A new model for the calculation of the growth rate of edge‐defined, film‐fed growth (EFG) crystals is proposed based on surface tension proportional to the area of the crystal/die interface. A comparison to the classical model, which includes a surface tension factor proportional to the length of the crystal's peripheral edge, is shown. Equations are derived that accurately predict the growth rate derived from weight versus time calculations. Examples are shown for various geometries of crystal shape.
{"title":"Growth Rate Calculations for Edge‐Defined, Film‐Fed Growth of Sapphire Crystals","authors":"F. Bruni","doi":"10.1002/crat.202000244","DOIUrl":"https://doi.org/10.1002/crat.202000244","url":null,"abstract":"A new model for the calculation of the growth rate of edge‐defined, film‐fed growth (EFG) crystals is proposed based on surface tension proportional to the area of the crystal/die interface. A comparison to the classical model, which includes a surface tension factor proportional to the length of the crystal's peripheral edge, is shown. Equations are derived that accurately predict the growth rate derived from weight versus time calculations. Examples are shown for various geometries of crystal shape.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"285 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75420084","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}
Z. Heiba, M. Mohamed, Noura M. Farag, Sameh I. Ahmed
Nano MnS and ZnS samples are prepared through a simple thermolysis procedure. The effect of synthesis temperature on the different phases formed and their percentages, and on the lattice parameters and crystallite size of MnS and ZnS is examined using Rietveld analysis for X‐ray diffraction patterns. The minimum synthesis temperature at which MnS can be formed by the present simple procedure is 250 °C, while ZnS can be prepared at a lower temperature of 200 °C. For manganese sulfide, traces of Mn3O4 phase appear at 300 °C and increase with temperature, while ZnS resists oxidation until 500 °C; pure ZnO forms at 700 °C. The MnS and ZnS samples, obtained at all temperatures, are found to be biphasic; cubic and hexagonal. The nano nature of the samples and the particle morphology are investigated by high‐resolution transmission electron microscopy. Fourier‐transform infrared spectroscopy is applied to follow the characteristic vibration bands in both systems. The values of the different energy gaps depend on the crystallite size, phases’ percentages, and the preparation temperature. The photoluminescence intensity and the emitted colors from MnS and ZnS depend on the synthesis temperature.
{"title":"Influence of Synthesis Temperature on the Phases Developed and Optical Properties of Manganese Sulfide and Zinc Sulfide","authors":"Z. Heiba, M. Mohamed, Noura M. Farag, Sameh I. Ahmed","doi":"10.1002/crat.202000201","DOIUrl":"https://doi.org/10.1002/crat.202000201","url":null,"abstract":"Nano MnS and ZnS samples are prepared through a simple thermolysis procedure. The effect of synthesis temperature on the different phases formed and their percentages, and on the lattice parameters and crystallite size of MnS and ZnS is examined using Rietveld analysis for X‐ray diffraction patterns. The minimum synthesis temperature at which MnS can be formed by the present simple procedure is 250 °C, while ZnS can be prepared at a lower temperature of 200 °C. For manganese sulfide, traces of Mn3O4 phase appear at 300 °C and increase with temperature, while ZnS resists oxidation until 500 °C; pure ZnO forms at 700 °C. The MnS and ZnS samples, obtained at all temperatures, are found to be biphasic; cubic and hexagonal. The nano nature of the samples and the particle morphology are investigated by high‐resolution transmission electron microscopy. Fourier‐transform infrared spectroscopy is applied to follow the characteristic vibration bands in both systems. The values of the different energy gaps depend on the crystallite size, phases’ percentages, and the preparation temperature. The photoluminescence intensity and the emitted colors from MnS and ZnS depend on the synthesis temperature.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"57 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85647661","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}
Jia Zhang, Zhen Wang, Lu Liu, Baorong Hu, Yilei Zhao, Shuang Zhao, Wenting Zhao, Shuang Li, Xi Chen, X. Hai
Semiconductor photocatalysis is considered a promising technology for destroying pollutants, while the faint carrier separation efficiency of the photocatalyst is one of the main limitations for obtaining high performance. This study reports a solid solution strategy to achieve effective carrier separation in Bi4O5BrxI2−x. The solid solution structure endows Bi4O5BrxI2−x with proper light adsorption, tunable band gap, and effective separation of photogenerated electrons and holes. As a result, Bi4O5BrxI2−x exhibits reduction and oxidation activities for highly efficient photocatalytic Cr(VI) reduction and tetracycline hydrochloride (HTC) degradation under visible light irradiation, with the activity reaching the maximum at x = 1. Within 30 min, the removal rates of Cr(VI) and HTC reach 90% and 100%, respectively. This study not only provides an effective strategy to increase the carrier separation of bismuth‐based semiconductors, but also opens new opportunities to rationally design other solid solution catalysts with high performance in wastewater treatment.
{"title":"Bi4O5BrI Solid Solution towards Boosted Photocatalytic Reduction and Oxidation Activities Induced by Efficient Carrier Separation","authors":"Jia Zhang, Zhen Wang, Lu Liu, Baorong Hu, Yilei Zhao, Shuang Zhao, Wenting Zhao, Shuang Li, Xi Chen, X. Hai","doi":"10.1002/crat.202000240","DOIUrl":"https://doi.org/10.1002/crat.202000240","url":null,"abstract":"Semiconductor photocatalysis is considered a promising technology for destroying pollutants, while the faint carrier separation efficiency of the photocatalyst is one of the main limitations for obtaining high performance. This study reports a solid solution strategy to achieve effective carrier separation in Bi4O5BrxI2−x. The solid solution structure endows Bi4O5BrxI2−x with proper light adsorption, tunable band gap, and effective separation of photogenerated electrons and holes. As a result, Bi4O5BrxI2−x exhibits reduction and oxidation activities for highly efficient photocatalytic Cr(VI) reduction and tetracycline hydrochloride (HTC) degradation under visible light irradiation, with the activity reaching the maximum at x = 1. Within 30 min, the removal rates of Cr(VI) and HTC reach 90% and 100%, respectively. This study not only provides an effective strategy to increase the carrier separation of bismuth‐based semiconductors, but also opens new opportunities to rationally design other solid solution catalysts with high performance in wastewater treatment.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"98 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81182317","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}
{"title":"Masthead: Crystal Research and Technology 4'2021","authors":"","doi":"10.1002/crat.202170017","DOIUrl":"https://doi.org/10.1002/crat.202170017","url":null,"abstract":"","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"10 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84217122","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}
Hang Liu, Mingwei Li, H. Yin, Duanyang Chen, H. Qi
A novel method of crystal growth by introducing jet flow to the pyramidal‐restriction long‐seed growth system of potassium dihydrogen phosphate (KH2PO4, KDP) in rotating crystal method, namely, the jet‐rotating crystal method, is proposed. To evaluate the prospect of this new method, three‐dimensional (3D) time‐dependent numerical simulations of flow and mass transfer involved in the jet‐rotating crystal method are conducted. Compared with the rotating crystal method, the jet‐rotating crystal method can improve the magnitude and distribution homogeneity of the prismatic face supersaturation and obtain high‐quality KDP crystals. The supersaturation on the prismatic face as a function of rotation rate, jet velocity, and crystal size is investigated. The effects of solution flow on mass transfer are analyzed in detail. A further improvement in the magnitude and distribution homogeneity of the prismatic face supersaturation can be observed through designing the jet flow pipes to swing periodically in vertical plane. Besides, the role of natural and forced convection in mass transport is discussed, which indicates that the effects of natural convection can be neglected when the jet velocity is equal to or greater than 0.6 m s–1.
提出了一种在旋转晶体法中，将射流引入到磷酸二氢钾(KH2PO4, KDP)锥形限制长粒生长体系中的新晶体生长方法，即射流旋转晶体法。为了评估这种新方法的前景，对射流旋转晶体方法中涉及的流动和传质进行了三维(3D)时间相关的数值模拟。与旋转晶体法相比，射流旋转晶体法可以改善棱柱面过饱和度的大小和分布均匀性，获得高质量的KDP晶体。研究了棱镜表面的过饱和度与旋转速率、射流速度和晶体尺寸的关系。详细分析了溶液流动对传质的影响。通过设计射流管在垂直平面上的周期性摆动，可以进一步改善棱柱面过饱和的大小和分布均匀性。此外，还讨论了自然对流和强迫对流在质量传递中的作用，表明当射流速度等于或大于0.6 m s-1时，自然对流的影响可以忽略不计。
{"title":"Numerical Simulation of the Hydrodynamics and Mass Transfer in the Cuboid KDP Crystal Growth under the Jet‐Rotating Crystal Method","authors":"Hang Liu, Mingwei Li, H. Yin, Duanyang Chen, H. Qi","doi":"10.1002/crat.202000241","DOIUrl":"https://doi.org/10.1002/crat.202000241","url":null,"abstract":"A novel method of crystal growth by introducing jet flow to the pyramidal‐restriction long‐seed growth system of potassium dihydrogen phosphate (KH2PO4, KDP) in rotating crystal method, namely, the jet‐rotating crystal method, is proposed. To evaluate the prospect of this new method, three‐dimensional (3D) time‐dependent numerical simulations of flow and mass transfer involved in the jet‐rotating crystal method are conducted. Compared with the rotating crystal method, the jet‐rotating crystal method can improve the magnitude and distribution homogeneity of the prismatic face supersaturation and obtain high‐quality KDP crystals. The supersaturation on the prismatic face as a function of rotation rate, jet velocity, and crystal size is investigated. The effects of solution flow on mass transfer are analyzed in detail. A further improvement in the magnitude and distribution homogeneity of the prismatic face supersaturation can be observed through designing the jet flow pipes to swing periodically in vertical plane. Besides, the role of natural and forced convection in mass transport is discussed, which indicates that the effects of natural convection can be neglected when the jet velocity is equal to or greater than 0.6 m s–1.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"84 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83375750","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}
Polymorphic control and crystal nucleation of α and β polymorphs of dl‐methionine, an essential amino‐acid, is attained from saturated aqueous solution through swift cooling crystallization process by generating wide range of supersaturation (0.02 < σ < 2.19) in the temperature range of 323–274 K. The type of nucleation is very much supersaturation dependent: while lower supersaturation range (0.02 < σ < 0.08) prefers the stable β form, higher supersaturation range (1.20 < σ < 2.19) yields metastable α form. In situ optical microscopy and X‐ray diffraction analyses confirm the morphological and structural distinction of the grown polymorphs.
{"title":"Polymorphic Control of α and β dl‐Methionine through Swift Cooling Crystallization Process","authors":"M. Suresh, K. Srinivasan","doi":"10.1002/crat.202000208","DOIUrl":"https://doi.org/10.1002/crat.202000208","url":null,"abstract":"Polymorphic control and crystal nucleation of α and β polymorphs of dl‐methionine, an essential amino‐acid, is attained from saturated aqueous solution through swift cooling crystallization process by generating wide range of supersaturation (0.02 < σ < 2.19) in the temperature range of 323–274 K. The type of nucleation is very much supersaturation dependent: while lower supersaturation range (0.02 < σ < 0.08) prefers the stable β form, higher supersaturation range (1.20 < σ < 2.19) yields metastable α form. In situ optical microscopy and X‐ray diffraction analyses confirm the morphological and structural distinction of the grown polymorphs.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83121971","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}
Powder X‐ray diffraction, scanning electron microscopy, and molecular simulation techniques are used to analyze the crystallization of piracetam under different solvents and different cooling rates. The crystallization of piracetam in methanol system is controlled by thermodynamics, and it is easy to form stable polymorph. The crystallization of piracetam in isopropanol system is controlled by kinetics and forms metastable polymorph. The crystallization of piracetam in the ethanol system is controlled by thermodynamics and kinetics, and the cooling rate affects the formation of the crystal polymorphs, which is easy to be mixed. Dmol3 is used to calculate the energy, electrostatic potential, and frontier orbital energy of piracetam molecules in form II and form III configurations molecules in different systems. The results show that the methanol system is easier to form stable polymorph than the ethanol system.
{"title":"Study on the Regulation of Piracetam Crystallization Behavior","authors":"R. Xu, Tingting Xu, Guosheng Wang","doi":"10.1002/crat.202000117","DOIUrl":"https://doi.org/10.1002/crat.202000117","url":null,"abstract":"Powder X‐ray diffraction, scanning electron microscopy, and molecular simulation techniques are used to analyze the crystallization of piracetam under different solvents and different cooling rates. The crystallization of piracetam in methanol system is controlled by thermodynamics, and it is easy to form stable polymorph. The crystallization of piracetam in isopropanol system is controlled by kinetics and forms metastable polymorph. The crystallization of piracetam in the ethanol system is controlled by thermodynamics and kinetics, and the cooling rate affects the formation of the crystal polymorphs, which is easy to be mixed. Dmol3 is used to calculate the energy, electrostatic potential, and frontier orbital energy of piracetam molecules in form II and form III configurations molecules in different systems. The results show that the methanol system is easier to form stable polymorph than the ethanol system.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"36 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90435967","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}
Zhen‐Hua Liu, Long Fan, Liping Peng, Jia Li, Yajun Fu, Zhengwei Xiong, Jin Wang, Jin Fang, Tingting Xiao, L. Cao, Wei-Dong Wu
In this work, the ZnO:Ga (GZO) single crystals are grown by the chemical vapor transport (CVT) method. The as‐grown crystals are annealed under an oxygen atmosphere at different temperatures. The GZO crystal's structure and its optical and electrical properties are characterized by X‐ray photoelectron spectroscopy (XPS), Raman spectroscopy, X‐ray diffraction (XRD), UV‐VIS spectrophotometry, and variable‐temperature Hall‐effect measurement. The XPS results indicate that the valence states of the majority of gallium atoms in the GZO crystals undergo transition from the metallic (Ga0) to the non‐metallic state (Gax+) with increasing annealing temperature. The Raman and XRD results show that the compressive stress along the biaxial c‐axis on GZO crystals increases gradually with annealing temperature. Meanwhile, the GZO crystal's transmittance within the range of 300 to 1000 nm is improved significantly from being opaque to about 57%. The GZO crystals exhibit a decrease in free‐carrier concentration (1020–1019 cm−3), an increase in carrier mobility (77.8–87.9 cm2/V−1s−1) and resistivity (10−4–10−2 Ω·cm). The annealed GZO crystal's carrier concentration is practically independent of temperature (90–300 K). These results show that the free‐carrier concentrations are affected by the change of valence states in gallium atoms present in the GZO crystal.
{"title":"Effect of Change in Valence State of Ga During Annealing on the Structural, Optical, and Electrical Properties of GZO Crystals","authors":"Zhen‐Hua Liu, Long Fan, Liping Peng, Jia Li, Yajun Fu, Zhengwei Xiong, Jin Wang, Jin Fang, Tingting Xiao, L. Cao, Wei-Dong Wu","doi":"10.1002/crat.202100001","DOIUrl":"https://doi.org/10.1002/crat.202100001","url":null,"abstract":"In this work, the ZnO:Ga (GZO) single crystals are grown by the chemical vapor transport (CVT) method. The as‐grown crystals are annealed under an oxygen atmosphere at different temperatures. The GZO crystal's structure and its optical and electrical properties are characterized by X‐ray photoelectron spectroscopy (XPS), Raman spectroscopy, X‐ray diffraction (XRD), UV‐VIS spectrophotometry, and variable‐temperature Hall‐effect measurement. The XPS results indicate that the valence states of the majority of gallium atoms in the GZO crystals undergo transition from the metallic (Ga0) to the non‐metallic state (Gax+) with increasing annealing temperature. The Raman and XRD results show that the compressive stress along the biaxial c‐axis on GZO crystals increases gradually with annealing temperature. Meanwhile, the GZO crystal's transmittance within the range of 300 to 1000 nm is improved significantly from being opaque to about 57%. The GZO crystals exhibit a decrease in free‐carrier concentration (1020–1019 cm−3), an increase in carrier mobility (77.8–87.9 cm2/V−1s−1) and resistivity (10−4–10−2 Ω·cm). The annealed GZO crystal's carrier concentration is practically independent of temperature (90–300 K). These results show that the free‐carrier concentrations are affected by the change of valence states in gallium atoms present in the GZO crystal.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"33 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79743778","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}
It is of great significance to explore and predict crystal growth behavior that can target the optimal growth conditions and obtain ideal properties. The ability to effectively treat schizophrenia and other psychoses has led to numerous studies of olanzapine (OZPN) polymorphs. There are four reported anhydrous forms of OZPN, but two of whose crystal morphologies (forms III and IV) are still unavailable in the laboratory. Based on the advanced spiral growth model, this study predicts the crystal morphologies of OZPN forms III and IV from vapor and different solvents (i.e., water, ethyl acetate, ethanol, cyclohexane, and dichloromethane), where the potential energies between dimeric growth units (stronger than specific energy cutoff) are considered as strong bond. It is demonstrated that the growth rate of form III increases with the increase of supersaturation from 1.01 to 1.07. Form III crystallizes from solvents with the block‐like shape, whereas form IV grows with the rectangular shape, that obviously differs from the flat‐square shapes of form I and form II. This mechanistic model is able to apply on various compounds, especially for the crystals with non‐centrosymmetric molecules to obtain important guidance for their experimental preparations.
{"title":"Crystal Morphology Prediction of Olanzapine Forms III and IV","authors":"Q. Lu, Imran Ali, Zhiyun Wei, Jinjin Li","doi":"10.1002/crat.202000215","DOIUrl":"https://doi.org/10.1002/crat.202000215","url":null,"abstract":"It is of great significance to explore and predict crystal growth behavior that can target the optimal growth conditions and obtain ideal properties. The ability to effectively treat schizophrenia and other psychoses has led to numerous studies of olanzapine (OZPN) polymorphs. There are four reported anhydrous forms of OZPN, but two of whose crystal morphologies (forms III and IV) are still unavailable in the laboratory. Based on the advanced spiral growth model, this study predicts the crystal morphologies of OZPN forms III and IV from vapor and different solvents (i.e., water, ethyl acetate, ethanol, cyclohexane, and dichloromethane), where the potential energies between dimeric growth units (stronger than specific energy cutoff) are considered as strong bond. It is demonstrated that the growth rate of form III increases with the increase of supersaturation from 1.01 to 1.07. Form III crystallizes from solvents with the block‐like shape, whereas form IV grows with the rectangular shape, that obviously differs from the flat‐square shapes of form I and form II. This mechanistic model is able to apply on various compounds, especially for the crystals with non‐centrosymmetric molecules to obtain important guidance for their experimental preparations.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"16 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88491160","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}
Xudong Liu, Lei Wang, Huiyun Yan, X. Bi, Xudong Sun
The work demonstrates combustion characteristics in growth chamber for Verneuil‐grown SrTiO3 crystal with two‐tube burner. Finite element (FE) simulation is performed to analyze the temperature distribution and its influencing factors. The central oxygen flows outward along the radial direction and reacts to hydrogen surrounding crystal, and the best ratio of hydrogen and oxygen is 2.5. The ratio less than 2.5 leads to increasing the center temperature of molten cap and greater than 2.5 leads to increasing the temperature around the molten cap, which probably causes the overflow problem. The surface temperature of molten cap increases first and then decreases gradually with the decreasing nozzle aperture of oxygen. The best diameter of nozzle aperture of oxygen is 4.5 mm. The surface temperature of molten cap is mainly related to the diameter of oxygen nozzle and the flow rate of oxygen. This work opens the stable growth process and the possibility for the industrial growth of large high quality SrTiO3 single crystals.
{"title":"Finite Element Simulation of Temperature Distribution in Growth Chamber for Verneuil‐Grown SrTiO3 Crystal","authors":"Xudong Liu, Lei Wang, Huiyun Yan, X. Bi, Xudong Sun","doi":"10.1002/crat.202000185","DOIUrl":"https://doi.org/10.1002/crat.202000185","url":null,"abstract":"The work demonstrates combustion characteristics in growth chamber for Verneuil‐grown SrTiO3 crystal with two‐tube burner. Finite element (FE) simulation is performed to analyze the temperature distribution and its influencing factors. The central oxygen flows outward along the radial direction and reacts to hydrogen surrounding crystal, and the best ratio of hydrogen and oxygen is 2.5. The ratio less than 2.5 leads to increasing the center temperature of molten cap and greater than 2.5 leads to increasing the temperature around the molten cap, which probably causes the overflow problem. The surface temperature of molten cap increases first and then decreases gradually with the decreasing nozzle aperture of oxygen. The best diameter of nozzle aperture of oxygen is 4.5 mm. The surface temperature of molten cap is mainly related to the diameter of oxygen nozzle and the flow rate of oxygen. This work opens the stable growth process and the possibility for the industrial growth of large high quality SrTiO3 single crystals.","PeriodicalId":10797,"journal":{"name":"Crystal Research and Technology","volume":"19 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84928555","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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