Origin of dislocation loops in α-silicon nitride

Dislocation loops and stacking fault formation mechanism in α–Si3N4 have been studied by annealing α–Si3N4 powders at 1500 °C and 1750 °C. Thermally activated vacancies and the structural vacancies generated with replacement of nitrogen by oxygen have been tentatively suggested to be two sources of vacancies in α–Si3N4. From the point of view of mechanism, incorporation of these vacancies is believed to lie at the building-up stage of α–Si3N4 lattice. As a result of the vacancies agglomeration, dislocation loops and stacking faults seem to be a distinctively structural feature of α–Si3N4 fabricated by different routes [chemical vapor deposition (CVD), silicon nitridation, silica carbothermal reduction, and imide decomposition]. A general discussion has been extended to the historical controversy over the oxygen and vacancy stabilization of α–Si3N4 lattice arisen from the fact that the observed unit cell dimension of α–Si3N4 has a wide variation, and also to some related phenomena in processing of Si3N4.

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On the carbo-thermal reduction of silica for carbon nano-fibre formation via CVD

MRS Proceedings ◽

10.1557/opl.2011.640 ◽

2011 ◽

Vol 1284 ◽

Author(s):

Alicja Bachmatiuk ◽

Felix Börrnert ◽

Imad Ibrahim ◽

Bernd Büchner ◽

Mark H. Rümmeli

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Carbothermal Reduction ◽

Carbon Nanostructures ◽

Reduction Process ◽

Chemical Vapor ◽

Deposition Process ◽

Thermal Reduction ◽

Fibre Formation ◽

Quartz Substrates

ABSTRACTThe formation of carbon nanostructures using silica nanoparticles from quartz substrates as a catalyst in an aerosol assisted chemical vapor deposition process was examined. The silica particles are reduced to silicon carbide via a carbothermal reduction process. The recyclability of the explored quartz substrates is also presented. The addition of triethyl borate improves the efficiency of the carbothermal reduction process and carbon nanotubes formation. Moreover, the addition of hydrogen during the chemical vapor deposition leads to the helical carbon nanostructures formation.

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FORMATION OF SILICON CARBIDE COATINGS BY CHEMICAL VAPOR DEPOSITION (review). Part 1

Proceedings of VIAM ◽

10.18577/2307-6046-2021-0-6-100-111 ◽

2021 ◽

pp. 100-111

Author(s):

D.V. Sidorov ◽

◽

A.A. Schavnev ◽

A.A. Melentev ◽

◽

...

Keyword(s):

Silicon Carbide ◽

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Chemical Vapor ◽

Point Of View ◽

Technological Parameters ◽

Technical Literature ◽

Pure Silicon ◽

Carbide Coatings ◽

Complex Process

The article provides an overview of the scientific and technical literature in the field of the formation of silicon carbide coatings by chemical vapor deposition (CVD). CVD is a complex process, approaches to which vary depending on the tasks being solved. Depending on the technological parameters, the initial reagents, the substrate for deposition, the type and design of the CVD reactors, it is possible to achieve both the deposition of pure silicon carbide and the co-deposition of silicon and/or carbon. In the first part of the article, attention is paid to the study of CVD from the point of view of the mechanisms of chemical reactions, the design of the deposition apparatus, the substrates for deposition.

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Microstructure observations of silicon carbide nanorods

Journal of Materials Research ◽

10.1557/jmr.2000.0290 ◽

2000 ◽

Vol 15 (9) ◽

pp. 2020-2026 ◽

Cited By ~ 12

Author(s):

H. Y. Peng ◽

X. T. Zhou ◽

H. L. Lai ◽

N. Wang ◽

S. T. Lee

Keyword(s):

Vapor Deposition ◽

Stacking Faults ◽

Chemical Vapor ◽

High Resolution Electron Microscopy ◽

Growth Direction ◽

Planar Defects ◽

Resolution Electron ◽

Short Nanorods ◽

Hot Filament ◽

Nanorod Growth

The microstructures of β-SiC nanorods synthesized by hot-filament chemical vapor deposition were studied in detail by high-resolution electron microscopy. Two distinct types of nanorods were identified. The longer nanorods (lengths > 0.1 mm) contained globules at their tips and a relatively low density of stacking faults perpendicular to their [111] growth direction. It was also observed that SiC nanorods that grew along [100] direction contained no planar defects. Meanwhile, Ni was found to be an effective catalyst for SiC nanorod growth. The short nanorods (lengths < 50 nm), which contained no globules at their ends, can grow along [111], [100], or [112] direction. The growth of these nanorods was interpreted by a two-dimensional vapor–solid mechanism.

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Chemical vapor deposition of carbon on particulate TiO2 from CH4 and subsequent carbothermal reduction for the synthesis of nanocrystalline TiC powders

Journal of the European Ceramic Society ◽

10.1016/j.jeurceramsoc.2010.11.027 ◽

2011 ◽

Vol 31 (5) ◽

pp. 869-876 ◽

Cited By ~ 21

Author(s):

S. Cetinkaya ◽

S. Eroglu

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Carbothermal Reduction ◽

Chemical Vapor

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Structural Defect-Related Photoluminescence in GaN

MRS Proceedings ◽

10.1557/proc-798-y5.55 ◽

2003 ◽

Vol 798 ◽

Author(s):

L. Chen ◽

B. J. Skromme ◽

M. K. Mikhov ◽

H. Yamane ◽

M. Aoki ◽

...

Keyword(s):

Vapor Deposition ◽

Metalorganic Chemical Vapor Deposition ◽

Bulk Material ◽

Stacking Faults ◽

Chemical Vapor ◽

Excitation Power ◽

Excitation Intensity ◽

Energy Peak ◽

Bulk Gan ◽

Low Temperature Photoluminescence

ABSTRACTBroad, low temperature photoluminescence (PL) peaks near 3.4–3.42 eV in GaN have previously been associated with basal-plane stacking faults. Recently, we observed unusually sharp and highly structured PL peaks in this region in high quality bulk GaN grown from a Na/Ga flux, some of which display characteristic shifts and narrowing as a function of excitation power. Here, we study these peaks as a function of excitation intensity and crystal polarity, and compare them to those observed in GaN grown on off-axis SiC or sapphire (0001) substrates by metalorganic chemical vapor deposition (MOCVD). In the off-axis material on either substrate, similar peaks are observed to those in the bulk samples. In addition, a low energy peak near 3.21 eV is observed, which does not occur in the bulk material.

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Arsenic Incorporation in Gallium Nitride grown by Metalorganic Chemical Vapor Deposition using Dimethylhydrazine and Tertiarybutylarsenic

MRS Proceedings ◽

10.1557/proc-622-t6.11.1 ◽

2000 ◽

Vol 622 ◽

Author(s):

S. Kellermann ◽

K. M. Yu ◽

E. E. Haller ◽

E. D. Bourret-Courchesne

Keyword(s):

Vapor Deposition ◽

Metalorganic Chemical Vapor Deposition ◽

Doping Concentration ◽

Stacking Faults ◽

Chemical Vapor ◽

Growth Conditions ◽

Flow Ratio ◽

As Doping ◽

Mocvd Growth ◽

Arsenic Incorporation

ABSTRACTMOCVD growth of As-doped GaN using dimethylhydrazine, triethylgallium and tertiarybutylarsenic has been investigated. A maximum doping concentration of 4.0 × 1019cm−3 at growth temperatures between 600°C and 800°C was obtained. At 1000°C the As doping level dropped below the SIMS detection limit of ∼1.0 × 1017cm−3. The As incorporation depended only weakly on variations of the V/III molar flow ratio between 11 and 61. Raising the As/V molar flow ratio from 0.01 to 0.06 increased the As concentration which then decreased by further increase to 0.11. Different morphologies of the layers were found depending on the growth conditions. A surfactant-like behavior of As was observed leading to smooth GaN films grown on top of the As-doped GaN layer. Two characteristic luminescence peaks at 3.31 eV and 3.425 eV were found for samples doped with As below 900°C. These spectral features are believed to originate at extended lateral defects - presumably stacking faults.

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Chemical Vapor Deposited Boron Carbide: Growth by a Vapor-Liquidsolid Process

MRS Proceedings ◽

10.1557/proc-97-127 ◽

1987 ◽

Vol 97 ◽

Cited By ~ 3

Author(s):

Ian D. R. Mackinnon ◽

Katherine L. Smith

Keyword(s):

Vapor Deposition ◽

Low Temperatures ◽

Growth Process ◽

Stacking Faults ◽

Chemical Vapor ◽

Growth Direction ◽

Chemical Vapor Deposited ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Oriented Parallel

ABSTRACTDetailed analytical electron microscope (AEM) studies of yellow whiskers produced by chemical vapor deposition (CVD)1 show that two basic types of whiskers are produced at low temperatures (between 1200°C and 1400°C) and low boron to carbon gas ratios. Both whisker types show planar microstructures such as twin planes and stacking faults oriented parallel to, or at a rhombohedral angle to, the growth direction. For both whisker types, the presence of droplet-like terminations containing both Si and Ni indicate that the growth process during CVD is via a vapor-liquid-solid (VLS) mechanism.

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Main Allotropes of Carbon

Sustainable Nanosystems Development, Properties, and Applications - Advances in Chemical and Materials Engineering ◽

10.4018/978-1-5225-0492-4.ch006 ◽

2017 ◽

pp. 185-213

Author(s):

Zahra Khalaj ◽

Majid Monajjemi ◽

Mircea V. Diudea

Keyword(s):

Carbon Atom ◽

Vapor Deposition ◽

Carbon Nanostructures ◽

Chemical Vapor ◽

Point Of View ◽

Diamond Like Carbon ◽

Chemical Bonds ◽

High Quality ◽

Carbon Allotropes ◽

Experimental Parameters

Carbon allotropes can be classified according to the carbon atom hybridization. In principle, there are different ways, based on various parameters, such as range dimensionality, type of chemical bonds, etc. which can be used to classify carbon nanostructures. Classifications vary function of the field of nanostructure applications. In a point of view, one can classify the carbon allotropes by the type of carbon atom hybridation. This chapter is a brief review introduction to some major allotropes: graphene/graphite, carbon nanotubes, diamond and amorphous carbon. In addition, Chemical Vapor Deposition (CVD) techniques, frequently used for synthesizing these structures are discussed. The influence of some important experimental parameters on the growth of high quality diamond and diamond-like carbon DLC are also investigated.

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