Plasma-Activated CVD for the Production of Protective Layers in Optics, Electronics and Mechanical Engineering

1987 ◽  
Vol 93 ◽  
Author(s):  
Knut Enke ◽  
Michael Geisler ◽  
Jörg Kieser ◽  
Wolf-Dieter Münz
Keyword(s):  
Chemical Properties ◽  
Chemical Vapor ◽  
Capacitive Coupling ◽  
Plasma Cvd ◽  
Cathode Voltage ◽  
Protective Layers ◽  
Deposition Parameters ◽  
Metal Organic ◽  
Organic Process ◽  
Physical And Chemical

ABSTRACTConventional chemical vapor deposition (CVD) has historically utilized high melting temperature substrates. Recently there has been an increased desire to coat temperaturesensitive materials such as aluminum, glass, steel, and even plastic. Thus “cold” CVDprocesses, most using plasma excitation, have been developed. In these processes gas molecules or atoms are excited by dc or ac glow discharge, thereby allowing the possibility of keeping substrates at room temperature.This paper describes plasma CVD reactors using capacitive coupling of r.f. voltage to an asymmetrical arrangement of electrodes. Using organic or metal-organic process gases and mixtures of them with inorganic gases, deposition takes place on the reactor walls, the anode, and the cathode. In this paper the emphasis is on deposition on negatively selfbiased substrate holders. Physical and chemical properties of plasma-CVD grown layers depend on about six process parameters, the most important of which are cathode voltage, gas pressure, choice of gases, and mixing ratio of gases. Map-like representations show the dependence of coating properties on deposition parameters. Layer materials discussed include amorphous hydrogenated carbon (a-C:H). WCx, SiOx:H, SiCxOy:H. and SnOx:H.

scholarly journals Synthesis of carbon nanowalls from a single-source metal-organic precursor

2018 ◽  
Vol 9 ◽  
pp. 1895-1905 ◽  
Author(s):  
André Giese ◽  
Sebastian Schipporeit ◽  
Volker Buck ◽  
Nicolas Wöhrl
Keyword(s):  
Surface Diffusion ◽  
Inductively Coupled Plasma ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Single Source ◽  
Organic Precursor ◽  
Inductively Coupled ◽  
Deposition Parameters ◽  
Metal Organic ◽  
Carbon Nanowalls

In this work, the deposition of carbon nanowalls (CNWs) by inductively coupled plasma enhanced chemical vapor deposition (ICP-PECVD) is investigated. The CNWs are electrically conducting and show a large specific surface area, which is a key characteristic to make them interesting for sensors, catalytic applications or energy-storage systems. It was recently discovered that CNW films can be deposited by the use of the single-source metal-organic precursor aluminium acetylacetonate. This precursor is relatively unknown in combination with the ICP-PECVD deposition method in literature and, thus, based on our previous publication is further investigated in this work to better understand the influence of the various deposition parameters on the growth. Silicon, stainless steel, nickel and copper are used as substrate materials. The CNWs deposited are characterized by scanning electron microscopy (SEM), Raman spectroscopy and Auger electron spectroscopy (AES). The combination of bias voltage, the temperature of the substrate and the substrate material had a strong influence on the morphology of the graphitic carbon nanowall structures. With regard to these results, a first growth model for the deposition of CNWs by ICP-PECVD and aluminium acetylacetonate is proposed. This model explains the formation of four different morphologies (nanorods as well as thorny, straight and curled CNWs) by taking the surface diffusion into account. The surface diffusion depends on the particle energies and the substrate material and thus explains the influence of these parameters.

Triclinic boron nanosheets high-efficient electrocatalysts for water splitting

2021 ◽  
Author(s):  
Maoping Xu ◽  
Rui Wang ◽  
Kan Bian ◽  
Chuang Hou ◽  
Yaxing Wu ◽  
...  
Keyword(s):  
Active Sites ◽  
Theoretical Calculations ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Energy Storage And Conversion ◽  
High Efficient ◽  
Long Time ◽  
Time Cycle ◽  
Metal Properties ◽  
Physical And Chemical

Abstract Recently, two-dimensional (2D) boron nanosheets have been predicted to exhibit exceptional physical and chemical properties, which is expected to be widely used in advanced electronics, optoelectronic, energy storage and conversion devices. However, the experimental application of 2D boron nanosheets in hydrogen evolution reactiuon (HER) has not been reported. Here, we have grown ultrathin boron nanosheets on tungsten foils via chemical vapor deposition (CVD). The prepared triclinic boron nanosheets are highly crystalline, which perfectly match the structure in the previous theoretical calculations. Notably, the boron nanosheets show excellent HER performance. The Tafel slope is only 64 mV/dec-1 and the nanosheets can maintain good stability under long-time cycle in acidic solution. The improvement of performance is mainly due to the metal properties and a large number of exposed active sites on the boron nanosheets, which is confirmed by first-principle calculations.

scholarly journals A Strategy to Synthesize Multilayer Graphene in Arc-Discharge Plasma in a Semi-Opened Environment

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2279 ◽  
Author(s):  
Hai Tan ◽  
Deguo Wang ◽  
Yanbao Guo
Keyword(s):  
Discharge Plasma ◽  
Arc Discharge ◽  
Chemical Reduction ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Chemical Components ◽  
Multilayer Graphene ◽  
Whole Process ◽  
Hazardous Chemical ◽  
Physical And Chemical

Graphene, as the earliest discovered two-dimensional (2D) material, possesses excellently physical and chemical properties. Vast synthetic strategies, including chemical vapor deposition, mechanical exfoliation, and chemical reduction, are proposed. In this paper, a method to synthesize multilayer graphene in a semi-opened environment is presented by introducing arc-discharge plasma technology. Compared with previous technologies, the toxic gases and hazardous chemical components are not generated in the whole process. The synthesized carbon materials were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, and Raman spectra technologies. The paper offers an idea to synthesize multilayer graphene in a semi-opened environment, which is a development to produce graphene with arc-discharge plasma.

Tuning Packing, Structural Flexibility, and Porosity in 2D Metal–Organic Frameworks by Metal Node Choice

2019 ◽  
Vol 72 (10) ◽  
pp. 797 ◽  
Author(s):  
Witold M. Bloch ◽  
Christian J. Doonan ◽  
Christopher J. Sumby
Keyword(s):  
Structural Changes ◽  
Metal Organic Frameworks ◽  
Chemical Properties ◽  
Complete Removal ◽  
Structural Flexibility ◽  
X Ray Diffraction ◽  
Metal Centre ◽  
Metal Organic ◽  
Physical And Chemical ◽  
And Chemical Properties

Understanding the key features that determine structural flexibility in metal–organic frameworks (MOFs) is key to exploiting their dynamic physical and chemical properties. We have previously reported a 2D MOF material, CuL1, comprising five-coordinate metal nodes that displays exceptional CO2/N2 selectively (L1=bis(4-(4-carboxyphenyl)-1H-pyrazolyl)methane). Here we examine the effect of utilising six-coordinate metal centres (CoII and NiII) in the synthesis of isostructural MOFs from L1, namely CoL1 and NiL1. The octahedral geometry of the metal centre within the MOF analogues precludes an ideal eclipse of the 2D layers, resulting in an offset stacking, and in certain cases, the formation of 2-fold interpenetrated analogues β-CoL1 and β-NiL1. We used a combination of thermogravimetric analysis (TGA), and powder and single crystal X-ray diffraction (PXRD and SCXRD) to show that desolvation is accompanied by a structural change for NiL1, and complete removal of the coordinated H2O ligands results in a reduction in long-range order. The offset nature of the 2D layers in combination with the structural changes impedes the adsorption of meaningful quantities of gases (N2, CO2), highlighting the importance of a five-coordinate metal centre in achieving optimal pore accessibility for this family of flexible materials.

Analysis of the Physical and Chemical Factors Determining Compositional Variations in the MOCVD Growth of Indium Gallium Arsenide

1990 ◽  
Vol 204 ◽  
Author(s):  
Erik O. Einset ◽  
Klavs F. Jensen ◽  
Thomas F. Kuech
Keyword(s):  
Transport Model ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Lattice Parameter ◽  
Organic Chemical ◽  
Mocvd Growth ◽  
Metal Organic ◽  
Compositional Variations ◽  
Wall Depletion ◽  
Physical And Chemical

ABSTRACTWe present an analysis of compositional variations in the growth of the compound semiconductor, InxGal-xAs, by metal organic chemical vapor deposition (MOCVD). A three dimensional transport model for fluid flow, heat, and mass transfer is solved using the finite element method. The Delta Lattice Parameter (DLP) model is used to describe the thermodynamics of the solid solution, and the Hertz-Langmuir equation is used to calculate the evaporation rate of indium from the growing crystal. Wall depletion is incorporated by allowing for explicit wall deposition of In vapor throughout the reactor.Comparison of model predictions with experimental observations by MOCVD of InGaAs in a horizontal reactor suggests that transport phenomena lead to composition variations across the substrate, and that solution thermodynamics have little effect on the InAs incorporation rate at a given deposition temperature. However, thermodynamic factors appear to influence the change in indium incorporation with growth temperature.

Graphene Research in China

2013 ◽  
Vol 1505 ◽  
Author(s):  
Kexin Chen
Keyword(s):  
Chemical Properties ◽  
Chemical Vapor ◽  
Dimensional Structure ◽  
Chemical Vapor Deposition Growth ◽  
Wide Range ◽  
The Status ◽  
Potential Applications ◽  
Number Of Publications ◽  
Physical And Chemical ◽  
And Chemical Properties

ABSTRACTGraphene, a monolayer of sp2-bonded carbon atoms, has been attracting worldwide interests because of its unique two-dimensional structure, various fascinating properties and a wide range of intriguing potential applications. The graphene research is very active in China and has been developing rapidly in the past few years, which covers nearly all the areas related to graphene including theories, synthesis, physical and chemical properties, and applications. Over 100 research institutions have been involved in graphene research with fast-growing project supports. In this paper, the status of graphene research in China is first discussed based on the number of publications and patents as well as the institutions involved. Then the projects and fundings from both government and companies for graphene research are briefly introduced. Finally, the highlights of graphene research in China are reviewed, which include chemical vapor deposition growth and transfer, mass production, and assembly of graphene, and its applications in energy storage, sensing, composites and solar cells.

scholarly journals Fluorinated Organic Porous Materials

2019 ◽  
Vol 01 (01) ◽  
pp. 019-029 ◽  
Author(s):  
Zhenglin Zhang ◽  
Ognjen Š. Miljanić
Keyword(s):  
Porous Materials ◽  
Organic Molecules ◽  
Metal Organic Frameworks ◽  
Molecular Crystals ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Metal Organic ◽  
Physical And Chemical ◽  
And Chemical Properties

Fluorine is in many aspects unique among the elements, and its incorporation into organic molecules can dramatically change their physical and chemical properties. This minireview will survey the existing classes of fluorinated porous materials, with a particular focus on all-organic porous materials. We will highlight our work on the preparation and study of metal–organic frameworks and porous molecular crystals derived from extensively fluorinated rigid aromatic pyrazoles and tetrazoles. Where possible, comparisons between fluorinated and nonfluorinated materials will be made.

scholarly journals Synthesis of zeolitic imidazolate framework-8 and gold nanoparticles in a sustained out-of-equilibrium state

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Brigitta Dúzs ◽  
Gábor Holló ◽  
Gábor Schuszter ◽  
Dezső Horváth ◽  
Ágota Tóth ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Crystal Growth ◽  
Chemical Properties ◽  
Zeolitic Imidazolate Framework ◽  
Crystalline Materials ◽  
Design And Synthesis ◽  
Mass Fluxes ◽  
Hydrogel Matrix ◽  
Metal Organic ◽  
Physical And Chemical

AbstractThe design and synthesis of crystalline materials are challenging due to the proper control over the size and polydispersity of the samples, which determine their physical and chemical properties and thus applicability. Metal − organic frameworks (MOFs) are promising materials in many applications due to their unique structure. MOFs have been predominantly synthesized by bulk methods, where the concentration of the reagents gradually decreased, which affected the further nucleation and crystal growth. Here we show an out-of-equilibrium method for the generation of zeolitic imidazolate framework-8 (ZIF-8) crystals, where the non-equilibrium crystal growth is maintained by a continuous two-side feed of the reagents in a hydrogel matrix. The size and the polydispersity of the crystals are controlled by the fixed and antagonistic constant mass fluxes of the reagents and by the reaction time. We also present that our approach can be extended to synthesize gold nanoparticles in a redox process.

Thiol Decorated Defective Metal-Organic Framework Embedded with Palladium Nanoparticles for Efficient Cr(VI) Reduction

2021 ◽  
Author(s):  
Sukhendu Mandal ◽  
Asha P. ◽  
R. K. Aparna ◽  
Balu P Ratheesh ◽  
Manju M Maman
Keyword(s):  
Palladium Nanoparticles ◽  
Metal Organic Framework ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Metal Organic ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Organic Framework

Engineering defective UiO-66 with functionalized modulator may create functionality with promising physical and chemical properties. Herein, we use 2-mercaptobenzoic acid (2-MBA) as a modulator for the functionalization of defective UiO-66...

Engineering Isoreticular 2D Metal–Organic Frameworks with Inherent Structural Flexibility

2017 ◽  
Vol 70 (5) ◽  
pp. 566 ◽  
Author(s):  
Alexandre Burgun ◽  
Witold M. Bloch ◽  
Christian J. Doonan ◽  
Christopher J. Sumby
Keyword(s):  
Metal Organic Frameworks ◽  
Mixed Valence ◽  
Chemical Properties ◽  
Fine Tuning ◽  
Gate Opening ◽  
Sterically Demanding ◽  
Metal Organic ◽  
Structure Metrics ◽  
Physical And Chemical ◽  
And Chemical Properties

The chemical mutability of metal–organic frameworks (MOFs) is an advantageous feature that allows fine-tuning of their physical and chemical properties. Herein, we report the successful isoreticulation of a MOF with an outstanding gas selectivity for CO2 versus N2: [Cu(L1)(H2O)]·xS (CuL1), where H2L1 = bis(4-(4-carboxyphenyl)-1H-pyrazolyl)methane) and S = solvate. By modifying the steric bulk and length of the original ligand, we synthesised three new MOFs with 2D networks isoreticular to CuL1, namely [Cu(L1Me)(H2O)]·xS (CuL1Me), [Cu(L2)(H2O)]·xS (CuL2), and [Cu(L2Me)(H2O)]·xS (CuL2Me) (where H2L1Me = bis(4-(4-carboxyphenyl)-3,5-dimethyl-1H-pyrazolyl)methane, H2L2 = bis(4-(4-carboxyphenyl)-(ethyne-2,1-yl)-1H-pyrazolyl)methane, and H2L2Me = bis(4-(4-carboxyphenyl)-(ethyne-2,1-yl)-3,5-dimethyl-1H-pyrazolyl)methane). Depending on the steric hindrance and structure metrics of the organic links, staggered and eclipsed arrangements of 2D 44 net layers were obtained. The anisotropy of the pore dimensions is proportional to the linker length (L2 and L2Me), which when increased, renders these materials non-porous. However, the more sterically demanding ligand L1Me gives a material that shows gate-opening behaviour in response to a CO2 absorbate. The synthesis and structure of an unexpected mixed-valence CuII/CuI 3D MOF, Cu3[Cu(L2Me)2]2(H2O)4]·xS (Cu5(L2Me)4), containing an unusual trimeric CuII node are also reported.

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