scholarly journals Gas Phase and Particle Diagnostic of Hmdso Plasmas by Infrared Absorption Spectroscopy

1998 ◽  
Vol 544 ◽  
Author(s):  
D. Magni ◽  
C.H. Deschenaux ◽  
C. Courteille ◽  
A. A. Howling ◽  
C.H. Hollenstein ◽  
...  
Keyword(s):  
Gas Phase ◽  
Infrared Absorption ◽  
Plasma Chemistry ◽  
Transmission Spectra ◽  
Infrared Transmission ◽  
Important Data ◽  
Additional Information ◽  
Particle Contamination ◽  
Gas Consumption ◽  
Radio Frequency Discharge

AbstractFTIR spectroscopy has been applied to a radio-frequency discharge in hexamethyldisiloxane (HMDSO) diluted with oxygen and helium, as typically used for industrial SiOx, deposition. By measuring the infrared absorption of the HMDSO molecule, the gas consumption during processing can be monitored, allowing process optimization. Additional information on various infrared active radicals formed within the plasma, such as CO, CO2 and aldehydes, helps to elucidate the plasma chemistry in HMDSO plasmas. Besides information on the formation of gaseous components in the plasma, infrared transmission spectra give at the same time important data on the nature of the particle contamination.

scholarly journals Localized surface plasmons in structures with linear Au nanoantennas on a SiO2/Si surface

2016 ◽  
Vol 7 ◽  
pp. 1519-1526 ◽  
Author(s):  
Ilya A Milekhin ◽  
Sergei A Kuznetsov ◽  
Ekaterina E Rodyakina ◽  
Alexander G Milekhin ◽  
Alexander V Latyshev ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Surface Plasmons ◽  
Infrared Absorption ◽  
Transmission Spectra ◽  
Localized Surface Plasmons ◽  
Optical Phonons ◽  
Infrared Transmission ◽  
Phonon Modes ◽  
Electromagnetic Simulations

The study of infrared absorption by linear gold nanoantennas fabricated on a Si surface with underlying SiO2 layers of various thicknesses allowed the penetration depth of localized surface plasmons into SiO2 to be determined. The value of the penetration depth derived experimentally (20 ± 10 nm) corresponds to that obtained from electromagnetic simulations (12.9–30.0 nm). Coupling between plasmonic excitations of gold nanoantennas and optical phonons in SiO2 leads to the appearance of new plasmon–phonon modes observed in the infrared transmission spectra the frequencies of which are well predicted by the simulations.

Deuterium Treatment and Infrared Transmission Spectra of Fused Silica

1981 ◽  
Vol 64 (12) ◽  
pp. C-178-C-180 ◽  
Author(s):  
Binod Kumar ◽  
N. Fernelius ◽  
J. A. Detrio
Keyword(s):  
Fused Silica ◽  
Transmission Spectra ◽  
Infrared Transmission

Transport properties of hydrogenated and chlorinated amorphous silicon Correlation with infrared transmission spectra

1984 ◽  
Vol 50 (4) ◽  
pp. 493-504 ◽  
Author(s):  
S. Al Dallal ◽  
S. Kalem ◽  
J. Bourneix ◽  
J. Chevallier ◽  
M. Toulemonde
Keyword(s):  
Amorphous Silicon ◽  
Transport Properties ◽  
Transmission Spectra ◽  
Infrared Transmission

Retrieval of trace gases from aerosol-influenced infrared transmission spectra observed by low-spectral-resolution Fourier-transform spectrometers

2005 ◽  
Vol 44 (3) ◽  
pp. 455 ◽  
Author(s):  
Nobuyuki Uemura ◽  
Satoshi Kuriki ◽  
Koji Nobuta ◽  
Tatsuya Yokota ◽  
Hideaki Nakajima ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Spectral Resolution ◽  
Trace Gases ◽  
Transmission Spectra ◽  
Infrared Transmission

Retrieval of stratospheric aerosol size and composition information from solar infrared transmission spectra

2003 ◽  
Vol 42 (12) ◽  
pp. 2140 ◽  
Author(s):  
Helen M. Steele ◽  
Annmarie Eldering ◽  
Bhaswar Sen ◽  
Geoffrey C. Toon ◽  
Franklin P. Mills ◽  
...  
Keyword(s):  
Stratospheric Aerosol ◽  
Transmission Spectra ◽  
Infrared Transmission

scholarly journals Plasma Catalysis: Distinguishing between Thermal and Chemical Effects

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 185 ◽  
Author(s):  
Guido Giammaria ◽  
Gerard van Rooij ◽  
Leon Lefferts
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Thermal Effects ◽  
External Surface ◽  
Plasma Chemistry ◽  
Internal Surface ◽  
Plasma Power ◽  
External Surface Area ◽  
Internal Surface Area ◽  
Chemical Effects

The goal of this study is to develop a method to distinguish between plasma chemistry and thermal effects in a Dielectric Barrier Discharge nonequilibrium plasma containing a packed bed of porous particles. Decomposition of CaCO3 in Ar plasma is used as a model reaction and CaCO3 samples were prepared with different external surface area, via the particle size, as well as with different internal surface area, via pore morphology. Also, the effect of the CO2 in gas phase on the formation of products during plasma enhanced decomposition is measured. The internal surface area is not exposed to plasma and relates to thermal effect only, whereas both plasma and thermal effects occur at the external surface area. Decomposition rates were in our case found to be influenced by internal surface changes only and thermal decomposition is concluded to dominate. This is further supported by the slow response in the CO2 concentration at a timescale of typically 1 minute upon changes in discharge power. The thermal effect is estimated based on the kinetics of the CaCO3 decomposition, resulting in a temperature increase within 80 °C for plasma power from 0 to 6 W. In contrast, CO2 dissociation to CO and O2 is controlled by plasma chemistry as this reaction is thermodynamically impossible without plasma, in agreement with fast response within a few seconds of the CO concentration when changing plasma power. CO forms exclusively via consecutive dissociation of CO2 in the gas phase and not directly from CaCO3. In ongoing work, this methodology is used to distinguish between thermal effects and plasma–chemical effects in more reactive plasma, containing, e.g., H2.

scholarly journals Properties of sub-Neptune atmospheres: TOI-270 system

2020 ◽  
Vol 495 (1) ◽  
pp. 962-970
Author(s):  
J Chouqar ◽  
Z Benkhaldoun ◽  
A Jabiri ◽  
J Lustig-Yaeger ◽  
A Soubkiou ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Signal To Noise Ratio ◽  
Spectral Features ◽  
Transmission Spectra ◽  
Infrared Transmission ◽  
Signal To Noise ◽  
Space Telescope ◽  
Molecular Features ◽  
James Webb Space Telescope ◽  
Mean Molecular Weight

ABSTRACT We investigate the potential for the James Webb Space Telescope (JWST) to detect and characterize the atmospheres of the sub-Neptunian exoplanets in the TOI-270 system. Sub-Neptunes are considered more likely to be water worlds than gas dwarfs. We model their atmospheres using three atmospheric compositions – two examples of hydrogen-dominated atmospheres and a water-dominated atmosphere. We then simulate the infrared transmission spectra of these atmospheres for JWST instrument modes optimized for transit observation of exoplanet atmospheres: NIRISS, NIRSpec, and MIRI. We then predict the observability of each exoplanet’s atmosphere. TOI-270c and d are excellent targets for detecting atmospheres with JWST transmission spectroscopy, requiring only 1 transit observation with NIRISS, NIRSpec, and MIRI; higher signal-to-noise ratio can be obtained for a clear H-rich atmosphere. Fewer than three transits with NIRISS and NIRSpec may be enough to reveal molecular features. Water-dominated atmospheres require more transits. Water spectral features in water-dominated atmospheres may be detectable with NIRISS in two or three transits. We find that the detection of spectral features in a cloudy, H-rich atmosphere does not require integrations as long as those required for the water-dominated atmosphere, which is consistent with the differences in atmospheric mean molecular weight. TOI-270c and d could be prime targets for JWST transit observations of sub-Neptune atmospheres. These results provide useful predictions for observers who may propose to use JWST to detect and characterize the TOI-270 planet atmospheres.

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