Journal of Crystal Growth最新文献

{"title":"Morphological evolution and optical properties of ZnO microstructures","authors":"Gaoxiang Fan,&nbsp;Jiling Li,&nbsp;Yuhua Yang","doi":"10.1016/j.jcrysgro.2024.128012","DOIUrl":"10.1016/j.jcrysgro.2024.128012","url":null,"abstract":"<div><div>Three kinds of ZnO microstructures are controlled synthesized on silicon substrates including microcolumns, microfences and hollow microcolumns. The morphological evolution of the prepared ZnO microstructures are systematically analyzed. It is found that the growth parameters play crucial roles on it, such as the growth temperature and the concentration of gaseous source atoms on the growth surface. Moreover, the optical characterizations suggest the structural advantages of ZnO microfence, that is, its excitation density has been enhanced due to its special symmetric hexagonal array, which has also switched on the p-band emission.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"651 ","pages":"Article 128012"},"PeriodicalIF":1.7,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719612","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":"Study of the structural, morphological, and J–V characteristics of Zr-doped barium calcium strontium titanate","authors":"Md. Parvej Mosaraf Sohel,&nbsp;Abdullah Al Moyeen,&nbsp;Ainul Islam Safi,&nbsp;Md. Sadrul Rahman Dipto,&nbsp;Shaadnan Bin Syed","doi":"10.1016/j.jcrysgro.2024.128011","DOIUrl":"10.1016/j.jcrysgro.2024.128011","url":null,"abstract":"<div><div>Barium calcium strontium titanate (BCST) ceramics are promising materials for energy storage and dielectric applications, but their performance is often limited by high leakage currents and structural instability. To address these, Zr-doped BCST (Ba_0.7Ca_0.15Sr_0.15Zr_xTi_(1-x)O₃; x = 0.0, 0.1, 0.15, 0.2) ceramics were synthesized via the solid-state reaction method with the objective of reducing leakage currents in BCST ceramics. X-ray diffraction (XRD) analysis confirmed a single-phase-pseudocubic ABO3 structure with space group <em>Pm-3m</em>n all samples and a secondary ZrO2 phase in Zr-doped samples. Rietveld refinement revealed an increase in lattice parameters and unit cell volumes with higher doping, ranging from 62.483 to 63.363 ų. The SEM images showed cubic and rod-shaped morphologies with agglomerates and pores, with grain sizes ranging between 0.543 μm and 0.727 μm. EDS analysis confirmed the presence of all constituent elements. Current density–voltage (J–V) analysis showed that the leakage current density increased non-linearly with voltage for all samples, with Zr doping significantly reducing leakage currents by enhancing chemical stability and suppressing electron jumps between Ti⁴⁺ and Ti³⁺. Among the samples, undoped BCST exhibited the highest leakage current, while Zr-doped samples showed improved resistivity and lower leakage currents. These properties make Zr-doped BCST ceramics promising candidates for energy storage devices and dielectric applications requiring high resistivity and low leakage currents.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"651 ","pages":"Article 128011"},"PeriodicalIF":1.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719610","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":"Effect of substrate misorientation angle on the structural properties of N-polar GaN grown by hot-wall MOCVD on 4H-SiC(0001̄)","authors":"Hengfang Zhang ,&nbsp;Jr.-Tai Chen ,&nbsp;Alexis Papamichail ,&nbsp;Ingemar Persson ,&nbsp;Dat Q. Tran ,&nbsp;Plamen P. Paskov ,&nbsp;Vanya Darakchieva","doi":"10.1016/j.jcrysgro.2024.127971","DOIUrl":"10.1016/j.jcrysgro.2024.127971","url":null,"abstract":"<div><div>The effects of substrate misorientation angle direction and degree on the structural properties of N-polar GaN grown by a novel multi-step temperature epitaxial approach using hot-wall metal–organic chemical vapor deposition (MOCVD) on 4H-SiC (000<span><math><mover><mrow><mn>1</mn></mrow><mrow><mo>̄</mo></mrow></mover></math></span>) substrates is investigated. The surface morphology and X-ray diffraction (XRD) rocking curves (RCs) for both symmetric and asymmetric Bragg peaks of the multi-step temperature N-polar GaN are compared to a material obtained in a two-step temperature process. In the latter the temperature in the second step was varied so that it corresponds to the growth temperatures in each of the steps of the multi-step process. Different step-flow patterns are obtained on the substrates with a misorientation angle of 4° depending on whether its direction is towards the <em>a</em>-plane or the <em>m</em>-plane. In contrast, for a misorientation angle of 1° towards the <em>m</em>-plane, the surface morphology of N-polar GaN is dominated by hexagonal hillocks when using the 2-step temperature process and a step meandering growth mode is observed when employing the multi-step temperature process. These results are discussed and explained in terms of kinetic and thermodynamic considerations. As the growth temperature of the GaN layer in the 2-step temperature process increases from 950 °C to 1100 °C, the surface roughness and RCs widths decrease for the three types of substrates indicating improved crystal quality at higher temperature. The multi-step epitaxial approach is shown to be beneficial for achieving smooth surface morphology and low defect density of N-polar GaN layers grown on C-face SiC substrates with a misorientation angle of 4° and an RMS value of 1.5 nm over an area of 20 <span><math><mi>μ</mi></math></span>m <span><math><mo>×</mo></math></span> 20 <span><math><mi>μ</mi></math></span>m is attained when the substrate mis-cut is towards the <em>m</em>-plane.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"651 ","pages":"Article 127971"},"PeriodicalIF":1.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing MPCVD systems for diamond growth through advanced microwave transmission theory","authors":"Xiaobin Hao ,&nbsp;Yicun Li ,&nbsp;Xia Kong ,&nbsp;Jilei Lyu ,&nbsp;Kunlong Zhao ,&nbsp;Jiwen Zhao ,&nbsp;Sen Zhang ,&nbsp;Dongyue Wen ,&nbsp;Kang Liu ,&nbsp;V.G. Ralchenko ,&nbsp;Benjian Liu ,&nbsp;Bing Dai ,&nbsp;Jiaqi Zhu","doi":"10.1016/j.jcrysgro.2024.128008","DOIUrl":"10.1016/j.jcrysgro.2024.128008","url":null,"abstract":"<div><div>Diamond, renowned for its exceptional properties, stands as the ultimate semiconductor material. Microwave plasma chemical vapor deposition (MPCVD) is pivotal in advancing diamond’s functional applications. The effectiveness of the MPCVD system hinges on the efficient transmission of microwave energy to the resonant cavity. Additionally, the system must form a large-area, high-intensity hemispherical standing-wave electric field in the deposition area. Thus, a well-conceived optimization design for the microwave transmission and resonance systems is imperative. This paper introduces a design methodology for MPCVD systems, aligning plasma requirements for diamond growth with the transmission and distribution characteristics of the microwave electromagnetic field, which means that system optimization can be achieved without the need for complex multiple physical fields simulations. The average electric field intensity up to 3.24 × 10⁵ V/m is obtained by using the dual-objective optimization function as the comprehensive optimization objective of the metal boundaries of the reactor. Based on simulation findings, an MPCVD system operating at 2450 MHz was designed, resulting in a single-crystal diamond with a high average growth rate of 11.5 μm/h. Further reduction of the microwave frequency to 915 MHz enabled the preparation of a 4-inch polycrystalline diamond film, achieving an average growth rate close to 3.5 μm/h.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"651 ","pages":"Article 128008"},"PeriodicalIF":1.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719611","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":"Growth and characterization of n-type Ga2O3 films on sapphire substrates by APMOVPE","authors":"Shun Ukita,&nbsp;Takeyoshi Tajiri,&nbsp;Kazuo Uchida","doi":"10.1016/j.jcrysgro.2024.128007","DOIUrl":"10.1016/j.jcrysgro.2024.128007","url":null,"abstract":"<div><div>In this study, n-type Ga₂O₃ thin films were grown on c-plane sapphire substrates by atmospheric pressure metalorganic vapor phase epitaxy using tetraethoxysilane (TEOS) as the silicon (Si) precursor. X-ray diffraction measurements confirmed that the deposited films were polycrystalline, predominantly consisting of the stable β-phase and the metastable κ-phase. Surface and optical characterizations indicated that lower growth temperature and appropriate Si doping reduce the grain size of three-dimensional Ga₂O₃ islands, thereby enhancing optical transmittance by mitigating surface scattering. Hall effect measurements demonstrated a maximum electron carrier concentration of approximately 1 × 10¹⁷ /cm³ at room temperature, while secondary ion mass spectrometry (SIMS) revealed that Si atomic concentrations were exceeding 1 × 10²⁰ /cm³ in all n-type samples indicating low doping efficiency of Si. Carbon (C) impurities were also measured by SIMS with concentrations as the same order or higher than that of Si, implying they may be one of the reasons for the degraded electrical conductivity and originated from incomplete decomposition of the precursors during low temperature growth. From these results, it is crucial to reduce C impurities and enhance surface flatness to improve electrical and optical properties.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 128007"},"PeriodicalIF":1.7,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703247","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":"Numerical simulation of flow and mass transport in KDP crystal growth using solution alternate jetting method","authors":"Hailin Li ,&nbsp;Chuan Zhou ,&nbsp;Mingwei Li","doi":"10.1016/j.jcrysgro.2024.127994","DOIUrl":"10.1016/j.jcrysgro.2024.127994","url":null,"abstract":"<div><div>In response to the limitations of some previous crystal growth method, which cannot generate ‘back-and-forth shear flow’ in rotating-crystal method and the partial realization of ‘back-and-forth shear flow’ in the crystal two-dimensional and three-dimensional motion methods, a novel KDP crystal growth method, named solution alternate jetting method, was proposed. This method can achieve complete coverage of crystal faces with ‘back-and-forth shear flow’. Numerical simulation results indicate that solution alternate jetting method outperforms rotating-crystal growth method and crystal two-dimensional and three-dimensional motion methods in terms of time-averaged supersaturation and its standard deviation on crystal faces. The jet velocity has a significant impact on the magnitude and distribution of time-averaged supersaturation on crystal faces. Other operating conditions, including the vertical distances from the nozzle outlet to the crystal surface, alternate jetting cycle, nozzle spray angle, and special motion velocity, have a relatively minor impact. Crystals grown with less than 50% ‘back-and-forth shear flow’ in the crystal two-dimensional and three-dimensional motion methods had significantly improved quality compared to rotating-crystal growth method. Therefore, the solution alternate jetting method, capable of achieving the ideal ‘back-and-forth shear flow’, undoubtedly holds promising application prospects.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 127994"},"PeriodicalIF":1.7,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703243","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":"Role of synthesis temperature in the formation of ZnO nanoparticles via the Sol-Gel process","authors":"A. Modrić-Šahbazović ,&nbsp;A. Smajlagić ,&nbsp;Z. Sakić ,&nbsp;M. Novaković ,&nbsp;N. Latas ,&nbsp;M. Popović ,&nbsp;M. Đekić ,&nbsp;S. Isaković ,&nbsp;A. Salčinović Fetić","doi":"10.1016/j.jcrysgro.2024.128003","DOIUrl":"10.1016/j.jcrysgro.2024.128003","url":null,"abstract":"<div><div>This study examines the synthesis of ZnO powder via the sol–gel method at temperatures of 25 °C and 60 °C. Characterization was conducted using standard techniques to investigate how these temperature conditions influence the physicochemical properties of the resulting material. XRD analysis confirmed high crystallinity with a pure hexagonal wurtzite structure, with average crystallite sizes of approximately 20 nm at 25 °C and 38 nm at 60 °C. Both SEM and TEM techniques established needle-like nanorods at 25 °C and nanoflower-like structures at 60 °C. Analyzing the high-resolution XPS spectra of the Zn2p and O1s photoelectron lines revealed a predominant Zn(II) state, with the contribution of ZnO increasing from 14.6 at.% to 41.6 at.% at higher temperatures. This change was accompanied by a decrease in defective oxygen and water content. Furthermore, DSC analysis revealed significant differences in thermal properties of ZnO powders synthesized at 25 °C and 60 °C, with distinct endothermic peaks around 120 °C corresponding to the evaporation of the solvent used in the synthesis process. The energy required for phase transitions was notably higher for the 25 °C synthesis, indicating greater thermal stability and energy demands compared to the 60 °C synthesis.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 128003"},"PeriodicalIF":1.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652409","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":"An electronic energy model for multi-stacking faults in reducing carrier lifetime in 4H-SiC epitaxial layers","authors":"Pengxiang Hou ,&nbsp;Pin Wang ,&nbsp;Yifei Li ,&nbsp;Weiliang Zhong ,&nbsp;Yuebin Han ,&nbsp;Jing Wang ,&nbsp;Le Yu ,&nbsp;Zheyang Li ,&nbsp;Rui Jin","doi":"10.1016/j.jcrysgro.2024.128005","DOIUrl":"10.1016/j.jcrysgro.2024.128005","url":null,"abstract":"<div><div>The effect of stacking faults (SFs) on carrier lifetime in 110 μm 4H-SiC epilayers has been studied using photoluminescence and microwave photoconductance decay. The carrier lifetimes are associated with different types of SFs. The SFs are distinguished as multi-SFs and mono-SFs in terms of their characteristic luminescence peaks. The average lifetime at multi-SFs is about 60 % of that at mono-SFs. Contrary to the quantum well models reported previously, multi-SFs decrease the minority carrier lifetime than mono-stacking faults even with shallower energy levels. A “step-structure” quantum well model is proposed to discuss the carrier dynamics for the enhanced recombination at the multi-stacking faults.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"650 ","pages":"Article 128005"},"PeriodicalIF":1.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703246","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":"Annealing, design and long-term operation of graphite crucibles for the growth of epitaxial graphene on SiC","authors":"Mykhailo Shestopalov ,&nbsp;Veronika Stará ,&nbsp;Martin Rejhon ,&nbsp;Jan Kunc","doi":"10.1016/j.jcrysgro.2024.127988","DOIUrl":"10.1016/j.jcrysgro.2024.127988","url":null,"abstract":"<div><div>We describe the annealing, geometry, storage, and lifespan of graphite crucibles for the growth of epitaxial graphene on SiC. We monitor residual gas content during the annealing of the as-manufactured graphite crucible before the growth of the first graphene samples. The high-temperature evolution of carbon monoxide points towards the reaction of solid carbon and residual water. Therefore, we propose a procedure consisting of four annealing cycles to eliminate this reaction. The residual gas evolution after long-term storage of well-baked crucibles in the air shows a similar increase in water and carbon monoxide as that in unbaked crucibles. Hence, we propose the crucible storage in argon ambient. Further, we discuss the role of the crucible shape on graphene quality. Namely, we compare the cylindrical semi-closed crucible to the flat opened crucibles. The flow-aided gas exchange in the opened crucible is more beneficial for graphene growth than the diffusion-driven gas exchange in the semi-closed cylindrical crucibles. The flow-aided gas exchange leads to more efficient removal of outgassed residual contaminants, thus outperforming the advantage of increased silicon vapor pressure in the semi-closed cylindrical crucible. We also study the graphite crucible lifespan, showing that the aged crucible leads to the enhanced inhomogeneous strain in graphene.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"651 ","pages":"Article 127988"},"PeriodicalIF":1.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719738","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":"Low-cost preparation and characterization of new CuO/ZnO and Cu3N/ZnO nanocomposites","authors":"R. Szczęsny ,&nbsp;P. Sędzicki ,&nbsp;M. Trzcinski ,&nbsp;M. Wiśniewski ,&nbsp;A. Ścigała ,&nbsp;B. Derkowska-Zielinska ,&nbsp;D.H. Gregory","doi":"10.1016/j.jcrysgro.2024.128004","DOIUrl":"10.1016/j.jcrysgro.2024.128004","url":null,"abstract":"<div><div>CuO/ZnO and Cu₃N/ZnO nanocomposites were prepared in a three-step synthesis consisting of the co-precipitation of Cu²⁺ and Zn²⁺ hydroxide carbonates (Cu/Zn-Carb) followed by their thermal treatment first in air and second in gaseous ammonia. The morphology and phase composition of the hydroxide carbonates were determined by the Cu:Zn molar ratio and the presence of polyvinylpyrrolidone (PVP) acting as a capping agent, respectively. The Cu/Zn-carbonates could be annealed in the air at 550 °C either as powders or as thin films. The latter were deposited on a silicon substrate using a choice of spin- or dip-coating techniques. The resulting CuO/ZnO samples were heated under gaseous ammonia at 300 °C in the final step of the process to form Cu₃N/ZnO nanocomposites. The fabricated samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) with energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), thermogravimetric − differential thermal analysis (TG-DTA) and infrared spectroscopy (IR). SEM and XRD analysis indicates that the average diameter of spherical particles was about 130 nm (CuO/ZnO) and 100 nm (Cu₃N/ZnO), composed of crystallites with 10–20 nm sizes. The thermal treatment under air and NH₃ did not affect the morphology of the composites. The implication is, therefore, that the shape and size of CuO/ZnO oxide and Cu₃N/ZnO nitride/oxide composite nanostructures are determined at the point of hydroxide carbonate coprecipitation and can be controlled during precursor synthesis. This has significant ramifications for the reproducible fabrication of nanocomposite films of precise stoichiometry and bespoke morphology.</div></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":"651 ","pages":"Article 128004"},"PeriodicalIF":1.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719737","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}