scholarly journals Fabrication and characterization of Si1-xGex nanocrystals in as-grown and annealed structures: A comparative study

2019 ◽  
Author(s):  
Muhammad Taha Sultan ◽  
Valentin Serban Teodorescu ◽  
Jón Tómas Guðmundsson ◽  
Andrei Manolescu ◽  
Magdalena Lidia Ciurea ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Self Assembly ◽  
Structural Changes ◽  
Nano Particles ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Interface Characteristics ◽  
Order Of Magnitude

Multilayer structure comprising of SiO2/SiGe/SiO2 were obtained by depositing SiO2 layers using reactive direct current magnetron sputtering (dcMS), whereas, Si and Ge were co-sputtered using dcMS and high impulse power magnetron sputtering (HiPIMS), respectively. The as-grown structures subsequently underwent rapid thermal annealing (550 – 900 °C for 1 min) in N2 ambient atmosphere. The structures were investigated using X-ray diffraction, high-resolution transmission electron microscopy along with photoconductive analysis, to explore structural changes and constituent properties. It is observed that the employment of HiPIMS facilitates the formation of SiGe nano-particles (~ 2.1 ± 0.8 nm) in the as-grown structure, and that presence of such nano-particles acts as a seed for heterogeneous nucleation, which upon annealing results in formation of periodically arranged columnar self-assembly of core-shell SiGe nanocrystals. Consequently an increase in photocurrent intensity by more than an order of magnitude was achieved by the annealing. Furthermore, a detailed discussion is provided on strain development within the structures, the consequent interface characteristics and its effect on the photocurrent spectra.

scholarly journals Fabrication and characterization of Si1− x Ge x nanocrystals in as-grown and annealed structures: a comparative study

2019 ◽  
Vol 10 ◽  
pp. 1873-1882 ◽  
Author(s):  
Muhammad Taha Sultan ◽  
Adrian Valentin Maraloiu ◽  
Ionel Stavarache ◽  
Jón Tómas Gudmundsson ◽  
Andrei Manolescu ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Self Assembly ◽  
Structural Changes ◽  
Ambient Atmosphere ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Interface Characteristics ◽  
Order Of Magnitude ◽  
Grown Structure

Multilayer structures comprising of SiO2/SiGe/SiO2 and containing SiGe nanoparticles were obtained by depositing SiO2 layers using reactive direct current magnetron sputtering (dcMS), whereas, Si and Ge were co-sputtered using dcMS and high-power impulse magnetron sputtering (HiPIMS). The as-grown structures subsequently underwent rapid thermal annealing (550–900 °C for 1 min) in N2 ambient atmosphere. The structures were investigated using X-ray diffraction, high-resolution transmission electron microscopy together with spectral photocurrent measurements, to explore structural changes and corresponding properties. It is observed that the employment of HiPIMS facilitates the formation of SiGe nanoparticles (2.1 ± 0.8 nm) in the as-grown structure, and that presence of such nanoparticles acts as a seed for heterogeneous nucleation, which upon annealing results in the periodically arranged columnar self-assembly of SiGe core–shell nanocrystals. An increase in photocurrent intensity by more than an order of magnitude was achieved by annealing. Furthermore, a detailed discussion is provided on strain development within the structures, the consequential interface characteristics and its effect on the photocurrent spectra.

scholarly journals Copper Containing Glass-Based Bone Adhesives for Orthopaedic Applications: Glass Characterization and Advanced Mechanical Evaluation

2020 ◽  
Author(s):  
Sahar. Mokhtari ◽  
Anthony.W. Wren
Keyword(s):  
Mechanical Properties ◽  
Photoelectron Spectroscopy ◽  
Structural Changes ◽  
Viscoelastic Behavior ◽  
Polymer Chains ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Data

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.

Synthesis and Characterization of Mesoporous Silica Nanoparticles Embedded Gadolinium Oxide

2011 ◽  
Vol 306-307 ◽  
pp. 1275-1279 ◽  
Author(s):  
Ning Qi Luo ◽  
Zhan Yun Huang ◽  
Ping Luo ◽  
Yuan Zhi Shao ◽  
Di Hu Chen
Keyword(s):  
Mesoporous Silica ◽  
Self Assembly ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Gadolinium Oxide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Mean

We first synthesized gadolinium oxide (Gd2O3) by a modified “polyol” strategy and then embedded it into mesoporous silica by a simple self-assembly sol-gel reaction. Scanning electron microscope (SEM) results show that the samples have good sphericity and good dispersibility. The structure of mesoporous silica was characterized by transmission electron microscopy (TEM) and small-angle X-ray diffraction (SAXRD). Results show that the mesoporous structure has not been destroyed after gadolinium oxide imbedding. The ratio of gadolinium and silica was determined by the mean of energy dispersive spectroscopy (EDS).

scholarly journals Structural characterization of Fe–C coatings prepared by reactive triode-magnetron sputtering

2010 ◽  
Vol 25 (9) ◽  
pp. 1859-1869 ◽  
Author(s):  
Isabelle Jouanny ◽  
Valérie Demange ◽  
Jaafar Ghanbaja ◽  
Elisabeth Bauer-Grosse
Keyword(s):  
Magnetron Sputtering ◽  
Gas Flow ◽  
Carbon Matrix ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Electron Energy Loss

Fe1–xCx coatings were synthesized by triode magnetron sputtering of an iron target in a methane/argon atmosphere with a large range of composition (x = 0.3 to 0.6 ± 0.06). Film surfaces were characterized by grazing incidence x-ray diffraction, scanning and transmission electron microscopies, and electron energy loss spectroscopy, to study effects of the variation of the methane gas flow rate on their structural properties. The coatings were constituted of the ε-Fe3C carbide (x = 0.3 and 0.36), in which carbon atoms are in octahedral sites, and of nanocomposite structure constituted of disordered and crystalline carbide nanograins embedded in a carbon matrix made of an amorphous and poorly crystallized graphenelike material (x = 0.55 and 0.60). In situ annealing of the nanocomposite Fe0.45C0.55 coating led to the formation of carbides θ-Fe3C and Fe7C3 (with carbon atoms in prismatic sites) and C-rich cubic carbide possibly related to the τ2-Fe2C7 compound.

Preparation, Characterization of Co3O4 Nano-Particles and its Catalytic Effect on the Combustion of Fuel Rich Propellants

2012 ◽  
Vol 560-561 ◽  
pp. 284-288 ◽  
Author(s):  
Wei Qiang Pang ◽  
Xiao Bing Shi ◽  
Yang Li
Keyword(s):  
Particle Size ◽  
Catalytic Effect ◽  
Solid Phase ◽  
Particle Size Analysis ◽  
Nano Particles ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Wide Size Distribution

The mono-dispersed Co3O4 nano-particles were prepared by means of solid phase synthetical method. The particle size, specific surface area, crystal structure and morphology of the samples were characterized by laser particle size analysis, x-ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The catalytic effects of nano-particles on the combustion of fuel rich propellant were investigated. The results show that the Co3O4 nano-particles prepared are uniform and with relatively wide size distribution curve. The catalytic effect of Co3O4 nano-particles on the fuel rich propellant is stronger than those of micro-sized Co3O4 particles and CuO nano-particles.

Synthesis and Characterization of Nano-Hexaferrites SrFe12O19 by Aqueous Solution Method

2011 ◽  
Vol 306-307 ◽  
pp. 404-409 ◽  
Author(s):  
Jian An Liu ◽  
Mei Mei Zhang ◽  
Yan Fei Zhang ◽  
Shu Jiang Liu
Keyword(s):  
Aqueous Solution ◽  
Magnetic Properties ◽  
Solution Method ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
Nanometer Materials ◽  
Transmission Electron ◽  
Fast Synthesis ◽  
Aqueous Solution Method

Nano-hexaferrite SrFe12O19 has been prepared using the aqueous solution method. The structure and magnetic properties of SrFe12O19 have systematically been investigated by X-ray diffraction (XRD), Thermo gravimetric (TG), Fourier transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM), as well as Vibrating Sample Magnetometer (VSM). The XRD and TEM results showed that the samples are composed of SrFe12O19 nano-particles which are on average 70×50nm in dimensions when treated at 1200°C for 2 hours. The magnetic properties indicated that the saturation magnetization and the intrinsic coercivity were 48 Am2/kg and 506KA/m, respectively. The aqueous solution method is generally applicable to produce the nano-hexaferrite SrFe12O19 and is proved to be a promising method for fast synthesis of nanometer materials using nitrate.

Structure of Fe-Based Metallic Glass after Crystallization Process

2010 ◽  
Vol 163 ◽  
pp. 165-168 ◽  
Author(s):  
Ryszard Nowosielski ◽  
Rafał Babilas ◽  
Grzegorz Dercz ◽  
Lucjan Pająk
Keyword(s):  
Magnetic Properties ◽  
Metallic Glass ◽  
Structural Changes ◽  
Crystallization Process ◽  
X Ray Diffraction ◽  
Soft Magnetic ◽  
After Effects ◽  
Transmission Electron ◽  
Saturation Induction

The work presents a crystallization process of Fe-based amorphous alloy by characterization of the influence of annealing temperature on structural changes and magnetic properties of Fe72B20Si4Nb4 metallic glass. The studies were performed on the samples in the form of ribbons and rods. Crystallization behaviour of the studied alloy was examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM) methods. The studies of soft magnetic properties of tested material involved magnetic permeability, saturation induction, coercive field and magnetic after-effects measurements.

Preparation for Nano-NiO by Electrolysis of Nickel in HOCH2CH2OH Solution

2011 ◽  
Vol 399-401 ◽  
pp. 593-596
Author(s):  
Chuan Gao Zhu ◽  
Feng Wu Wang
Keyword(s):  
High Purity ◽  
Sol Gel ◽  
Nano Particles ◽  
Metal Alkoxide ◽  
Oxide Material ◽  
X Ray Diffraction ◽  
Laser Raman ◽  
Transmission Electron ◽  
Laser Raman Spectra

A method to prepare nickel oxide material which has a high purity and nano-sized particle was developed. nano NiO was synthesized by sol-gel method using nickel alkoxide as precursors. The structural characterization of the obtained materials was performed by thermal analysis TG-DTA, X-ray diffraction (XRD), Laser Raman spectra and Transmission Electron Microscopy (TEM). The characterization results indicated that NiO nano-particles (size 25–35 nm) are obtained by hydrolyzing of metal alkoxide of Ni(OCH2CH2OH)2 and possess high purity.

Synthesis and Characterization of Antimony Doped Tin Oxide Conductive Nanoparticles by Alkoxide Hydrolysis Method

2013 ◽  
Vol 702 ◽  
pp. 167-171 ◽  
Author(s):  
Fu Liang Zhu ◽  
Yan Shuang Meng
Keyword(s):  
Tin Oxide ◽  
Raw Materials ◽  
Volume Resistivity ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
Hydrolysis Method ◽  
Optimum Parameters ◽  
Transmission Electron ◽  
Average Size

Antimony doped tin oxide (ATO) conductive nano-particles are synthesised by alkoxide hydrolysis method using SnCl4•5H2O and SbCl3 as raw materials. The optimum parameters are determined as: Sb3+ doped molar concentration 15%, reaction temperature 60°C and roasting temperature 600°C. Under optimum conditions, the synthesised nano-particles are characterized by means of X-ray diffraction (XRD) and transmission electron microscope (TEM). XRD results show that all Sb ions came into the SnO2 lattice to substitute Sn ions. The image of TEM shows the ATO conductive nano-particles average size is 5 nm. Volume resistivity lowest value of ATO nano-particles is 141 Ω•cm.

Microscopical Study of Au Nanocrystals Self-Assembled on (100)Si and SiO2/(100)Si Substrates

2006 ◽  
Vol 959 ◽  
Author(s):  
Emanuela Piscopiello ◽  
Leander Tapfer ◽  
Marco Vittori Antisari ◽  
Pasquale Paiano ◽  
Paola Prete ◽  
...  
Keyword(s):  
Self Assembly ◽  
Au Nanoparticles ◽  
Microscopical Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Au Film ◽  
Assembly Method ◽  
Transmission Electron

ABSTRACTThis work reports on the structural characterization of Au nanocrystals directly prepared on the surface of (100)Si and 150 nm-thick SiO2 deposited (100)Si substrates, by a physical self-assembly method, consisting in the UHV evaporation of a thin Au film and its successive high temperature annealing. The morphology, orientation, and crystalline structure of Au nanocrystals were characterized by scanning and high-resolution transmission electron microscopy and X-ray diffraction, respectively. Experimental results show that the nature of the substrate strongly influences the process of Au nanocrystal formation upon heat treatment, by affecting the interaction of deposited Au with the underlying material. In the case of clean (100)Si substrates the Au strongly interacts with Si, so that Au nanoislands are obtained with a well defined epitaxial relationships with the substrate, i.e. [100]AuÐÐ[110]Si and [110]AuÐÐ[311]Si. The nanoisland shape is affected by faceting at the Au/Si interface, the Au nanocrystal being limited by the {111}, {311}, {711} and {-111} planes of Si. In the case of SiO2/(100)Si substrates spherical shaped Au nanoparticles with random crystal orientation are instead, produced.

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