Nucleation and growth of Si quantum nanocrystals in silicon-rich oxide films

The observation of photoluminescence and electroluminescence in Si nanocrystals has generated renewed interest in these novel silicon based materials for their possible application as light emitters and detectors. Silicon Rich Oxide (SRO) films with a uniform dispersion of silicon nanocrystallites in a wider bandgap SiO2 matrix manifest electroluminescence and photoluminescence in the infrared and visible portions of the spectrum. Understanding the nucleation and growth kinetics of these crystallites in amorphous matrix is of critical importance in the fabrication of future optoelectronic devices. One route to the fabrication of Si nanocrystals is by the crystallization of amorphous SiO2-x. Consider the case when x=1. The reaction leading to the formation of Si crystallites can be written as;(1)The nucleation, growth and coarsening processes of Si nanocrystals each require bulk diffusion of Si atoms through the amorphous matrix.

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Characteristics of Hydrogen Effusion from the Si-H Bonds in Si Rich Silicon Oxynitride Films for Nanocrystalline Silicon Based Photovoltaic Applications

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.854.69 ◽

2013 ◽

Vol 854 ◽

pp. 69-74 ◽

Cited By ~ 1

Author(s):

Andrey Sarikov ◽

M. Voitovych ◽

Igor Lisovskyy ◽

V. Naseka ◽

A. Hartel ◽

...

Keyword(s):

Chemical Vapor ◽

Nanocrystalline Silicon ◽

Silicon Oxynitride ◽

Tandem Solar Cells ◽

Si Nanocrystals ◽

Photovoltaic Applications ◽

Silicon Based ◽

Kinetics Of ◽

Hydrogen Effusion

This work is devoted to determination of characteristics of hydrogen effusion from SiH bonds in Si rich silicon oxynitride (SRON) films, obtained by plasma enhanced chemical vapor deposition, as a result of thermal anneals at temperatures from 400 to 800°C. The values of the concentrations of SiH bonds in HSi (Si3nOn) (0 n 3) complexes contributing to the structure of SRON films are obtained from the analysis of infrared absorption spectra in the range of 2000-2400 cm1. The kinetics of the decrease of SiH concentrations as a result of anneals is described in the framework of a model with distributed activation energy of hydrogen emission. The median value and the mean-square deviation of this distribution as well as the attempt frequencies of SiH bond breaks are determined from the comparison of experimental and calculated SiH concentrations in SRON films. These characteristics are compatible with such characteristics found for the case of the depassivation of PbH centers at the Si/SiO2 interfaces. Obtained results are useful for the controlled formation of the layers of Si nanocrystals in dielectric matrix for Si based tandem solar cells applications.

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Crystallization of ternary Zr-based glasses—Kinetics and microstructure

Journal of Materials Research ◽

10.1557/jmr.1998.0065 ◽

1998 ◽

Vol 13 (2) ◽

pp. 504-517 ◽

Cited By ~ 11

Author(s):

G. K. Dey ◽

R. T. Savalia ◽

E. G. Baburaj ◽

S. Banerjee

Keyword(s):

Metallic Glasses ◽

Composition Range ◽

Amorphous Matrix ◽

Primary Crystallization ◽

Nucleation And Growth ◽

Crystal Nucleation ◽

Cubic Phase ◽

Eutectic Crystallization ◽

Kinetics Of

The effect of ternary addition on the thermal stability and the sequence and the kinetics of crystallization of metallic glasses Zr76Fe(24−x)Nix (x = 0, 4, 8, 12, 16, 20, 24) have been examined. It has been found that the surface crystallization occurs in the composition range 16 < x < 20, leading to the formation of an ordered Fe-rich (Fe, Ni)3Zr cubic phase, followed by the transformation of the bulk to a mixture of α−Zr and Zr2Ni. Crystallization of alloys containing 12 to 20% Fe occurs at lower temperatures by primary crystallization of Zr3(Fe, Ni), followed by decomposition of the remaining amorphous matrix by eutectic crystallization giving rise to α−Zr + Zr2Ni. At higher temperatures these alloys transform polymorphically to Zr3(Fe, Ni) in which Ni partially substitutes Fe in the Zr3Fe lattice. Copious nucleation of Zr3(Fe, Ni) phase in these alloys, leading to the formation of a nanophase structure, has been observed. This is consistent with the prediction of increasing nucleation rate for Fe-rich compositions. The crystal nucleation and growth kinetics have been examined for primary, eutectic, and polymorphic crystallization processes. The observed nucleation and growth behaviors have been rationalized by considering the role of the quenched in nuclei and the activation energies of nucleation and growth.

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AEM analysis of crystallization in Ti-based amorphous alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075142 ◽

1983 ◽

Vol 41 ◽

pp. 270-271

Author(s):

A.R. Pelton ◽

A.F. Marshall ◽

Y.S. Lee

Keyword(s):

Magnetic Properties ◽

Amorphous Alloys ◽

Amorphous Materials ◽

Isothermal Annealing ◽

Amorphous Matrix ◽

Nucleation And Growth ◽

Current Interest ◽

Amorphous Films ◽

Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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In situ observation of the martensitic transformation in (Mg,Y)-PSZ

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144036 ◽

1986 ◽

Vol 44 ◽

pp. 500-501

Author(s):

R-R. Lee

Keyword(s):

Martensitic Transformation ◽

High Strength ◽

Nucleation And Growth ◽

In Situ Observation ◽

Considerable Potential ◽

Transmission Electron ◽

Structural Applications ◽

Applied Stresses ◽

Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

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Diffusion Enhancement in Glassy Metals Under Non-Equilibrium Conditions

MRS Proceedings ◽

10.1557/proc-400-149 ◽

1995 ◽

Vol 400 ◽

Author(s):

S. Bellini ◽

G. Mazzone ◽

A. Montone ◽

M. Vittori-antisari Enea ◽

C.R. Casaccia

Keyword(s):

Free Volume ◽

Growth Kinetics ◽

Bulk Diffusion ◽

High Energy ◽

First Case ◽

Diffusion Enhancement ◽

Glass Crystal ◽

Kinetics Of ◽

Crystal Interface ◽

Diffusion Properties

AbstractThe diffusion properties of a Ni-Zr metallic glass formed at the interface of a bulk diffusion couple have been studied in conditions far from a fully relaxed state. The growth kinetics of the interface film have been enhanced by both plastic deformation and high energy electron irradiation. Different results have been obtained in the two cases, since in the first case the film grows exponentially with time, while in the second case the usual square root dependence on time is observed. This behaviour has been interpreted as a consequence of the annihilation kinetics of the excess free volume introduced in the glass by the above methods. Two different mechanisms of free volume annihilation , namely exchange with a crystal vacancy at the glass-crystal interface and structural relaxation in the bulk glassy phase have been considered to be operative so that the nature of the growth kinetics has been found to depend on the mechanism predominant in each experimental condition.

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Inhomogeneous Swelling Near Grain Boundaries in Irradiated Materials: Cavity Nucleation and Growth Saturation Effects

MRS Proceedings ◽

10.1557/proc-650-r1.4 ◽

2000 ◽

Vol 650 ◽

Author(s):

S. L. Dudarev

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Nucleation And Growth ◽

Homogeneous Distribution ◽

Rate Theory ◽

Diffusional Growth ◽

Standard Rate ◽

Saturation Effects ◽

Kinetics Of ◽

Cascade Damage

ABSTRACTThe effect of inhomogeneous nucleation and growth of cavities near grain boundaries illustrates the failure of the standard rate theory to describe the kinetics of phase transformations in irradiated materials under cascade damage conditions. The enhanced swelling observed near grain boundaries is believed to result from the competition between the diffusional growth of cavities and their shrinkage due to the interaction with mobile interstitial clusters. Swelling rates associated with the two processes behave in a radically different way as a function of the size of growing cavities. For a spatially homogeneous distribution of cavities this gives rise to the saturation of swelling in the limit of large irradiation doses.We investigate the evolution of the population of cavities nucleating and growing near a planar grain boundary. We show that a cavity growing near the boundary is able to reach a size that is substantially larger than the size of a cavity growing in the interior region of the grain. For a planar grain boundary the magnitude of swelling at maximum is found to be up to eight times higher than the magnitude of swelling in the grain interior.

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In Situ Observation of Nucleation and Growth of Carbon Nanotubes from Iron Carbide Nanoparticles

MRS Proceedings ◽

10.1557/proc-1142-jj02-02 ◽

2008 ◽

Vol 1142 ◽

Author(s):

Hideto Yoshida ◽

Seiji Takeda ◽

Tetsuya Uchiyama ◽

Hideo Kohno ◽

Yoshikazu Homma

Keyword(s):

Carbon Nanotubes ◽

Iron Carbide ◽

Bulk Diffusion ◽

Chemical Vapor ◽

Nucleation And Growth ◽

Atomic Scale ◽

In Situ Observation ◽

Transmission Electron ◽

Cvd Growth

ABSTRACTNucleation and growth processes of carbon nanotubes (CNTs) in iron catalyzed chemical vapor deposition (CVD) have been observed by means of in-situ environmental transmission electron microscopy. Our atomic scale observations demonstrate that solid state iron carbide (Fe3C) nanoparticles act as catalyst for the CVD growth of CNTs. Iron carbide nanoparticles are structurally fluctuated in CVD condition. Growth of CNTs can be simply explained by bulk diffusion of carbon atoms since nanoparticles are carbide.

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