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Fabrication of Isotropic Pyrocarbon at 1400 ℃ by Thermal Gradient chemical vapor deposition Apparatus

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Journal of Wuhan University of Technology(Materials Science) 2009年第5期24卷 728-731页

作者：郭领军 State Key Laboratory of Thermostructure Composites Materials Northwestern Polytechnical University

An experiment was designed to prepare isotropic pyrocarbon by thermal gradient chemical vapor deposition apparatus. The deposition was performed under ambient atmosphere at 1400 ℃, with natural gas volume flow of 3.5 m^3/h for 80 h. The results show that the thickness and the bulk density of the deposit are about 1.95 g/cm^3 and 10 mm, respectively. The microstructure of the deposit was examined by polarized light microscopy and scanning electron microscopy, which shows that the deposit is constituted of sphere isotropic pyrocarbon, pebble pyrocarbon and laminar pyrocarbon.

关键词： isotropic pyrocarbon chemical vapor deposition laminar pyrocarbon pebble pyrocarbon

Synthesis of Aligned Carbon Nanotubes by Thermal chemical vapor deposition

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Journal of Wuhan University of Technology(Materials Science) 2009年第1期24卷 15-19页

作者：李刚周明 Jiangsu Key Laboratory of Center for Photon Manufacturing Science and Technology Jiangsu University School of Automobile and Traffic Engineering Jiangsu University

Single crystal silicon was found to be very beneficial to the growth of aligned carbon nanotubes by chemical vapor deposition with C2H2 as carbon source. A thin film of Ni served as catalyst was deposited on the Si substrate by the K575X Peltier Cooled High Resolution Sputter Coater before growth. The growth properties of carbon nanotubes were studied as a function of the Ni catalyst layer thickness. The diameter, growth rate and areal density of the carbon nanotubes were controlled by the initial thickness of the catalyst layer. Steric hindrance between nanotubes forces them to grow in well-aligned manner at an initial stage of growth. Transmission electron microscope analysis revealed that nanotubes grew by a tip growth mechanism.

关键词： carbon nanombes magnetron sputtering chemical vapor deposition tip-growth

Controllable synthesis of Ni-catalyzed tetragonal tungsten nanowires via chemical vapor deposition

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Progress in Natural Science:Materials International 2012年第5期22卷 514-519页

作者： Chao Wang a,Yuehui He a,Chaoqun Peng b,Shiliang Wang a,c,Xinli Liu a a State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China b School of Material Science and Engineering,Central South University,Changsha 410083,China c School of Physics Science and Technology,Central South University,Changsha 410083,China [a] State Key Laboratory of Powder Metallurgy Central South University Changsha 410083 China [b] School of Material Science and Engineering Central South University Changsha 410083 China [c] School of Physics Science and Technology Central South University Changsha 410083 China

Tetragonal single-crystal tungsten nanowires were successfully synthesized by chemical vapor deposition(CVD) catalyzed by Ni *** influences of the catalysts,temperature and growth time on the formation of the nanowires were *** was found that the tetragonal tungsten nanowires(WNWs) arrays were obtained by deterministic growth from the ordered Ni catalyst particles with one-to-one relation in size and position between the catalysts and *** large-scale tungsten nanowire arrays were synthesized at the low temperature of 950℃.Samples were characterized by X-ray diffraction(XRD),field-emission scanning electron microscopy(FE-SEM),transmission electron microscopy(TEM) and high-resolution transmission electron microscopy(HRTEM).Increasing growth time at 950℃,the tip of the WNWs changed from four(211) planes to four(110) *** controls of the orientation and structure of WNWs arrays were important for adjusting their properties to satisfy different requirements of potential nanodevices.

关键词： Tungsten nanowires Ni catalysts chemical vapor deposition Nanostructures

Criteria for the growth of large-area adlayer-free monolayer graphene films by chemical vapor deposition

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Journal of Materiomics 2019年第3期5卷 463-470页

作者： Changqing Shen Xingzhou Yan Fangzhu Qing Xiaobin Niu Richard Stehle Samuel S.Mao Wanli Zhang Xuesong Li School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu610054China State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu610054China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu610054China Department of Mechanical Engineering Sichuan University-Pittsburgh InstituteSichuan UniversityChengdu610207China Institute of New Energy Shenzhen518031China Department of Mechanical Engineering University of California at BerkeleyBerkeleyCA94720USA

Homogeneity is important to material applications for good performance of individual devices,for making AB-stacked bilayer graphene in a layer-by-layer stacking order,and from the point of view of industrial *** many properties to be controlled,for the case of graphene,the thickness(or layer number)uniformity is the *** vapor deposition(CVD)of C precursors on Cu substrates is the most popular method to produce large-area graphene *** date,precise control on the number of graphene layers as well as the uniformity over a large area is still very *** this work,with a further understanding of the factors affecting adlayer growth,the synthesis of large-area adlayer-free monolayer graphene(MLG)films was achieved up to tens of squared centimeters in area by just using untreated Cu foil and a normal CVD *** found that keeping equal C precursor concentration on the two sides of the Cu substrate is a criterion in addition to other factors such as the ratio of H:C and the substrate surface morphology for the growth of adlayer-free *** finding is not only of great significance for the industrial production of large-area adlayer-free MLG films but also instructive for the synthesis of homogeneous few-layer graphene.

关键词： Graphene Adlayer-free chemical vapor deposition Monolayer Bilayer

Preparation of the highly dense ceramic-metal fuel particle with fine-grained tungsten layer by chemical vapor deposition for the application in nuclear thermal propulsion

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Tungsten 2022年第1期4卷 1-9页

作者： Li-Hua Guo Feng Zhang Lin-Yuan Lu Yan You Jun-Qiang Lu Li-Bing Zhu Jun Lin Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China Wuwei Institute of New Energy Wuwei 733000China Shanghai Nuclear Engineering Research and Design Institute Co. Ltd.Shanghai 200233China

The cermet fuel element was achieved by dispersing the UO_(2)particles with or without tungsten(W)coating layer uniformly in the W *** is considered to be a robust and secure fuel for use in nuclear thermal propulsion in the near *** this study,the effect of deposition temperature on the densification and grain refinement of the W coating layer was investigated.A high-density(19.24 g·cm^(-3))W layer with a uniform thickness(~10μm)and fine grains(~297 nm)was prepared by spouted-bed chemical vapor *** prepared high-density,fine-grained W layer has the following *** can prevent direct contact between fuel particles,resulting in a more uniform fuel *** addition,it can decrease the reaction probability between the fuel kernel and H2,and prevent the release of fission products from the fuel kernel by extending the diffusion path at grain boundaries more ***,the high-density,fine-grained W layer showed outstanding thermal and mechanical *** average hardness and Young's modulus were approximately 7 and 200 GPa,*** thermal conductivity of the W film was 101-124 W·m^(-1)·K^(-1)at 298-773 *** work furthers our understanding of the potential application of the high-density,fine-grained W layer in nuclear thermal propulsion.

关键词： deposition temperature Tungsten layer Ceramic-metal fuel particle Nuclear thermal propulsion chemical vapor deposition

Synthesis and photoluminescence properties of CdS hollow nanospheres by chemical vapor deposition

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Optoelectronics Letters 2011年第3期7卷 161-163页

作者：莫家庆冯志强侯军伟贾振红吕小毅 College of Information Science & Engineering Xinjiang University School of Electronic and Information Engineering Xi'an Jiaotong University School of Materials Science and Engineering Tongji University Postdoctoral Station of Computer Science and Technology Xinjiang University

High-density CdS hollow nanospheres are successfully synthesized by a simple chemical vapor deposition *** crystal structure,compositional information,and morphological structure are characterized by X-ray diffraction(XRD),scanning electronic microscopy(SEM),transmission electronic microscopy(TEM),and energy-dispersive X-ray spectrometer(EDX).The results show that the as-prepared CdS hollow nanospheres have uniform size about 1-3 μm in *** Kirkendall phenomenon is proposed for the formation of the CdS nanostructures.A strong emission located at 580 nm is observed.

关键词： Cadmium compounds chemical vapor deposition Crystal structure Nanospheres X ray diffraction

Influence of reaction parameters on synthesis of high-quality single-layer graphene on Cu using chemical vapor deposition

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Chinese Physics B 2014年第9期23卷 1-5页

作者：杨贺申承民田园王高强林少雄张一顾长志李俊杰高鸿钧 Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

Large-area monolayer graphene samples grown on polycrystalline copper foil by thermal chemical vapor deposition with differing CH4 flux and growth time are investigated by Raman spectra, scanning electron microscopy, atomic force microscopy, and scanning tunneling microscopy. The defects, number of layers, and quality of graphene are shown to be controllable through tuning the reaction conditions： ideally to 2-3 sccm CH4 for 30 minutes.

关键词： graphene chemical vapor deposition Raman spectra

Recent Advances in Spin-coating Precursor Mediated chemical vapor deposition of Two-Dimensional Transition Metal Dichalcogenides

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Precision Chemistry 2024年第7期2卷 282-299页

作者： Dingyi Shen Yejun Jin Zucheng Zhang Rong Song Miaomiao Liu Wei Li Xin Li Ruixia Wu Bo Li Jia Li Bei Zhao Xidong Duan Hunan Key Laboratory of Two-Dimensional Materials State Key Laboratory for Chemo/Biosensing and ChemometricsCollege of Chemistry and Chemical EngineeringHunan University410082 ChangshaChina Key Laboratory of Quantum Materials and Devices of Ministry of Education School of PhysicsSoutheast UniversityNanjing 211189China Key Laboratory of Two-Dimensional Materials State Key Laboratory for Chemo/Biosensing and ChemometricsCollege of Chemistry and Chemical EngineeringHunan University410082 ChangshaChina

Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered widespread interest in the scientific community and industry for their exceptional physical and chemistry properties,and great potential for applications in diverse fields including(opto)electronics,electrocatalysis,and energy *** vapor deposition(CVD)is one of the most compelling growth methods for the scalable growth of high-quality 2D ***,the conventional CVD process for synthesis of 2D TMDs still encounters significant challenges,primarily attributed to the high melting point of precursor powders,and achieving a uniform distribution of precursor atmosphere on the substrate to obtain controllable smaple domains is *** spin-coating precursor mediated chemical vapor deposition(SCVD)strategy provides refinement over traditional methods by eliminating the use of solid precursors and ensuring a more clean and uniform distribution of the growth material on the ***,the SCVD process allows fine-tuning of material thickness and purity by manipulating solution composition,concentration,and the spin coating *** Review presents a comprehensive summary of recent advances in controllable growth of 2D TMDs with a SCVD ***,a series of various liquid precursors,additives,source supply methods,and substrate engineering strategies for preparing atomically thin TMDs by SCVD are ***,2D TMDs heterostructures and novel doped TMDs fabricated through the SCVD method are ***,the current challenges and perspectives to synthesize 2D TMDs using SCVD are discussed.

关键词： Spin-coating chemical vapor deposition Liquid precursor Substrate Two-dimensional materials Heterostructure Doping Film

PARTICLE COATING BY chemical vapor deposition IN A FLUIDIZED BED REACTOR

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China Particuology 2005年第1期3卷 105-112页

作者： Gregor Czok Joachim Werther Department of chemical Engineering I Technical University Hamburg-Harburg Germany

Aluminum coatings were created onto glass beads by chemical vapor deposition in a fluidized bed reactor at different temperatures. Nitrogen was enriched with Triisobutylaluminum (TIBA) vapor and the latter was thermally decomposed inside the fluidized bed to deposit the elemental aluminum. To ensure homogeneous coating on the bed material, the fluidizing conditions necessary to avoid agglomeration were investigated for a broad range of temperatures. The deposition reaction was modeled on the basis of a discrete particle simulation to gain insight into homogeneity and thickness of the coating throughout the bed material. In particular, the take-up of aluminum was traced for selected particles that exhibited a large mass of deposited aluminum.

关键词： chemical vapor deposition fluidized bed reactor particle coating