Pub Date : 2025-11-19DOI: 10.1016/j.jcrysgro.2025.128422
Umar Bashir , Saud Bin Anooz , Martin Schmidbauer , Lukas M. Eng , Matthias Bickermann , Steffen Ganschow
The compositional homogeneity of nominally LiNb1−xTaxO3 (x = 0.45) single crystals is studied using micro-X-ray fluorescence and high-resolution X-ray diffraction. Highly homogeneous regions are reported with less than 1 % Ta variation over areas as large as 4 × 4 mm2 in z-cut specimens. To our knowledge, this represents the most detailed study of homogeneity in lithium niobate tantalate (LNT) solid solutions to date, establishing a quantitative benchmark for future studies. Spectroscopic ellipsometry shows a decreasing refractive index and blue-shift in optical absorption with increasing Ta content, while the dielectric response remains structurally consistent. These investigations establish a quantitative benchmark for selecting compositionally homogeneous LNT crystals suitable for applications such as second-harmonic generation, Raman spectroscopy, piezoresponse force microscopy, and domain wall conductivity.
{"title":"Structural and optical characterization of highly homogeneous lithium niobate tantalate single-crystal solid solutions","authors":"Umar Bashir , Saud Bin Anooz , Martin Schmidbauer , Lukas M. Eng , Matthias Bickermann , Steffen Ganschow","doi":"10.1016/j.jcrysgro.2025.128422","DOIUrl":"10.1016/j.jcrysgro.2025.128422","url":null,"abstract":"<div><div>The compositional homogeneity of nominally LiNb<sub>1−x</sub>Ta<sub>x</sub>O<sub>3</sub> (x = 0.45) single crystals is studied using micro-X-ray fluorescence and high-resolution X-ray diffraction. Highly homogeneous regions are reported with less than 1 % Ta variation over areas as large as 4 × 4 mm<sup>2</sup> in z-cut specimens. To our knowledge, this represents the most detailed study of homogeneity in lithium niobate tantalate (LNT) solid solutions to date, establishing a quantitative benchmark for future studies. Spectroscopic ellipsometry shows a decreasing refractive index and blue-shift in optical absorption with increasing Ta content, while the dielectric response remains structurally consistent. These investigations establish a quantitative benchmark for selecting compositionally homogeneous LNT crystals suitable for applications such as second-harmonic generation, Raman spectroscopy, piezoresponse force microscopy, and domain wall conductivity.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"676 ","pages":"Article 128422"},"PeriodicalIF":2.0,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-19DOI: 10.1016/j.jcrysgro.2025.128424
Mirza Nusrat Sweety , Shariful Islam
A novel crystallographic study has been conducted on a simplified synthesis of anatase TiO2 nanocrystals derived from a sol–gel process, utilizing TTIP as the precursor at a pH of 2, assisted by ultrasonic means. The Reitveld refinement analysis performed using whole powder pattern fitting (WPPF) confirmed the complete formation of the TiO2 anatase, verifying its tetragonal structure [α = β = γ = 90.0°; a = b = 3.7877 Å, c = 9.5090 Å]. Peak profiling indicated that the highest preferred orientation occurred along the (1 0 1) plane at 2θ = 25.357°, with a d-spacing of 0.35096 nm and an intensity of 6913 cps. The computed unit cell volume was 136.424 Å3, and additional measurements indicated a dislocation density of 0.00615 nm−2, lattice strain of 0.58 %, microstrain of 0.00815, crystallinity of 63.279 %, and a crystallinity index of 1.37, all suggesting lattice expansion and a significant capacity for defect tolerance, crucial for applications in electronics and catalysis. According to the Scherrer equation, the average crystallite size was determined to be 12.75 nm; using the Monshi-Scherrer model, it was calculated at 12.17 nm; the Williamson-Hall model yielded 27.57 nm; the LSLM of the Scherrer equation resulted in 13.57 nm; the Size-Strain plot model estimated it to be 6.48 nm; and the Halder-Wagner model provided a size of 7.20 nm. Energy dispersive spectroscopy (EDS) analysis confirmed the elemental purity, showing 34.89 % Ti and 65.11 % O, while scanning electron microscopy (SEM) revealed a uniform distribution of non-clumped nanoparticles. The UV study show cased that a blue-shifted intense absorption peak of TA (3.31 eV) compared to the bulk material reported in the literature (3.2 eV). The maximum photo-degradation efficiency under the dosage 30 mg, initial dye concentration 10 ppm, degradation time 60 min were found to be 98.8 %. By integrating a straightforward synthesis approach with comprehensive refinement, this detailed analysis of structural, optical and surface morphology along with photo-catalytic activity provides a reliable foundation for the production of pure anatase phase TiO2 nanocrystals.
{"title":"A reitveld refinement in WPPF analysis for crystallographic behavior study of nanocrystal anatase TiO2 synthesized by ultrasonic-assisted sol–gel method and its photocatalytic activity","authors":"Mirza Nusrat Sweety , Shariful Islam","doi":"10.1016/j.jcrysgro.2025.128424","DOIUrl":"10.1016/j.jcrysgro.2025.128424","url":null,"abstract":"<div><div>A novel crystallographic study has been conducted on a simplified synthesis of anatase TiO<sub>2</sub> nanocrystals derived from a sol–gel process, utilizing TTIP as the precursor at a pH of 2, assisted by ultrasonic means. The Reitveld refinement analysis performed using whole powder pattern fitting (WPPF) confirmed the complete formation of the TiO<sub>2</sub> anatase, verifying its tetragonal structure [α = β = γ = 90.0°; a = b = 3.7877 Å, c = 9.5090 Å]. Peak profiling indicated that the highest preferred orientation occurred along the (1<!--> <!-->0<!--> <!-->1) plane at 2θ = 25.357°, with a d-spacing of 0.35096 nm and an intensity of 6913 cps. The computed unit cell volume was 136.424 Å<sup>3</sup>, and additional measurements indicated a dislocation density of 0.00615 nm<sup>−2</sup>, lattice strain of 0.58 %, microstrain of 0.00815, crystallinity of 63.279 %, and a crystallinity index of 1.37, all suggesting lattice expansion and a significant capacity for defect tolerance, crucial for applications in electronics and catalysis. According to the Scherrer equation, the average crystallite size was determined to be 12.75 nm; using the Monshi-Scherrer model, it was calculated at 12.17 nm; the Williamson-Hall model yielded 27.57 nm; the LSLM of the Scherrer equation resulted in 13.57 nm; the Size-Strain plot model estimated it to be 6.48 nm; and the Halder-Wagner model provided a size of 7.20 nm. Energy dispersive spectroscopy (EDS) analysis confirmed the elemental purity, showing 34.89 % Ti and 65.11 % O, while scanning electron microscopy (SEM) revealed a uniform distribution of non-clumped nanoparticles. The UV study show cased that a blue-shifted intense absorption peak of T<sub>A</sub> (3.31 eV) compared to the bulk material reported in the literature (3.2 eV). The maximum photo-degradation efficiency under the dosage 30 mg, initial dye concentration 10 ppm, degradation time 60 min were found to be 98.8 %. By integrating a straightforward synthesis approach with comprehensive refinement, this detailed analysis of structural, optical and surface morphology along with photo-catalytic activity provides a reliable foundation for the production of pure anatase phase TiO<sub>2</sub> nanocrystals.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"675 ","pages":"Article 128424"},"PeriodicalIF":2.0,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-17DOI: 10.1016/j.jcrysgro.2025.128420
C.W. Lan
Step-flow dynamics during SiC solution growth critically shape surface morphology and defect formation, yet conventional models often average step densities or encounter front-tracking singularities, missing transient bunching and debunching. We introduce a quasi-discrete 2D/3D model that couples advection–diffusion transport with Gaussian-regularized Robin boundary conditions, representing macrosteps as localized, integral-matched sinks. Each macrostep is resolved by a few Gaussian-weighted nodes while solute transport is computed on a fine finite-element mesh, ensuring stability and mass conservation. Simulations reveal that parallel flow drives strong bunching, producing wide terraces with amplified supersaturation; bunched steps advance more slowly due to solute depletion, while high-supersaturation pockets accelerate leading steps and trigger debunching. Conversely, anti-parallel flow advects depletion upstream and preserves uniform step spacing, with no bunching across tested conditions. In three dimensions, parallel flow yields stripe coalescence, while anti-parallel flow stabilizes step trains. By quantifying terrace supersaturation’s link to polytype nucleation, this robust, efficient model offers a predictive tool for optimizing step morphology and minimizing defects in high-quality SiC crystal growth.
{"title":"Quasi-discrete modeling of step-flow dynamics: capturing bunching and debunching in sic solution growth","authors":"C.W. Lan","doi":"10.1016/j.jcrysgro.2025.128420","DOIUrl":"10.1016/j.jcrysgro.2025.128420","url":null,"abstract":"<div><div>Step-flow dynamics during SiC solution growth critically shape surface morphology and defect formation, yet conventional models often average step densities or encounter front-tracking singularities, missing transient bunching and debunching. We introduce a quasi-discrete 2D/3D model that couples advection–diffusion transport with Gaussian-regularized Robin boundary conditions, representing macrosteps as localized, integral-matched sinks. Each macrostep is resolved by a few Gaussian-weighted nodes while solute transport is computed on a fine finite-element mesh, ensuring stability and mass conservation. Simulations reveal that parallel flow drives strong bunching, producing wide terraces with amplified supersaturation; bunched steps advance more slowly due to solute depletion, while high-supersaturation pockets accelerate leading steps and trigger debunching. Conversely, anti-parallel flow advects depletion upstream and preserves uniform step spacing, with no bunching across tested conditions. In three dimensions, parallel flow yields stripe coalescence, while anti-parallel flow stabilizes step trains. By quantifying terrace supersaturation’s link to polytype nucleation, this robust, efficient model offers a predictive tool for optimizing step morphology and minimizing defects in high-quality SiC crystal growth.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"675 ","pages":"Article 128420"},"PeriodicalIF":2.0,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145532754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-16DOI: 10.1016/j.jcrysgro.2025.128421
Lin Hou , Dedong Gao , Shan Wang , Wenyong Zhang , Haixin Lin , Yan An , Xin Liu
In the manufacturing of Czochralski-grown silicon single crystals, production control mainly relies on operator experience and conventional feedback strategies, which are often insufficient for addressing the nonlinear, time-varying nature and sensitivity to disturbances of the process. Consequently, real-time tracking of key parameter dynamics remains challenging, resulting in adjustment delays and limiting improvements in product quality and production efficiency. To overcome these challenges, this study proposes a hybrid framework that integrates a Particle Swarm Optimization (PSO)-based Long Short-Term Memory (LSTM) prediction model with a Model-Free Adaptive Control (MFAC) method. PSO is employed to optimize the hyperparameters of LSTM and MFAC, thereby improving prediction accuracy and enhancing the responsiveness and stability of diameter regulation. Experimental results demonstrate that the PSO-LSTM prediction model significantly improves prediction accuracy, enabling more effective decision support during crystal growth. Moreover, the combined PSO-MFAC strategy achieves faster diameter control response than traditional PID control. This work integrates predictive modeling and advanced control techniques into the Czochralski silicon crystal growth process, offering a practical approach to enhancing production reliability and efficiency.
{"title":"Particle swarm optimization-optimized long short-term memory prediction and Model-Free Adaptive Control for Czochralski silicon crystal growth","authors":"Lin Hou , Dedong Gao , Shan Wang , Wenyong Zhang , Haixin Lin , Yan An , Xin Liu","doi":"10.1016/j.jcrysgro.2025.128421","DOIUrl":"10.1016/j.jcrysgro.2025.128421","url":null,"abstract":"<div><div>In the manufacturing of Czochralski-grown silicon single crystals, production control mainly relies on operator experience and conventional feedback strategies, which are often insufficient for addressing the nonlinear, time-varying nature and sensitivity to disturbances of the process. Consequently, real-time tracking of key parameter dynamics remains challenging, resulting in adjustment delays and limiting improvements in product quality and production efficiency. To overcome these challenges, this study proposes a hybrid framework that integrates a Particle Swarm Optimization (PSO)-based Long Short-Term Memory (LSTM) prediction model with a Model-Free Adaptive Control (MFAC) method. PSO is employed to optimize the hyperparameters of LSTM and MFAC, thereby improving prediction accuracy and enhancing the responsiveness and stability of diameter regulation. Experimental results demonstrate that the PSO-LSTM prediction model significantly improves prediction accuracy, enabling more effective decision support during crystal growth. Moreover, the combined PSO-MFAC strategy achieves faster diameter control response than traditional PID control. This work integrates predictive modeling and advanced control techniques into the Czochralski silicon crystal growth process, offering a practical approach to enhancing production reliability and efficiency.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"675 ","pages":"Article 128421"},"PeriodicalIF":2.0,"publicationDate":"2025-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.jcrysgro.2025.128418
M. Naddaf
In this report, amorphous silica powder was extracted from an open atmosphere burned wild barley (Hordeum murinum ssp. leporinum) straw using the alkali leaching method. Nitrogen adsorption–desorption measurements, energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) results, and analysis reveal that the as-extracted amorphous silica is mesoporous with a large surface area (357 m2/g) and somewhat high content of carbon. X-ray diffraction (XRD) patterns showed that the extracted silica crystallized into the cristobalite phase, on heating it in an air atmosphere for 90 min at 1000 ˚C. The effect of the crystallization process on morphological and structural properties of porous silicon (PSi) produced from the extracted silica by magnesiothermic reduction has been investigated. The reduction process of the amorphous extracted silica resulted in the formation of a mixed phase of cubic Si and silicon carbide (SiC), which has a crystallinity index of 52 %, meso/micropores embedded in macro-size voids, average size of Si crystallites of ∼ 70 nm, and specific surface area of ∼ 160 m2/g. In comparison, the PSi produced from the crystallized silica exhibited a single cubic silicon nanocrystalline phase, higher purity, better crystallinity and a smaller average size of Si nano-crystallites. These suggest that the pre-crystallization of agriculture-derived silica precursor can be used as an effective way to produce high-quality PSi. The present work contributes to the previous reported literature on HF-free synthesis of PSi, a promising material for a wide range of applications.
{"title":"Porous silicon prepared by magnesiothermic reduction of silica extracted from a barley straw: Effect of silica crystallization","authors":"M. Naddaf","doi":"10.1016/j.jcrysgro.2025.128418","DOIUrl":"10.1016/j.jcrysgro.2025.128418","url":null,"abstract":"<div><div>In this report, amorphous silica powder was extracted from an open atmosphere burned wild barley (Hordeum murinum ssp. leporinum) straw using the alkali leaching method. Nitrogen adsorption–desorption measurements, energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FTIR) results, and analysis reveal that the as-extracted amorphous silica is mesoporous with a large surface area (357 m<sup>2</sup>/g) and somewhat high content of carbon. X-ray diffraction (XRD) patterns showed that the extracted silica crystallized into the cristobalite phase, on heating it in an air atmosphere for 90 min at 1000 ˚C. The effect of the crystallization process on morphological and structural properties of porous silicon (PSi) produced from the extracted silica by magnesiothermic reduction has been investigated. The reduction process of the amorphous extracted silica resulted in the formation of a mixed phase of cubic Si and silicon carbide (SiC), which has a crystallinity index of 52 %, meso/micropores embedded in macro-size voids, average size of Si crystallites of ∼ 70 nm, and specific surface area of ∼ 160 m<sup>2</sup>/g. In comparison, the PSi produced from the crystallized silica exhibited a single cubic silicon nanocrystalline phase, higher purity, better crystallinity and a smaller average size of Si nano-crystallites. These suggest that the pre-crystallization of agriculture-derived silica precursor can be used as an effective way to produce high-quality PSi. The present work contributes to the previous reported literature on HF-free synthesis of PSi, a promising material for a wide range of applications.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"674 ","pages":"Article 128418"},"PeriodicalIF":2.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145578077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.jcrysgro.2025.128417
J. Nava-Martínez , M. Ballesteros-Balbuena , O.F. Olea-Mejía , A.R. Vilchis-Néstor , V.H. Castrejón-Sánchez , S. Camacho-López , M. Camacho-López
In the present work commercial zinc primer was used for the synthesis of sea urchin-like zinc oxide nanostructures. Zn primer was deposited on ceramic square plates followed by drying at ambient conditions. Using a tubular furnace, these samples were subjected to thermal oxidation at 420 °C in air for different treatment times in the range from 20 to 360 min. This allowed us to follow the growth of sea urchin-like nanostructures by scanning electron microscopy (SEM), where we found that the length of the needles of the sea urchin-like nanostructures becomes longer as the thermal oxidation time increases. A series of samples synthesized at 420 °C for 100, 180, and 360 min were prepared to be characterized by Raman spectroscopy, X-Ray diffraction, and scanning electron microscopy (SEM). The Raman spectra indicate the formation of nanometric ZnO in all prepared samples. The X-ray diffractograms gave evidence of a mixture of Zn and ZnO in all samples. Once properly characterized, these samples were used to perform adsorption tests of the model molecule Methylene Blue (MB). All three samples proved effective for MB removal at 78 % efficiency. The results presented in this work, show that the simple and low cost method of using a commercially available primer on ceramic substrates, and its thermal treatment in a conventional furnace, presents a simple and reproducible approach to obtaining sea urchin-like ZnO nanostructures with excellent adsorption retention features of MB dye.
{"title":"Sea urchin-like ZnO nanostructures from a zinc commercial primer for removal of methylene blue dye","authors":"J. Nava-Martínez , M. Ballesteros-Balbuena , O.F. Olea-Mejía , A.R. Vilchis-Néstor , V.H. Castrejón-Sánchez , S. Camacho-López , M. Camacho-López","doi":"10.1016/j.jcrysgro.2025.128417","DOIUrl":"10.1016/j.jcrysgro.2025.128417","url":null,"abstract":"<div><div>In the present work commercial zinc primer was used for the synthesis of sea urchin-like zinc oxide nanostructures. Zn primer was deposited on ceramic square plates followed by drying at ambient conditions. Using a tubular furnace, these samples were subjected to thermal oxidation at 420 °C in air for different treatment times in the range from 20 to 360 min. This allowed us to follow the growth of sea urchin-like nanostructures by scanning electron microscopy (SEM), where we found that the length of the needles of the sea urchin-like nanostructures becomes longer as the thermal oxidation time increases. A series of samples synthesized at 420 °C for 100, 180, and 360 min were prepared to be characterized by Raman spectroscopy, X-Ray diffraction, and scanning electron microscopy (SEM). The Raman spectra indicate the formation of nanometric ZnO in all prepared samples. The X-ray diffractograms gave evidence of a mixture of Zn and ZnO in all samples. Once properly characterized, these samples were used to perform adsorption tests of the model molecule Methylene Blue (MB). All three samples proved effective for MB removal at 78 % efficiency. The results presented in this work, show that the simple and low cost method of using a commercially available primer on ceramic substrates, and its thermal treatment in a conventional furnace, presents a simple and reproducible approach to obtaining sea urchin-like ZnO nanostructures with excellent adsorption retention features of MB dye.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"674 ","pages":"Article 128417"},"PeriodicalIF":2.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145578079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-13DOI: 10.1016/j.jcrysgro.2025.128419
Fuming Deng , Ziyi Liu , Wenli Deng , Xiaozhou Chen , Liqiu Huang , Xiaotian Xing , Houzhen Chen , Junzhe Yu , Can Li
Diamond is the hardest and most stable crystal in nature (lattice constant 3.567 Å, bond length 1.54 Å) formed by carbon atoms bonded by SP3 and large-size diamond single crystals have a wide range of applications, which is one of the research hotspots of superhard materials nowadays. This study focuses on the high-pressure high-temperature (HPHT) method to produce large-size (≥15 ct) single crystals using an optimized China-type apparatus (CHPA). The effects of different catalyst melts on crystal growth rates were investigated by simulating the temperature field and convection field within the composite cavity—key factors influencing crystal growth rates—using the finite element method (FEM) and the Finite Volume Method (FVM).
The research results indicate that using the high-temperature, high-pressure method to produce synthetic diamonds with Fe-Co and Fe-Co-C catalysts can make the temperature distribution in the synthesis chamber more uniform and the carbon convection rate more stable, and provide “visualization” of the growth process for high-temperature, high-pressure synthetic diamonds. It can also adapt to the production needs of diamonds of different shapes, providing new ideas for resolving the conflict between speed and quality in the production of large, high-quality diamonds.
{"title":"Simulation of temperature and convection field of diamond large single crystal growth with different catalyst systems","authors":"Fuming Deng , Ziyi Liu , Wenli Deng , Xiaozhou Chen , Liqiu Huang , Xiaotian Xing , Houzhen Chen , Junzhe Yu , Can Li","doi":"10.1016/j.jcrysgro.2025.128419","DOIUrl":"10.1016/j.jcrysgro.2025.128419","url":null,"abstract":"<div><div>Diamond is the hardest and most stable crystal in nature (lattice constant 3.567 Å, bond length 1.54 Å) formed by carbon atoms bonded by SP<sup>3</sup> and large-size diamond single crystals have a wide range of applications, which is one of the research hotspots of superhard materials nowadays. This study focuses on the high-pressure high-temperature (HPHT) method to produce large-size (≥15 ct) single crystals using an optimized China-type apparatus (CHPA). The effects of different catalyst melts on crystal growth rates were investigated by simulating the temperature field and convection field within the composite cavity—key factors influencing crystal growth rates—using the finite element method (FEM) and the Finite Volume Method (FVM).</div><div>The research results indicate that using the high-temperature, high-pressure method to produce synthetic diamonds with Fe-Co and Fe-Co-C catalysts can make the temperature distribution in the synthesis chamber more uniform and the carbon convection rate more stable, and provide “visualization” of the growth process for high-temperature, high-pressure synthetic diamonds. It can also adapt to the production needs of diamonds of different shapes, providing new ideas for resolving the conflict between speed and quality in the production of large, high-quality diamonds.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"674 ","pages":"Article 128419"},"PeriodicalIF":2.0,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145578078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Methylammonium lead tribromide (MAPbBr3) is a promising material that can be utilized in optoelectronic devices due to its excellent photon-electron conversion efficiency. To prevent the recombination of photogenerated electron-hole pairs during current transport, a high-quality single crystal with minimal defects is necessary. We have developed a localized thermal drive inverse temperature crystallization (LTDITC) method for MAPbBr3 single crystal growth. The temperature distribution of the localized heat crystal growth setup was monitored with a thermal imager in specific areas during the crystal growth process. The presence of a single-phase diffraction peak and the narrow full width at half maximum (FWHM) of the (200) peak in the X-ray diffraction (XRD) pattern indicates that the crystal grown by the new LTDITC method is a high-quality single crystal. A comparison of the (200) peak FWHM for the grown crystal with that of crystals produced by the traditional oil bath method indicates a much lower defect density in the new crystal. Photoluminescence (PL) and Raman spectra reveal a narrow peak at 545 nm and 327 cm−1, respectively, indicating superior crystalline quality. The new crystal’s bandgap is 2.19 eV, which is determined by a sharp UV–Vis absorption edge. Additionally, space charge limited current (SCLC) calculations reveal a low trap-state density of 6.5 × 109 cm−3 and a carrier mobility of 64 cm2 V−1 s−1, further confirming its exceptional optoelectronic properties.
{"title":"Thermally driven growth of MAPbBr3 single crystals","authors":"Tzu-Lung Chang , Yu-Li Hsieh , Hseuh-Hsing Hung , Jau-Wern Chiou , Hui-Huang Hsieh","doi":"10.1016/j.jcrysgro.2025.128410","DOIUrl":"10.1016/j.jcrysgro.2025.128410","url":null,"abstract":"<div><div>Methylammonium lead tribromide (MAPbBr<sub>3</sub>) is a promising material that can be utilized in optoelectronic devices due to its excellent photon-electron conversion efficiency. To prevent the recombination of photogenerated electron-hole pairs during current transport, a high-quality single crystal with minimal defects is necessary. We have developed a localized thermal drive inverse temperature crystallization (LTDITC) method for MAPbBr<sub>3</sub> single crystal growth. The temperature distribution of the localized heat crystal growth setup was monitored with a thermal imager in specific areas during the crystal growth process. The presence of a single-phase diffraction peak and the narrow full width at half maximum (FWHM) of the (200) peak in the X-ray diffraction (XRD) pattern indicates that the crystal grown by the new LTDITC method is a high-quality single crystal. A comparison of the (200) peak FWHM for the grown crystal with that of crystals produced by the traditional oil bath method indicates a much lower defect density in the new crystal. Photoluminescence (PL) and Raman spectra reveal a narrow peak at 545 nm and 327 cm<sup>−1</sup>, respectively, indicating superior crystalline quality. The new crystal’s bandgap is 2.19 eV, which is determined by a sharp UV–Vis absorption edge. Additionally, space charge limited current (SCLC) calculations reveal a low trap-state density of 6.5 × 10<sup>9</sup> cm<sup>−3</sup> and a carrier mobility of 64 cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>, further confirming its exceptional optoelectronic properties.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"674 ","pages":"Article 128410"},"PeriodicalIF":2.0,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-08DOI: 10.1016/j.jcrysgro.2025.128409
Yanshen Wang , Mingzhi Zhu , Yuan Liu
As a typical wide-bandgap semiconductor, Gallium oxide (Ga2O3) crystal is an ideal substrate material for power and deep-ultraviolet devices. The traditional growth process for Ga2O3 single crystal requires extremely expensive Ir crucibles, which greatly hinders its application and development. This article aims to develop the induction skull melting (ISM) process for high-purity melting and single crystal growth of Ga2O3, without iridium crucible. Based on the multi-field coupling model, a systematical simulation was conducted to study the effect of frequency and magnitude of the induction power on the temperature evolution, the fluid flowing pattern, the meniscus shape, and the skull morphology. Simultaneously, the ignition and solidification process were also displayed. There is a good agreement between the theoretical calculations and the experimental results. The studied results demonstrate that the ISM process has the potential for the melting and growth of Ga2O3 single crystal.
{"title":"Numerical simulation of induction skull melting process of gallium oxide compounds","authors":"Yanshen Wang , Mingzhi Zhu , Yuan Liu","doi":"10.1016/j.jcrysgro.2025.128409","DOIUrl":"10.1016/j.jcrysgro.2025.128409","url":null,"abstract":"<div><div>As a typical wide-bandgap semiconductor, Gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) crystal is an ideal substrate material for power and deep-ultraviolet devices. The traditional growth process for Ga<sub>2</sub>O<sub>3</sub> single crystal requires extremely expensive Ir crucibles, which greatly hinders its application and development. This article aims to develop the induction skull melting (ISM) process for high-purity melting and single crystal growth of Ga<sub>2</sub>O<sub>3</sub>, without iridium crucible. Based on the multi-field coupling model, a systematical simulation was conducted to study the effect of frequency and magnitude of the induction power on the temperature evolution, the fluid flowing pattern, the meniscus shape, and the skull morphology. Simultaneously, the ignition and solidification process were also displayed. There is a good agreement between the theoretical calculations and the experimental results. The studied results demonstrate that the ISM process has the potential for the melting and growth of Ga<sub>2</sub>O<sub>3</sub> single crystal.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"674 ","pages":"Article 128409"},"PeriodicalIF":2.0,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-07DOI: 10.1016/j.jcrysgro.2025.128407
Henry Chen , Susan Kutcher , Cory Rosemier , Julie Wen , Sudhir Trivedi
Although cadmium zinc telluride (CZT) is currently the material of choice for high resolution room temperature nuclear radiation detection, it has several drawbacks, making it very difficult to produce in large volumes and at low cost simultaneously. In this work, we introduce cadmium magnesium telluride (CdMgTe) as a promising alternative room temperature semiconductor detector that solves these issues. The advantages of CdMgTe over CZT, the growth, material characterization of CdMgTe, and ultimately its nuclear radiation response are studied and reported here, where energy resolution of single channel form was as good as 1.5 % at 662 keV gamma without any signal correction.
{"title":"Crystal growth and spectroscopic performance of CdMgTe radiation detector","authors":"Henry Chen , Susan Kutcher , Cory Rosemier , Julie Wen , Sudhir Trivedi","doi":"10.1016/j.jcrysgro.2025.128407","DOIUrl":"10.1016/j.jcrysgro.2025.128407","url":null,"abstract":"<div><div>Although cadmium zinc telluride (CZT) is currently the material of choice for high resolution room temperature nuclear radiation detection, it has several drawbacks, making it very difficult to produce in large volumes and at low cost simultaneously. In this work, we introduce cadmium magnesium telluride (CdMgTe) as a promising alternative room temperature semiconductor detector that solves these issues. The advantages of CdMgTe over CZT, the growth, material characterization of CdMgTe, and ultimately its nuclear radiation response are studied and reported here, where energy resolution of single channel form was as good as 1.5 % at 662 keV gamma without any signal correction.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"673 ","pages":"Article 128407"},"PeriodicalIF":2.0,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145518525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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