- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Comparative study of radiation defect dynamics in 3C-SiC by X-ray diffraction, Raman scattering, and ion channeling
摘要： At moderately elevated temperatures, radiation defects in SiC exhibit pronounced dynamic annealing, which remains poorly understood. Here, we study 3C-SiC bombarded at 100°C with pulsed beams of 500 keV Ar ions. Radiation damage is monitored by a combination of X-ray diffraction, Raman scattering, and ion channeling. Similar damage buildup behavior but with different defect relaxation time constants, ranging from ～1 to ～6 ms, is observed for the different types of lattice defects probed by these techniques. A correlation between relaxation times and the nature of the defects is proposed. These results reveal additional complexity of radiation defect dynamics in SiC and demonstrate that results of different defect characterization techniques are needed for a better understanding of dynamic annealing processes in solids.
关键词： X-ray diffraction,Ion channeling,Raman scattering,Dynamic annealing,Radiation defects,3C-SiC
更新于2025-09-23 15:19:57
-
Hydration of Ti3C2Tx MXene: an interstratification process with major implications on physical properties
摘要： The MXenes, among which Ti3C2Tx is the most studied, are a large family of 2D materials with proven potential in a variety of application fields (e.g., energy storage and conversion, water purification, electromagnetic interference shielding, humidity sensor, etc). For most of these applications, MXenes properties depend, at least partly, on their water sorption ability and on the induced structural swelling, which is commonly considered a stepwise process, like in clay-like materials. In the present study, we rather evidence the systematic coexistence of different hydrates in MXene interstratified crystals. Hydration heterogeneity and related structure disorder are described from the quantitative analysis of X-ray diffraction data. This specific methodological approach allows disentangling the complex interstratification and rationalizing the prediction of MXene electrical properties. The widespread use of this approach paves the way for a systematic and thorough determination of MXene structure, including order-disorder, and thus for grasping the influence of structural disorder (hydration heterogeneity) on a large number of MXene physical properties (e. g. optical transparency, capacitance). Deciphering this complex structural disorder is also essential in the design of new MXene-based materials for a variety of applications (supercapacitors, batteries, water treatment…).
关键词： MXenes,Ti3C2Tx,electrical properties,X-ray diffraction,hydration,interstratification
更新于2025-09-23 15:19:57
-
Investigation of Dimethylammonium Solubility in MAPbBr <sub/>3</sub> Hybrid Perovskite: Synthesis, Crystal Structure, and Optical Properties
摘要： The possible existence of mixed methylammonium (MA)/dimethylammonium (DMA) lead bromide hybrid perovskites of general formula MA1?xDMAxPbBr3 (0 ≤ x ≤ 1) was investigated. A combined X-ray di?raction and solid-state nuclear magnetic resonance approach indicates that DMA can be incorporated up to about x = 0.30 while retaining the cubic lattice of MAPbBr3. By increasing the DMA content (x), the absorption shows a progressive blue shift and the band gap moves from about 2.17 eV (x = 0) to about 2.23 (x = 0.30) with a concomitant slightly faster recombination in the mixed cation powders.
关键词： X-ray diffraction,hybrid perovskites,optical properties,mixed methylammonium,solid-state nuclear magnetic resonance,lead bromide,dimethylammonium
更新于2025-09-23 15:19:57
-
Investigation of Statistical Broadening in InGaN Alloys
摘要： Optical and structural properties of thick InGaN layers grown by MOCVD and MBE were studied by photoluminescence, optical transmission and Raman spectroscopies and X-ray diffraction analysis. Optical bandgap, Urbach energy, and full widths at half maximum (FWHM) of photoluminescence and Raman spectra depending on the InGaN alloy composition were determined experimentally. Minimal theoretical linewidth of photoluminescence spectra resulted from random distribution of In and Ga atoms in cation sublattice was calculated.
关键词： optical bandgap,photoluminescence,Urbach energy,X-ray diffraction,InGaN,Raman spectroscopy
更新于2025-09-23 15:19:57
-
European Microscopy Congress 2016: Proceedings || Indexation of diffraction patterns for overlapping crystals in TEM thin foils - Application to orientation mappings
摘要： Application of diffraction gratings for overcoming limitations in organic light-emitting diodes (OLEDs) for displays. The study focuses on enhancing light extraction efficiency and managing color shifts in OLEDs using a novel grating design. The experimental approach involves fabricating and characterizing grating structures on OLED substrates, with results showing significant improvements in efficiency and color stability compared to conventional methods.
关键词： diffraction gratings,color shift,efficiency,OLEDs,light extraction
更新于2025-09-19 17:15:36
-
Principles for Sensitive and Robust Biomolecular Interaction Analysis: The Limits of Detection and Resolution of Diffraction-Limited Focal Molography
摘要： Label-free biosensors enable the monitoring of biomolecular interactions in real time, which is key to the analysis of the binding characteristics of biomolecules. While refractometric optical biosensors such as surface plasmon resonance (SPR) are sensitive and well-established, they are susceptible to any change of the refractive index in the sensing volume caused by minute variations in composition of the sample buffer, temperature drifts, and most importantly nonspecific binding to the sensor surface in complex fluids such as blood. The limitations arise because refractometric sensors measure the refractive index of the entire sensing volume. Conversely, diffractometric biosensors–for example, focal molography–only detect the diffracted light from a coherent assembly of analyte molecules. Thus any refractive index distribution that is noncoherent with respect to this molecular assembly does not add to the coherent signal. This makes diffractometric biosensors inherently robust and enables sensitive measurements without reference channels or temperature stabilization. The coherent assembly is generated by selective binding of the analyte molecules to a synthetic binding pattern–the mologram. Focal molography has been introduced theoretically [C. Fattinger, Phys. Rev. X 4, 031024 (2014)] and verified experimentally [V. Gatterdam, A. Frutiger, K.-P. Stengele, D. Heindl, T. Lübbes, J. V?r?s, and C. Fattinger, Nat. Nanotechnol. 12, 1089 (2017)] in previous papers. However, further understanding of the underlying physics and a diffraction-limited readout is needed to unveil its full potential. This paper introduces refined theoretical models, which can accurately quantify the amount of biological matter bound to the mologram from the diffracted intensity. In addition, it presents measurements of diffraction-limited molographic foci, i.e., Airy discs. These improvements enable us to demonstrate a resolution in real-time binding experiments comparable to the best SPR sensors without the need for temperature stabilization or drift correction and to detect low-molecular-weight compounds label free in an endpoint format. The presented experiments exemplify the robustness and sensitivity of the diffractometric sensor principle.
关键词： biomolecular interaction analysis,diffractometric biosensors,focal molography,diffraction-limited foci,robustness,label-free detection,sensitivity
更新于2025-09-19 17:15:36
-
Investigation on growth, physico-chemical properties, density functional theory and anti-microbial studies of a new organic acentric NLO crystal: Bis (2-aminobenzimidazolium) phthalate
摘要： Highly transparent NLO crystal bis (2-aminobenzimidazolium) phthalate (B2ABP) was successfully grown by solvent evaporation method. The lattice parameters and crystalline nature were confirmed by X-ray diffraction studies. The FT-IR and Raman spectrum were used to assert the various functional groups present in title compound. NMR studies evidently portray the molecular structure of the grown crystals. A UV study shows the high transmittance range of B2ABP crystal. Photoluminescence study shows sharp emission peak. The mechanical stability of the grown crystal was investigated by Vickers microhardness test. Etching studies were carried for the grown crystal. The dielectric studies have been carried out as a function of frequency at different temperatures. SHG efficiency was found to be 1.9 times greater than that of standard KDP. Laser damage threshold value for B2ABP was found to be 2.2 GW/cm2. Melting point of B2ABP was studied by means of TG-DTA studies. HOMO-LUMO energy gap and first order hyperpolarizability value was theoretically predicted. The anti-microbial activity of B2ABP was determined.
关键词： SHG,Anti-microbial activity,TG-DTA,2-Aminobenzimidazole,Dielectric,X-ray diffraction
更新于2025-09-19 17:15:36
-
Growth, Thermal and Spectroscopic Studies of Bis-thiourea Nickel Barium Chloride Single Crystals
摘要： Bis-thiourea nickel barium chloride was synthesized and crystals were grown by slow aqueous solvent evaporation technique. The powder XRD analysis of grown crystal was suggested to have orthorhombic crystal structure. The unit cell parameters of grown crystal as: a = 9.70 ?, b = 10.68 ? and c = 17.95 ?. The contents of nickel and barium in the grown crystals was analyzed using EDAX. The presence of various functional groups was confirmed by FTIR spectroscopy studies. From the UV-visible spectrum, the material has about 90 % optical transparency in the entire visible region. From the thermogravimetric analysis, it was found that the crystals remained stable up to 170 oC. The endothermic reactions were identified from the differential thermal analysis.
关键词： Crystal growth,Slow evaporation technique,Bis-thiourea nickel barium chloride,Powder X-ray diffraction
更新于2025-09-19 17:15:36
-
Why it is so hard to detect Luttinger liquids in angle resolved photo-emission spectroscopy?
摘要： The problem of photoemission from a quasi-1D material is studied. We identify two issues that play a key role in the detection of gapless Tomonaga–Luttinger liquid (TLL) phase. Firstly, we show how a disorder—backward scattering as well as forward scattering component—is able to significantly obscure the TLL states, hence the initial state of angle resolved photo-emission spectroscopy (ARPES). Secondly, we investigate the photo-electron propagation towards a sample’s surface. We focus on the scattering path operator contribution to the final state of ARPES. We show that, in the particular conditions set by the 1D states, one can derive an exact analytical solution for this intermediate stage of ARPES. The solution shows that for particular energies of incoming photons the intensity of photo-current may be substantially reduced. Finally, we put together the two aspects (the disorder and the scattering path operator) to show the full, disruptive force of any inhomogeneities on the ARPES amplitude.
关键词： nanotubes,Fresnel diffraction,quasi-1D materials,disorder,ARPES,Tomonaga–Luttinger liquids
更新于2025-09-19 17:15:36
-
Structural, photoluminescence and dielectric investigations of phosphatic shale
摘要： In the current study, the structural and spectroscopic properties of phosphatic shale samples obtained from the Atomic Minerals Directorate for Exploration and Research were probed for potential use as a phosphor material. X‐ray diffraction and Raman and Fourier transform infrared spectroscopy revealed that the beneficiated phosphatic shale samples were primarily monophasic consisting of fluorapatite [Ca5(PO4)3F, (FAP)] with minor traces of haematite (α‐Fe2O3) and calcite (CaCO3). Energy dispersive X‐ray fluorescence revealed the presence of U, Eu, Dy and Tb in the FAP matrix substituted at Ca(I) and Ca(II) sites of FAP. A reduced optical direct band gap of 4.46 eV was calculated from the Tauc plot. Photoluminescence spectral studies revealed multicolour emissions (red, yellow, green and blue) on ultraviolet light excitation that were attributed to luminescence spectra from rare earth ions Eu3+, Tb3+, U4+ and U6+ in the FAP matrix. The overall emissions for the rare earth and actinide‐doped FAP were obtained in the cool white region and the corresponding Commission Internationale de l’Eclairage chromaticity coordinates were calculated to be (0.274, 0.317). The corresponding colour correlated temperature obtained was 9342 K. Furthermore, phosphatic shale had a high room temperature dielectric constant of 11 at a frequency of 1 kHz that demonstrated its suitability for use in biological sensors. The study showed that natural phosphatic shale could be a potential material for optical, biological and dielectric applications.
关键词： dielectric studies,photoluminescence,phosphor,X‐ray diffraction
更新于2025-09-19 17:15:36