Journal of Crystal Growth最新文献_第9页

Origin of giant dielectric constant in Ta+Gd co-doped TiO2 single crystals by optical traveling floating zone method 用光学行进浮动区法研究掺杂 Ta+Gd 的 TiO2 单晶中巨型介电常数的起源

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-06 DOI: 10.1016/j.jcrysgro.2024.127990

Jiangtao Fan , Zhanggui Hu , Yicheng Wu

{"title":"Origin of giant dielectric constant in Ta+Gd co-doped TiO2 single crystals by optical traveling floating zone method","authors":"Jiangtao Fan , Zhanggui Hu , Yicheng Wu","doi":"10.1016/j.jcrysgro.2024.127990","DOIUrl":"10.1016/j.jcrysgro.2024.127990","url":null,"abstract":"<div><div>The co-doped TiO<sub>2</sub> polycrystalline ceramics have dramatic dielectric behavior (>10<sup>4</sup>), but its source is still not completely clarified. Compared to ceramic materials, single crystals can maintain most of the original properties of the material and eliminate the grain boundary and pore interferences, thus facilitating the exploration of the source of the dielectric properties. Here, we chose Gd<sup>3+</sup> with a moderate ionic radius as the acceptor ion and Ta<sup>5+</sup> as the donor, preparing (Gd<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>0.01</sub>Ti<sub>0.99</sub>O<sub>2</sub> single crystals by the optical traveling floating zone method to investigate giant dielectric properties. It was found that a dielectric constant (<em>ε</em>′ ∼1.5 × 10<sup>4</sup>), and a dielectric loss (tanδ ∼ 0.07) were achieved simultaneously in (Gd<sub>0.5</sub>Ta<sub>0.5</sub>)<sub>0.01</sub>Ti<sub>0.99</sub>O<sub>2</sub> single crystals at 10<sup>5</sup>Hz. Electrochemical impedance spectroscopy and XPS analyses indicate that the high dielectric properties are mainly attributed to electrons pinning defective dipoles clusters. In addition, dielectric relaxation behavior under DC bias suggests that electrode effects also affect the dielectric constant. This study provides insights for the origin of the large dielectric constant and the growth of single crystals in TiO<sub>2</sub>-based materials.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127990"},"PeriodicalIF":1.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652416","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}

引用次数: 0

High-quality InAs homoepitaxial layers grown by molecular beam epitaxy 通过分子束外延生长的高质量砷化镓同外延层

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-05 DOI: 10.1016/j.jcrysgro.2024.127989

Hao Zhou , Yiqiao Chen , Chang Liu

{"title":"High-quality InAs homoepitaxial layers grown by molecular beam epitaxy","authors":"Hao Zhou , Yiqiao Chen , Chang Liu","doi":"10.1016/j.jcrysgro.2024.127989","DOIUrl":"10.1016/j.jcrysgro.2024.127989","url":null,"abstract":"<div><div>The growth conditions for InAs homoepitaxy by molecular beam epitaxy were comprehensively studied across a broad spectrum of substrate temperatures, As2/In flux ratios, and growth rates. It was found that the surface morphology and overall quality of the InAs layers were significantly influenced by these parameters. Optimal conditions, including a lower growth temperature, reduced As2 flux, and slower growth rate, were pivotal in achieving high-quality InAs layers. Two primary characterization techniques, differential interference contrast microscopy and atomic force microscopy, were employed to evaluate the material quality. High-quality InAs homoepitaxial layers were successfully grown at a substrate temperature of 455 °C and a growth rate of 0.33 monolayers per second (ML/s). These layers exhibited a remarkably low defect density of approximately 300 defects per square centimeter, which is over an order of magnitude lower than previously reported, and a notably low root-mean-square roughness of 0.116 nm. At a growth rate of 0.33 ML/s, the growth temperature range for InAs homoepitaxial layers was found to be quite broad, whereas the As2/In flux ratio remained within a narrow range. This study underscores the critical role of precise control over growth parameters in the molecular beam epitaxy process for producing high-quality InAs homoepitaxial layers.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127989"},"PeriodicalIF":1.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652461","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}

引用次数: 0

Eco-Friendly ZnO/CuO/Ni Nanocomposites: Enhanced photocatalytic dye adsorption and hydrogen evolution for sustainable energy and water purification 生态友好型 ZnO/CuO/Ni 纳米复合材料：增强光催化染料吸附和氢进化，实现可持续能源和水净化

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-05 DOI: 10.1016/j.jcrysgro.2024.127984

Souhaila Meneceur , Salah Eddine Laouini , Hamdi Ali Mohammed , Abderrhmane Bouafia , Chaima Salmi , Johar Amin Ahmed Abdullah , Fahad Alharthi

{"title":"Eco-Friendly ZnO/CuO/Ni Nanocomposites: Enhanced photocatalytic dye adsorption and hydrogen evolution for sustainable energy and water purification","authors":"Souhaila Meneceur , Salah Eddine Laouini , Hamdi Ali Mohammed , Abderrhmane Bouafia , Chaima Salmi , Johar Amin Ahmed Abdullah , Fahad Alharthi","doi":"10.1016/j.jcrysgro.2024.127984","DOIUrl":"10.1016/j.jcrysgro.2024.127984","url":null,"abstract":"<div><div>Nanomaterials and nanocomposites, known for their unique properties, are increasingly vital in diverse fields such as energy and environmental remediation. This study presents biogenically synthesized ZnO/CuO/Ni nanocomposites using <em>Mentha Pulegium L.</em> leaf extract. The investigation focuses on their applications in photocatalytic dye adsorption and hydrogen evolution. Characterization via XRD, FTIR spectroscopy, SEM, and UV–visible spectroscopy confirms the nanocomposites’ semiconducting nature with a narrow bandgap energy of 2.46 eV. Structural analysis reveals cubic crystal structures with an average crystallite size of 29.1 nm. Under solar irradiation, the nanocomposites exhibit exceptional photocatalytic activity, degrading 99 % of 4-BP and 98 % of TB. Moreover, they achieve a notable hydrogen evolution rate of 5.79 mmol/g over six hours. These results underscore the efficacy of ZnO/CuO/Ni nanocomposites as catalysts for sustainable energy and water purification. Employing <em>Mentha Pulegium L.</em> extract for environmentally friendly synthesis enhances their photocatalytic properties, offering a cost-effective route to sustainable energy and clean water technologies.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127984"},"PeriodicalIF":1.7,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652459","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}

引用次数: 0

Advances in defect characterization techniques using polarized light observation in SiC wafers for power devices 利用偏振光观测功率器件碳化硅晶片缺陷表征技术的进展

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-05 DOI: 10.1016/j.jcrysgro.2024.127982

Shunta Harada , Kenta Murayama

引用次数: 0

“Catalyzed” nucleation: A critical review of proposed theories "催化 "成核：对拟议理论的批判性审查

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-04 DOI: 10.1016/j.jcrysgro.2024.127973

Rasmus A.X. Persson

{"title":"“Catalyzed” nucleation: A critical review of proposed theories","authors":"Rasmus A.X. Persson","doi":"10.1016/j.jcrysgro.2024.127973","DOIUrl":"10.1016/j.jcrysgro.2024.127973","url":null,"abstract":"<div><div>In industrial-scale crystallization, secondary nucleation is the most important type of nucleation. In most cases, this phenomenon can be adequately explained as the result of mechanical forces that break existing crystallites apart, the strength of the effect being a smooth function of supersaturation and stirring vigor. However, in some special cases, crystallites of other polymorphs appear and/or no nucleation occurs except at a catastrophic rate above a supersaturation threshold, mimicking primary nucleation. In this paper, we review published theories for this latter type of secondary nucleation, for which we find contradicting explanations in the literature. We divide these explanations into two broad classes, depending on whether the secondary nucleation is mediated through local deviations of the bulk thermodynamic state variables (indirect effects) or directly through the interaction energy of the surface and growth units (direct effects). We argue that theoretical explanations of the second type are insufficient and while we can find no conclusive and theoretically consistent explanation for this well-established experimental phenomenon, it is hoped that this review will stimulate further research into this puzzle.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127973"},"PeriodicalIF":1.7,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652414","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}

引用次数: 0

Microstructural evolution and crystalline behavior in silicon carbide nano-powder during selective laser melting: A molecular dynamics simulation 选择性激光熔化过程中碳化硅纳米粉体的微结构演变和结晶行为：分子动力学模拟

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-02 DOI: 10.1016/j.jcrysgro.2024.127985

Amin Hamed Mashhadzadeh , Maryam Zarghami Dehaghani , Haris Doumanidis , Boris Golman , Konstantinos V. Kostas , Christos Spitas

{"title":"Microstructural evolution and crystalline behavior in silicon carbide nano-powder during selective laser melting: A molecular dynamics simulation","authors":"Amin Hamed Mashhadzadeh , Maryam Zarghami Dehaghani , Haris Doumanidis , Boris Golman , Konstantinos V. Kostas , Christos Spitas","doi":"10.1016/j.jcrysgro.2024.127985","DOIUrl":"10.1016/j.jcrysgro.2024.127985","url":null,"abstract":"<div><div>Silicon carbide (SiC), with its isotropic three-dimensional diamond lattice structure, emerges as a promising candidate for SiC device production through selective laser melting (SLM). The appeal lies in its simplified fabrication process, coupled with outstanding thermal properties, high hardness, and remarkable wear resistance. This potential of SiC in SLM not only streamlines the fabrication process but also harnesses the exceptional properties inherent in SiC. In this study, we utilized molecular dynamics (MD) simulations to model the SLM process. A nanopowder bed made up of approximately half a million atoms of SiC was simulated as a two-layer quasi-2D system. Controlled heating of SiC meltpools, slightly surpassing the melting temperature, facilitated the monitored coalescence of nano-powders, resulting in successful melting and the formation of continuous domains within the meltpools. The observed reduction in crystalline structures is due to the elevated thermal energy imparted to the SiC atoms during the heating process, which disrupts the atomic arrangement and leads to a transition from crystalline to amorphous states. The subsequent solidification process, characterized by a high cooling rate, led to the establishment of final amorphous solidified domains. Looking ahead, our research aims to delve into exploring the structural and functional characteristics of the produced SiC devices, evaluating their potential applications across diverse technological domains.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127985"},"PeriodicalIF":1.7,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652413","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}

引用次数: 0

Ammonia-free quasi-atmospheric MOCVD of InN/Al2O3 (0001) InN/Al2O3 (0001) 的无氨准大气 MOCVD

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-02 DOI: 10.1016/j.jcrysgro.2024.127980

Hisashi Yamada , Tokio Takahashi , Takahiro Gotow , Naoto Kumagai , Tetsuji Shimizu , Toshihide Ide , Tatsuro Maeda

引用次数: 0

Transferrable GaN-based Micro-LED heterostructures grown on h-BN for optogenetic applications 在 h-BN 上生长的可转移 GaN 基微型 LED 异质结构用于光遗传学应用

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-11-02 DOI: 10.1016/j.jcrysgro.2024.127979

T.M. Tran , A. Kassem , V. Ottapilakkal , P. Vuong , R. Gujrati , M. Bourras , A. Srivastava , A. Perepeliuc , T. Moudakir , S. Gautier , S. Bouchoule , M. Tchernycheva , P.L. Voss , S. Sundaram , J.P. Salvestrini , A. Ougazzaden

{"title":"Transferrable GaN-based Micro-LED heterostructures grown on h-BN for optogenetic applications","authors":"T.M. Tran , A. Kassem , V. Ottapilakkal , P. Vuong , R. Gujrati , M. Bourras , A. Srivastava , A. Perepeliuc , T. Moudakir , S. Gautier , S. Bouchoule , M. Tchernycheva , P.L. Voss , S. Sundaram , J.P. Salvestrini , A. Ougazzaden","doi":"10.1016/j.jcrysgro.2024.127979","DOIUrl":"10.1016/j.jcrysgro.2024.127979","url":null,"abstract":"<div><div>Individually transferrable GaN-based MQWs micro-LED structures grown on two-dimensional (2D) hexagonal boron nitride (h-BN) have been demonstrated. Different sizes (60 × 30 µm, 60 × 60 µm, 90 × 60 µm and 90 × 90 µm) of GaN-based LED heterostructures on layered h-BN were grown on dielectric SiN patterned sapphire substrates using Metal Organic Vapor Phase Epitaxy (MOVPE). Scanning electron microscope (SEM) images show micro-LEDs were grown with high selectivity within the mask opening areas. Consistent MQWs emission from micro-LEDs was observed at 452 ± 2 nm by cathodoluminescence (CL) spectroscopy for all micro-LED sizes. The structural and optical quality were similar to the GaN-based-LEDs grown on unpatterned substrates. In addition, we have successfully demonstrated the lift-off and transfer of individual micro-LEDs to arbitrary flexible templates using a transfer printing machine, which can be addressed by full front-end process. These studies highlight the role of combination of van der Waals (vdW) epitaxy and selective area growth (SAG) in facilitating the direct realization of dimensionally defined III-Nitride micro-LED structures and the mechanical release and transfer of these micro-LEDs to templates suitable for flexible display and optogenetics applications.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127979"},"PeriodicalIF":1.7,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652415","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}

引用次数: 0

Hydrothermal growth of potassium tantalate niobate crystals 钽酸铌酸钾晶体的水热生长

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-10-30 DOI: 10.1016/j.jcrysgro.2024.127983

Jingfang Tong , Haitao Zhou , Huajian Yu , Wenyuan Wu , Xudong Song , Weidi Zhao , Changlong Zhang , Xuping Wang

引用次数: 0

Evaluation of AlN insertion layer on the properties of heterogeneous integrated Ga2O3 films on sapphire 评估氮化铝插入层对蓝宝石上异质集成 Ga2O3 薄膜特性的影响

IF 1.7 4区材料科学

Journal of Crystal Growth Pub Date : 2024-10-30 DOI: 10.1016/j.jcrysgro.2024.127977

Anfeng Wang , Ming-Qian Yuan , Yun-Duo Guo , Lin Gu , Yi Shen , Chengxi Ding , Xuejun Yan , Qing-Chun Zhang , Li Zhang , Xiao-Dong Zhang , Hong-Ping Ma

{"title":"Evaluation of AlN insertion layer on the properties of heterogeneous integrated Ga2O3 films on sapphire","authors":"Anfeng Wang , Ming-Qian Yuan , Yun-Duo Guo , Lin Gu , Yi Shen , Chengxi Ding , Xuejun Yan , Qing-Chun Zhang , Li Zhang , Xiao-Dong Zhang , Hong-Ping Ma","doi":"10.1016/j.jcrysgro.2024.127977","DOIUrl":"10.1016/j.jcrysgro.2024.127977","url":null,"abstract":"<div><div>Integration of gallium oxide (Ga<sub>2</sub>O<sub>3</sub>) with highly thermal conductive AlN/sapphire substrate is more effective to dissipate heat in the Ga<sub>2</sub>O<sub>3</sub>-based devices. In this work, the properties of Ga<sub>2</sub>O<sub>3</sub> films grown on sapphire and AlN/sapphire substrates via MOCVD were both examined via various experimental methods. The X-ray diffraction (XRD) analysis showed good crystallinity and different orientations of Ga<sub>2</sub>O<sub>3</sub> and AlN thin films. The absorption properties and band gaps were extracted from UV/Vis spectra. The atomic force microscopy (AFM) scanning images showed smooth Ga<sub>2</sub>O<sub>3</sub> surfaces on sapphire and AlN/sapphire substrates (RMSs of 2.4 nm and 4.8 nm, respectively). The scanning electron microscopy (SEM) highlighted well-defined grains of Ga<sub>2</sub>O<sub>3</sub> and distinct boundaries of both heterostructures. X-ray photoelectron spectroscopy (XPS) analysis depicted the distributions of various components throughout the films. Finally, by using the time-domain thermoreflectance (TDTR) method, the thermal conductivity and the thermal boundary conductivity of Ga<sub>2</sub>O<sub>3</sub> without AlN interlayer were found to be 3.1 W/(m·K) and 70.1 MW/(m<sup>2</sup>·K) respectively. By comparison, adding AlN interlayer made the thermal conductivity and thermal boundary conductivity rise to 3.3 W/(m·K) and 111.5 MW/(m<sup>2</sup>·K) respectively. These findings have demonstrated the high-quality Ga<sub>2</sub>O<sub>3</sub>/AlN integration and good heat dissipation provided by AlN interlayer, opening up new prospects for Ga<sub>2</sub>O<sub>3</sub>/AlN devices in the future.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"649 ","pages":"Article 127977"},"PeriodicalIF":1.7,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572812","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}

引用次数: 0