Plasma-Initiated Laser Deposition of Polycrystalline and Monocrystalline Silicon Films

1983 ◽  
Vol 29 ◽  
Author(s):  
J. M. Gee ◽  
P. J. Hargis ◽  
M. J. Carr ◽  
D. R. Tallant ◽  
R. W. Light
Keyword(s):  
Polycrystalline Silicon ◽  
Monocrystalline Silicon ◽  
Laser Deposition ◽  
Laser Raman Spectroscopy ◽  
Epitaxial Silicon ◽  
Laser Raman ◽  
Laser Fluences ◽  
Transmission Electron ◽  
Plasma Species ◽  
Deposited Film

ABSTRACTIn this paper we report a new method of silicon deposition using the interaction between the radiation from a pulsed-ultraviolet excimer laser and the plasma species produced in a glow discharge in silane (SiH4). Examination of the deposited film by laser Raman spectroscopy and by transmission electron microscopy revealed that the morphology ranged from polycrystalline silicon at laser fluences of 0.13–0.17 J/cm2 to epitaxial silicon at fluences of 0.4–0.6 J/cm2 . Growth rates of 100 nm/min for polycrystalline silicon and 30 nm/min for monocrystalline silicon were achieved.

Synthesis of CeO2/e-HTiNbO5 Nanocomposite and Its Application for Photocatalytic Oxidation Desulfurization

NANO ◽  
2016 ◽  
Vol 11 (02) ◽  
pp. 1650018 ◽  
Author(s):  
Yuanjiao Zhang ◽  
Ningning Wang ◽  
Jie He ◽  
Liangguo Da ◽  
Zhong Li
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Oxidation ◽  
Diffuse Reflectance Spectroscopy ◽  
Proton Exchange ◽  
Light Irradiation ◽  
Laser Raman Spectroscopy ◽  
Natural Light ◽  
X Ray Diffraction ◽  
Laser Raman ◽  
Transmission Electron

Nanoscaled CeO2/e-HTiNbO5 composite was assembled by a facile process using colloidal TiNbO[Formula: see text] (e-HTiNbO5) nanosheet and CeO2 colloid as precursors at room temperature. The nanosheet e-HTiNbO5 was obtained through proton-exchange and exfoliation process from its parent KTiNbO5. The microstructures and properties of the as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Laser Raman spectroscopy (LRS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS), etc. The photocatalytic activity of the obtained nanocomposite is evaluated by the adsorption and photocatalytic oxidation of ethyl mercaptan (EM) under natural light irradiation. The results show that CeO2 nanoparticles are dispersed uniformly on the surface of e-HTiNbO5 and the layered structure of e-HTiNbO5 nanosheet maintains integrity. The interaction between dispersed CeO2 particles and e-HTiNbO5 results in lower bandgap compared to its precursors, and the photocatalytic activity of CeO2/e-HTiNbO5 are enhanced under natural light irradiation.

Preparation, Characterization and Thermal Properties of Polyacrylonitrile/Alpha-Zirconium Phosphate Nanocomposites by Gelation/Crystallization

2010 ◽  
Vol 150-151 ◽  
pp. 951-955
Author(s):  
Dan Dan Yang ◽  
Hai Ping Xu ◽  
Lu Ping Zhu ◽  
Yi Hua Wu
Keyword(s):  
Thermal Stability ◽  
Zirconium Phosphate ◽  
Cetyl Trimethyl Ammonium Bromide ◽  
Laser Raman Spectroscopy ◽  
Ammonium Bromide ◽  
Laser Raman ◽  
Transmission Electron ◽  
Cetyl Trimethyl Ammonium ◽  
Thermal Stability Property ◽  
Thermal Stability Of

Nanocomposites of polyacrylonitrile (PAN) and Organophilic alpha-zirconium phosphate (OZrP) were prepared by gelation/crystallization. OZrP was prepared using cetyl trimethyl ammonium bromide (CTAB). The structure of PAN/OZrP nanocomposites was characterized by X-ray diffractometry (XRD) and high resolution transmission electron microscopy (HRTEM). The results showed that an intercalated or exfoliated structure was formed. Thermogravimetric analysis (TGA) was applied to characterize thermal stability property, which indicated that the thermal stability of PAN/OZrP nanocomposites was improved compared with that of pure PAN. HRTEM and Laser Raman spectroscopy were used to analyze the microstructure of the chars of PAN/OZrP nanocomposites.

Hot-Wire Chemical Vapor Deposition for Epitaxial Silicon Growth On Large-Grained Polycrystalline Silicon Templates

2003 ◽  
Vol 762 ◽  
Author(s):  
M. S. Mason ◽  
C.M. Chen ◽  
H.A. Atwater
Keyword(s):  
Epitaxial Growth ◽  
Polycrystalline Silicon ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Solid Phase Epitaxy ◽  
Epitaxial Silicon ◽  
Hot Wire ◽  
Transmission Electron ◽  
Silicon Growth

AbstractWe investigate low-temperature epitaxial growth of thin silicon films on Si [100] substrates and polycrystalline template layers formed by selective nucleation and solid phase epitaxy (SNSPE). We have grown 300 nm thick epitaxial layers at 300°C on silicon [100] substrates using a high H2:SiH4 ratio of 70:1. Transmission electron microscopy confirms that the films are epitaxial with a periodic array of stacking faults and are highly twinned after approximately 240 nm of growth. Evidence is also presented for epitaxial growth on polycrystalline SNSPE templates under the same growth conditions.

MECHANOCHEMICAL SYNTHESIS OF NANOCRYSTALLINE FLUORINATED HYDROXYAPATITE

2005 ◽  
Vol 04 (04) ◽  
pp. 643-649 ◽  
Author(s):  
N. RAMESHBABU ◽  
T. S. SAMPATH KUMAR ◽  
R. MURUGAN ◽  
K. PRASAD RAO
Keyword(s):  
Laser Raman Spectroscopy ◽  
Mechanochemical Processing ◽  
Fluorine Substitution ◽  
X Ray ◽  
Laser Raman ◽  
Fine Grain ◽  
Transmission Electron ◽  
Ft Ir ◽  
Synthetic Hydroxyapatite ◽  
Nano Size

Synthetic hydroxyapatite ( Ca 10( PO 4)6( OH )2, HA ) is an important material used for orthopaedic and dental implant applications. The biological hydroxyapatite in the human bone and tooth is of nano size and differs in composition from the stiochiometric HA by the presence of other ions such as carbonate, magnesium and fluoride, etc. Osseointegration is enhanced by using nanocrystalline HA . This stimulates the interest in synthesizing nanocrystalline HA by different routes and among the methods, mechanochemical seems to form fine grain size and uniform characteristic nanocrystalline materials. Fluorinated hydroxyapatite ( FHA , Ca 10( PO 4)6( OH )2-x F x) possesses higher corrosion resistance in biofluids than pure HA and reduces the risk of dental caries. The present work deals with the synthesis of nanocrystalline FHAs by mechanochemical processing. The nanomaterials were characterized using X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) methods. Nano FHA of about 27-46 nm size was observed. The functional groups present in the FHA powders were ascertained by Fourier transform infrared spectroscopy (FT-IR) and Laser Raman spectroscopy. A gradual decrease in intensity of the OH - band at 655 and 3572 cm-1 has been observed with increasing fluorine substitution. The TEM micrograph shows that the powder is highly agglomerated and particle size is below 50 nm.

The study of the valence and distribution of radiogenic Pb in monazite by using XPS and TEM

2020 ◽  
Author(s):  
Xu Tang ◽  
Qiu-li Li ◽  
Lin-xin Gu
Keyword(s):  
Crystal Lattice ◽  
Photoelectron Spectroscopy ◽  
Atomic Scale ◽  
Laser Raman Spectroscopy ◽  
Heterogeneous Distribution ◽  
Laser Raman ◽  
Transmission Electron ◽  
Phosphate Mineral ◽  
Monazite Crystal

<p>Monazite((Ce,Y,La,Th)PO<sub>4</sub>) is an important phosphate mineral and is one of the widely used minerals for U-Th-Pb dating in geochronology. In this study, we have examined the crystallinity, the valence and coordination of radiogenic Pb in a natural RW-1 monazite standard (ThO<sub>2</sub> up to13.5 wt% and Pb up to ~5000 ppm) with a <sup>207</sup>Pb/<sup>235</sup>U age of 904.15 ± 0.26 Ma from a Norwegian pegmatite by using laser Raman spectroscopy (LRS), X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy (TEM). The Raman spectrum analysis revealed that this monazite is well crystalline and is not damaged by α-particles. The results of XPS and TEM suggest that the radiogenic Pb produced by the α-decay of U and Th is divalent and radiogenic Pb atom substitutes the Ce-site within the monazite crystal lattice. The qualitative analyses conducted on the HAADF-STEM data reveal heterogeneous distribution of radiogenic Pb within the monazite crystal lattice. This is the first work on the determination of the oxidation state, the atomic location and distribution of radiogenic Pb in a natural monazite (CePO<sub>4</sub>). The deeply study of radiogenic Pb in monazite at the nanoscale and atomic scale provides a good insight for us to understand the mechanisms of nano-isotopic mobility and the nano-geochronology  that has been poorly understood so far.</p>

Microstructural characterization of YBa2Cu3O7−x

1987 ◽  
Vol 2 (6) ◽  
pp. 736-742 ◽  
Author(s):  
M. Sarikaya ◽  
B. L. Thiel ◽  
I. A. Aksay ◽  
W. J. Weber ◽  
W. S. Frydrych
Keyword(s):  
Microstructural Characterization ◽  
Laser Raman Spectroscopy ◽  
Ion Milling ◽  
Detailed Characterization ◽  
Planar Defects ◽  
Resistivity Measurements ◽  
Laser Raman ◽  
Transmission Electron ◽  
Characterization Study

A detailed characterization study on polycrystalline specimens of YBa2Cu3Oy-x that were prepared by solid-state reaction techniques has been carried out. In the samples studied. magnetization and resistivity measurements indicate superconductivity onset temperatures of up to 89 K. Transmission electron microscopy (TEM) techniques have been used to facilitate direct microstructural characterization. It is shown that the planar defects on (001) planes form during the ion milling of the samples and are not directly connected with superconductivity. Laser Raman spectroscopy has revealed that these materials are sensitive to environmental degradation.

Preparation of Graphene by Green Reduction Method and Characterization

2013 ◽  
Vol 807-809 ◽  
pp. 515-520 ◽  
Author(s):  
Dong Zhi Chen ◽  
Xue Mei Lin
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Graphite Oxide ◽  
Laser Raman Spectroscopy ◽  
X Ray Diffraction ◽  
Ultrasonic Dispersion ◽  
Environment Friendly ◽  
X Ray ◽  
Laser Raman ◽  
Transmission Electron

Graphite oxide was prepared by Hummers method and got graphene oxide by ultrasonic dispersion in water, and using a cheap and environment-friendly fructose as reductant, graphene oxide could be reduced into graphene under mild condition. Meanwhile, the structure and morphology of obtained product was characterized and analyzed by testing methods such as Fourier transform Infrared spectroscopy, X-ray diffraction, Laser Raman spectroscopy, Transmission electron microscope and so on. In addition, the electrical conductivity of obtained graphene was determinated.The experimental results show that graphite oxide can be reduced by fructose under mild conditions and can get graphene with good structure and dispersibility. And the electrical conductivity of graphene prepared by the reduction of graphite oxide with fructose is 35.7 Scm-1, which has great improvement on conducting performance compared with graphite oxide. Moreover, It is non-toxic, non-polluting and friendly to the environment in preparation process of graphene, which lays the groundwork for mass production of graphene materials.

The Structure Feature of Novel Cu2O/e-HTi2NbO7 Nanocomposite and Their Enhanced Photocatalytic Activity

NANO ◽  
2017 ◽  
Vol 12 (08) ◽  
pp. 1750100 ◽  
Author(s):  
Jie Li ◽  
Lei Xu ◽  
Jie He ◽  
Pan Zhou ◽  
Lifang Hu ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Oxidation ◽  
Laser Raman Spectroscopy ◽  
The Novel ◽  
Diffuse Reflection Spectroscopy ◽  
X Ray Diffraction ◽  
Laser Raman ◽  
Transmission Electron ◽  
Light Region ◽  
Adsorption Desorption

The novel Cu2O/[Formula: see text]-HTi2NbO7 heterojunction nanocomposite was assembled through a facile exfoliation-restacking route. The as-prepared nanocomposite and its precursors, Cu2O and [Formula: see text]-HTi2NbO7, were characterized by means of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), N2 adsorption–desorption measurements, laser Raman spectroscopy (LRS) and UV–Vis diffuse reflection spectroscopy (UV–Vis DRS). The photocatalytic performance was evaluated by photocatalytic oxidation of ethyl mercaptan (EM) and photocatalytic degradation of methylene blue (MB) dyes under sunlight irradiation. The results showed that Cu2O nanoparticles were successfully distributed on the surface of [Formula: see text]-HTi2NbO7 nanosheets, and the intensity of spectral absorption of the as-prepared nanocomposite in the visible-light region was significantly enhanced. The as-prepared nanocomposite displayed the enhanced photocatalytic activity than the Cu2O nanoparticles and HTi2NbO7 nanosheets due to the formation of a heterojunction structure between Cu2O nanoparticles and HTi2NbO7 nanosheet and a possible photocatalytic mechanism was suggested.

scholarly journals Enhanced Photocatalytic Activity by Cu2O Nanoparticles Integrated H2Ti3O7 Nanotubes for Removal of Mercaptan

NANO ◽  
2017 ◽  
Vol 12 (06) ◽  
pp. 1750075 ◽  
Author(s):  
Chunli Guo ◽  
Lei Xu ◽  
Jie He ◽  
Lifang Hu ◽  
Bin Wang ◽  
...  
Keyword(s):  
Spectral Response ◽  
Laser Raman Spectroscopy ◽  
Diffuse Reflection Spectroscopy ◽  
X Ray Diffraction ◽  
Sunlight Irradiation ◽  
Laser Raman ◽  
Transmission Electron ◽  
Light Region ◽  
Cu2o Nanoparticles ◽  
Adsorption Desorption

The Cu2O@H2Ti3O7 nanocomposite was prepared through a facile hydrothermal method. The as-prepared samples were investigated by powder X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), laser Raman spectroscopy (LRS), N2 adsorption-desorption measurements and UV-Vis diffuse reflection spectroscopy (UV-Vis–DRS). The photocatalytic performance of the as-prepared Cu2O@H2Ti3O7 nanocomposite is evaluated by the oxidation of ethyl mercaptan (EM) under sunlight irradiation. The results indicate that the Cu2O nanoparticles are integrated uniformly on H2Ti3O7 nanotubes, and the absorption edge of the nanocomposite has obviously shifted to visible light region compared to H2Ti3O7 nanotubes. There is an obvious synergistic effect existing between the dispersed Cu2O nanoparticles and H2Ti3O7 nanotubes, and the Cu2O@H2Ti3O7 composite shows stronger visible spectral response and wider absorbance. Then, an enchanced photodegradation activity is obtained for the removal of EM under sunlight irradiation compared to its precursors.

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