UV Photoemission Study of Defect States in Polyethylene Films

1983 ◽  
Vol 24 ◽  
Author(s):  
W. Pong ◽  
D. Brandt ◽  
A. Sato ◽  
W. Imaino ◽  
M. Farrow
Keyword(s):  
Photoelectron Spectra ◽  
Defect States ◽  
Vacuum Level ◽  
Polyethylene Films ◽  
Contact Charging ◽  
Gold Substrates ◽  
Photoemission Study ◽  
Diffuse Glow ◽  
Reduced Pressures ◽  
Photoemission Threshold

ABSTRACTPhotoemission from evaporated Polyethylene films was measured in the spectral region between 6 and 11 eV. A significant increase in photoemission yield was observed after the films were exposed to O2 and to air containing ozone and ions from a diffuse glow discharge at reduced pressures. The enhancement can be attributed to oxygen and ozone reacting with the defects in the evaporated polyethylene films, which are unsaturated carbon double bonds in the polyethylene chain. For the ozonized polymer films deposited on gold substrates, the photoelectron spectra show a relatively high density of occupied states at 6.8 ± 0.3 eV below the vacuum level of the polymer and a photoemission threshold of 3.8 ± 0.3 eV. The implication of the results to contact charging of polyethylene is discussed.

The Effect of Adsorbeb Oxygen Ions on the Inelastic Scattering of Photo-Electrons at the Metal-Vacuum Interface

1984 ◽  
Vol 41 ◽  
Author(s):  
W. Pong ◽  
D. Brandt ◽  
Z. X. He ◽  
W. Imaino
Keyword(s):  
Inelastic Scattering ◽  
Energy Levels ◽  
Film Deposition ◽  
Photoelectron Spectra ◽  
Aluminum Films ◽  
Vacuum Level ◽  
Oxygen Ions ◽  
Resonant States ◽  
Initial Stage ◽  
Vacuum Interface

AbstractMeasurements of uv photoemission from evaporated aluminum films were made at photon energies 7.7–11 eV as a function of time after film deposition. Evidence of the initial stage of chemisorption of oxygen can be seen in the uv photoelectron spectra. The spectra taken immediately after film deposition showed a smooth energy distribution characteristic of clean aluminum. Structure in the spectra was found to appear at approximately 60 minutes after deposition at 10−9 Torr. Three noticeable features were observed at 1.0, 1.3, and 2.5 eV above the vacuum level. They appeared stationary with increasing photon energy. The structure can be attributed to inelastic scattering of photoelectrons into resonant states associated with oxygen ions on the metal surface. The energy levels of the calculated resonant states of a helium-like system are compared with the energy of the observed structure. The agreement suggests that there are adsorbed 0− ions to which photoelectrons can be scattered at the metal-vacuum interface.

UV Photoemission Study of Interfaces Related to Organic EL Devices

1997 ◽  
Vol 488 ◽  
Author(s):  
Kiyoshi Sugiyama ◽  
Kazuhiko Seki ◽  
Eisuke Ito ◽  
Yukio Ouchi ◽  
Hisao ISHII
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Electronic Structures ◽  
Organic Molecule ◽  
Negative Charge ◽  
Photoemission Spectroscopy ◽  
Level Shift ◽  
Vacuum Level ◽  
Organic Electroluminescent ◽  
Photoemission Study

AbstractInterfacial electronic structures related to organic electroluminescent (EL) devices were studied by UV photoemission spectroscopy (UPS). The two classes of interfaces studied were: (1) interfaces in a typical multilayer device AI/AIq3TPD/ITO, where Alq3 is tris(8-hydroxyquinolino)- aluminum, TPD is N,N×-diphenyl-NN×-(3-methylphenyl)- 1, 1‘-biphenyl-4,4’-diamine, and ITO is indium tin oxide, and (2) TTN/metals and TCNQ/metals interfaces, where TTN is tetrathianaphthacene and TCNQ is tetracyanoquinodimethane. The UPS studies of the specimen formed by the successive deposition of TPD, Alq3, and Al on ITO revealed interfacial energy diagrams, with the vacuum level shift of - 0.25 eV (downward) and - 0.1 eV (downward) at the TPD / ITO and the Alq3 / TPD interfaces, respectively. The deposition of TTN and TCNQ on metals showed opposite direction of the shift of the vacuum level, with the positive and negative charge at the vacuum side. This can be explained by considering the chargetransfer between the metal and the organic molecule, with these directions being consistent with the electron donating and accepting ability of these molecules.

Photoemission Study of Metal-Deposited p-Sexiphenyl Film

1999 ◽  
Vol 598 ◽  
Author(s):  
E. Ito ◽  
N. Koch ◽  
H. Oji ◽  
H. Ishii ◽  
G. Leising ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Alkali Metals ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Level Shift ◽  
Vacuum Level ◽  
X Ray ◽  
Photoemission Study ◽  
Gap States

ABSTRACTMetal deposition on a p-sexiphenyl (6P) film was studied by ultraviolet photoelectron spectroscopy (UPS), metastable atom electron spectroscopy (MAES), and X-ray photoelectron spectroscopy (XPS). The deposited metals were Au, Mg, and several alkali metals (K, Na, Rb, and Cs). No chemical reaction between 6P and Au or Mg was observed in the measured spectra, while additional gap states appeared in the UPS and MAES spectra by deposition of the alkali metals. The diffusion of Au and Mg atoms into the 6P film was observed in the MAES spectra. We found the trend of the vacuum level shift is different between the systems of the 6P on the Au and its reversed systems (Au on the 6P film), suggesting the different formation of the interface depending on the deposition sequence.

Photoemission Study of the Physical Nature of the InP Near-Surface Defect States

1986 ◽  
Vol 77 ◽  
Author(s):  
K. K. Chin ◽  
R. Cao ◽  
T. Kendelewicz ◽  
K. Miyano ◽  
J. J. Yeh ◽  
...  
Keyword(s):  
Surface Defect ◽  
Physical Nature ◽  
Defect States ◽  
Band Bending ◽  
Near Surface ◽  
Fermi Level Pinning ◽  
Low Temperature Annealing ◽  
Donor States ◽  
Photoemission Study ◽  
P Type

ABSTRACTThe physical nature of the InP near-surface defect acceptor and donor states are studied by using photoemission spectroscopy. It is found that the In/n-InP(110) interface band bending does not start until the In coverage reaches about 0.3 monolayer (ML), while the In/p-InP(110) band bending is almost saturated at 0.3 ML. The annealing effect on the band bending of clean cleaved n-and p-type InP(llO) surfaces is also studied. It is found that annealing of the clean surface creates an irreversible band bending effect on the p-InP(110), but the n-InP(110) almost does not show any band bending after low temperature annealing. Based on these two striking differences in the band bending behavior of n- and p-type InP, it is proposed that the physical nature of InP near-surface defect acceptor and donor levels may be different and that phosphorus vacancies are the cause of p-InP surface Fermi level pinning.

Photoemission Study of Quantum Well States in Thin ErAs Films on GaAs(100)

1998 ◽  
Vol 05 (01) ◽  
pp. 299-303 ◽  
Author(s):  
C. Wigren ◽  
L. Ilver ◽  
J. Kanski ◽  
P. O. Nilsson ◽  
U. O. Karlsson
Keyword(s):  
Quantum Well ◽  
Photoelectron Spectra ◽  
Electron Motion ◽  
Surface Layers ◽  
Effective Masses ◽  
Photoemission Study ◽  
Quantum Well States

Quantum well states in very thin epitaxial ErAs layers on GaAs(100) have been found in angle-resolved photoelectron spectra. From the dispersive properties of the quantum well states effective masses are obtained representing electron motion parallel to the surface layers and orthogonal to the layers.

The analysis of “Gels” in polymer films

1989 ◽  
Vol 47 ◽  
pp. 362-363
Author(s):  
G. M. Brown ◽  
D. F. Brown ◽  
J. H. Butler
Keyword(s):  
Molecular Weight ◽  
Film Industry ◽  
Local Stress ◽  
Melt Index ◽  
Polyethylene Films ◽  
Crosslinked Polymer ◽  
Polymeric Gels ◽  
Mineral Particles ◽  
Polymeric Species ◽  
Special Concern

The term “gel”, in the jargon of the plastics film industry, may refer to any inclusion that produces a visible artifact in a polymeric film. Although they can occur in any plastic product, gels are a principle concern in films where they detract from the cosmetic appearance of the product and may compromise its mechanical strength by acting as local stress concentrators. Many film gels are small spheres or ellipsoids less than one millimeter in diameter whereas other gels are fusiform-shaped and may reach several centimeters in length. The actual composition of gel inclusions may vary from miscellaneous inorganics (i.e. glass and mineral particles) and processing additives to heavily oxidized, charred or crosslinked polymer. The most commonly observed gels contain polymer differing from the bulk of the sample in its melt viscosity, density or molecular weight.Polymeric gels are a special concern in polyethylene films. Over the years and with the examination of a variety of these samples three predominant polymeric species have been observed: density gels which have different crystallinity than the film; melt-index gels in which the molecular weight is different than the film and crosslinked gels which are comprised of crosslinked polyethylene.

Photoemission study on the valence bands of DMe-DCNQI derived charge-transfer salts

1991 ◽  
Vol 1 (9) ◽  
pp. 1347-1354 ◽  
Author(s):  
D. Schmeißer ◽  
A. Gonzales ◽  
J. U. von Schütz ◽  
H. Wachtel ◽  
H. C. Wolf
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Salts ◽  
Valence Bands ◽  
Photoemission Study
Sign in / Sign up

Export Citation Format

Share Document