Effect of Surface Coverage on Porous Silicon Photoluminescence: Transmission FTIR Studies

1991 ◽  
Vol 256 ◽  
Author(s):  
M. B. Robinson ◽  
A. C. Dillon ◽  
D. R. Haynes ◽  
S. M. George
Keyword(s):  
Fourier Transform ◽  
Porous Silicon ◽  
Ftir Spectroscopy ◽  
Surface Coverage ◽  
Ultrahigh Vacuum ◽  
Photoluminescence Intensity ◽  
Ftir Studies ◽  
Photoluminescence Studies ◽  
Effect Of Surface

ABSTRACTTransmission Fourier Transform Infrared (FTIR) Spectroscopy was utilized to monitor the effect of surface coverage on photoluminescent porous silicon. These experiments were performed in situ in an ultrahigh vacuum (UHV) chamber to correlate simultaneously surface coverage and photoluminescence intensity. The goal of these FTIR and photoluminescence studies was to clarify the mechanism of the photoluminescence from porous silicon.

In situ FTIR studies of 4-cyanopyridine adsorption at the Au(111) electrode

1996 ◽  
Vol 74 (11) ◽  
pp. 2321-2330 ◽  
Author(s):  
A.C. Chen ◽  
D.F. Yang ◽  
J. Lipkowski ◽  
S.G. Sun ◽  
B. Pettinger
Keyword(s):  
Fourier Transform ◽  
Gold Electrode ◽  
Surface Coverage ◽  
Electrochemical Studies ◽  
In Situ Ftir ◽  
Deformation Bands ◽  
Ftir Studies ◽  
Vibrational Bands ◽  
The Stability

In situ electromodulated reflectance Fourier transform infrared (FTIR) spectroscopy has been employed to study the adsorption of 4-cyanopyridine (4-CNPy) at an Au(111) electrode surface. The vibrational spectra have been used to study (i) the dependence of the band intensity on the surface coverage, (ii) the character of surface coordination, and (iii) the stability of adsorbed 4-CNPy molecules. It has been observed that the vibrational bands in the spectra acquired in the electroreflection experiment are significantly broader than the corresponding spectra acquired in a transmission cell. Some weaker bands seen in the spectra recorded in transmission were not observed in the electroreflectance experiment. The electroreflectance spectra were dominated by the two ring deformation bands observed at 1416 cm−1 and 1554 cm−1. The intensities of these bands correlated well with the surface concentrations of 4-CNPy molecules determined from independent electrochemical studies. The integrated absorption intensities of the bands recorded in the electroreflection experiments were larger by a factor of five than the absorption intensities measured in the transmission cell. This indicates that the electric field of the photon acting on a molecule, present in front of the gold electrode, is significantly enhanced by reflection from the electrode. The infrared experiments suggest that at positive potentials the 4-CNPy molecules are coordinated to the metal surface through the nitrogen atom of the aromatic ring. The 4-CNPy molecules are oxidized at the Au electrode at potentials higher than 0.6 V (SCE) and are reduced to form (4-CNPy)−• ion at potentials lower than −1.1 V (SCE). Key words: adsorption, infrared spectroscopy, 4-cyanopyridine, gold electrode.

scholarly journals Porous Silicon Structural Evolution from In-Situ Luminescence and Raman Measurements

1996 ◽  
Vol 431 ◽  
Author(s):  
D. R. Tallant ◽  
M. J. Kelly ◽  
T. R. Guilinger ◽  
R. L. Simpson
Keyword(s):  
Porous Silicon ◽  
Silicon Surface ◽  
Structural Evolution ◽  
Surface Oxidation ◽  
Ethanol Solution ◽  
Nonradiative Recombination ◽  
Photoluminescence Intensity ◽  
Exciton Migration ◽  
Photoluminescence Mechanism

AbstractWe performed in-situ photoluminescence and Raman measurements on an anodized silicon surface in the HF/ethanol solution used for anodization. The porous silicon thereby produced, while resident in HF/ethanol, does not immediately exhibit intense photoluminescence. Intense photoluminescence develops spontaneously in HF/ethanol after 18–24 hours or with replacement of the HF/ethanol with water. These results support a quantum confinement mechanism in which exciton migration to traps and nonradiative recombination dominates the de-excitation pathways until silicon nanocrystals are physically separated and energetically decoupled by hydrofluoric acid etching or surface oxidation. The porous silicon surface, as produced by anodization, shows large differences in photoluminescence intensity and peak wavelength over millimeter distances. Parallel Raman measurements implicate nanometer-size silicon particles in the photoluminescence mechanism.

Optical Studies of porous Silicon

1993 ◽  
Vol 298 ◽  
Author(s):  
T. Lin ◽  
M. E. Sixta ◽  
J. N. Cox ◽  
M. E. Delaney
Keyword(s):  
Optical Properties ◽  
Fourier Transform ◽  
Steady State ◽  
Porous Silicon ◽  
Ftir Spectroscopy ◽  
Optical Studies ◽  
Etched Silicon ◽  
Bending Modes ◽  
P Type ◽  
Over Time

AbstractThe optical properties of both electrochemically anodized and chemically stain-etched porous silicon are presented. Fourier transform infrared (FTIR) spectroscopy showed that absorbance in stain-etched samples was 3x and 1.7x greater than in anodized samples for the SiH/SiH2 stretch and scissors-bending modes, respectively. Also, oxygen is detected in stain-etched samples immediately after formation, unlike anodized samples. Photoluminescence measurements showed different steady state characteristics. Electrochemical-etched silicon samples stored in air increased in photoluminescent intensity over time, unlike the stain-etched samples. A photoluminescent device made by anodization on epitaxial p-type material (0.4 Ωm) on n-type substrate (0.1 Ω-cm) did not exhibit electroluminescence.

In situ attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy combined with non-negative matrix factorization for investigating the synthesis reaction mechanism of 3-amino-4-amino-oxime furazan

2018 ◽  
Vol 10 (48) ◽  
pp. 5817-5822 ◽  
Author(s):  
Tianlong Zhang ◽  
Ting He ◽  
Chunhua Yan ◽  
Xinyu Gao ◽  
Junxiu Ma ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Reaction Mechanism ◽  
Ftir Spectroscopy ◽  
Matrix Factorization ◽  
Fourier Transform Infrared ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Synthesis Reaction ◽  
Non Negative Matrix Factorization

In situ ATR-FTIR combined with non-negative matrix factorization for investigating the synthesis reaction mechanism of 3-amino-4-aminoximefurazan.

scholarly journals Crystallinity of regenerated cellulose from [Bmim]Cl dependent on the hydrogen bond acidity/basicity of anti-solvents

RSC Advances ◽  
2017 ◽  
Vol 7 (65) ◽  
pp. 41004-41010 ◽  
Author(s):  
Zhaosheng Fan ◽  
Jianbo Chen ◽  
Wenji Guo ◽  
Fang Ma ◽  
Suqin Sun ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Fourier Transform ◽  
Ftir Spectroscopy ◽  
Molecular Diffusion ◽  
Diffusion Processes ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Regenerated Cellulose ◽  
Hydrogen Bond Acidity

Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to monitor the molecular diffusion processes of four anti-solvents in situ.

Optical Characteristics of Chemically Prepared ZnO Nanostructures on Silica Modified Polyaniline Nanocomposites

2014 ◽  
Vol 548-549 ◽  
pp. 196-200 ◽  
Author(s):  
Katherine M. Emphasis ◽  
Reynaldo M. Vequizo ◽  
Rolando T. Canditato ◽  
Majvell Kay G. Odarve ◽  
Filchito Renè G. Bagsican ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Fourier Transform ◽  
Ftir Spectroscopy ◽  
Chemical Bath Deposition ◽  
In Situ Polymerization ◽  
Visible Region ◽  
Optical Characteristics ◽  
Zno Nanostructures ◽  
Vis Spectroscopy

Zinc oxide (ZnO) on silica modified polyaniline (SM-PANI) was prepared via chemical bath deposition and in situ polymerization. The optical characteristics of the nanocomposites were investigated using ultraviolet-visible (UV-Vis) spectroscopy. The bands showed higher absorbance in the visible region. Fourier transform infrared (FTIR) spectroscopy revealed that there is an interaction between SM-PANI and ZnO.

Influence of gas packing and orientation on FTIR activity for CO chemisorption to the Cu paddlewheel

2015 ◽  
Vol 17 (40) ◽  
pp. 26766-26776 ◽  
Author(s):  
Cheng-Yu Wang ◽  
Paramita Ray ◽  
Qihan Gong ◽  
Yonggang Zhao ◽  
Jing Li ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Ftir Spectroscopy ◽  
Metal Organic Framework ◽  
Specific Adsorption ◽  
Structural Defects ◽  
Site Specific ◽  
Co Chemisorption ◽  
Metal Organic ◽  
Adsorption Of Co

In situ Fourier-transform infrared (FTIR) spectroscopy is able to probe structural defects via site-specific adsorption of CO to the Cu-BTC (BTC = 1,3,5-benzenetricarboxylate) metal–organic framework (MOF).

In situ FTIR studies on the oxidation of isopropyl alcohol over SnO2 as a function of temperature up to 600 °C and a comparison to the analogous plasma-driven process

2018 ◽  
Vol 20 (14) ◽  
pp. 9053-9062 ◽  
Author(s):  
P. A. Christensen ◽  
Z. T. A. W. Mashhadani ◽  
Abd Halim Bin Md Ali
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Isopropyl Alcohol ◽  
Fourier Transform Infrared ◽  
In Situ Ftir ◽  
Paper Report ◽  
Ftir Studies

This paper report the application of in situ reflectance Fourier Transform InfraRed spectroscopy to the study of the thermal and plasma driven reaction of IsoPropyl Alcohol (IPA) at SnO2-coated Macor.

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