Crystal Research and Technology最新文献

Cover image provided courtesy of Jianguang Zhou, Research Center for Analytical Instrumentation, Institute of Cyber-Systems and Control, State Key Laboratory of Industrial Control Technology, Zhejiang University, China.

This research presents the successful synthesis of Cu_0.79Co_0.21La_xFe_2-xO₄ (0.0 ≤ x ≤ 0.8) (spinel ferrite) nanoparticles via the sol-gel auto combustion technique, with varying La³⁺ dopant concentrations. In this study, the estimated crystallite size (D) is found to be in the range of (27.92–40.90) nm. The microstructural parameter determination in XRD data is improved using Rietveld refinement. Fourier Transform Infrared Spectroscopy (FTIR) spectra exhibit two distinct metal stretching vibrational bands within (400–600) cm⁻¹ range, a characteristic fingerprint region for all ferrites. Field Emission Scanning Electron Microscopy (FESEM) analysis reveals the agglomeration of particles due to magnetic interactions and non-uniform distribution of average particle sizes ranging from (1.06–1.87) µm. Energy Dispersive X-Ray Analysis (EDX) validates the chemical composition's accuracy. Owing to the dilution effect resulting from the introduction of non-magnetic La³⁺ ions into the ferrite structure, there is a reduction in the saturation magnetization value, decreasing from 37.28 to 6.24 emu g⁻¹ in the Vibrating Sample Magnetometery (VSM) study. The electrochemical analysis reveals the impressive electrochemical characteristics of the newly developed ferrites, highlighting a remarkable specific capacitance of 270.0 F g⁻¹. This finding positions them as highly promising contenders for a wide range of energy storage supercapacitor applications.

I am very glad to share that our SSN Research Centre, Department of Physics, and SSN Institutions in association with the International Organization for Crystal Growth and Indian Association for Crystal Growth had organized the 3rd International Symposium on “Modeling of Crystal Growth Processes and Devices (MCGPD-2023)” during March 06–08, 2023. The 3 days international symposium was highly propitious for the researchers who are working in the field of modeling and simulation of various crystal growth processes, semiconductor devices, NLO, and piezoelectric devices. The goal of the symposium was to give a fundamental understanding of modeling prospects to young researchers in exploring recent and advanced developments. The symposium included 31 Plenary/Keynote/Invited lectures by eminent experts from foreign and Indian institutions. Around 230 posters/oral presentations from the researchers were presented. Professors/Scientists from leading crystal growth countries like the USA, Israel, Japan, Germany, France, Russia, Romania, and Taiwan participated and presented their work in the symposium. In our country, Professors/Scientists, and young researchers from various leading institutes like IITs, IISc, CSIR labs, Central and state universities, and colleges took active participation.

The 3 days symposium was conducted in 12 technical sessions, which were constituted of 25 Keynote lectures, 6 Plenary talks, and 230 post/oral presentations. The symposium started with a welcome address by Prof. P. Ramasamy, President of the Indian Association for Crystal Growth, following that Prof. Umesh V Wgahmare, President, IASc, Banglore, and Prof. Noritaka Usami, Nagoya University, Japan gave Chief Guest addresses. The symposium was inaugurated with the release of the MCGPD-2023 abstract book by Prof. Koichi Kakimoto, President of the International Organization for Crystal Growth, and felicitated by Prof. Kozo Fujiwara, Tohoku University, Japan, and Prof. Jyh-Chen Chen, Vice-President, National Central University Taiwan, etc.,

The main motive of the 2nd Indo-Japan Joint Workshop on Photovoltaics (IJWP-2023) workshop was to bring together eminent researchers from India and Japan to share their ideas and recent developments in the field of photovoltaic technologies. Around 70 abstracts have been submitted to IJWP-2023, of which only high-quality papers are accepted to be presented as posters in this event. The chief highlights of this workshop are the 13 talks delivered by distinguished scientists like Prof. Noritaka Usami, Nagoya University, Prof. Yoshitaka Okada, RCAST, The University of Tokyo, Dr.Kosuke O. Hara, University of Yamanashi, Dr. Kentaro Kutsukake, RIKEN, Nagoya University, Dr.Yutaka Ohno, Tohoku University, Dr.P.Ramasamy, SSN Institutions, Dr. Anil Kottantharayil IIT Bombay, Dr. J. K. Bath IIT Madras, Dr. Vamsi Krishna IIT Delhi, Dr. C.V Kannan, Adani Solar, Dr. Sanjay K. Srivastava NPL, Dr S Sudhakar, CSIR-CEERI, Dr.Ka

Recovering manganese from waste batteries is an important issue to promote the development of new energy. Herein, nickel sulfate and cobalt sulfate, representative impurities in waste battery leachate, are selected to examine their influence on the crystallization thermodynamics and crystal nucleation of manganese sulfate monohydrate. This work assessed alterations in solubility and metastable zone width (MSZW) due to the presence of impurities. The results showed a decrease in manganese sulfate monohydrate solubility in water with increasing impurity concentrations of either nickel sulfate or cobalt sulfate. The effects of initial concentration, heating rate, and impurity concentration on MSZW demonstrated a consistent increase in MSZW as these factors increased. The MSZW data are fitted using the self-consistent Nývlt-like model and the classical 3D nucleation theory model. The results revealed a general increase in the nucleation rate constant, K, with increasing saturation temperature or decreasing nickel sulfate concentration. Conversely, the solid-liquid interface energy, γ, generally decreases with increasing saturation temperature or decreasing nickel sulfate concentration. Based on the influence observed on the interface energy, a possible mechanism is proposed that suggests that impurities inhibit crystal nucleation through adsorption.

Herein transparent iron nanosheets deposited by the ionic coating technique onto glass and WO₃ dielectric lenses are studied and characterized. The thickness of Fe nanosheets is varied in the range of 70–350 nm. It is observed that the transmittance and reflectance of the Fe nanosheets are highly affected by the layer roughness. Coating of iron nanosheets onto WO₃ dielectric lenses increases the light absorption of WO₃ by more than 240 times and red-shifts the energy bandgap. Remarkable enhancements in the dielectric constant and in the optical conductivity are achieved via Fe coatings. In addition, iron coated dielectric lenses show higher terahertz cutoff limits varying in the range of 1.0–30 THz. Iron nanosheets remarkably increase the free charge carrier density and plasmon frequency in the infrared range of light. Moreover, the temperature dependent electrical conductivity shows high temperature stability and an increased electrical conductivity by more than 7 orders of magnitude by coating WO₃ with 70 nm thick Fe nanosheets. The stability of the electrical conductivity at low temperatures and the wide range of terahertz cutoff limits in addition to the well-enhanced light absorbability makes the iron coated tungsten oxide dielectric lenses promising for multifunction optoelectronic applications.

In this communication, the synthesis and characterizations of modified strontium manganate (SrCu_1/3Mn_1/3W_1/3O₃) (SCMWO) by high-temperature solid-state method are reported. The structural analysis predicts a monoclinic structure with a crystallite size of 36.8 nm. The analysis of the Raman active modes reveals the presence of all the constituent atomic vibrations. The study of the ultraviolet–visible spectrum provides a bandgap energy of 1.71 eV, which may be suitable for photovoltaic applications. A Maxwell-Wanger type of polarization effect is observed at low frequency while low dielectric loss makes the material suitable for energy storage devices. The study of the impedance plots reveals the negative temperature coefficient of resistance (NTCR) character. The activation energy increases with both frequency and temperature in the modified perovskite suggesting that conductivity of the sample increases and material characters are changing from dielectric to semiconducting. The symmetrical curves in the electrical modulus plots and shift toward higher frequency region agree with the results of the non-Debye-type of relaxation mechanism. The semicircular curves in the Cole–Cole plots confirm the semiconducting nature and are also well supported by the results of Nyquist plots. The studied material exhibits a semiconductor nature, which may be found suitable for energy storage device applications.

In this study, two morphologies of cerium oxide (CeO₂) abrasive particles, octahedral and spheroidal, are synthesized by solvothermal method using cerium nitrate hexahydrate (Ce(NO₃)₃-6H₂O) as raw material. Fourier infrared spectroscopy, X-ray diffractometer (XRD) and scanning electron microscopy (SEM) are used to characterize the composition and morphology of CeO₂ abrasive particles. The synthesized CeO₂ is used for chemical mechanical polishing (CMP) of the Si surface of 6H-SiC wafers, and the surface morphology of the polished wafers are observed using atomic force microscopy (AFM). After polishing with octahedral and spheroidal abrasive particles, the surface roughness of the wafers are 0.327 and 0.287 nm, and the material removal rates (MRR) are 870 and 742 nm h⁻¹, respectively. Calculations comparing the ultraviolet absorption spectra and bandgap energies of the two types of abrasive particles as well as molecular dynamics (MD) simulations reveal that the synthesized octahedral CeO₂ particles possessed stronger surface chemical activity and material removal performance.

In Cz–Si growth, the shape of the solid–liquid interface and the v/G ratio significantly impact crystal quality. This study utilizes a data-driven approach, employing multilayer perceptron (MLP) neural networks and Bayesian optimization, to investigate the scale-up process of Cz–Si under conditions of partial similarity. The focus is on exploring the influence of various process and furnace geometry parameters, as well as radiation shield material properties, on the critical measures of crystal quality. Axisymmetric CFD modeling produces 340 sets of 18D raw data, from which 14-dimensionless derived data tuples are generated for the design and training of the MLP. The best MLP obtained demonstrates the ability to accurately assess the complex nonlinear dependencies among dimensionless numbers derived from CFD data and, on the output side, interface deflection and v/G. These relationships, crucial for scale-up, are successfully generalized across a wide range of parameters.

In this study, Cadmium Sulfide (CdS) semiconductor films are electrodeposited on Indium Tin Oxide (ITO) substrates at 80 °C base temperature for different boric acid (H₃BO₃) ratios. The effect of boric acid on these films is investigated. For this, first of all, the structural change of the films is examined. Among the films obtained with different boric acid ratios, the optimum film is achieved with 0.06 m boric acid doped. From the basic absorption spectra (αhʋ) of the obtained CdS:B films, the variation of hʋ is drawn and it is determined that the CdS:B semiconductor films has a direct band transition. From the basic absorption spectra of the obtained CdS:B films, it is observed that the CdS:B semiconductor films has a direct band transition. In addition, the optical energy bandgap values obtained are in agreement with the values in the available literatures. The results of the structural, optical, and morphological properties of the films produced in this study indicate that among the selected additive ratios, 1% boric acid gives the best and optimum deposition condition. The thin films obtained are also found to be useful as absorber layers in photovoltaic solar cells.