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Structural and optical properties of a revived Pb0.5Ba1.5BiVO <sub/>6</sub> perovskite oxide
摘要： The polycrystalline ceramic Pb0:5Ba1:5BiVO6 manifesting the complex double perovskite structure was tailored by the conventional solid state route at a moderate temperature. Qualitative phase analysis and formation of the ceramic were affirmed by XRD analysis. The X-ray powder diffraction pattern of the compound explored at room temperature affirms the single phase formation with double perovskite structure exhibiting rhombohedral phase. Microstructural analysis of the studied compound procured from the Scanning Electron Microscope (SEM) validates the formation of dense microstructures and nonuniformly distributed grains with minimal voids. Compositional analysis was shaped through the Electron Diffraction Spectroscopy (EDS) confirming the absence of contamination of any other metals apart from the mentioned ones. Dielectric (Cr and tan δ) parameters of the compound were studied using the LCR analyzer at different temperatures and wide range of frequencies. The polarization and dielectric study affirms the presence of ferroelectricity in the material with transition temperature much above the room temperature. The tangent dielectric loss of this sample being almost minimal at room temperature attributes it to find applications in different grounds of electronics. Optical equities of the ceramic were further analyzed by the RAMAN, FTIR, UV–Vis and Photoluminescence spectroscopy.
关键词： EDS,Ceramic,X-Ray diffraction,LCR,optical properties
更新于2025-11-14 14:48:53
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Multipulse laser ablation of BiSn eutectic: Noncongruent element transfer and morphology analysis
摘要： The surface of a eutectic BiSn target was ablated by several series of pulses at different spots using an excimer laser with a wavelength of 351 nm and a pulse duration of 20 ns. Morphology of ablation craters formed under a different number of pulses was analyzed with a scanning electron microscope, an optical profilometer, and an energy dispersion spectroscope (EDS). Laser-induced breakdown spectroscopy (LIBS) measurements were taken for each crater with the last pulse in the series of pulses. The ratio of peak intensities (Bi I peak at 472.25 nm and Sn I 563.16 nm) of LIBS spectra for craters formed by different series of pulses decreased from maximum at a single pulse to a stable magnitude after a series of 70 pulses. EDS mapping of crater areas for different series of pulses shows a decrease in Bi atoms abundance, in correlation with the decrease in normalized intensity of Bi peak LIBS spectra. The change of the chemical composition in the ablation area is explained based on the Knudsen evaporation model. For the first time, pronounced hydrodynamic effects resulting in the formation of 50 μm-high rims were observed. The unusual morphology of the ablated area is explained on the basis of hydrodynamic effects and recoil pressure.
关键词： LIBS,BiSn eutectic,laser ablation,EDS,SEM
更新于2025-09-23 15:21:01
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The impact of laser surface treatment on the microstructure, wear resistance and hardness of the AlMg5 aluminum alloy
摘要： Light metal alloys due to several unique properties such as low density and high corrosion resistance are increasingly used in various technical applications, where the automotive industry is one of the most important sectors. The automotive applications use mostly aluminum alloys, where the strength to density ratio of the material plays a crucial factor. Unfortunately, relatively low mechanical properties limit their applications for parts where a high surface hardness and wear resistance is expected. The classic heat treatment of aluminum alloys can only in some limited ranges improve the bulk material properties. Despite this, surface treatment with laser processing has developed significantly over the past 20 years. The laser beam treatment allows the introduction of a wide range of alloying elements to the surface layer of an aluminum alloy and thus, as a result of the precipitation of numerous intermetallic phases, significantly increases hardness, and abrasion resistance. The purpose of this work was to modify the aluminum surface layer using high-power fiber laser (HPFL). During this process, a mixture of titanium and iron powders (90/10 wt.%) was introduced onto the surface of the AlMg5 alloy. The microhardness tests carried out by the Vickers method and tribological tests showed a significant increase in mechanical properties in the entire volume of the obtained layer. Research on light and scanning microscopy revealed fragmentation of primary precipitates and the formation of numerous intermetallic phases rich in titanium and aluminum.
关键词： Aluminium alloy,Laser treatment,EDS analysis,Tribological properties,High power fibre laser
更新于2025-09-23 15:19:57
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Combined microscopy and spectroscopy techniques to characterize a fossilized feather with minimal damage to the specimen
摘要： The study of fossil feathers has been revitalized in the last few decades and has contributed significantly to paleontological studies of dinosaurs and birds. Specific morphological and physicochemical characteristics of the microscale structures of feathers and the protein keratin are key targets when preserved during the fossilization process. Keratin is a fibrous protein that composes some hard tissues such as hair, nails and feathers. It is part of the so called intermediate filaments inside keratinocyte cells and is rich in sulfur containing amino acid cysteine. To date, different microscopy and analytical methods have been used for the analysis and detailed characterization and classification of feathers. However, in this work we showed that analytical optical and electron microscopies can be quick and precise methods with minimal effects on the sample during analysis. This association of different approaches on the same sample results in correlative data albeit in different length scales. Intracellular bodies called melanosomes originally present in melanocyte cells were identified with Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), and had well-defined orientation and a mean aspect ratio comparable to melanosomes extant in dark feathers. The detection of sulphur in melanosomes via Energy Dispersive Spectroscopy both in SEM and TEM shows that, along the fossilization process, sulphur from the degraded keratin matrix could have been trapped inside the melanosomes. Chemical groups that make up keratin and melanin in the fossil sample were detected via FT-IR Spectroscopy and Confocal Laser Scanning Microscopy (CLSM). The use of combined analytical microscopy techniques can contribute significantly to the study of fossils generating precise results with minimum damage to the original sample.
关键词： EDS,Crato Formation,TEM,CLSM,FT-IR Spectroscopy,SEM
更新于2025-09-19 17:15:36
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Plasma Diagnostic by Optical Emission Spectroscopy on Dolomite and Cross-Validation Using Scanning Electron Microscopy Coupled with Energy Dispersive X-ray Spectroscopy and Electron Probe Micro-Analysis
摘要： Dolomite [CaMg(CO3)2] is an important carbonate mineral mainly composed of calcium magnesium carbonate. The correct determination of magnesium content in carbonate rocks is important for accessing its suitability for different applications; however, presence of different phases with varying magnesium contents makes their analysis difficult. In the present work, a natural carbonate mineral dolomite is analyzed qualitatively and quantitatively using laser-induced breakdown spectroscopy along with X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy and electron-probe microanalysis. The optical emission spectra recorded in 200–720 nm wavelength region revealed presence of emission lines for Ca, Mg, Al, Sr, and Na with varying intensities. We used two different techniques, that is, Boltzmann plot and Saha–Boltzmann plot methods to calculate the plasma temperature, and an average value of 4500 ± 450 K was deduced.The Stark broadening line profile method was exploited to calculate the electron number density using calcium and magnesium lines which resulted in 2.39 × 1017 cm–3. The quantitative compositional analysis was carried out using calibration-free laser-induced breakdown spectroscopy method for which the local thermodynamic equilibrium and optically thin plasma conditions were satisfied.The composition for dolomite major constituents calcium and magnesium were estimated as 68.58 and 31.41%, respectively.The results demonstrated the LIBS, EDS, and EPMA ability as an effective, powerful and complementary analytical techniques for the elemental composition analysis of carbonate minerals.
关键词： magnesium,calibration-free laser-induced breakdown spectroscopy,EPMA,plasma diagnostic techniques,dolomite,EDS
更新于2025-09-19 17:13:59
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Mechanism of PbI2 situ-passivated perovskite films for enhancing performance of perovskite solar cells
摘要： Perovskite solar cells have brought tremendous research interests because of their tolerance of defects, low cost, and facile processing. In perovskite solar cells devices, PbI2 has been utilized to passivate defects at perovskite films surface and grain boundaries, yet a systematic mechanism of PbI2 situ-passivating for enhancing the efficiency has not been fully explored. Here, this work systematically studies the role of the precise PbI2 ratio, and the PbI2 situ-passivation mechanism based on trap density, carrier lifetime, and Fermi level etc. This study finds that the appropriate ratio of I:Pb is around 2.57:1 using energy dispersive spectroscopy. After the moderate excess PbI2 situ-passivating, the trap density is reduced from 6.12 × 1016 cm-3 to 3.38 × 1016 cm-3, and the carrier lifetime is extended from 168.35 ps to 368.77 ps by using femtosecond transient absorption spectroscopy. This result indicates that the moderate excess PbI2 situ-passivation can reduce the trap density and suppress non-radiative recombination. The efficiency of solar cell has realized a nearly 11.3% improvement of 19.55% for the I:Pb ratio of 2.57:1 compared with 2.69:1. It demonstrates that the efficiency can be enhanced effectively by PbI2 situ-passivation.
关键词： SnO2,EDS-mapping,transient absorption spectroscopy,perovskite solar cells,PbI2,passivation mechanism
更新于2025-09-12 10:27:22
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European Microscopy Congress 2016: Proceedings || Analytical electron microscopy characterization of light-emitting diodes based on ordered InGaN nanocolumns
摘要： Self-assembled nanocolumns (NCs) with InGaN/GaN disks constitute an alternative to conventional light emitting diodes (LED) planar devices [1]. However, their efficiency and reliability are hindered by a strong dispersion of electrical characteristics among individual nanoLED. Polychromatic emission derives from an inhomogeneous distribution of indium concentration due to the inherent tendency of InGaN alloys to develop composition fluctuations as a function of the polarity of the growth crystallographic planes [2]. The recent development of selective area growth of NCs by molecular beam epitaxy has allowed the achieving of highly homogeneous and controllable GaN/InGaN NCs with improved crystalline quality and higher control over the indium distribution [3]. In this work, we present the characterization performed on LEDs based on ordered NCs with InGaN active disks (figure 1). The detailed structural characterization of the nanostructures has been performed by scanning transmission electron microscopy (STEM) carried out on an aberration-corrected JEOL-JEMARM200 microscope. High crystal quality of the NCs is set by the analysis of atomically-resolved high angle annular dark field (HAADF) images. The indium distribution within the InGaN disks is studied by EDS elemental mapping while the polarity of the semiconductor NCs is followed by locating the nitrogen atomic columns in annular bright field (ABF) images while (figure2). Direct correlation of the optical and structural properties on a nanometer-scale was achieved using low temperature cathodoluminescence (CL) spectroscopy in an FEI STEM Tecnai F20 [4].
关键词： nanowires,EDS,annular bright field,InGaN,LEDs,atomic-resolution STEM
更新于2025-09-12 10:27:22
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Synthesis, characterisation, and antimicrobial activity of ZnO-based nanocomposites
摘要： In this study, ZnO-based nanocomposites including ZnO/CuO (S1), ZnO/MnO (S2), and ZnO/MnO/CuO (S3), were synthesised. S1, S2, and S3 were characterised through Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Also, the antimicrobial property of the samples was examined against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli through the colony forming count method. FTIR analysis confirmed the presence of Zn–O, Mn–O, and Cu–O in the samples. The crystalline structure of the sample was analysed by XRD. The surface morphology of the prepared compounds was studied with SEM images. EDS technique was employed for ensuring the presence of Zn, Mn, and Cu elements in the samples. The results clearly showed S1, S2, and S3 had high-antimicrobial activity especially for S3.
关键词： SEM,EDS,FTIR,XRD,antimicrobial activity,ZnO-based nanocomposites
更新于2025-09-10 09:29:36
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The Effects of Thermal Neutron Irradiation on Current-Voltage and Capacitance-Voltage Characteristics of Au/n-Si/Ag Schottky Barrier Diodes
摘要： To observe the neutron transmutation and displacement damage effects, Au/n-Si/Ag Schottky barrier diodes were exposed to thermal neutron irradiation. Irradiation induced changes in Schottky barrier height, saturation current, and donor concentration were investigated by using current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the diodes. The irradiation for 10 s caused a little change in the Schottky diode parameters which were obtained from I-Vand C-V measurements. Observable changes in the parameters occurred after the second irradiation of 30 s duration. After the total dose, an increase in saturation current and barrier height inhomogeneties took into place and a decrease in carrier concentration was observed due to the carrier removal effect of thermal neutron-induced damages. Whereas the values of zero bias barrier height have little change after irradiations, the values of ideality factor increased after irradiations. The values of zero-bias barrier height for all diodes was also calculated from reverse bias current characteristics. After second dose, the values of zero-bias barrier height decreased for all diodes. The values of series resistance were determined by Cheung functions before and after irradiations. Before irradiations, the values were found between 2.10 kΩ and 2.76 kΩ. After second dose, the values of series resistance of all diodes decreased and were found between 1.59 kΩ and 2.20 kΩ. Furthermore, the proof of thermal neutron transmu- tation of elements in the devices was given via energy dispersive spectroscopy (EDS) mapping.
关键词： Semiconductor device radiation effects,Schottky diode,Electrical characterization,EDS mapping,Silicon,Thermal neutron irradiation
更新于2025-09-04 15:30:14
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An X-ray TES Detector Head Assembly for a STEM–EDS System and Its Performance
摘要： A detector head for an energy-dispersive X-ray spectroscopy (EDS) for a scanning transmission electron microscope (STEM) was designed, fabricated, and tested. A 64-pixel TES X-ray microcalorimeter and 64 SQUID array amplifiers (SAAs) are mounted on a detector head which is cooled to about 100 mK. The body of the detector head is a copper rod of about 1 cm2 cross section and 10 cm length with 3 cm cubic structure at the bottom. The TES microcalorimeter is mounted at the top of the rod while the SAAs are mounted on the four side surfaces of the cubic structure. In order to reduce the number of wire bondings, we adopted a flip-chip bonding for the SAAs. In order to reduce the stress imposed on the flip-chip bondings due to the difference in the linear thermal expansion of the SAA chip and the mounting surfaces, we mounted the SAAs and connectors to the room-temperature electronics on sapphire circuit board and mounted the SAAs and connectors using a superconducting flip-chip bonding technology. Then, both the TES and the sapphire circuit board were mounted on the rod and are connected to the print circuit like superconducting wires, which are created on the multiple surfaces of the rod, with Al wire bondings. We reduced the number of wire bondings from 768 to 256. The yield of the flip-chip bonding was not perfect but relatively high. We installed the detector head in the STEM EDS system, confirmed that the energy resolution and counting requirements, (cid:2)E < 10 eV with 5 kcps were fulfilled.
关键词： EDS,TES,Superconducting flip-chip bonding,STEM
更新于2025-09-04 15:30:14