Chapter 12. Non-emission Microwave Plasma Spectroscopic Techniques and Tandem Sources

Fundamental characteristics of a microwave plasma sustained in nitrogen (Agilent 4200 MP-ES) are investigated by a combination of thermochemical modelling and spectroscopic techniques, including Thomson scattering.

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Structural Transformation upon Nitrogen Doping of Ultrananocrystalline Diamond Films by Microwave Plasma CVD

Journal of Nanomaterials ◽

10.1155/2009/621208 ◽

2009 ◽

Vol 2009 ◽

pp. 1-7 ◽

Cited By ~ 7

Author(s):

Chien-Chung Teng ◽

Shin-Min Song ◽

Chien-Min Sung ◽

Chhiu-Tsu Lin

Keyword(s):

Surface Morphology ◽

Structural Changes ◽

Microwave Plasma ◽

Nanocrystalline Diamond ◽

Spectroscopic Techniques ◽

Plasma Cvd ◽

Xps Spectra ◽

Spatially Resolved ◽

Ultrananocrystalline Diamond ◽

Microwave Plasma Cvd

The molecular properties and surface morphology of undoped and N-doped ultra-nanocrystalline diamond (UNCD) films deposited by microwave plasma CVD with addition of nitrogen are investigated with various spectroscopic techniques. The results of spatially resolved Raman scattering, ATR/FT-IR and XPS spectra show more amorphous andsp2/sp3ratio characteristics in N-doped UNCD films. The surface morphology in AFM scans shows larger nanocrystalline diamond clusters in N-doped UNCD films. Incorporation of nitrogen into UNCD films has promoted an increase of amorphoussp2-bonded carbons in the grain boundaries and the size of nanocrystalline diamond grains that are well correlated to the reported enhancement of conductivity and structural changes of UNCD films.

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Laser Diagnostics of Plasma in Synthesis of Graphene-Based Materials

Volume 2B: Advanced Manufacturing ◽

10.1115/imece2013-63823 ◽

2013 ◽

Author(s):

Alfredo D. Tuesta ◽

Aizaz Bhuiyan ◽

Robert P. Lucht ◽

Timothy S. Fisher

Keyword(s):

Spatial Distribution ◽

Carbon Nanostructures ◽

Carbon Nanomaterials ◽

Microwave Plasma ◽

Laser Diagnostics ◽

Rotational Temperature ◽

Plasma Generator ◽

Plasma Sheath ◽

In Situ Monitoring ◽

Spectroscopic Techniques

Scalable production of carbon nanostructures to exploit their extraordinary properties and potential technological applications requires an improved understanding of the chemical environment responsible for their synthesis. In this study the spatial distribution of the rotational temperature of hydrogen is investigated via coherent anti-Stokes Raman scattering spectroscopy in the plasma of a microwave plasma chemical vapor deposition reactor under parametrically controlled conditions. The reactor pressure is varied from 10 to 30 Torr and the plasma generator power from 300 to 700 W, simulating the conditions required for the synthesis of carbon nanotubes, graphene and graphitic nanopetals. Temperature measurements are conducted within the plasma sheath and up to 6 mm away from the puck surface in order to elucidate the spatial distribution of temperature within and around the plasma region. The results indicate a linear increase in rotational temperature of H2 with respect to the distance normal from the puck surface. Temperatures also increase with pressure. At 10 Torr the temperature range is approximately 850–1150 K while at 30 Torr it is approximately 1200–1650 K for a plasma generator power of 500 W. In addition, the temperature increases with plasma generator power and the introduction of other substances such as CH4 and N2. These findings may aid in understanding the function of the chemical composition and reactions in the plasma environment of these reactors which, to date, remains obscure. The spectroscopic techniques applied in this work may prove to be suitable in-situ monitoring methods for the scalable manufacturing of carbon nanomaterials.

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Differential polarization imaging of sickled cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102390 ◽

1988 ◽

Vol 46 ◽

pp. 62-63

Author(s):

Marcos F. Maestre

Keyword(s):

Optical Properties ◽

Theoretical Approach ◽

Polarized Light ◽

Polarization Microscopy ◽

Spectroscopic Techniques ◽

Polarization Imaging ◽

Circularly Polarized Light ◽

Circularly Polarized ◽

Microscopic Scale ◽

Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

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Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106466 ◽

1988 ◽

Vol 46 ◽

pp. 880-881

Author(s):

Bradley L. Thiel ◽

Chan Han R. P. ◽

Kurosky L. C. Hutter ◽

I. A. Aksay ◽

Mehmet Sarikaya

Keyword(s):

Grain Boundary ◽

Cuprous Oxide ◽

Room Temperature ◽

Boundary Phase ◽

Spectroscopic Techniques ◽

Transition Width ◽

Practical Applications ◽

Thin Foils ◽

Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

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