A Novel Apparatus for the Synthesis of Graphite Encapsulated Metallic Nanocrystals

1999 ◽  
Vol 577 ◽  
Author(s):  
K.L. Klug ◽  
D.L. Johnson ◽  
V.P. Dravid
Keyword(s):  
Data Storage ◽  
Chemical Vapor ◽  
Electric Arc ◽  
Raw Material ◽  
Magnetic Data ◽  
Metal Nanocrystals ◽  
New Class ◽  
Potential Applications ◽  
New Apparatus ◽  
Encapsulated Nanoparticles

ABSTRACTGraphite encapsulated metal nanocrystals (GEM nanocrystals) are a promising new class of materials with both scientific and industrial significance. Several encapsulating graphite layers protect the nanoscale metallic core without compromising the inherent magnetic properties of the metal, thereby enhancing studies of small particle magnetism. The size and single domain nature of these particles immediately suggest a wide variety of potential applications ranging from increased density magnetic data storage to immunoassays. Encapsulated nanoparticles have traditionally been synthesized by evaporating a composite metal/graphite anode via an electric arc. While effective, that method also results in a great deal of unwanted amorphous carbon debris in the product. Based on past synthesis runs and observations, an improved apparatus for GEM production has been designed with the goals of increasing GEM yield and reducing soot production. The four segment system consists of I ) a chamber capable of arc or resistive evaporation of raw material(s), 2) a tube furnace for the chemical vapor deposition of carbon on raw material(s) via hydrocarbon dissociation, 3) an increased-efficiency powder collection unit, and 4) a final powder reservoir. Details of the new apparatus are presented here.

scholarly journals Microstructural Study of CMR Films as a Function of Growth Temperature, As-Deposited and Annealed

1995 ◽  
Vol 401 ◽  
Author(s):  
M. E. Hawley ◽  
X. D. Wu ◽  
P. N. Arendt ◽  
C. D. Adams ◽  
M. F. Hundley ◽  
...  
Keyword(s):  
Data Storage ◽  
Growth Temperature ◽  
Magnetic Data ◽  
Storage Devices ◽  
Colossal Magnetoresistive ◽  
Step Flow ◽  
Transmission Electron ◽  
The Family ◽  
Complex Metal Oxides ◽  
Potential Applications

AbstractThe properties encompassed by the family of complex metal oxides span the spectrum from superconductors to insulating ferroelectrics. Included in this family are the new colossal magnetoresistive perovskites with potential applications in advanced high density magnetic data storage devices based on single or multilayer thin films units of these materials fabricated by vapor phase deposition (PVD) methods. The realization of this potential requires solving basic thin film materials problems requiring understanding and controlling the growth of these materials. Toward this end, we have grown La0.7Ca0.3MnO3 and La0.7Sr0.3MnO3 on LaAlO3 single crystal substrates by pulsed laser and RF sputter deposition at temperatures from 500° C to 900° C and annealed at over 900° C for about 10 hours. The evolution of the microstructure of these films was studied by scanning probe microscopies and transmission electron microscopy (TEM).The results of SPM characterization showed that at the lower end of the growth temperature range, the as-grown films were polygranular with grain size increasing with temperature. The 500° C as-grown films appeared to be amorphous while the 750° C film grains were layered with terrace steps often one unit cell high. In contrast, films grown at 900° C consisted of coalesced islands with some 3-D surface crystals. After annealing, all films had coalesced into very large extended layered islands. The change in microstructure was reflected in a decreased resistivity of coalesced films over their unannealed granular precursors. Previous reported work on the growth of La0.84 Sr0.16MnO3 and La0.8Sr0 2CoO3 grown demonstrated the sensitivity of the microstructure to substrate and deposition conditions. Films grown on an “accidental” vicinal surface grew by a step flow mechanism.

Novel organic, polymeric materials for electronics applications

2002 ◽  
Vol 722 ◽  
Author(s):  
Ram W. Sabnis ◽  
Mary J. Spencer ◽  
Douglas J. Guerrero
Keyword(s):  
Optical Density ◽  
Chemical Vapor ◽  
Polymeric Materials ◽  
Substantial Improvement ◽  
Polymeric Systems ◽  
Patterned Wafers ◽  
Visible Spectra ◽  
Potential Applications ◽  
Deep Ultraviolet ◽  
Deposited Films

AbstractNovel organic, polymeric materials and processes of depositing thin films on electronics substrates by chemical vapor deposition (CVD) have been developed and the lithographic behavior of photoresist coated over these CVD films at deep ultraviolet (DUV) wavelength has been evaluated. The specific monomers synthesized for DUV applications include [2.2](1,4)- naphthalenophane, [2.2](9,10)-anthracenophane and their derivatives which showed remarkable film uniformity on flat wafers and conformality over structured topography wafers, upon polymerization by CVD. The chemical, physical and optical properties of the deposited films have been characterized by measuring parameters such as thickness uniformity, solubility, conformality, adhesion to semiconductor substrates, ultraviolet-visible spectra, optical density, optical constants, defectivity, and resist compatibility. Scanning electron microscope (SEM) photos of cross-sectioned patterned wafers showed verticle profiles with no footing, standing waves or undercut. Resist profiles down to 0.10 νm dense lines and 0.09 νm isolated lines were achieved in initial tests. CVD coatings generated 96-100% conformal films, which is a substantial improvement over commercial spin-on polymeric systems. The light absorbing layers have high optical density at 248 nm and are therefore capable materials for DUV lithography applications. CVD is a potentially useful technology to extend lithography for sub-0.15 νm devices. These films have potential applications in microelectronics, optoelectronics and photonics.

scholarly journals Controlled Fabrication of Quality ZnO NWs/CNTs and ZnO NWs/Gr Heterostructures via Direct Two-Step CVD Method

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1836
Author(s):  
Nicholas Schaper ◽  
Dheyaa Alameri ◽  
Yoosuk Kim ◽  
Brian Thomas ◽  
Keith McCormack ◽  
...  
Keyword(s):  
Direct Synthesis ◽  
Chemical Vapor ◽  
Single Walled Carbon Nanotubes ◽  
Materials Synthesis ◽  
Oxide Nanowires ◽  
Cvd Method ◽  
Thermal Actuators ◽  
Potential Applications ◽  
Walled Carbon Nanotubes ◽  
Scalable Production

A novel and advanced approach of growing zinc oxide nanowires (ZnO NWs) directly on single-walled carbon nanotubes (SWCNTs) and graphene (Gr) surfaces has been demonstrated through the successful formation of 1D–1D and 1D–2D heterostructure interfaces. The direct two-step chemical vapor deposition (CVD) method was utilized to ensure high-quality materials’ synthesis and scalable production of different architectures. Iron-based universal compound molecular ink was used as a catalyst in both processes (a) to form a monolayer of horizontally defined networks of SWCNTs interfaced with vertically oriented ZnO NWs and (b) to grow densely packed ZnO NWs directly on a graphene surface. We show here that our universal compound molecular ink is efficient and selective in the direct synthesis of ZnO NWs/CNTs and ZnO NWs/Gr heterostructures. Heterostructures were also selectively patterned through different fabrication techniques and grown in predefined locations, demonstrating an ability to control materials’ placement and morphology. Several characterization tools were employed to interrogate the prepared heterostructures. ZnO NWs were shown to grow uniformly over the network of SWCNTs, and much denser packed vertically oriented ZnO NWs were produced on graphene thin films. Such heterostructures can be used widely in many potential applications, such as photocatalysts, supercapacitors, solar cells, piezoelectric or thermal actuators, as well as chemical or biological sensors.

Graphene nanocomposites: A review on processes, properties, and applications

2021 ◽  
pp. 152808372110242
Author(s):  
Kadir Bilisik ◽  
Mahmuda Akter
Keyword(s):  
Textile Industry ◽  
In Situ Polymerization ◽  
Resin Transfer Molding ◽  
Single Layer ◽  
Chemical Vapor ◽  
Synthesis Process ◽  
Graphene Nanocomposites ◽  
Transfer Molding ◽  
Potential Applications ◽  
Nano Graphene

In this paper, graphene, graphene/matrix, and graphene/fiber nanocomposites, including their synthesis process, fabrication, properties, and potential applications, were reviewed. It was found that several synthesis techniques for nanographene were developed, such as liquid-phase exfoliation and chemical vapor deposition. In addition, some fabrication processes of graphene/matrix and graphene/fiber-based nanocomposites were made, including in-situ polymerization, nanostitching in that single layer nano graphene plate could be interconnected by means of carbon nanotube stitching, resin transfer molding, and vacuum-assisted resin transfer molding. Several properties, including mechanical, thermal, and electrical, on the graphene nanoplatelets materials were summarized in this review paper. It was realized that graphene, graphene/matrix, and graphene/fiber nanocomposites have extraordinary mechanical, thermal, and electrical properties used in advanced engineering applications, including soft robotics, microelectronics, energy storage, biomedical and biosensors as well as textile industry.

scholarly journals Nanostructured ZnFe2O4: An Exotic Energy Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1286
Author(s):  
Murtaza Bohra ◽  
Vidya Alman ◽  
Rémi Arras
Keyword(s):  
Data Storage ◽  
Smart Materials ◽  
Energy Demand ◽  
Ceramic Materials ◽  
Magnetic Data ◽  
Processing Route ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Reduced Toxicity ◽  
Cation Arrangement

More people, more cities; the energy demand increases in consequence and much of that will rely on next-generation smart materials. Zn-ferrites (ZnFe2O4) are nonconventional ceramic materials on account of their unique properties, such as chemical and thermal stability and the reduced toxicity of Zn over other metals. Furthermore, the remarkable cation inversion behavior in nanostructured ZnFe2O4 extensively cast-off in the high-density magnetic data storage, 5G mobile communication, energy storage devices like Li-ion batteries, supercapacitors, and water splitting for hydrogen production, among others. Here, we review how aforesaid properties can be easily tuned in various ZnFe2O4 nanostructures depending on the choice, amount, and oxidation state of metal ions, the specific features of cation arrangement in the crystal lattice and the processing route used for the fabrication.

scholarly journals Ferroelectric HfO2-based materials for next-generation ferroelectric memories

2016 ◽  
Vol 06 (02) ◽  
pp. 1630003 ◽  
Author(s):  
Zhen Fan ◽  
Jingsheng Chen ◽  
John Wang
Keyword(s):  
Random Access ◽  
Complementary Metal Oxide Semiconductor ◽  
Ferroelectric Materials ◽  
Oxide Semiconductor ◽  
Next Generation ◽  
New Class ◽  
Generation Cost ◽  
Potential Applications ◽  
Cost Efficient ◽  
Ferroelectric Memories

Ferroelectric random access memory (FeRAM) based on conventional ferroelectric perovskites, such as Pb(Zr,Ti)O3 and SrBi2Ta2O9, has encountered bottlenecks on memory density and cost, because those conventional perovskites suffer from various issues mainly including poor complementary metal-oxide-semiconductor (CMOS)-compatibility and limited scalability. Next-generation cost-efficient, high-density FeRAM shall therefore rely on a material revolution. Since the discovery of ferroelectricity in Si:HfO2 thin films in 2011, HfO2-based materials have aroused widespread interest in the field of FeRAM, because they are CMOS-compatible and can exhibit robust ferroelectricity even when the film thickness is scaled down to below 10 nm. A review on this new class of ferroelectric materials is therefore of great interest. In this paper, the most appealing topics about ferroelectric HfO2-based materials including origins of ferroelectricity, advantageous material properties, and current and potential applications in FeRAM, are briefly reviewed.

Growth, Structural and Mechanical Characterization and Reliability of Chemical Vapor Deposited Co and Co3O4 Thin Films as Candidate Materials for Sensing Applications

2011 ◽  
Vol 495 ◽  
pp. 108-111 ◽  
Author(s):  
Vasiliki P. Tsikourkitoudi ◽  
Elias P. Koumoulos ◽  
Nikolaos Papadopoulos ◽  
Costas A. Charitidis
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Elastic Modulus ◽  
Data Storage ◽  
Mechanical Stability ◽  
Chemical Vapor ◽  
Magnetic Sensors ◽  
Functional Coatings ◽  
Sensing Applications ◽  
Chemical Vapor Deposited

The adhesion and mechanical stability of thin film coatings on substrates is increasingly becoming a key issue in device reliability as magnetic and storage technology driven products demand smaller, thinner and more complex functional coatings. In the present study, chemical vapor deposited Co and Co3O4thin films on SiO2and Si substrates are produced, respectively. Chemical vapor deposition is the most widely used deposition technique which produces thin films well adherent to the substrate. Co and Co3O4thin films can be used in innovative applications such as magnetic sensors, data storage devices and protective layers. The produced thin films are characterized using nanoindentation technique and their nanomechanical properties (hardness and elastic modulus) are obtained. Finally, an evaluation of the reliability of each thin film (wear analysis) is performed using the hardness to elastic modulus ratio in correlation to the ratio of irreversible work to total work for a complete loading-unloading procedure.

Field-Emission Triode of Tetrapod-Like ZnO Film Using Metal Mesh

2011 ◽  
Vol 233-235 ◽  
pp. 2600-2603 ◽  
Author(s):  
Li An Ma ◽  
Chao Xing Wu ◽  
Jin Yang Lin ◽  
Li Qin Hu ◽  
Tai Liang Guo
Keyword(s):  
Chemical Vapor Deposition ◽  
Field Emission ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Raw Material ◽  
Anode Current ◽  
Zno Film ◽  
Metal Mesh ◽  
Turn On ◽  
Field Emitters

Using Zn powder as the raw material, Tetrapod-like ZnO nanoneedles with controllable morphology and size were successfully prepared by chemical vapor deposition. A screen printed normal-gated triode with Tetrapod-like ZnO nanoneedles field emitters is demonstrated. Field emission measurements show that the Tetrapod-like ZnO nanoneedles FED triode devices posses a good field emission property. The turn-on voltage is 270V. An anode current of 2.75 mA and a gate current of 0.43 mA are extracted at a gate voltage of 600 V with a brightness of 2300 cd/m2.

New Class of Microporous Materials: Porous Metal Phosphonate Thin Films

1996 ◽  
Vol 431 ◽  
Author(s):  
Lori A. Vermeulen ◽  
J. Pattanayak ◽  
Travis Fisher ◽  
Monica Hansford ◽  
Scott J. Burgmeyer
Keyword(s):  
Thin Films ◽  
Solid State ◽  
Porous Metal ◽  
Porous Solids ◽  
New Class ◽  
Metal Phosphonates ◽  
Metal Phosphonate ◽  
Potential Applications ◽  
Shape Selective ◽  
Film Assembly

AbstractSolid state metal phosphonates (M(O3P-R-PO3) or M(O3P-R)2 (M = metal)) have layered structures where the metal atoms lie in planar sheets and the intervening R groups take up the interlamellar space. Microporous metal phosphonates can be prepared by reaction of the metal with a mixture of large and small phosphonates (M(O3P-LARGE)x(O3P-SMALL)2-x. The larger group acts as a pillar that holds the layers apart. Void spaces result from the presence of the smaller groups. The porous nature of these solids make them potential candidates for applications as sensors, size- and shape- selective catalysts, and chromatographic materials. Metal diphosphonates (M(O3P-R-PO3) can also be prepared one layer at a time on a surface, resulting in the construction of interesting superstructures that are not accessible through the solid state synthesis. For example, these superstructures can contain different components in sequential layers and may have applications in energy conversion, vectorial electron transport, and NLO devices. The preparation of microporous thin films would combine the desirable potential applications of the porous solids with the interesting parallel superstructures that can be prepared from the thin film assemblies. We report our progress toward the construction of microporous metal phosphonate thin films. The two methods that are currently being developed include: 1) phosphonate exchange of pre-assembled films, and 2) co-deposition of different large and small phosphonates during film assembly.

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