A New Method for Preparing Ge Nano-Crystallites Embedded in SiNY Matrices

1994 ◽  
Vol 358 ◽  
Author(s):  
Kunji Chen ◽  
Xuexuan Qu ◽  
Xinfan Huang ◽  
Zhifeng Li ◽  
Duan Feng
Keyword(s):  
Laser Annealing ◽  
Hydrogen Plasma ◽  
New Method ◽  
Transmission Electron ◽  
Scattering Spectra ◽  
Ion Laser ◽  
New Type ◽  
Raman Scattering Spectra ◽  
Average Size ◽  
20 Nm

ABSTRACTWe report a new method for synthesizing Ge nano-crystallites embedded in SiNy film matrices. On the basis of the effect of the reactant precursors and preferential chemical bonding of Si-N and Ge-Ge, thin films with Ge clusters embedded in SiNy matrices have been prepared in the PECVD system with reactant gases of SiH4, GeH4 and NH3 mixed in the hydrogen plasma. The as-deposited films were then crystallized by Ar ion laser annealing or thermal annealing technique to form nanometer-sized Ge crystallites.The composition and microstructures of these new type of sample were characterized by infrared absorption spectra, transmission electron microscopy, X-ray diffraction and Raman scattering spectra. The results indicated that the average size of Ge crystallites was estimated to be 2-20 nm depending on the deposition and annealing parameters and can be controlled by a designed manner.

Transmission Electron Microscopy Observation of Constrained Crystallization in a-Si:H/a-SiNx:H Multilayer Film

1994 ◽  
Vol 358 ◽  
Author(s):  
Xinfan Huang ◽  
Weihua Shi ◽  
Kunji Chen ◽  
Shidong Yu ◽  
Duan Feng
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Multilayer Film ◽  
Laser Annealing ◽  
Annealing Treatment ◽  
Multilayer Structures ◽  
Lattice Image ◽  
Transmission Electron ◽  
Ion Laser ◽  
Average Size

ABSTRACTThe constrained crystallization in a-Si:H/a-SiNx:H multilayer structures by Ar ion laser annealing treatment has been studied by high-resolution transmission electron microscopy (HRTEM) and Raman scattering. HRTEM photograph shows that the a-Si:H layers crystallize without disturbing the multilayer structures and that the interfaces after the crystallization are atomically smooth and uniform. The lattice image of the Si crystallites arrayed one by one can be seen clearly in Si layers and the average size is roughly equal to the thickness of Si layer. The thermodynamics of constrained crystallization within multilayer structures has been discussed.

Growth of Few Layers Graphene on Silicon Carbide from Nickel Silicide Supersaturated with Carbon

2010 ◽  
Vol 645-648 ◽  
pp. 589-592 ◽  
Author(s):  
Konstantin Vassilevski ◽  
Irina P. Nikitina ◽  
Alton B. Horsfall ◽  
Nicolas G. Wright ◽  
C. Mark Johnson
Keyword(s):  
Silicon Carbide ◽  
Raman Scattering ◽  
Optical Microscopy ◽  
Nickel Silicide ◽  
Raman Scattering Spectroscopy ◽  
Wet Processing ◽  
Scattering Spectra ◽  
Raman Scattering Spectra ◽  
20 Nm ◽  
Lorentzian Shape

Few Layers Graphene (FLG) films were grown on the carbon-terminated surface of 4H-SiC from nickel silicide supersaturated with carbon. The process was realised by annealing of thin Ni films deposited on silicon carbide followed by wet processing to remove the nickel silicide. To identify and characterize the fabricated FLG films, micro-Raman scattering spectroscopy, AFM and optical microscopy have been used. The films grown on samples with initially deposited nickel thinner than 20 nm show clear graphene footprints in micro-Raman scattering spectra, namely a single component, Lorentzian shape 2D band with FWHM remarkably lower than that of the 2D peak of graphite.

Sintering and Dielectric Properties of Ba(Mg1/3Ta2/3)O3 Particle Prepared by Spray Pyrolysis

2008 ◽  
Vol 388 ◽  
pp. 245-248 ◽  
Author(s):  
Hiroki Yamada ◽  
Takashi Okawa ◽  
Takashi Ogihara
Keyword(s):  
Electron Microscopy ◽  
Spray Pyrolysis ◽  
Ultrasonic Spray Pyrolysis ◽  
Nano Particles ◽  
Ultrasonic Spray ◽  
Transmission Electron ◽  
Powder Particles ◽  
Average Size ◽  
Micrometer Size ◽  
20 Nm

Ba(Mg1/3Ta2/3)O3 (BMT) powders were successfully prepared by ultrasonic spray pyrolysis from an aqueous solution of Ba, Mg and Ta. The particles characteristics of BMT nano-sized powders were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). As-prepared powder particles had a sub-micrometer size with a narrow distribution. Transmission electron microscopy (TEM) observation revealed that the average size of the BMT nano-particles was around 20 nm, and that these particles were aggregated. The dielectric constant (r) of 23.2 and the Q・f of 98,300 were obtained at 1550°C by a spray pyrolysis.

Microstructure and interdiffusion behaviour of β-FeSi2 flat islands grown on Si(111) surfaces

2013 ◽  
Vol 46 (4) ◽  
pp. 1076-1080
Author(s):  
Sung-Pyo Cho ◽  
Yoshiaki Nakamura ◽  
Jun Yamasaki ◽  
Eiji Okunishi ◽  
Masakazu Ichikawa ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Single Phase ◽  
Spherical Aberration ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Abrupt Interface ◽  
Average Size ◽  
20 Nm

β-FeSi2 flat islands have been fabricated on ultra-thin oxidized Si(111) surfaces by Fe deposition on Si nanodots. The microstructure and interdiffusion behaviour of the β-FeSi2/Si(111) system at the atomic level were studied by using spherical aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. The formed β-FeSi2 flat islands had a disc shape with an average size of 30–150 nm width and 10–20 nm height, and were epitaxically grown on high-quality single-phase Si with a crystallographic relationship (110)β-FeSi2/(111)Si and [001]β-FeSi2/[1\bar 10]Si. Moreover, the heterojunction between the β-FeSi2(110) flat islands and the Si(111) substrate was an atomically and chemically abrupt interface without any irregularities. It is believed that these results are caused by the use of ultra-thin SiO2 films in our fabrication method, which is likely to be beneficial particularly for fabricating practical nanoscaled devices.

Fullerene C60 Films Cross-Linked with Octane-1,8-Dithiol: Preparation, Characterization and the Use as Template for Chemical Deposition of Gold Nanoparticles

2008 ◽  
Vol 8 (8) ◽  
pp. 3828-3837 ◽  
Author(s):  
Víctor Meza-Laguna ◽  
Elena V. Basiuk ◽  
Edgar Alvarez-Zauco ◽  
Taras Yu. Gromovoy ◽  
Oscar Amelines-Sarria ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Density Functional ◽  
Chemical Deposition ◽  
Density Functional Theory Calculations ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Covalent Bonds ◽  
Transmission Electron ◽  
Average Size ◽  
20 Nm

We report on the preparation of fullerene C60 thin films chemically cross-linked with octane-1,8-dithiol, which are capable of binding gold nanoparticles. The formation of a polymer was directly proved by means of laser desorption/ionization time-of-flight mass spectra, in which we observed the cleavage of fullerene–dithiol polymer at different bonds. Fourier-transform infrared, Raman and UV-visible spectra of the functionalized films exhibited notorious changes due to the formation of new covalent bonds between C60 molecules and bifunctional thiol. We further demonstrated that the dithiol-functionalized fullerene can be employed as a support for stable and homogeneous deposition of gold nanoparticles. Their average size is about 5 nm according to high-resolution transmission electron microscopy observations, and up to 20 nm, as found from scanning tunneling microscopy images. The proposed binding mechanism is through a strong coordination attachment between Au nanoclusters and sulfur donor atoms of the functionalized fullerene, as supported by density functional theory calculations.

Effect of fuel content on formation of zinc aluminate nano and micro-particles synthesised by high rate sol–gel autoignition of glycine-nitrates

2016 ◽  
Vol 70 (3) ◽  
Author(s):  
Shiva Salem
Keyword(s):  
Thermal Analyses ◽  
Sol Gel ◽  
High Rate ◽  
Zinc Aluminate ◽  
X Ray Diffraction ◽  
Micro Particles ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Average Size ◽  
20 Nm

AbstractThe autoignition technique using glycine as fuel and related nitrate salts as an oxidiser is able to produce zinc aluminate spinel. The precursors were synthesised with lean and rich fuel at pH of 7.0 and the materials so obtained were calcined at various temperatures ranging from 600-1200°C. The autoignition process of precursors was studied by the simultaneous thermo-gravimetric and differential thermal analyses to determine the ignition mechanism. The calcined powders were characterised by X-ray diffraction, Brunauer-Emmett-Teller technique and transmission electron microscopy. The product contains nano-sized particles with an average size of approximately 20 nm. The XRD patterns showed the formation of ZnO in the powder obtained by the fuel-rich precursor and calcined at 600°C which disappears at 800°C due to solid-state reaction and proper crystallisation after heat treatment. The results presented here can be useful in manufacturing nano and micro-sized ZnAl

Preparation of Colloidal Silver Nanoparticles by Laser Ablation; Evaluation and Study on its Developed Applications

2012 ◽  
Vol 488-489 ◽  
pp. 1409-1413
Author(s):  
Adeleh Granmayeh Rad ◽  
Hamed Abbasi
Keyword(s):  
Silver Nanoparticles ◽  
Laser Ablation ◽  
Colloidal Silver ◽  
Laser Ablation Method ◽  
Colloidal Silver Nanoparticles ◽  
Novel Approach ◽  
Transmission Electron ◽  
Good Potential ◽  
Average Size ◽  
20 Nm

In this work we report the preparation of colloidal silver nanoparticles. In order to prepare the silver nanoparticles laser ablation method has been used.A silver coin as a target (purity 99.9 %) was ablated by a Q-Switched Nd:YAG laser with a fluence of about 91 mJ/cm2 at a repetition rate of 10 Hz at room temperature. In order to evaluate these particles transmission electron microscopy (TEM) and spectrophotometry (from UV to NIR) have been used. The average size of prepared nanoparticles is ~ 20 nm. The importance of morphology of nanoparticles has been investigated. Developed applications of silver nanoparticles have been studied,silver nanoparticles are considered as biocompatible and low in toxicity and have good potential for biological applications. Lately silver nanoparticles have found a novel approach in different fields of medicine, biology and industry.

Polycaprolactone/α-Alumina and Hydroxyapatite-based Micro- and Nano- Structured Hybrid Fibers

2013 ◽  
Vol 1569 ◽  
pp. 185-191 ◽  
Author(s):  
Simón Y. Reyes-Lopéz ◽  
Bonifacio Alvarado-Tenorio ◽  
Ángel Romo-Uribe
Keyword(s):  
Structural Model ◽  
Polarized Light ◽  
Inorganic Nanoparticles ◽  
Alumina Nanoparticles ◽  
Size Analysis ◽  
Hybrid Fibers ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Average Size ◽  
20 Nm

ABSTRACTThe micro- and nanostructured phase behavior of non-woven hybrid electrospun fibers of Polycaprolactone (PCL-f), Polycaprolactone/α-Alumina (PCL/AA) and Polycaprolactone/Hydroxyapatite (PCL/HA) were elucidated. Nanoparticles of Hydroxyapatite featured 7-20 nm while α-Alumina was 500 nm in average size. Analysis by Transmission Electron Microscopy (TEM), Small-Angle Light Scattering (SALS), Polarized Optical Microscopy (POM) and Differential Scanning Calorimetry (DSC) enabled us to suggest a simple structural model for the series of hybrid fibers. PCL with a molecular weight of 70,000 g/mol was dissolved in chloroform. POM exhibited qualitative birefringent regions for all samples at the microscale level. Furthermore, polarized light distinguished between amorphous and micro-ordered structures along the fibers. On the other hand, SALS patterns suggested a needle-like morphology for all fibers. The influence of both, Hydroxyapatite and α-Alumina, was apparent in the SALS patterns of the PCL semicrystalline phase. Thermal analysis by DSC showed that the crystalline phase of PCL was disrupted by the presence of the inorganic nanoparticles. TEM micrographs showed that Hydroxyapatite and α-Alumina nanoparticles were embedded along the structure of PCL microfibers.

Reduction of thermal conductivity in semiconducting composite films consisting of silicon and transition-metal silicide nanocrystals

2013 ◽  
Vol 1456 ◽  
Author(s):  
N. Uchida ◽  
Y. Ohishi ◽  
K. Kurosaki ◽  
S. Yamanaka ◽  
T. Tada ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
High Efficiency ◽  
Phonon Scattering ◽  
Composite Films ◽  
Metal Silicide ◽  
Transmission Electron ◽  
Microscope Images ◽  
Scattering Spectra ◽  
Raman Scattering Spectra

ABSTRACTWe observed significant reduction of thermal conductivity in semiconducting composite films of Si and molybdenum (Mo)-silicide nanocrystals (NCs). These films were synthesized by phase separation due to annealing at 700 -1000°C from sputtered amorphous Mo–Si alloy. Transmission electron microscope images showed that the NCs were grown to diameters of∼10 nm in the films by annealing at 800°C. Raman scattering spectra showed lower shift of peak positions of Si transverse optical (TO) phonon due to the confinement effect and the tensile stress. The electrical resistivity of the films was 0.17- 9 Ωm at room temperature and showed a semiconducting temperature dependence at 20-400 K. Thermal conductivity of the film was reduced to 4.4 W/mK by enhancement of phonon scattering at NC interfaces, suggesting that the composite film is promising as a high-efficiency Si-based thermoelectric material.

Microstructures of Luminescent nc-Si by Excimer Laser Annealing of a-Si:H

1996 ◽  
Vol 452 ◽  
Author(s):  
Xinfan Huang ◽  
Wei Wu ◽  
Honghui Shen ◽  
Wei Li ◽  
Xiaoyuan Chen ◽  
...  
Keyword(s):  
Energy Density ◽  
Pulse Energy ◽  
Laser Annealing ◽  
Laser Wavelength ◽  
Pulse Number ◽  
Excimer Laser Annealing ◽  
Pulse Energy Density ◽  
Transmission Electron ◽  
Ion Laser ◽  
Si Films

AbstractWe have reported for the first time on visible photoluminescence (PL) in crystallized a-Si:H/a-SiNx:H multilayer structures by CW Ar ion laser annealing treatments. In this paper we present new results on visible PL from crystallized a-Si:H by using KrF excimer pulse laser (wavelength 248 nm) irradiating treatments. The transmission electron microscopy and Raman scattering studies reveal the microstructures of crystallized Si films, which depend on the pulse number and the pulse energy density of KrF laser. When the laser pulse energy density is higher than 520 mJ/cm2, the nanosized Si crystallites (nc-Si) can be formed from a-Si:H layers with a thickness of 100 nm and strong PL with a peak wavelength of 610 nm has been observed at room temperature.

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