Femtosecond Excimer (248 NM) Laser Micro-Machining of Teflon (PTFE)

2001 ◽  
Author(s):  
K. P. Adhi ◽  
R. L. Owings ◽  
T. A. Railkar ◽  
W. D. Brown ◽  
A. P. Malshe
Keyword(s):  
Excimer Laser ◽  
Photoelectron Spectroscopy ◽  
Laser Processing ◽  
Ablation Threshold ◽  
Micro Machining ◽  
X Ray ◽  
Laser Micro Machining ◽  
Edge Quality ◽  
Micrometer Size

Abstract We have investigated, using X-ray photoelectron spectroscopy (XPS), the surface of polyterafluoroethylene (PTFE) films which were subjected to micromachining by femtosecond UV radiation from an excimer laser (KrF: λ = 248 nm, tp ∼ 380 fs) in air ambient. Bulk characterization of processed PTFE films by Fourier transform infrared spectroscopy (FTIR) allowed us to study laser-induced modifications of the material at energy densities below the ablation threshold. No features in the XPS or FTIR spectra indicated incorporation of hydrogen and/or oxygen or the formation of cross-linked networks of carbon, indicating chemically clean processing in contrast to nanosecond excimer laser processing which chemically degrades the surface being machined. Scanning electron microscopy (SEM) of micrometer size microvias indicates mechanically and thermally damage-free processing of PTFE with good edge quality, again in contrast to nanosecond excimer laser processing.

X-ray diffraction and x-ray photoelectron spectroscopy study of partially strained SiGe layers produced via excimer laser processing

1997 ◽  
Vol 82 (1) ◽  
pp. 147-154 ◽  
Author(s):  
S. Martelli ◽  
I. Vianey ◽  
R. Larciprete ◽  
E. Borsella ◽  
J. Castro ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Photoelectron Spectroscopy ◽  
Laser Processing ◽  
Spectroscopy Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Strained Sige

The Growth and Characterization of Germanium-Carbon Alloy Thin Films

1992 ◽  
Vol 270 ◽  
Author(s):  
Haojie Yuan ◽  
R. Stanley Williams
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vacuum Chamber ◽  
Optical Band Gap ◽  
High Vacuum ◽  
Optical Absorption Spectroscopy ◽  
Alloy Thin Film ◽  
New Materials ◽  
X Ray

ABSTRACTThin films of pure germanium-carbon alloys (GexC1−x with x ≈ 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been grown on Si(100) and A12O3 (0001) substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray θ-2θ diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00eV to 0.85eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples has a bonding configuration that is a mixture of sp2 and sp3 hybridizations.

Monitoring and characterization of creation of geopolymers prepared from fly ash and metakaolin by X-ray photoelectron spectroscopy method

2014 ◽  
Vol 34 (3) ◽  
pp. 841-849 ◽  
Author(s):  
M. Kanuchova ◽  
L. Kozakova ◽  
M. Drabova ◽  
M. Sisol ◽  
A. Estokova ◽  
...  
Keyword(s):  
Fly Ash ◽  
Photoelectron Spectroscopy ◽  
Spectroscopy Method ◽  
X Ray

Characterization of columns grown during KrF laser micromachining of Al2O3–TiC ceramics

2003 ◽  
Vol 18 (5) ◽  
pp. 1123-1130 ◽  
Author(s):  
V. Oliveira ◽  
R. Vilar
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Laser Pulses ◽  
Formation Mechanisms ◽  
X Ray ◽  
Reducing Conditions ◽  
Transmission Electron ◽  
Column Formation ◽  
Krf Laser

This paper aims to contribute to the understanding of column formation mechanisms in Al2O3–TiC ceramics micromachined using excimer lasers. Chemical and structural characterization of columns grown in Al2O3–TiC composite processed with 200 KrF laser pulses at 10 J/cm2 was carried out by scanning electron microscopy, transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Fully developed columns consist of a core of unprocessed material surrounded by an outer layer of Al2TiO5, formed in oxidizing conditions, and an inner layer, formed in reducing conditions, composed of TiC and Al3Ti or an AlTi solid solution. Possible mechanisms of column formation are discussed.

Preparation of Carbon Nanofibers from Polyacrylonitrile Nanofibers by Electrospinning

2011 ◽  
Vol 415-417 ◽  
pp. 642-647
Author(s):  
En Zhong Li ◽  
Da Xiang Yang ◽  
Wei Ling Guo ◽  
Hai Dou Wang ◽  
Bin Shi Xu
Keyword(s):  
Electron Microscope ◽  
Carbon Nanofibers ◽  
Photoelectron Spectroscopy ◽  
Solution Concentration ◽  
Dimethyl Formamide ◽  
Ultrafine Fibers ◽  
X Ray ◽  
Scanning Electron ◽  
Pan Fibers

Ultrafine fibers were electrospun from polyacrylonitrile (PAN)/N,N-dimethyl formamide (DMF) solution as a precursor of carbon nanofibers. The effects of solution concentration, applied voltage and flow rate on preparation and morphologies of electrospun PAN fibers were investigated. Morphologies of the green fibers, stabilized fibers and carbonized fibers were compared by scanning electron microscope (SEM). The diameter of PAN nanofibers is about 450nm and the distribution of diameter is well-proportioned. Characterization of the elements changes of fibers were performed by X-ray photoelectron spectroscopy (XPS).

scholarly journals X-ray spectroscopy characterization of self-assembled monolayers of nitrile-substituted oligo(phenylene ethynylene)s with variable chain length

2012 ◽  
Vol 3 ◽  
pp. 12-24 ◽  
Author(s):  
Hicham Hamoudi ◽  
Ping Kao ◽  
Alexei Nefedov ◽  
David L Allara ◽  
Michael Zharnikov
Keyword(s):  
Chain Length ◽  
Photoelectron Spectroscopy ◽  
Self Assembled Monolayers ◽  
Phenylene Ethynylene ◽  
X Ray ◽  
Molecular Length ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Gold Thiolate

Self-assembled monolayers (SAMs) of nitrile-substituted oligo(phenylene ethynylene) thiols (NC-OPEn) with a variable chain length n (n ranging from one to three structural units) on Au(111) were studied by synchrotron-based high-resolution X-ray photoelectron spectroscopy and near-edge absorption fine-structure spectroscopy. The experimental data suggest that the NC-OPEn molecules form well-defined SAMs on Au(111), with all the molecules bound to the substrate through the gold–thiolate anchor and the nitrile tail groups located at the SAM–ambient interface. The packing density in these SAMs was found to be close to that of alkanethiolate monolayers on Au(111), independent of the chain length. Similar behavior was found for the molecular inclination, with an average tilt angle of ~33–36° for all the target systems. In contrast, the average twist of the OPEn backbone (planar conformation) was found to depend on the molecular length, being close to 45° for the films comprising the short OPE chains and ~53.5° for the long chains. Analysis of the data suggests that the attachment of the nitrile moiety, which served as a spectroscopic marker group, to the OPEn backbone did not significantly affect the molecular orientation in the SAMs.

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