Comparison of crystalline thin poly(vinylidene (70%)–trifluoroethylene (30%)) copolymer films with short chain poly(vinylidene fluoride) films

We compare the photoemission and electron energy loss spectra of crystalline poly(vinylidene-fluoride with trifluoroethylene: 70%: 30%), P(VDF–TrFE), films, fabricated by the Langmuir–Blodgett technique and annealed in vacuum, with in situ thermally evaporated films of poly(vinylidene-fluoride) (PVDF) in vacuum. The electronic structure and vibrational modes of the short chain PVDF films compare well with the crystalline P(VDF–TrFE) films indicating that vacuum annealed films prepared ex situ are free of significant surface contamination once vacuum annealed. The electronic structure for the short chain PVDF films exhibits, however, different temperature dependence than the crystalline P(VDF–TrFE) films. PACS: 68.47.Mn; 71.20.Rv; 63.22.+m; 73.22.-

Thin crystalline functional group copolymer poly(vinylidene fluoride–trifluoroethylene) film patterning using synchrotron radiation

The photodegradation mechanism due to synchrotron radiation exposure of crystalline poly[vinylidene fluoride–trifluoroetylene, P(VDF–TrFE)] copolymer thin films has been studied with ultraviolet photoemission spectroscopy (UPS) and mass spectroscopy. Upon increasing exposure to x-ray white light (h ν≤1000 eV), UPS measurements reveal that substantial chemical modifications occur in P(VDF–TrFE) 5 monolayer films, including the emergence of new valence band features near the Fermi level, indicating a semimetallic photodegradeted product. The photodetached fragments of the copolymer consist mainly of H2, HF, CHF, CH2. This x-ray exposure study demonstrates that P(VDF–TrFE) films, possessing unique technologically important properties, can be directly patterned by x-ray lithographic processes. ©2000 American Institute of Physics

Optimization of the 3 m TGM beamline, at CAMD, for constant initial state spectroscopy

The 3 m toroidal grating monochromator (TGM) VUV beamline at CAMD/LSU was realigned to achieve better illumination of the monochromator gratings with the goal of substantially increasing the flux at the higher photon energies. This is partly accomplished through a tilting of the monochromator (by about of 13.5°), with respect to the plane defined by the synchrotron, providing a smaller grazing angle at the initial mirrors. The improved performance of the beamline permits resonant photoemission studies at Gd 4d core threshold without resorting to second order light, which we demonstrate for Gd doped HfO2

Pattern transfer by direct photo etching of poly(vinylidene fluoride) using X rays

A direct pattern transfer method has been developed by photo etching poly(vinylidene fluoride) (PVDF) using X rays (1-16 keV) from a synchrotron storage ring. The ability to pattern thin film of PVDF, a piezoelectric, pyroelectric and ferroelectric polymer, has potential applications in the areas of MEMS, nonlinear optics, and nonvolatile ferroelectric random access memory technology. Without the use of any reactive chemical gas, a maximum etched depth in excess of 9 μm is achieved. The etched depth for a given photon energy approaches saturation with respect to exposure time. An in situ mass spectrometry revealed the evolution of hydrogen, fluorine, and hydrogen fluoride species. The etched regions turned dark in color indicating a possible increase in the fraction of carbon atoms. The X-ray transmittance of photo etched PVDF approached that of a pure carbon as the exposure time is increased. Upon etching the root mean-square surface roughness of the etched portion increased by more than a factor of two. The rate of etching increased at elevated sample temperatures

Installation and operation of the LNLS double-crystal monochromator at CAMD

A new x-ray beamline has been installed at CAMD utilizing a two-crystal monochromator designed and built at LNLS. The beamline will operate in the 2-18 keV range using up to 4 mrad of dipole radiation from the CAMD storage ring. The monochromator maintains a fixed exit beam and fixed positions of the beam on the two crystals using mutually perpendicular elastic translations. With the ring operating at 1.5 GeV and 160 mA, Si(220) crystals will provide a flux of ∼3(109) photons/s/mrad at 8 keV, with an energy resolution ΔE\u3c2 eV, to the experimental hutch. The beamline is equipped with an EXAFS endstation and will also be used for other x-ray applications at CAMD. First results are presented. © 1995 American Institute of Physics

Status of the Center for Advanced Microstructures and Devices (CAMD) - 2010

The J. Bennett Johnston, Sr., Center for Advanced Microstructures and Devices (CAMD) is a 1.3 GeV synchrotron-radiation facility owned and operated by the State of Louisiana. Fifteen beamlines provide radiation for CAMD users and cover the spectral range from the far IR to X-rays of ca. 40 keV. Eleven of them receive radiation from bending magnets and four from a 7 T wavelength shifter. A wide range of basic and applied scientific experiments as well as microfabrication are performed at these beamlines. The nanomaterial synthesis and characterization laboratory at CAMD continues to add new instruments such as SQUID magnetometer (Quantum Deign MPMS XL5) and high precision microfluidic-based nanomaterials synthesis equipment complementing already available facilities. We have recently received NSF MRI funding for a multipole 7.5 T wiggler that will become operational in 2012. Generous equipment donations from the University of California at Riverside (Professor Jory Yarmoff) and the University of Bonn (ELSA facility) will provide users with two additional VUV beamlines in the near future. © 2011 Elsevier B.V. All rights reserved

Status of the Center for Advanced Microstructures and Devices (CAMD)-2007

The J. Bennett Johnston, Sr., Center for Advanced Microstructures and Devices (CAMD) is a 1.3 GeV synchrotron-radiation facility owned and operated by the State of Louisiana. Sixteen beamlines provide radiation for CAMD users and cover the spectral range from the far IR to X-rays of ca. 40 keV. Twelve of them receive radiation from bending magnets with the remaining four from a 7-T wavelength shifter. A wide range of scientific experiments related to basic and applied sciences and engineering as well as microfabrication are performed at these beamlines. A nanomaterials synthesis laboratory is present at CAMD which very effectively utilizes the available facilities. © 2007 Elsevier B.V. All rights reserved

Photoemission study of pristine and photodegraded poly(methyl methacrylate)

Degradation of poly(methyl methacrylate) (PMMA) thin films by vacuum ultraviolet (VUV) monochromatic synchrotron radiation was investigated by ultraviolet photoelectron spectroscopy. The photodegradation reaction was analyzed, for the first time, by different spectrometry techniques and ab initio molecular orbital calculations. It is concluded that the main degradation mechanism in PMMA by VUV photons is ascribed to the disappearance of ester groups and formation of double bonds in the polymer chain. The final product of the degradation seems to possess a relatively rich conjugation of unsaturated bonds. The rate constant of the degradation by VUV photons is evaluated to be 2.4×10-17 photons-1 cm2. © 1998 American Institute of Physics