Laser Induced Oxidation Effects in Bismuth Thin Films

2012 ◽  
Vol 1477 ◽  
Author(s):  
Marco A. Zepeda ◽  
Michel Picquart ◽  
Emmanuel Haro-Poniatowski
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Laser Irradiation ◽  
Raman Spectra ◽  
Exposure Time ◽  
Oxidation Process ◽  
Energy Dispersion Spectroscopy ◽  
Irradiation Power ◽  
Pure Bismuth ◽  
532 Nm

ABSTRACTThe Laser induced oxidation process of bismuth was investigated using Raman spectroscopy. Upon laser irradiation (λ = 532 nm) pure Bismuth was transformed gradually into Bi2O3. Raman spectra of the samples showed the characteristics peaks for pure Bi located at 71 cm-1 and 96 cm-1. The oxidation process was monitored by Raman spectra with four additional bands located at about 127 cm-1, 241 cm-1, 313 cm-1 and 455 cm-1. Maintaining constant the exposure time of irradiation, the intensity of these bands depended on laser irradiation power. The presence of Bi2O3 in the sample was confirmed through by energy dispersion spectroscopy (EDS).

scholarly journals Resonance-Enhanced Raman Spectroscopy on Explosives Vapor at Standoff Distances

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Anneli Ehlerding ◽  
Ida Johansson ◽  
Sara Wallin ◽  
Henric Östmark
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Wavelength Range ◽  
Vapor Phase ◽  
Cross Sections ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Resonance Enhancement ◽  
Enhancement Factors ◽  
532 Nm

Resonance-enhanced Raman spectroscopy has been used to perform standoff measurements on nitromethane (NM), 2,4-DNT, and 2,4,6-TNT in vapor phase. The Raman cross sections for NM, DNT, and TNT in vapor phase have been measured in the wavelength range 210–300 nm under laboratory conditions, in order to estimate how large resonance enhancement factors can be achieved for these explosives. The results show that the signal is enhanced up to 250,000 times for 2,4-DNT and up to 60,000 times for 2,4,6-TNT compared to the nonresonant signal at 532 nm. Realistic outdoor measurements on NM in vapor phase at 13 m distance were also performed, which indicate a potential for resonance Raman spectroscopy as a standoff technique for detection of vapor phase explosives. In addition, the Raman spectra of acetone, ethanol, and methanol were measured at the same wavelengths, and their influence on the spectrum from NM was investigated.

Nanoindentation-Induced Phase Transformation in Silicon Thin Films

2013 ◽  
Vol 586 ◽  
pp. 112-115 ◽  
Author(s):  
Radim Ctvrtlik ◽  
Jan Tomastik ◽  
Vaclav Ranc
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Phase Transformation ◽  
Raman Spectra ◽  
Structural Changes ◽  
Berkovich Indenter ◽  
Silicon Thin Films ◽  
Free Silicon ◽  
Amorphous Si

Nanoindentation-induced phase transformation of amorphous, annealed amorphous and microcrystalline hydrogen-free silicon thin films were studied. Series of nanoindentation experiments were performed with a sharp Berkovich indenter at various unloading rates. The structural changes in indentation deformed regions were examined using Raman spectroscopy. Analyses of indentation curves and Raman spectra suggest that high pressure phases appear more easily in annealed amorphous Si thin films than in microcrystalline ones.

INDIUM SELENIDE THIN FILMS BY LASER IRRADIATION OF In/Se LAYERED STRUCTURE

2013 ◽  
Vol 20 (06) ◽  
pp. 1350058 ◽  
Author(s):  
R. E. ORNELAS-ACOSTA ◽  
S. SHAJI ◽  
D. AVELLANEDA ◽  
G. A. CASTILLO ◽  
T. K. DAS ROY ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Laser Irradiation ◽  
Layered Structure ◽  
Optical And Electrical Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Structure Morphology ◽  
532 Nm

In this work, we report the formation of In 6 Se 7 thin films by laser irradiation of In / Se layered structure. Indium layer was deposited on glass substrates by thermal evaporation on which selenium thin film was grown by chemical bath deposition from an aqueous solution containing 10 ml of sodium selenosulphate (0.1 M), 1.0 ml acetic acid (25%) and 70 ml distilled water during 5 min. The In / Se coated glass substrates were irradiated using a 532 nm continuous laser for 3–5 min. Structure, morphology, optical and electrical properties of the irradiated thin films were analyzed using various techniques. X-ray diffraction analysis showed that the irradiated thin films were In 6 Se 7 of monoclinic structure. X-ray photoelectron spectroscopic study on the laser irradiated samples provided uniform relative composition of In and Se in the thin films formed after laser irradiation. The morphology, optical and electrical properties of the irradiated samples were investigated. The optical band gap of the In 6 Se 7 thin films was 2.2 eV and also, the thin films were photoconductive.

Microchip Lasers as a Compact Excitation Source for Raman Spectroscopy

2000 ◽  
Vol 54 (5) ◽  
pp. 739-741 ◽  
Author(s):  
Alfons Schulte ◽  
Chris Fredricksen ◽  
Scott Buchter ◽  
Greg Mizell
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Solid State ◽  
Raman Spectra ◽  
Solid State Laser ◽  
Microchip Laser ◽  
Laser Source ◽  
Spectral Measurements ◽  
Microchip Lasers ◽  
Raman Spectral

The application of a new microchip laser source for Raman spectral measurements is demonstrated. The performance of the device is evaluated and illustrated by Raman spectra of diamond thin films and a solid-state laser host material.

Laser-induced structural transformations in MoO3 investigated by Raman spectroscopy

1998 ◽  
Vol 13 (4) ◽  
pp. 1033-1037 ◽  
Author(s):  
E. Haro-Poniatowski ◽  
C. Julien ◽  
B. Pecquenard ◽  
J. Livage ◽  
M. A. Camacho-López
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Low Temperature ◽  
Laser Irradiation ◽  
Data Storage ◽  
Glass Phase ◽  
Structural Transformations ◽  
Storage Medium ◽  
Irradiation Power ◽  
Power Densities

The glass-crystalline transformation induced by laser irradiation is studied in MoO3. Before crystallization we have found that the system evolves from a low temperature glass phase to a high temperature glass phase. The crystallization kinetics depend strongly on the initial irradiation power. The power densities needed to induce the phase transformations, of the order of 15 W/mm2, are relatively low and suggest the possibility of using this material as a data storage medium.

Raman spectra of charge transfer organic compounds: Conductors And Semiconductors

1995 ◽  
Vol 413 ◽  
Author(s):  
R. Gómez ◽  
R. Ridaura ◽  
M. Quintana ◽  
M. L. Marquina ◽  
V. Marquina ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Charge Transfer ◽  
Raman Spectra ◽  
Coordination Compounds ◽  
Room Temperature ◽  
Molecular Solids ◽  
Donor And Acceptor ◽  
Ft Ir ◽  
Degree Of Charge Transfer

ABSTRACTA series of coordination compounds -macrocycle tetraaza derivatives with extended electronic conjugations- as molecular solids have been synthesized and analyzed by Raman spectroscopy. Their resistivity vs. temperature characteristics, measured in thin films, show three types of behavior: metallic, semiconductor and, in some cases, semiconductor with a transition to metallic below certain temperature. Room temperature Raman spectra were obtained in a FT-IR spectrometer and some stretching modes show different Raman shifts depending on the reactants. We relate these shifts with the degree of charge transfer between donor and acceptor radicals.

Photo darkening in As50Se50 thin films by 532 nm laser irradiation

2017 ◽  
Vol 90 ◽  
pp. 158-164 ◽  
Author(s):  
Ramakanta Naik ◽  
C. Sripan ◽  
R. Ganesan
Keyword(s):  
Thin Films ◽  
Laser Irradiation ◽  
532 Nm

scholarly journals Identifying Raman modes of Sb2Se3 and their symmetries using angle-resolved polarised Raman spectra

2020 ◽  
Vol 8 (17) ◽  
pp. 8337-8344 ◽  
Author(s):  
Nicole Fleck ◽  
Theodore D. C. Hobson ◽  
Christopher N. Savory ◽  
John Buckeridge ◽  
Tim D. Veal ◽  
...  
Keyword(s):  
Thin Films ◽  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Density Functional ◽  
Functional Theory ◽  
Raman Modes

Vibrational symmetry assignments using Raman spectroscopy and density functional theory on oriented crystals also enabling orientation optimisation of thin films.

Raman Spectroscopy of Redox Activity in Cathodically Electrodeposited Nickel Hexacyanoferrate Thin Films

2002 ◽  
Vol 56 (8) ◽  
pp. 1021-1029 ◽  
Author(s):  
William A. Steen ◽  
Kavita M. Jeerage ◽  
Daniel T. Schwartz
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Oxidation State ◽  
Principal Component ◽  
Redox Activity ◽  
Nickel Hexacyanoferrate ◽  
The Matrix ◽  
Electrodeposited Nickel ◽  
Spectral Variance

The intercalation of cations into electrodeposited nickel hexacyanoferrate (NiHCF) depends on the stoichiometry and oxidation state of the material. To better understand this material's performance as a cation separation matrix, the oxidation state needs to be measured independently from the stoichiometry, regardless of the particular intercalated cation. Reported is the use of Raman spectroscopy to quantify the absolute oxidation state of NiHCF thin films. Raman spectroscopy probes NiHCF's cyanide bonds, which are sensitive to the oxidation state of the matrix. The oxidation state is controlled via potentiostatic experiments in electrolytes containing Na+, K+, and Cs+ (NO3− is the common anion). Principal component analysis (PCA) on the Raman spectra shows that more than 90% of the spectral variance is captured by one principal component, with a score value shown to be directly related to the oxidation state of the film. A universal, predictive regression model was developed using these score values as the dependent variables and Raman spectra as the independent variables. The results were confirmed with electrochemistry and energy dispersive X-ray spectroscopy.

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