Two-dimensional (2D) materials such as transition metal dichalcogenides (TMDs) are receiving increasing attention due to their unique optical and electronic properties. Their possible applications include the production of transistors, photo detectors, light emitting diodes (LEDs) and photovoltaic cells. In order to produce high-quality devices, synthesis processes must be evaluated efficiently. Thus, non-destructive imaging techniques are required for monitoring crystal properties and features such as grain boundaries, layer number, defect density, doping and strain fields.
In our new application note, we present a series of measurements of CVD-grown mono-layer molybdenum disulfide (MoS2), which illustrate the advantages of correlative Raman, second harmonic generation (SHG) and photoluminescence (PL) microscopy for investigating TMDs. All measurements were performed at the same area of interest using a WITec alpha300 microscope equipped with a 532 nm laser for Raman and PL imaging and a picosecond-pulsed 1064 nm laser for SHG excitation.
Strain fields in the crystal were visualized by Raman and PL imaging, as both the frequency of the E2g Raman mode (upper left image) and the wavelength of the PL signal (lower left image) were red-shifted in the same areas. Rim effects around the border of the MoS2 flake were clearly visible in the PL image (lower left image), as well as in the image of the A1g Raman mode (see the attached application note).
SHG microscopy is sensitive to changes in crystal orientation and symmetry and visualized grain boundaries in the MoS2 flake (upper right picture). Additionally, polarization-dependent SHG measurements can identify the crystal orientation and reveal strain fields. To this end, the excitation polarization is rotated while recording the intensity of the SHG signal component that has the same polarization as the incident light. Polarization series were recorded in a fully automated manner at three positions of the MoS2 flake (lower right picture). The distinct patterns observed indicate different strain levels.
Correlative Raman, PL and SHG imaging yields complementary and consistent information for characterizing single-layer TMD crystals by visualizing features of the crystal structure, such as grain boundaries or strain fields, without damaging the sample.
For more details, including further pictures and references, please download our 2-page application note on correlative high-resolution imaging of MoS2.
Raman imaging is a non-destructive tool for evaluating the quality of 2D materials as strain, doping, defects and layer number can be assessed. These two large-area Raman images visualize defect density (top) and strain fields (bottom) in a CVD-grown graphene flake at high spatial resolution (100 nm per pixel). They were acquired using the fully automated Raman microscope alpha300 apyron equipped with a 532 nm laser for excitation and TrueSurface for focus stabilization.
The upper Raman image is color-coded according to the intensity of the D-band in the recorded Raman spectra. It visualizes crystal defects, as the D-band intensity depends on the defect density in the carbon lattice. The observed width of the fine structures is very close to the diffraction limited lateral resolution achievable with 532 nm excitation, demonstrating the microscope’s high performance.
The lower Raman image is color-coded according to the peak position of the 2D-band, which was quantified by a Pseudo-Voigt fit. The image visualizes local strain/doping effects, as the frequency of the 2D-band is influenced by local strain and, to a lesser extent, by doping.
These examples offer conclusive proof that with an advanced and highly sensitive system, Raman imaging alone can provide access to the finest details of graphene crystal properties.
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A paper just published in the Journal of Biophotonics describes how Raman spectoscopy can enable the detection of RNA viruses in human saliva. Dr. Amit Dutt's group at the Tata Memorial Centre, based in Mumbai, obtained raw data with a WITec Raman microscope and carried out statistical analysis to find a set of 65 Raman spectral features that positively identified the presence or absence of viruses in a sample.
The analysis could be performed in less than a minute without adding a reagent to increase the signal. Their signal set was able to achieve 92.5% sensitivity and 88.8% specificity.
“This conceptual framework to detect RNA viruses in saliva could form the basis for field application of Raman Spectroscopy in managing viral outbreaks, such as the ongoing COVID-19 pandemic,” said the researchers.
Increased capacity required to meet growing demand for Raman imaging microscopes
June 10th, 2020
WITec GmbH, the technology leader in correlative Raman microscopy, is expanding its headquarters building in Ulm.
The new addition will offer more space for production and quality assurance, laboratories for development and customer demonstrations or sample measurements, larger conference rooms and greater logistical capability. When complete, the new addition will double the amount of space available at WITec’s core location.
“It was time to expand,” says Joachim Koenen, Co-founder and Managing Director of WITec. “We made advanced Raman imaging much more accessible by simplifying operation through our user-interface and extensive automation. The scientific community and marketplace have reacted very positively to these developments. As more researchers put our instruments in their labs, the word got out, and now we need the increased production capacity.”
WITec’s current headquarters was completed in 2009. Its design reflects the modularity and versatility of the scientific instruments produced within. An open and light-filled interior provides an environment for employees that is conducive to the exchange of ideas. Research and development, sales, applications, production, marketing, administration, technical service and logistics teams all work together hand-in-hand. This greatly contributes to WITec’s vaunted technological agility and preserves its innovative spirit.
As described by Olaf Hollricher, Co-founder and Managing Director of R&D at WITec, “Our headquarters was purpose-built to encourage cross-departmental interaction, from development through shipping, and it’s had a very positive effect on the dynamics and performance of our company. The new expansion will allow us to scale up while adhering to this concept.”
Construction of the new addition will continue through 2020 with an anticipated opening toward the end of 2021.
- WITec New Building Expansion Rendering (3.7 MB)
- Press Release - New Building Expansion - English (DOCX) (442 KB)
- Press Release - New Building Expansion - German (DOCX) (444 KB)
WITec has created a new portal for instructional video content on our company website. It provides direct access to comprehensive tutorials and measurement demonstrations along with links to archived on-demand presentations.
As many scientists have recently increased their use of web-based resources to keep current with the latest in research techniques and technology, we’ve decided to consolidate our online webcast offerings in one point of entry. From the comfort of home offices, the many forms and applications of Raman imaging and correlative microscopy can be viewed at your convenience. Please check back regularly for updates as we continue to expand our webinar library.
WITec Reveals New Generation alpha300 apyron - Automated Raman Imaging Microscope with AutoBeam™ Technology.
Self-aligning, self-optimizing system keeps the focus on results.
April 28th, 2020
WITec GmbH, pioneer of Raman imaging and correlative microscopy, establishes the next level of automation and user-friendliness with the introduction of the new alpha300 apyron. Its AutoBeam technology unlocks the full potential of WITec’s industry-leading alpha300 series. The alpha300 apyron’s entirely new optical, analytical and remote operation capabilities mark the furthest advance yet in speed, sensitivity and resolution.
The alpha300 apyron can self-align and self-calibrate, which substantially reduces the researcher’s experimental workload by requiring less user input, enhancing reproducibility and eliminating potential sources of error. This is made possible by a complete set of WITec’s AutoBeam opto-mechanical components, a new and versatile tool kit that can be configured to create the perfect experimental setup for every investigation.
New functionalities provided by AutoBeam modules include polarization-dependent measurements with motorized polarizer and analyzer rotation, push-button spectrometer connection and signal maximization, and automated adjustment of both iris diaphragms. Software-driven automation also allows the alpha300 apyron to be operated completely remotely, whether in an environmental enclosure such as a glove box, or from another location.
According to Olaf Hollricher, Co-founder and Managing Director of Research and Development at WITec, “The alpha300 apyron, with its AutoBeam tool kit, is the culmination of our efforts to fully automate the Raman imaging process. It allows remote control, even from home, and can self-optimize for every measurement so researchers always get the best possible results.”
Available with a wide variety of excitation wavelengths from the ultraviolet through the visible into the near infrared, alpha300 apyron microscopes can be equipped with up to three ultra-high throughput WITec UHTS spectrometers and their accompanying range of detectors. Raman imaging and correlative measurements are defined, executed, saved and evaluated with WITec’s Suite FIVE software and intuitive EasyLink handheld controller.
WITec began automating Raman imaging measurements with the first generation apyron. Its advanced technology was introduced to the alpha300 line in stages of spiral development. The new consolidated alpha300 series is a continuous spectrum, from the entry-level access up to the flagship apyron. They all share the same rock-solid stability, fiber-based flexibility and integrated software environment.
As described by Joachim Koenen, Co-founder and Managing Director of WITec, “Many cutting-edge automated features of the apyron have made their way into the alpha300 line of microscopes over the past five years. As we developed new optical capabilities and hardware, they were built to a common standard. Now someone can configure an access, an apyron, or anything in between to meet the specific requirements of their research, even as it evolves.”
The user-friendliness of the alpha300 apyron makes advanced confocal Raman imaging accessible to researchers of all experience levels and fields of application. Scientists working in materials science, environmental science and microparticle analysis, life science, food science, geology, pharmaceutics and many other fields will benefit from automated alignment routines that provide consistently optimized performance. The alpha300 apyron accelerates both the experimental setup and subsequent measurement workflow.
You can find more information about the new alpha300 apyron here:
- WITec alpha300 apyron product picture (2.8 MB)
- Press Release alpha300 apyron English (DOCX) (268 KB)
- Press Release alpha300 apyron German (DOCX) (213 KB)
Every year, the WITec Paper Award competition recognizes three exceptional peer-reviewed publications that feature results acquired with a WITec microscope. A record number of 113 publications was submitted this year, in a clear demonstration of the power of Raman imaging for diverse fields of application such as cancer research, electrochemistry, semiconductor research, geology and microplastics research, to name only a few. WITec thanks all participants for their outstanding contributions from all over the world. The Paper Awards 2020 go to researchers from Japan, Poland and Austria and acknowledge impressive studies and methodologies from the fields of electrochemistry, biomedicine and polymer science, respectively.
- GOLD: Ankur Baliyan and Hideto Imai (2019) Machine Learning based Analytical Framework for Automatic Hyperspectral Raman Analysis of Lithium-ion Battery Electrodes. Scientific Reports 9: 18241. doi.org/10.1038/s41598-019-54770-2
- SILVER: Ewelina Wiercigroch, Elzbieta Stepula, Lukasz Mateuszuk, Yuying Zhang, Malgorzata Baranska, Stefan Chlopicki, Sebastian Schlücker and Kamilla Malek (2019) ImmunoSERS Microscopy for the Detection of Smooth Muscle Cells in Atherosclerotic Plaques. Biosensors and Bioelectronics 133: 79-85. doi.org/10.1016/j.bios.2019.02.068
- BRONZE: Ruth Schmidt, Harald Fitzek, Manfred Nachtnebel, Claudia Mayrhofer, Hartmuth Schröttner and Armin Zankel (2019) The Combination of Electron Microscopy, Raman Microscopy and Energy Dispersive X-Ray Spectroscopy for the Investigation of Polymeric Materials. Macromolecular Symposia 384: 1800237. doi.org/10.1002/masy.201800237
For a list of all previous Paper Award winners, please visit www.witec.de/paper-award.
The Paper Award GOLD: Automated quality control of lithium-ion batteries
Lithium-ion batteries (LIBs) provide the power for most electric devices that we use every day, such as cell phones, tablets and laptops. Their development was honored with the Nobel Prize in Chemistry last year. Automated real-time quality control of LIB materials is necessary for industrial research and production. Ankur Baliyan and Hideto Imai from Nissan Arc. (Yokosuka, Japan) win the Gold Paper Award 2020 for their machine learning-based approach to analyzing Raman data of LIBs. Raman images of LIB cathodes can visualize the spatial distribution of the active cathode material (lithium nickel manganese cobalt oxide, abbreviated as LiMO2) and the surrounding carbon matrix. In order to automate and accelerate the process of identifying the spectral signatures in Raman datasets, the authors developed a machine learning-based analytical framework. It starts by automatically pre-processing the Raman data to remove the baseline and cosmic rays. Next, algorithms determine the number of components, extract the corresponding spectral signatures, and identify them. The spectra are finally used to train a neural network, which can then automatically analyze Raman data from the same or a different LIB sample. The authors demonstrated that data analysis by the trained neural network yielded results consistent with results from an experienced user. However, the algorithm found two minor signatures in addition to the main components of carbon and LiMO2 that corresponded to a residual background signal and one of the main components exhibiting increased fluorescence signals. The presented approach requires very little user input and is thus suitable for real-time quality control using Raman data from lithium-ion batteries and other applications.
The Paper Award SILVER: Characterizing atherosclerotic plaques with iSERS microscopy
“Atherosclerosis is one of the major causes of death worldwide. Understanding the mechanism of its formation still remains a great challenge in medicine. Powerful techniques for monitoring the composition and stability of atherosclerotic plaques are thus needed,” says Ewelina Wiercigroch from Jagiellonian University (Krakow, Poland), winner of the Silver Paper Award 2020. Atherosclerotic plaques form at arterial walls and narrow the blood vessels. Monitoring the stability of the plaques is of clinical relevance because their rupture can result in a stroke or heart attack. As smooth muscle cells (SMCs) play a key role in stabilizing the plaques, their presence can serve as a marker for plaque stability. Ewelina Wiercigroch, Elzbieta Stepula, Lukasz Mateuszuk, Yuying Zhang, Malgorzata Baranska, Stefan Chlopicki, Sebastian Schlücker and Kamilla Malek from Jagiellonian University and the University of Duisburg-Essen (Germany) demonstrated the suitability of immuno surface-enhanced Raman scattering (iSERS) microscopy for staining SMCs in atherosclerotic plaques. SERS labels were conjugated either with a primary antibody directed against α-actin of SMCs (direct iSERS) or with an appropriate secondary antibody (indirect iSERS). The iSERS images of mouse artery sections visualized regions containing SMCs and cluster analysis allowed the quantification of the percentage of SMCs located in the plaques. Results from iSERS staining agreed qualitatively and quantitatively with those from immunofluorescence (IF) staining. IF is the current gold standard in visualizing atherosclerotic constituents, but iSERS offers some advantages, such as higher photostability. The study thus establishes iSERS as a promising technique for visualizing and quantifying SMCs in atherosclerotic plaques.
The Paper Award BRONZE: Correlative Raman imaging of polymeric materials
Ruth Schmidt from Graz University of Technology (Graz, Austria) receives the Bronze Paper Award 2020, together with her colleagues Harald Fitzek, Manfred Nachtnebel, Claudia Mayrhofer, Hartmuth Schröttner and Armin Zankel. The group demonstrated the potential of correlative Raman Imaging and Scanning Electron (RISE) microscopy and Energy Dispersive X-Ray Spectroscopy (EDXS) for investigating polymers. Polymeric materials are popular in many applications due to their wide variety of useful properties, such as high elasticity or toughness. For characterizing their properties, the advantages of three imaging techniques were combined. Scanning Electron Microscopy (SEM) acquired high-resolution structural information, while Raman imaging revealed the chemical composition and was complemented by elemental information from EDXS. The publication provides a detailed methodology chapter which describes different sample preparation approaches and imaging modes. For example, it explains strategies for SEM imaging without coating the sample, which would hinder subsequent Raman imaging. Three polymer specimens were investigated with RISE and EDXS, yielding complementary information from the same sample region. Coarse and fine structures of the samples were correlated with chemical properties and the layer structure of packaging materials was visualized. Particulate additives in a polymer matrix were identified and their size distribution was investigated. The authors stressed that combined SEM, Raman imaging and EDXS offers great possibilities for analyzing polymeric materials.
The competition continues: WITec Paper Award 2021
Scientists from all fields of application are invited to participate in the Paper Award 2021 contest (www.witec.de/paper-award). Articles published in 2020 in a peer-reviewed journal that feature data obtained with a WITec microscope can be submitted to firstname.lastname@example.org until January 31st, 2021. WITec is again looking forward to receiving many new and exceptional publications.
- Press Release Paper Award 2020 EN (PDF) (686 KB)
- Press Release Paper Award 2020 EN (DOCX) (306 KB)
- Picture Paper Award 2020 Gold (JPG) (2.4 MB)
- Picture Paper Award 2020 Silver Copyright: E. Wiercigroch (JPG) (2.1 MB)
- Picture Paper Award 2020 Bronze Copyright: FELMI-ZFE (JPG) (2.5 MB)
To better serve our growing business in Japan, WITec K.K. has relocated the national office to Yokohama. Within a two-minute walk from the JR Kannai station and close to Yokohama Stadium, home of the Baystars baseball team, our new office is conveniently accessible from all over Japan.
In addition to delivering Raman imaging solutions with superior performance, customer satisfaction through excellent service and support is the key to WITec’s success. The new office provides a great environment for pursuing these objectives.
Our team is ready to work with existing and potential customers in the new equipment demonstration/sample measurement laboratory on their individual applications and requirements. A meeting and training space will host workshops and serve as a conference room for Japan’s Raman imaging community.
We look forward to welcoming you into our new home.
The WITec K.K. Team
1-1-5 Furo-cho, Naka-ku,
Yokohama City, Kanagawa Pref.
2019 MRS秋季会议期间，Physics World杂志对WITec创始人兼研发总监Olaf Hollricher博士进行了深度访谈。
WITec's ParticleScout has been nominated for a SelectScience Scientists' Choice Award in the category of Best New Spectroscopy Product. We're very excited to be in the competition and thankful to our customers around the world for their enthusiasm.
The Scientists' Choice Awards are presented annually to recognize the laboratory products introduced in the preceding year that helped researchers the most in the course of their work. Scientists themselves directly nominate, review, and vote for the winners.
WITec's ParticleScout is an automated microparticle anaylsis tool for the alpha300 line of confocal Raman microscopes that can find, classify and identify microplastics and other particles with industry-leading speed and precision. If you'd like to voice your support for this revolutionary and timely technology, please vote through the link below. All participants are entered into a drawing for the chance to win a $500/£400/450€ Amazon Gift Card. Voting ends February 21st.
WITec GmbH, industry-leading manufacturer of 3D confocal Raman imaging and correlative microscopy systems, has updated its organizational structure in France to streamline communication and better leverage in-house technical expertise.
Dr. Maxime Tchaya, a longtime member of the WITec team, will manage the French market directly. His responsibilities include all sales activities and the coordination of technical support, equipment demonstrations and sample measurements.
Dr. Tchaya is native French speaker who began with WITec as an applications scientist before bringing his thorough, practical knowledge of WITec microscopes to the sales department. This experience will enable him to precisely address the requirements of the local client base while providing them with a direct conduit to WITec’s research and development group.
WITec renforce son service commercial et technique sur le marché français
WITec GmbH, leader de la microscopie confocale Raman 3D et fabriquant de plateformes de microscopie corrélative, renforce son organisation en France.
Dr. Maxime Tchaya, membre de longue date de l'équipe WITec, prend la responsabilité de la commercialisation et du support des solutions WITec en France.
Sa longue expérience au sein de l’équipe d’application, et son excellente connaissance du marché français, sont autant d’atouts qui lui permettront de répondre avec précision et efficacité aux besoins de la clientèle, tout en la rapprochant davantage de l’équipe R&D pour les demandes spécifiques.
Dr. Maxime Tchaya
Area Manager France - Canada - Poland
89081 Ulm, Germany
Tel: +49 (0) 731 140700