Pub Date : 2025-03-29DOI: 10.1016/j.jcrysgro.2025.128167
Xianyang Wang , Yutong Fan , Peng Dai , Cheng Ji , Jian Wu , Liming Shen , Shuai Wang , Ningzhong Bao
Langasite (La3Ga5SiO14, LGS) crystals have garnered significant attention due to their excellent piezoelectric and photoelectric properties. However, the issue of cracking during the crystal growth process has long remained a persistent challenge in this field. This work numerically simulates the stress distribution of crystals prone to cracking during the Czochralski growth process. The results demonstrate that the thermal stress at the shoulder of the crystal is relatively high, often resulting in surface cracking in this region. By optimizing the temperature field structure, 2-inch crack-free LGS crystals with high macroscopic quality were grown in air. The crystal shows high crystallographic uniformity, with an average rocking curve full width at half maximum (FWHM) of approximately 32.02″ for a 2-inch wafer. The crystal demonstrates excellent optical transmittance (∼80%) and stability after annealed at high-temperature in various atmospheres. These findings provide valuable guidance for achieving large-sized, high-quality LGS crystals.
{"title":"Thermal stress analysis and growth of high quality La3Ga5SiO14 crystals","authors":"Xianyang Wang , Yutong Fan , Peng Dai , Cheng Ji , Jian Wu , Liming Shen , Shuai Wang , Ningzhong Bao","doi":"10.1016/j.jcrysgro.2025.128167","DOIUrl":"10.1016/j.jcrysgro.2025.128167","url":null,"abstract":"<div><div>Langasite (La<sub>3</sub>Ga<sub>5</sub>SiO<sub>14</sub>, LGS) crystals have garnered significant attention due to their excellent piezoelectric and photoelectric properties. However, the issue of cracking during the crystal growth process has long remained a persistent challenge in this field. This work numerically simulates the stress distribution of crystals prone to cracking during the Czochralski growth process. The results demonstrate that the thermal stress at the shoulder of the crystal is relatively high, often resulting in surface cracking in this region. By optimizing the temperature field structure, 2-inch crack-free LGS crystals with high macroscopic quality were grown in air. The crystal shows high crystallographic uniformity, with an average rocking curve full width at half maximum (FWHM) of approximately 32.02″ for a 2-inch wafer. The crystal demonstrates excellent optical transmittance (∼80%) and stability after annealed at high-temperature in various atmospheres. These findings provide valuable guidance for achieving large-sized, high-quality LGS crystals.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"661 ","pages":"Article 128167"},"PeriodicalIF":1.7,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143785151","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 : 2025-03-27DOI: 10.1016/j.jcrysgro.2025.128155
Arved Wintzer, Iason Tsiapkinis, Stefan Püschel, Christo Guguschev, Kaspars Dadzis
Numerical modeling of the Czochralski (CZ) growth process, which includes the multiphysical interactions of electromagnetism, heat transfer, phase change, and melt flow, is an essential tool for process development and optimization. However, validation of such models is mostly insufficient due to the lack of in-situ measurement data, and open-source models are hardly available. To address these issues, a new 2D and 3D CZ growth model has been developed using the open-source tools Elmer for global time-harmonic electromagnetism, steady-state heat transfer and phase change modeling, coupled with OpenFOAM for transient or steady-state melt flow modeling. The model is published under an open-source license. The model is validated with a focus on electromagnetism and heat transfer using a model experiment with cesium iodide (CsI, melting point: 627 °C), targeting oxide/fluoride materials. For the 2D model, a satisfying agreement between model experiment and simulation regarding crucible and crystal temperature is achieved in regions with constant crystal diameter. With the 3D model, 3D flow patterns caused by an asymmetric crucible temperature distribution due to an asymmetric magnetic field of the induction heater are observed and in reasonable agreement with the experiment. However, both models yield heater currents up to 38 % higher than those observed in the experiment. The transferability of the validation results to calcium fluoride (CaF2) growth for laser cooling application is discussed. The CaF2 growth process is modeled in 3D to investigate the cause of a rough crystal surface observed in the experiment. It might be caused by a rotating 3D flow structure, while the observation window in the insulation and after-heater is of low influence on the temperature distribution and, thus, the crystal surface structure.
{"title":"Validation of a numerical model for Czochralski growth of cesium iodide and calcium fluoride","authors":"Arved Wintzer, Iason Tsiapkinis, Stefan Püschel, Christo Guguschev, Kaspars Dadzis","doi":"10.1016/j.jcrysgro.2025.128155","DOIUrl":"10.1016/j.jcrysgro.2025.128155","url":null,"abstract":"<div><div>Numerical modeling of the Czochralski (CZ) growth process, which includes the multiphysical interactions of electromagnetism, heat transfer, phase change, and melt flow, is an essential tool for process development and optimization. However, validation of such models is mostly insufficient due to the lack of in-situ measurement data, and open-source models are hardly available. To address these issues, a new 2D and 3D CZ growth model has been developed using the open-source tools Elmer for global time-harmonic electromagnetism, steady-state heat transfer and phase change modeling, coupled with OpenFOAM for transient or steady-state melt flow modeling. The model is published under an open-source license. The model is validated with a focus on electromagnetism and heat transfer using a model experiment with cesium iodide (CsI, melting point: 627<!--> <!-->°C), targeting oxide/fluoride materials. For the 2D model, a satisfying agreement between model experiment and simulation regarding crucible and crystal temperature is achieved in regions with constant crystal diameter. With the 3D model, 3D flow patterns caused by an asymmetric crucible temperature distribution due to an asymmetric magnetic field of the induction heater are observed and in reasonable agreement with the experiment. However, both models yield heater currents up to 38<!--> <!-->% higher than those observed in the experiment. The transferability of the validation results to calcium fluoride (CaF<sub>2</sub>) growth for laser cooling application is discussed. The CaF<sub>2</sub> growth process is modeled in 3D to investigate the cause of a rough crystal surface observed in the experiment. It might be caused by a rotating 3D flow structure, while the observation window in the insulation and after-heater is of low influence on the temperature distribution and, thus, the crystal surface structure.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"661 ","pages":"Article 128155"},"PeriodicalIF":1.7,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761215","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 : 2025-03-26DOI: 10.1016/j.jcrysgro.2025.128161
Qiangwei Hu , Haixiang Xu
To promote the resource utilization of phosphogypsum (PG) and reduce environmental pollution, this study utilizes the autoclave method with various organic acids and their sodium salts as crystallization agents to convert PG into α-hemihydrate gypsum (α-HH). The study investigates the effects and mechanisms of these crystallization agents on the crystal morphology and strength of α-HH using X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), zeta potential measurements, and molecular dynamics simulations. The results indicate that adding various organic acids and their sodium salts as crystallization agents can effectively regulate the strength and crystal morphology of the α-HH obtained from PG to reduce the aspect ratio of the α-HH crystals. Sodium citrate demonstrated the optimal efficacy as a crystallization agent in controlling the crystal morphology of α-HH. Reducing the aspect ratio to 1.25:1. The absolute dry compressive strength increased to 40.3 MPa when sodium citrate was used, meeting the requirements for high-strength gypsum, specifically α40. Sodium salts of various organic acids demonstrate greater ability than their corresponding organic acids in regulating the crystal morphology of α-HH. This is mainly attributed to the fact that compared to organic acids, the carbon-based oxygen atoms in sodium salts have stronger electron-donating capacity and higher molecular polarity. These characteristics facilitate the formation of cyclic chelates with Ca2+ ions within α-HH crystals, thereby enhancing crystal morphology control and increasing α-HH strength.
{"title":"Crystallization agents modifying conversion of phosphogypsum to α-hemihydrate gypsum: Effects of the charge and molecular polarity of carbon-based oxygen atoms","authors":"Qiangwei Hu , Haixiang Xu","doi":"10.1016/j.jcrysgro.2025.128161","DOIUrl":"10.1016/j.jcrysgro.2025.128161","url":null,"abstract":"<div><div>To promote the resource utilization of phosphogypsum (PG) and reduce environmental pollution, this study utilizes the autoclave method with various organic acids and their sodium salts as crystallization agents to convert PG into α-hemihydrate gypsum (α-HH). The study investigates the effects and mechanisms of these crystallization agents on the crystal morphology and strength of α-HH using X-ray diffraction, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), zeta potential measurements, and molecular dynamics simulations. The results indicate that adding various organic acids and their sodium salts as crystallization agents can effectively regulate the strength and crystal morphology of the α-HH obtained from PG to reduce the aspect ratio of the α-HH crystals. Sodium citrate demonstrated the optimal efficacy as a crystallization agent in controlling the crystal morphology of α-HH. Reducing the aspect ratio to 1.25:1. The absolute dry compressive strength increased to 40.3 MPa when sodium citrate was used, meeting the requirements for high-strength gypsum, specifically α40. Sodium salts of various organic acids demonstrate greater ability than their corresponding organic acids in regulating the crystal morphology of α-HH. This is mainly attributed to the fact that compared to organic acids, the carbon-based oxygen atoms in sodium salts have stronger electron-donating capacity and higher molecular polarity. These characteristics facilitate the formation of cyclic chelates with Ca<sup>2+</sup> ions within α-HH crystals, thereby enhancing crystal morphology control and increasing α-HH strength.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"660 ","pages":"Article 128161"},"PeriodicalIF":1.7,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725457","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 : 2025-03-26DOI: 10.1016/j.jcrysgro.2025.128162
Lehua Wang, Yuanyuan Zhang, Ruining Wang, Xingyuan San
Calcium formate is an important chemical compound with multiple uses. However, the current preparation method of calcium formate mainly uses calcium carbonate/calcium hydroxide as raw material. It is short of precise synthesis of crystalline calcium formate. In this study, we proposed a controlled method for the synthesis of β-calcium formate by using the biologicalaragonite shell. This method only uses biological aragonite and formic acid as raw materials, without other additives, to synthesize β-calcium formate crystals with regular octahedral morphology. The morphology, composition, structure and thermal stability of the calcium formate material were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal analysis, respectively. The thermodynamic properties of β-calcium formate crystals and α-calcium formate crystals were compared and analyzed by first-principles calculations. The reasons why can synthesis of β-calcium formate crystals compared with the common α-calcium formate were discussed in combination with experimental and theoretical calculation data, which provides an important reference for the precise synthesis and preparation of polycrystalline calcium formate in the future.
{"title":"Controlled synthesis of calcium formate from biological aragonite","authors":"Lehua Wang, Yuanyuan Zhang, Ruining Wang, Xingyuan San","doi":"10.1016/j.jcrysgro.2025.128162","DOIUrl":"10.1016/j.jcrysgro.2025.128162","url":null,"abstract":"<div><div>Calcium formate is an important chemical compound with multiple uses. However, the current preparation method of calcium formate mainly uses calcium carbonate/calcium hydroxide as raw material. It is short of precise synthesis of crystalline calcium formate. In this study, we proposed a controlled method for the synthesis of β-calcium formate by using the biologicalaragonite shell. This method only uses biological aragonite and formic acid as raw materials, without other additives, to synthesize β-calcium formate crystals with regular octahedral morphology. The morphology, composition, structure and thermal stability of the calcium formate material were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal analysis, respectively. The thermodynamic properties of β-calcium formate crystals and α-calcium formate crystals were compared and analyzed by first-principles calculations. The reasons why can synthesis of β-calcium formate crystals compared with the common α-calcium formate were discussed in combination with experimental and theoretical calculation data, which provides an important reference for the precise synthesis and preparation of polycrystalline calcium formate in the future.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"661 ","pages":"Article 128162"},"PeriodicalIF":1.7,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761214","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 : 2025-03-24DOI: 10.1016/j.jcrysgro.2025.128160
Bo Li , Weilong Wu , Zifeng Niu , Lu Meng , Haoran Chen , Shijie Ma , Jun Zhang , Wei Tian , Jahangeer Ahmed , Chengchun Tang , Yanming Xue
Direct pyrolysis of specific crystal precursors has long been a favored approach for synthesizing high-quality hexagonal boron nitride (h-BN). In this study, two types of single-crystal borates were identified as effective precursors for direct pyrolysis to h-BN. Single-crystal X-ray diffraction analysis revealed their structures as new pentaborates: [C4H11N10][B5O6(OH)4] (crystal-I) and [C2H5N4][C2N4H4B5O6(OH)4] (crystal-II). The pyrolysis process and resultant products were thoroughly examined using TG-DTA, FT-IR, SEM,TEM and XRD, providing insights into the mechanism of h-BN formation. Notably, these pentaborates enable the preparation of spherical h-BN with a size ranging from 1μm to tens of micrometers. Crystal-II emerged as a more promising precursor due to its pre-existing dative B←N bonds, which facilitated a higher conversion rate to h-BN.
{"title":"New pentaborates for pyrolytic boron nitride","authors":"Bo Li , Weilong Wu , Zifeng Niu , Lu Meng , Haoran Chen , Shijie Ma , Jun Zhang , Wei Tian , Jahangeer Ahmed , Chengchun Tang , Yanming Xue","doi":"10.1016/j.jcrysgro.2025.128160","DOIUrl":"10.1016/j.jcrysgro.2025.128160","url":null,"abstract":"<div><div>Direct pyrolysis of specific crystal precursors has long been a favored approach for synthesizing high-quality hexagonal boron nitride (<em>h</em>-BN). In this study, two types of single-crystal borates were identified as effective precursors for direct pyrolysis to <em>h</em>-BN. Single-crystal X-ray diffraction analysis revealed their structures as new pentaborates: [C<sub>4</sub>H<sub>11</sub>N<sub>10</sub>][B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>] (<em>crystal-I</em>) and [C<sub>2</sub>H<sub>5</sub>N<sub>4</sub>][C<sub>2</sub>N<sub>4</sub>H<sub>4</sub>B<sub>5</sub>O<sub>6</sub>(OH)<sub>4</sub>] (<em>crystal-II</em>). The pyrolysis process and resultant products were thoroughly examined using TG-DTA, FT-IR, SEM,TEM and XRD, providing insights into the mechanism of <em>h</em>-BN formation. Notably, these pentaborates enable the preparation of spherical <em>h</em>-BN with a size ranging from 1μm to tens of micrometers. <em>Crystal-II</em> emerged as a more promising precursor due to its pre-existing dative B←N bonds, which facilitated a higher conversion rate to <em>h</em>-BN.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"660 ","pages":"Article 128160"},"PeriodicalIF":1.7,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715145","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 : 2025-03-24DOI: 10.1016/j.jcrysgro.2025.128159
Jiapan Zheng , Hao Wu , Xuan Zhang , Jingyi Liu , Jiaru Wang , Zixuan Song , Ruiqing Gong , Yuxia Zhang , Wenjuan Han , Junhai Liu , Honghao Xu
Three Pr,Yb:YCa4O(BO3)3 (Pr,Yb:YCOB) crystals (Pr0.0075Yb0.0375Y0.955COB, Pr0.006Yb0.06Y0.934COB and Pr0.005Yb0.075Y0.92COB) were first grown by the Czochralski method. The polarized absorption spectra, polarized fluorescence spectra, fluorescence decay curves and energy transfer process were measured and analyzed at room temperature (300 K). The absorption cross-section of the Pr0.005Yb0.075Y0.92COB crystal is 2.64 × 10-20 cm2 at 449 nm, indicating a relatively large value, while that of the Pr0.006Yb0.06Y0.934COB crystal is 1.30 × 10-20 cm2 at 976 nm, also representing a relatively large value. The energy transfer from Pr3+ to Yb3+ was confirmed through polarized fluorescence spectra. The decay lifetime of the 3P0 energy level of the three crystals were fitted to be 21.4 μs (Pr0.0075Yb0.0375Y0.955COB), 19.2 μs (Pr0.006Yb0.06Y0.934COB) and 18.7 μs (Pr0.005Yb0.075Y0.92COB), respectively. And the decay lifetime of the 2F5/2 energy level of the three crystals were fitted to be 1.90 ms, 1.76 ms and 1.62 ms.
{"title":"Growth and spectroscopic properties studies of Pr-Yb co-doped YCa4O(BO3)3 crystal","authors":"Jiapan Zheng , Hao Wu , Xuan Zhang , Jingyi Liu , Jiaru Wang , Zixuan Song , Ruiqing Gong , Yuxia Zhang , Wenjuan Han , Junhai Liu , Honghao Xu","doi":"10.1016/j.jcrysgro.2025.128159","DOIUrl":"10.1016/j.jcrysgro.2025.128159","url":null,"abstract":"<div><div>Three Pr,Yb:YCa<sub>4</sub>O(BO<sub>3</sub>)<sub>3</sub> (Pr,Yb:YCOB) crystals (Pr<sub>0.0075</sub>Yb<sub>0.0375</sub>Y<sub>0.955</sub>COB, Pr<sub>0.006</sub>Yb<sub>0.06</sub>Y<sub>0.934</sub>COB and Pr<sub>0.005</sub>Yb<sub>0.075</sub>Y<sub>0.92</sub>COB) were first grown by the Czochralski method. The polarized absorption spectra, polarized fluorescence spectra, fluorescence decay curves and energy transfer process were measured and analyzed at room temperature (300 K). The absorption cross-section of the Pr<sub>0.005</sub>Yb<sub>0.075</sub>Y<sub>0.92</sub>COB crystal is 2.64 × 10<sup>-20</sup> cm<sup>2</sup> at 449 nm, indicating a relatively large value, while that of the Pr<sub>0.006</sub>Yb<sub>0.06</sub>Y<sub>0.934</sub>COB crystal is 1.30 × 10<sup>-20</sup> cm<sup>2</sup> at 976 nm, also representing a relatively large value. The energy transfer from Pr<sup>3+</sup> to Yb<sup>3+</sup> was confirmed through polarized fluorescence spectra. The decay lifetime of the <sup>3</sup>P<sub>0</sub> energy level of the three crystals were fitted to be 21.4 μs (Pr<sub>0.0075</sub>Yb<sub>0.0375</sub>Y<sub>0.955</sub>COB), 19.2 μs (Pr<sub>0.006</sub>Yb<sub>0.06</sub>Y<sub>0.934</sub>COB) and 18.7 μs (Pr<sub>0.005</sub>Yb<sub>0.075</sub>Y<sub>0.92</sub>COB), respectively. And the decay lifetime of the <sup>2</sup>F<sub>5/2</sub> energy level of the three crystals were fitted to be 1.90 ms, 1.76 ms and 1.62 ms.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"660 ","pages":"Article 128159"},"PeriodicalIF":1.7,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704982","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 : 2025-03-23DOI: 10.1016/j.jcrysgro.2025.128156
Yang Li , Jia Chen , Kui Pan , Qinzhong Chen , Ke Zhang , Zhihe Lin , Kaixin Zhang , Hengshan Liu , Tailiang Guo , Qun Yan , Jie Sun
GaN and related III-nitrides have attracted significant attention due to their excellent performance and extensive applications. However, the substrates for epitaxial growth of III-nitride films are limited to a few options, such as SiC, Si, and sapphire, which suffer from significant shortcomings including high cost, lattice mismatch, and thermal expansion coefficient mismatch. In this study, AlN film with c-axis orientation was deposited on a 2-inch polycrystalline Mo substrate using reactive magnetron sputtering, leveraging the advantages of Mo. Additionally, the influence of a two-dimensional graphene (Gr) insertion layer on the epitaxy of III-nitrides on Mo was investigated. The introduction of Gr slightly reduced the grain size of the AlN by about 10 nm. However, the Gr induced some in-plane tensile strain in the AlN film, which compensated the compressive strain in the subsequently grown GaN, resulting in a more undistorted GaN lattice with a c-axis strain of only 0.01 %. Continuous GaN films were successfully epitaxially grown on the sputtered AlN buffer layers, which are with c-axis preferred orientation and ultraviolet emission at ∼3.36 eV. The grain size of GaN increased by about 5 nm and the full width at half maximum of the photoluminescence spectra also decreased by about 2.5 nm after the insertion of Gr. Our investigation indicates that Mo or Gr/Mo substrates are promising candidates for the heteroepitaxial growth of GaN films using sputtered AlN buffer layers. This work also provides a valuable strategy for low-cost and high-quality heteroepitaxy of other III-nitrides.
{"title":"Polycrystalline Mo as the substrate for heteroepitaxy of GaN using sputtered AlN buffer layer","authors":"Yang Li , Jia Chen , Kui Pan , Qinzhong Chen , Ke Zhang , Zhihe Lin , Kaixin Zhang , Hengshan Liu , Tailiang Guo , Qun Yan , Jie Sun","doi":"10.1016/j.jcrysgro.2025.128156","DOIUrl":"10.1016/j.jcrysgro.2025.128156","url":null,"abstract":"<div><div>GaN and related III-nitrides have attracted significant attention due to their excellent performance and extensive applications. However, the substrates for epitaxial growth of III-nitride films are limited to a few options, such as SiC, Si, and sapphire, which suffer from significant shortcomings including high cost, lattice mismatch, and thermal expansion coefficient mismatch. In this study, AlN film with c-axis orientation was deposited on a 2-inch polycrystalline Mo substrate using reactive magnetron sputtering, leveraging the advantages of Mo. Additionally, the influence of a two-dimensional graphene (Gr) insertion layer on the epitaxy of III-nitrides on Mo was investigated. The introduction of Gr slightly reduced the grain size of the AlN by about 10 nm. However, the Gr induced some in-plane tensile strain in the AlN film, which compensated the compressive strain in the subsequently grown GaN, resulting in a more undistorted GaN lattice with a c-axis strain of only 0.01 %. Continuous GaN films were successfully epitaxially grown on the sputtered AlN buffer layers, which are with c-axis preferred orientation and ultraviolet emission at ∼3.36 eV. The grain size of GaN increased by about 5 nm and the full width at half maximum of the photoluminescence spectra also decreased by about 2.5 nm after the insertion of Gr. Our investigation indicates that Mo or Gr/Mo substrates are promising candidates for the heteroepitaxial growth of GaN films using sputtered AlN buffer layers. This work also provides a valuable strategy for low-cost and high-quality heteroepitaxy of other III-nitrides.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"660 ","pages":"Article 128156"},"PeriodicalIF":1.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704981","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 : 2025-03-20DOI: 10.1016/j.jcrysgro.2025.128157
Sarang R. Daf , Dilip S. Badwaik , Shrikant M. Suryawanshi , Bhupendra T. Kumbhare , Bhaurao R. Balbudhe , Rupesh S. Wandhare
Spinel ferrite nanoparticles (SFNPs), such as Mg0.2Ni0.6Zn0.2Fe2O4, have unique properties that are influenced by their synthesis methods. Different bottom-up approaches, including sol–gel, auto-combustion, hydrothermal, and co-precipitation method were used to prepare these nanoparticles. Structural, morphological, optical and magnetic properties were analysed using techniques like X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Crystallite sizes measured using Scherrer’s formula were 28.9 nm, 20.2 nm, and 7.5 nm for the respective synthesis methods. FTIR spectra indicated metal–oxygen bond formation, TEM and SEM confirms cubical shaped morphology while VSM analysis revealed the pseudo-single domain nature of the synthesized SFNPs. The observed and estimated parameter strongly suggests that these materials could be used in biomedical and electronic applications.
{"title":"Effects of synthesis methods on the structural and magnetic properties of Mg0.2Ni0.6Zn0.2Fe2O4 spinel ferrite","authors":"Sarang R. Daf , Dilip S. Badwaik , Shrikant M. Suryawanshi , Bhupendra T. Kumbhare , Bhaurao R. Balbudhe , Rupesh S. Wandhare","doi":"10.1016/j.jcrysgro.2025.128157","DOIUrl":"10.1016/j.jcrysgro.2025.128157","url":null,"abstract":"<div><div>Spinel ferrite nanoparticles (SFNPs), such as Mg<sub>0.2</sub>Ni<sub>0.6</sub>Zn<sub>0.2</sub>Fe<sub>2</sub>O<sub>4</sub>, have unique properties that are influenced by their synthesis methods. Different bottom-up approaches, including sol–gel, auto-combustion, hydrothermal, and co-precipitation method were used to prepare these nanoparticles. Structural, morphological, optical and magnetic properties were analysed using techniques like X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), scanning electron microscope (SEM) and vibrating sample magnetometer (VSM). Crystallite sizes measured using Scherrer’s formula were 28.9 nm, 20.2 nm, and 7.5 nm for the respective synthesis methods. FTIR spectra indicated metal–oxygen bond formation, TEM and SEM confirms cubical shaped morphology while VSM analysis revealed the pseudo-single domain nature of the synthesized SFNPs. The observed and estimated parameter strongly suggests that these materials could be used in biomedical and electronic applications.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"660 ","pages":"Article 128157"},"PeriodicalIF":1.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715148","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 : 2025-03-18DOI: 10.1016/j.jcrysgro.2025.128154
J. Weng , J. Liu , X.J. Chen , F. Liu , F.J. Cui , J.H. Wang , L.W. Xiong
In this work, the growth environment for the SCDs and the diamond film are improved by refine the arrangement of the substrate holder in our self-developed MPCVD apparatus. The arrangement of the substrate holder is controlled by the △h which is kept less than 3.0 mm. The plasma around the substrate holder is systematically researched with multi-physical simulation and OES. The △h is finally selected at 1.5 mm and 0.5 mm to prepare SCDs and diamond film. Using the arrangement of the substrate holder, the cracks in the SCDs put at the edge of the Mo substrate and the fragmentation of the freestanding diamond film are effective avoided. The results turn out that the uniformity of the plasma can be enhanced by reasonable selecting the △h, and in this way the edge effect of the substrate can be effectively utilized. The obtained results provide a guidance for the scalable production of diamond material.
{"title":"Investigation on the effect of refine adjusting substrate holder on the preparation of diamond","authors":"J. Weng , J. Liu , X.J. Chen , F. Liu , F.J. Cui , J.H. Wang , L.W. Xiong","doi":"10.1016/j.jcrysgro.2025.128154","DOIUrl":"10.1016/j.jcrysgro.2025.128154","url":null,"abstract":"<div><div>In this work, the growth environment for the SCDs and the diamond film are improved by refine the arrangement of the substrate holder in our self-developed MPCVD apparatus. The arrangement of the substrate holder is controlled by the △h which is kept less than 3.0 mm. The plasma around the substrate holder is systematically researched with multi-physical simulation and OES. The △h is finally selected at 1.5 mm and 0.5 mm to prepare SCDs and diamond film. Using the arrangement of the substrate holder, the cracks in the SCDs put at the edge of the Mo substrate and the fragmentation of the freestanding diamond film are effective avoided. The results turn out that the uniformity of the plasma can be enhanced by reasonable selecting the △h, and in this way the edge effect of the substrate can be effectively utilized. The obtained results provide a guidance for the scalable production of diamond material.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"659 ","pages":"Article 128154"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644329","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 : 2025-03-18DOI: 10.1016/j.jcrysgro.2025.128143
Tianyu Wang , Chuan Tang , Qian Wu , Wen Li , Zhen Jia , Yuntao Wu , Mingjun Xia
A crack-free Rb4Li2TiOGe4O12 (RLTG) bulk crystal with dimensions up to 43 × 42 × 27 mm3 was grown by the high-temperature solution method and investigated for luminescence properties under UV and X-ray excitation for the first time. RLTG crystal displays an exceptional bluish-green photoluminescence peaking at 481 nm with a photoluminescence quantum yield 55.81 %. The fluorescence of the RLTG crystal comes from the isolated distorted TiO5 square pyramids. The light yield of RLTG crystal was measured to be 12,000 photons/MeV under steady-state X-ray excitation, surpassing that of the commercial scintillator Bi4Ge3O12 (BGO).
{"title":"Luminescence properties of Rb4Li2TiOGe4O12 single crystal grown by high-temperature solution growth","authors":"Tianyu Wang , Chuan Tang , Qian Wu , Wen Li , Zhen Jia , Yuntao Wu , Mingjun Xia","doi":"10.1016/j.jcrysgro.2025.128143","DOIUrl":"10.1016/j.jcrysgro.2025.128143","url":null,"abstract":"<div><div>A crack-free Rb<sub>4</sub>Li<sub>2</sub>TiOGe<sub>4</sub>O<sub>12</sub> (RLTG) bulk crystal with dimensions up to 43 × 42 × 27 mm<sup>3</sup> was grown by the high-temperature solution method and investigated for luminescence properties under UV and X-ray excitation for the first time. RLTG crystal displays an exceptional bluish-green photoluminescence peaking at 481 nm with a photoluminescence quantum yield 55.81 %. The fluorescence of the RLTG crystal comes from the isolated distorted TiO<sub>5</sub> square pyramids. The light yield of RLTG crystal was measured to be 12,000 photons/MeV under steady-state X-ray excitation, surpassing that of the commercial scintillator Bi<sub>4</sub>Ge<sub>3</sub>O<sub>12</sub> (BGO).</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"659 ","pages":"Article 128143"},"PeriodicalIF":1.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143684074","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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