318, Leipzig, Germany
| | - Bernd Abel
- Leibniz-Institut für Oberflächenmodifizierung (IOM), Chemical Department, Permoserstraße 15, 04318, Leipzig, Germany
| | - Stefan C B Mannsfeld
- Technische Universität Dresden, Center for Advancing Electronics Dresden (cfaed), Würzburger Str. 46, 01187, Dresden, Germany
| | - Katrin R Siefermann
- Leibniz-Institut für Oberflächenmodifizierung (IOM), Chemical Department, Permoserstraße 15, 04318, Leipzig, Germany
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8
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Martín Sabanés N, Ohto T, Andrienko D, Nagata Y, Domke KF. Electrochemical TERS Elucidates Potential‐Induced Molecular Reorientation of Adenine/Au(111). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704460] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Tatsuhiko Ohto
- Graduate School of Engineering ScienceOsaka University 1-3 Machikaneyama Toyonaka 560-8531 Japan
| | - Denis Andrienko
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Yuki Nagata
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
| | - Katrin F. Domke
- Max Planck Institute for Polymer Research Ackermannweg 10 55128 Mainz Germany
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