Microscopic Raman Spectroscopy Research Articles

Temperature dependence mechanism of high-temperature oxidation of transition metal silicide MoSi2

Transition metal silicides represented by MoSi2 have excellent oxidation resistance and are widely used as high-temperature anti-oxidation coatings in hot end components of power equipment. However, the mechanism of temperature-dependent growth of MoSi2 oxidation products has not been revealed. Therefore, this study investigated the formation characteristics of oxide film and silicide-poor compound on MoSi2 at temperatures of 1000 °C–1550 °C through high-temperature oxidation experiments, combined with microscopic Raman spectroscopy, scanning electron microscope, and x-ray diffraction (XRD) characterizations. The result showed that MoSi2 underwent high-temperature selective oxidation reactions at 1000 °C–1200 °C, forming MoO2 and SiO2 oxide film on the substrate. As the oxidation temperature increased to 1550 °C, after 100 h of oxidation, along with the disappearance of MoO2 and the phase transformation of SiO2, a continuous Mo5Si3 layer with a thickness of approximately 47 μm was formed at the SiO2–MoSi2 interface. Thermodynamics and kinetic calculations further revealed the mechanism of temperature-dependent growth of oxidation products (MoO2 and Mo5Si3) during high-temperature oxidation process of MoSi2. As the temperature increased, the diffusion flux ratio of O and Si decreased, leading to a decrease in oxygen concentration at the interface and promoting the growth of the Mo5Si3 layer. Its thickness is an important indicator for evaluating the oxidation resistance of MoSi2 coatings during service. This study provides experimental and mechanistic insights into the temperature-dependent growth behavior of Mo5Si3 during the high-temperature oxidation of MoSi2 coating, and provides guidance for predicting the service life and improving the oxidation resistance of silicide coatings.

A miniature world: Revealing warring states period shell paintings from zhongshan state by multiple-methods

The use of shells as a medium for painting is an exceptionally rare discovery in archaeology, representing a art form that has been largely overlooked. In this study, we present two shell paintings of the Warring States period (476–221 BCE) discovered in Zhongshan State, Hebei, China. Employing various techniques, including microscopic observation, computed tomography (CT), X-ray fluorescence (XRF), multispectral imaging, and Raman spectroscopy, we non-destructively unveil the exquisite images obscured by soil and reveal the unparalleled shallow relief technique employed in their creation. The identified pigments for the different paintings include cinnabar, charcoal black, and malachite. These elaborate depictions offer insights into the costume, rituals, life, hierarchy, and art of the Warring States period. The meticulous use of prominent lines emphasizes color patches rather than the brushstrokes relied upon in later stereotypical Chinese painting, significantly reshaping previous notions about the early development of Chinese painting. This unique expression undoubtedly refreshes our understanding of early ancient art.

Scientific analysis of two compound eye beads unearthed in Hejia Village, Zhouling

The glass compound eye bead is the exquisite embodiment of the glassmaking technology of ancient craftsmen, and is an example of the cultural exchange between China and the West during the Warring States Period. This study takes two dots and mesh beads with seriously weathered surfaces excavated from Hejia village, Zhouling as the research object. Micromorphology, X-ray fluorescence spectroscopy (XRF), microscopic laser Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were respectively used to determine the chemical elements, valence states and compositions of the glass matrix and its weathering products. In this study, the valence state analysis of group-d elements is used to reveal the electron transition mode and explain the colour formation reason of blue-black glass matrix. In terms of weathering products, in addition to the identification of common cerusite [PbCO3] and barite [BaSO4], the study also found the blue weathering product alforsite [Ba5(PO4)3Cl] for the first time. The study also makes reasonable assumptions about the reasons for their appearance. The X-ray photoelectron spectroscopy (XPS) used in this study has positive significance for the study of the formation mechanism of glass colour. The scientific and technological analysis data of these two glass beads provide basic data for the related research of the lead-barium glass system produced in China, and also provide a certain scientific basis for the related protection research.

Characterization of microplastics in the atmosphere of megacity Tehran (Iran).

In this study, the characteristics of ambient airborne microplastics were investigated in Tehran to obtain insights into their origins. For this purpose, sampling operations took place at locations with different backgrounds in summer and autumn by using TSP and PM10 high-volume samplers. As a result of microscopic analysis and Raman spectroscopy, the color, shape, number, size, and type of microplastic particles were investigated. Seven types of chemical structures were identified in the particles, among which polypropylene (18.7%) in summer and polystyrene (20%) in autumn had the dominant share. The average number of particles collected using the TSP and PM10 samplers were 1165 ± 147.64 and 1006.5 ± 147.64, respectively. The size of microplastic particles in different stations varied between 4 and 3094 μm. In the seasonal examination of the identified colors, black (38-43%), red (17-19%), gold (13-14%), brown (12% in both seasons), blue (7-10%), yellow (3-5%), and green (2-5%) had the largest proportions, respectively. The examined microplastics were in three forms: fiber, bead, and fragment, among which the predominant form was fiber, and the most infrequent particles were fragments. Statistical comparisons showed that the sampling location does not have a significant effect on the number and size of particles (p value > 0.05). The season was not identified as a determining parameter for particle size (p value > 0.05). On the other hand, seasonal changes can have a tremendous effect on the microplastic particle number (p value < 0.05). Lastly, to obtain more detailed information about the origin of these particles, continuous and long-term monitoring near known industries and suspected sources of plastic materials and source apportionment studies were suggested.

НАУЧНЫЙ АНАЛИЗ ФИОЛЕТОВОГО ВОСЬМИУГОЛЬНОГО СТОЛБЧАТОГО ИЗДЕЛИЯ, НАЙДЕННОГО НА МОГИЛЬНИКЕ ХЭЦЗЯ, СЯНЬЯН, ШЭНЬСИ, И СВЯЗАННЫЕ С ЭТИМ ВОПРОСЫ

In this paper, we chose late war purple octagonal prismatic ware excavated at the Hejia Cemetery in Xianyang as the object of study, and carried out scientific analysis using ultra-deep field microscopy, scanning electron microscopy and energy spectrum analysis, X-ray diffraction, and microscopic Raman spectroscopy. First of all, the features of the formation and weathering process were determined, then the samples of unweathered areas obtained by the sectioning method were examined, and it was confirmed that all 12 samples are barium copper silicate with the main phases of Chinese violet (BaCuSi2O6) and Chinese dark blue (BaCu2Si2O7) colors. Based on compositional characteristics, etc. it was also found that this group of purple octagonal vessels embodies two different manufacturing processes and may represent an evolution of the process from lead-barium glass to cupro-barium silicate. On this basis, issues such as the population, distribution area and functional characteristics of this type of dish are discussed in order to obtain new ideas and evidence for relevant research.

Pharmaceutical Evaluation of Levofloxacin Orally Disintegrating Tablet Formulation Using Low Frequency Raman Spectroscopy.

We evaluated the pharmaceutical properties of levofloxacin (LV) in the form of an orally disintegrating tablet (LVODT) to find a new usefulness of low frequency (LF) Raman spectroscopy. LVODT contained dispersed granules with diameters in the order of several hundred micrometers, which were composed of the active pharmaceutical ingredient (API), as confirmed by infrared (IR) microspectroscopy. On the contrary, the API and inactive pharmaceutical ingredients (non-APIs) were homogeneously distributed in LV tablet (LVT) formulations. Microscopic IR spectroscopy and thermal analyses showed that LVODT and LVT contained the API in different crystalline forms or environment around the API each other. Furthermore, powder X-ray diffraction showed that LVT contained a hemihydrate of the API, while LVODT showed a partial transition to the monohydrate form. This result was confirmed by microscopic LF Raman spectroscopy. Moreover, this method confirmed the presence of thin layers coating the outer edges of the granules that contained the API. Spectra obtained from these thin layers indicated the presence of titanium dioxide, suggesting that the layers coexisted with a polymer that masks the bitterness of API. The microscopic LF Raman spectroscopy results in this study indicated new applications of this method in pharmaceutical science.

Multi-Method Analysis of Painting Materials in Murals of the North Mosque (Linqing, China)

The murals of Ming Dynasty North Mosque in Linqing, Shandong Province, Eastern China, are of significant cultural and historical importance. Their final restoration date remains uncertain, making a comprehensive investigation critical before initiating preservation and renovation work. This research project examined the painting materials of the murals using various analytical techniques, including polarized light microscopy (PLM), scanning electron microscopy (SEM), X-ray energy spectrometer (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), microscopic Raman spectroscopy (M-Raman), X-ray photoelectron spectroscopy (XPS), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis. Results indicated that the pigments employed included ultramarine, emerald green, cinnabar, kaolinite, gypsum, and carbon black, while the gum binder used was protein-based adhesive materials. As synthetic ultramarine and emerald green were not introduced to China until the late Qing Dynasty, this suggests that these murals were restored no earlier than this period. The study also revealed that the mural materials used in the North Mosque mural were similar to those found in other architectural murals in China. Thus, the knowledge gained from the conservation and restoration efforts of similar architectural murals can be leveraged to enhance the conservation and restoration efforts of the North Mosque murals.

Detection of microplastic samples based on spatial heterodyne microscopic differential Raman spectroscopy

AbstractAs a new global pollutant, microplastics have been widely a concern in recent years. The traditional microplastic detection technology has the disadvantages of weak signal, high cost, and complicated operation. Therefore, this paper designs and builds a set of spatial heterodyne microscopic differential Raman spectroscopy (SHMDRS) system for microplastic detection. The system combines the spatial heterodyne system (SHS) with the microscopic differential Raman system (MDRS). The system was simulated and designed by ZEMAX software, and the SHMDRS system was built on the experimental platform. The 531.742‐ and 532.567‐nm dual‐wavelength lasers were used as the excitation light source. Four kinds of microplastic samples, namely, PS, PC, PP, and HDPE, were tested to verify the feasibility of the system. Under the integration time of 10 s and the laser power of 200 mW, the microplastic samples were detected by the SHMDRS system and dispersive spectrometer, respectively. The signal‐to‐noise ratio (SNR) of Raman spectra of different systems was compared and calculated. The differential Raman spectra of four kinds of microplastic samples were obtained by dual‐wavelength laser, and the pure Raman spectra of four kinds of microplastic samples were restored by multiple constrained iterative algorithm. The results show that the spectral resolution of the SHMDRS system is 2.809 cm−1, and the spectral range is 255.47–2023.21 cm−1. The SNRs of the Raman spectra obtained by the SHMDRS system are better than those of the dispersive spectrometer, and the differential Raman spectroscopy can effectively remove the interference of the fluorescence background. This method has a good development prospect.

Intangible cultural heritage complexes in China: Representation and restoration of pigmented reliefs in Kaiping Diaolou

Restoration techniques were explored for the patterns, materials, and surface pigments of the pigments decoration art of Kaiping Diaolou and Villages, a world cultural heritage site in southern China. Field investigation was supplemented by scanning electron microscopy, microscopic Raman spectroscopy characterization, colorimetric tests, and tensile tests. Materials and concepts for the restoration of the Kaiping Diaolou pigments were analyzed. Raman spectroscopy was used to characterize the surface pigments display of pigments decorative patterns. The main colors of restoration included green, red, white, and blue. The green color was a mixture of colored copper arsenate minerals. The red color was made of hematite (Fe2O3). White was calcite, and blue was lapis lazuli or synthetic ultramarine. SEM revealed both pigments show similar flake flocculent section morphologies. UV accelerated aging experiments showed that the Ultraviolet absorber and antioxidants effectively inhibited the degradation of the interface matrix. The interface was less prone to cracking. The tension test showed that the bond stress reached a maximum value of 0.193 MPa at a curing temperature of 20 °C under 95% ambient humidity. The results provide strong evidence for pigment restoration in Kaiping Diaolou. This study also provides a scientific reference for the pigment conservation of other architectural decorations from the same historical period.

Jedi Spinel from Man Sin, Myanmar: Color, Inclusion, and Chemical Features

In the present study, we collected and investigated spinels from the Man Sin deposit in Myanmar using standard gemological testing, microscopic observation, EDXRF, and Raman spectrometry. The color observation was performed under various lighting conditions to show color differences. A very high Cr/Fe ratio is linked with exceptionally strong red fluorescence. Microscopic observation and Raman spectroscopy identified mineral inclusions of colorless phlogopite, molybdenite, hauerite, native sulfur, and calcite. Man Sin spinels are typical Fe– and Zn–poor spinels. Binary and ternary diagrams were used to discriminate each deposit (i.e., Man Sin, Mogok, and Namya in Myanmar) with high reliability. Jedi spinel fever in the Asian market, due to their unique neon color appearance and exceptionally strong fluorescence, is also discussed.

Raman Spectroscopy and STR Analysis of the Elongated Skulls from the Paracas Mummies of Peru

Between 1880-1947, several hundred mummified bodies were excavated from burial sites in the Paracas peninsula of Peru. Each set of recovered remains displayed reduced stature and severe cranial elongation, which led many anthropologists and archaeologists to question the genetic origins of what would be colloquially referred to as the “Cone Head mummies.” Since the discovery of these bodies, suggestions have been made that the mummies’ cranial deformations point to another human species, an unknown hominid species, or even within some groups, an alien. This project sought to employ commonly used forensic techniques, including but not limited to Raman spectroscopy and DNA fingerprinting, to investigate the hair structure and genetic profile from tissue and hair samples derived from the Paracas skulls. Tissue and hair samples were subjected to comparative hair analysis, Raman spectroscopy, and DNA typing using short tandem repeat (STR) analysis. Comparative microscopic hair analysis and Raman spectroscopy of samples collected from the Paracas skull as well as from humans of varying ethnicities revealed very similar hair structures and characteristics that are associated with human hairs. Following DNA extraction and amplification of tissue samples, STR typing results demonstrated allelic profiles similar and consistent with those DNA profiles observed in modern human populations. Moreover, no foreign DNA or unusual patterns/profiles were observed in any of the samples tested. Data generated to this point strongly suggest that the Paracas mummies are of the same species as humans and not from an unknown hominid or alien society.

Single Crystalline, Non‐stoichiometric Cocrystals of Hydrogen‐Bonded Organic Frameworks

AbstractPorous frameworks composed of non‐stoichiometrically mixed multicomponent molecules attract much attention from a functional viewpoint. However, their designed preparation and precise structural characterization remain challenging. Herein, we demonstrate that cocrystallization of tetrakis(4‐carboxyphenyl)hexahydropyrene and pyrene derivatives (CP‐Hp and CP‐Py, respectively) yields non‐stoichiometric mixed frameworks through networking via hydrogen bonding. The composition ratio of CP‐Hp and CP‐Py in the framework was determined by single crystalline X‐ray crystallographic analysis, indicating that the mixed frameworks were formed over a wide range of composition ratios. Furthermore, microscopic Raman spectroscopy on the single crystal indicates that the components are not uniformly distributed such as ideal solid solution, but are done gradationally or inhomogeneously.

Single Crystalline, Non-stoichiometric Cocrystals of Hydrogen-Bonded Organic Frameworks.

Porous frameworks composed of non-stoichiometrically mixed multicomponent molecules attract much attention from a functional viewpoint. However, their designed preparation and precise structural characterization remain challenging. Herein, we demonstrate that cocrystallization of tetrakis(4-carboxyphenyl)hexahydropyrene and pyrene derivatives (CP-Hp and CP-Py, respectively) yields non-stoichiometric mixed frameworks through networking via hydrogen bonding. The composition ratio of CP-Hp and CP-Py in the framework was determined by single crystalline X-ray crystallographic analysis, indicating that the mixed frameworks were formed over a wide range of composition ratios. Furthermore, microscopic Raman spectroscopy on the single crystal indicates that the components are not uniformly distributed such as ideal solid solution, but are done gradationally or inhomogeneously.

Detection and analysis of microplastics in offshore sediment by microscopic differential Raman spectroscopy.

In view of the problems of low pre-screening efficiency, a weak Raman signal, and strong fluorescence interference in the detection of microplastics by traditional Raman spectroscopy, a set of rapid detection system and research methods for microplastics, including fluorescence imaging technology, differential Raman spectroscopy technology, and confocal microscopic Raman technology, are constructed in this paper. A 784/785nm dual-wavelength laser was used as the excitation light source in the rapid detection system for microplastics. The sediment in the coastal waters of Qingdao Shilaoren was taken as the research object. Polycarbonate and high-density polyethylene with a particle size of 40µm in the samples were accurately detected and analyzed. The research method for microplastics proposed in this study breaks through relevant key technologies, which we believe will help promote the development of microplastic monitoring technology in the global marine environment and provide strong technical support for the healthy development of the global marine ecological environment.

Underwater Raman microscopy—a novel in situ tool for deep-sea microscale target studies

Microscale processes and interactions in the ocean are pervasive. They play a fundamental role in global biogeochemical cycles and have a significant impact on benthic marine ecosystems. However, our understanding of microscale processes and interactions that appeared in the benthic environment is still very limited, particularly for the deep ocean, due to a lack of appropriate in situ observation and detection methods. To address this challenge, we have developed an in situ observation and detection system for microscopic targets suitable for the deep sea and have successfully deployed the instrument on a remotely operated vehicle (ROV) to achieve in situ microscopic Raman detection of targets on the seabed over a depth of 770 m. This is a combined system that integrated microscopic imaging and Raman detection techniques for in situ observation and analysis of underwater microscale targets. The complete system consists of an electronics chamber, a detection probe, and a precision external positioning device. Power supply and real-time data transmission are achieved via ROV tethers. This allows researchers to operate the instrument in real time to perform microscopic imaging capture and Raman spectroscopy acquisition of interesting targets on the seafloor. The first sea trial of the system was conducted in the South China Sea in 2020, and during the cruise, microscopic image acquisition and in situ compositional analysis of shell fragments, seabed rock samples, and live sea stars were successively performed. The system has solved the key technical challenges of deep-sea microscopic imaging, demonstrated the feasibility of deep-sea microscopic imaging, and illustrated the great potential of combining Raman spectroscopy and microscopic imaging in marine research. In this paper, we present the unique design of the instrument and the deep-sea results. With further optimization, the system promises to be a versatile instrument providing a unique perspective for deep-sea geochemical and biochemical studies.

Identifying the polymorphs of serpentine with micro‐Raman spectroscopy: Clear separation in biaxial plots

AbstractSerpentine, Mg3Si2O5(OH)4, is a phyllosilicate mineral having several polymorphs, that is, antigorite, chrysotile, lizardite, and polygonal. Because the crystal structure is dependent on thermodynamic environment where serpentine was produced, it has been desired for the polymorphs to be distinguished for geoscientific investigation. While crystal structures are analyzed by X‐ray crystallography in many cases, it is difficult to apply the X‐ray technique to small and/or non‐uniform samples. In the present study, we achieved to unambiguously determine the serpentine's polymorphs with microscopic Raman spectroscopy. Among various Raman‐active vibrational modes, we focused on the SiOSi symmetric stretching mode and bending vibration of SiO4 units because layer structure of SiO4 tetrahedral sheets (T‐sheets) alters with the crystal structure. With the peak wavenumbers determined with subpixel accuracy, the polymorphs were clearly separated in biaxial plots of the peak wavenumbers. As a result, we succeeded in distinguishing lizardite and polygonal serpentine, which were believed to be indistinguishable from Raman spectra, for the first time. Because microscopic Raman spectroscopy is nondestructive method that requires neither large single crystals nor any pretreatment of samples, it is applicable to small (&lt;1 mm), fragile, rare, and/or heterogeneous samples. This feature advantages our technique for the investigation on non‐uniform and a trace amount of serpentines in terrestrial mantle rocks from seafloor and in meteorites from asteroids carrying complex histories of their formation and aqueous alteration.

Study on Scientific Analysis about Red Pigment And Binder - The Korean Ancient Red Pottery -

From the collection of the National Kimhae Museum, qualitative analyses using microscopic observation, SEM-EDS, Raman spectroscopy, FT-IR-ATR spectroscopy, and GC-MS were conducted on three burnished red potteries—Jeoksaekmaoyeonwa burnished red pottery (Neolithic age red pottery), Dandomaoyeonwan burnished red pottery(Bronze age red pottery) and Jeoksaekmaoyeongajimun burnished red pottery(Bronze age red pottery)—to investigate the components of the red pigments and the binder. After the layers of the primer were separated from the red surface, crystals of red pigment particles and minerals were found on the red surface. Through SEM-EDS, Raman estimates that the red pigment is Among soil pigments with iron oxide(Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) as the main color development source, Red Ocher(Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;). A band characteristic of the Urushiol polymer was detected in the FTIR-ATRspectra(4000∼600cm-1), GC-MS analysis confirmed the presence of the benzenemethanol-2-prophenyl, 4-heptylphenol, 1-tetracecanol, heptafluorobutyric texidecane, all of which are the ingredients of the directional structure of the lacquer present in the red layer. Therefore, it seemed that the three burnished red pottery: Jeoksaekmaoyeonwan pottery(Neolithic age burnished red pottery), Dandomaoyeonwan pottery(bronze age burnished red pottery) and the Jeoksaekmaoyeongajimun pottery(bronze age burnished red pottery) made by mixing minerals and Red Ocher(Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;), with lacquer.

Catalytic effects of inherent AAEM on char gasification: A mechanism study using in-situ Raman

Despite a small proportion of mineral in coal, inherent alkali and alkaline earth metals (AAEM) catalytically affected thermal conversion of coal. The gasification of raw and leached coal char was investigated by using an operando microscopic Raman spectroscopy to explore the effect of content and chemical form of the inherent AAEM on morphology and carbon structure evolution of a single particle during in-situ char gasification. The removal of water-soluble and ion-exchangeable AAEM reduced the R0.5 of SF, NM and YN char by 53.31%, 49.09% and 35.02%, respectively. As a result, the shrinkage of leached coal char progressed slower than that of the raw coal char. Besides, both water-soluble and ion-exchangeable AAEM accelerated char gasification because of an inhibition of the orderly evolution of carbon structure. Higher gasification temperature weakened the catalytic performance of ion-exchangeable AAEM. With the consumption of carbon, carbon microcrystalline structure of the residual char tended to be ordered, which led to a decrease in active free carbon sites for gasification reaction. Kinetic analysis indicated both water-soluble and ion-exchangeable AAEM reduced the activation energy of SF, NM and YN char by 20.97, 20.82 and 9.38 kJ∙mol−1, respectively, and the effect of ion-exchangeable AAEM was more significant.

Isolation of Quartz Grains for Optically Stimulated Luminescence (OSL) Dating of Quaternary Sediments for Paleoenvironmental Research

This protocol is for the isolation of quartz grains by size for luminescence dating of sediments. Outlined are physical cleansing and chemical digestions by soaking sequentially in H2O2, HCl, HF, and HCl again to isolate quartz grains. The quartz purity is quantified with microscopic assessment, Raman spectroscopy, and IR depletion ratio.

Growth of High Sn Concentration Germanium-Tin Films on Insulators by Microsecond Laser Annealing

1. IntroductionThanks to their high carrier mobility, germanium based group IV semiconductors are promising materials to realize next generation electronics [1]. Especially, germanium tin alloys (GeSn) having high Sn concentration (> 6 at. %) are attracting much attention due to their direct band structure [2]. To apply such significant advantage to thin-film devices such as thin-film transistors (TFTs) or three dimensional large-scale integrated circuits (3D-LSIs), various groups are working on to crystallize these materials on insulating substrates by various approaches such as germanium condensation [3], solid phase crystallization [4], and so on.Recently, we have established a technique to grow highly strained germanium based materials on insulating substrates by microsecond annealing using novel high speed continuous wave laser annealing (CWLA) system [5]. Here, in this presentation, we will introduce our recent achievements in GeSn crystal growth by the microsecond annealing technique.2. Experimental ProcedureIn the experiment, amorphous GeSn films with Sn concentration of 15% (thickness: 100 nm) were firstly deposited on quartz substrates by molecular beam deposition. Then the samples were annealed by the high speed CWLA system, which can scan laser light (focused to 20 μm diameter) on samples with very high speed up to 15 m/s. The laser irradiation time (tirr) can be varied from 1.5 to 6.0 μs by controlling the scanning speed. Here, Nd:YVO4 solid state laser with wavelength of 532 nm was used as a light source, and laser power was controlled from 350 to 1000 mW. After the laser annealing, the samples were characterized by microscopic Raman spectroscopy and electron back scattered diffraction (EBSD) method.3. Results and DiscussionsFig. 1(a) shows Nomarski microscopic image after laser annealing (500 mW, tirr: 1.5 μs), which shows bright contrast at annealed region. Raman signals measured at surface of GeSn thin film before and after LA (tirr: 1.5 μs) are shown in Fig. 1(b). We can see clear peak around 300 cm-1 due to Ge-Ge atomic bond at the annealed region, which supports that GeSn film has been successfully crystallized by the annealing.To discuss about the growth feature of GeSn films, EBSD measurements were carried out. Mapping images of Ge and Sn phase signals at surfaces of samples are summarized in Fig. 2 as a function of tirr. Here, we can clearly see that the area of Sn phase signal is expanding by increasing tirr. These results (Raman and EBSD) suggest that by increasing tirr, Sn precipitation toward surface of GeSn occurs after crystallization of GeSn films, due to excess annealing. As a result, by increasing tirr, substitutional Sn concentration in the films decreases after LA [Fig. 3], showing that short time annealing is essential to prevent the precipitations. Fig. 4 summarizes substitutional Sn concentration in GeSn films grown with shortest irradiation time (1.5 μs) as a function of laser power. By minimizing the irradiation time and tuning laser power to minimum value for crystallization, we could realize GeSn thin films with a high substitutional Sn concentration (13 %) on insulating substrates. These are very attracting results to realize next generation electronics.Detailed physics and further tin concentration improvement methods will be discussed in the presentation.[References][1] J.R. Haynes, W. Shockley, Phys. Rev. 81 835–843 (1951).[2] S. Gupta, K. C. Saraswat, et.al., J. Appl. Phys. 113 073707 (2013).[3] S. Nakaharai, S. Takagi, et. al., J. Appl. Phys. 105 024515 (2009).[4] K. Toko, et. al., Sci. Rep., 7, 16981 (2017)[5] R. Matsumura, N. Fukata, ECS J. Solid State Sci. Technol, 9 063002 (2020). Figure 1