Inelastic scattering rate for electrons in thin aluminum films determined from the minimum frequency for microwave stimulation of superconductivity

1984 ◽  
Vol 29 (3) ◽  
pp. 1503-1505 ◽  
Author(s):  
P. C. van Son ◽  
J. Romijn ◽  
T. M. Klapwijk ◽  
J. E. Mooij
Keyword(s):  
Inelastic Scattering ◽  
Aluminum Films ◽  
Minimum Frequency ◽  
Scattering Rate ◽  
Thin Aluminum ◽  
Stimulation Of

Time-Resolved, Laser-Induced Phase Transformation in Aluminum

1984 ◽  
Vol 35 ◽  
Author(s):  
S. Williamson ◽  
G. Mourou ◽  
J.C.M. Li
Keyword(s):  
Point Defect ◽  
Long Range ◽  
Rapid Heating ◽  
Range Order ◽  
Nucleation Theory ◽  
Long Range Order ◽  
Time Resolved ◽  
Aluminum Films ◽  
Thin Aluminum ◽  
Initial Nucleus

ABSTRACTThe technique of picosecond electron diffraction is used to time resolve the laser-induced melting of thin aluminum films. It is observed that under rapid heating conditions, the long range order of the lattice subsists for lattice temperatures well above the equilibrium point, indicative of superheating. This superheating can be verified by directly measuring the lattice temperature. The collapse time of the long range order is measured and found to vary from 20 ps to several nanoseconds according to the degree of superheating. Two interpretations of the delayed melting are offered, based on the conventional nucleation and point defect theories. While the nucleation theory provides an initial nucleus size and concentration for melting to occur, the point defect theory offers a possible explanation for how the nuclei are originally formed.

scholarly journals Superlayer Residual Stress Effect on the Indentation Adhesion Measurements

1999 ◽  
Vol 594 ◽  
Author(s):  
Alex A. Volinsky ◽  
Neville R. Moody ◽  
William W. Gerberich
Keyword(s):  
Residual Stress ◽  
Sputter Deposition ◽  
Work Of Adhesion ◽  
Stress Effect ◽  
Aluminum Films ◽  
Nanoindentation Testing ◽  
Deposition Parameters ◽  
Thin Aluminum ◽  
Residual Stress Effect ◽  
Sputter Deposited

AbstractThe practical work of adhesion has been measured in thin aluminum films as a function of film thickness and residual stress. These films were sputter deposited onto thermally oxidized silicon wafers followed by sputter deposition of a one micron thick W superlayer. The superlayer deposition parameters were controlled to produce either a compressive residual stress of 1 GPa or a tensile residual stress of 100 MPa. Nanoindentation testing was then used to induce delamination and a mechanics based model for circular blister formation was used to determine practical works of adhesion. The resulting measured works of adhesion for all films between 100 nm and 1 μm thick was 30 J/m2 regardless of superlayer stress. However, films with the compressively stressed superlayers produced larger blisters than films with tensile stressed superlayers. In addition, these films were susceptible to radial cracking producing a high variability in average adhesion values.

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.

Investigations on the Aluminum/Para-Hexaphenyl Interface in Light Emitting Devices

1997 ◽  
Vol 488 ◽  
Author(s):  
N. Koch ◽  
L.-M. Yu ◽  
J.-L. Guyaux ◽  
Y. Morciaux ◽  
G. Leising ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Material ◽  
Direct Interaction ◽  
Metal Electrode ◽  
Insulating Layer ◽  
Aluminum Films ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Thin Aluminum

AbstractBlue light emitting devices (LED) with para-hexaphenyl (PHP) as the active material and aluminum as cathode exhibit very high quantum efficiencies. To further optimize device performance it is crucial to understand the physical properties of the involved interfaces. We have performed Rutherford-Backscattering experiments on actual devices to show the importance of oxygen in the interface formation at the cathode as this leads to the formation of a layer of AlxOy between PHP and aluminum. In devices, where the organic film is exposed to air before the metal electrode is evaporated, an insulating layer on the metal-side therefore is inherent. It has been shown that the introduction of an intermediate layer between active material and electrodes results in a higher quantum efficiency of the LED, the most common concepts being charge-transport-layers, or insulators on the other hand. Our results underline the need for a better control of the LED processing. Ultraviolet- and X-ray photoelectron spectroscopy in situ growth studies of thin aluminum films on PHP have been made to reveal the change in the electronic structure of the active medium in a LED in the absence of oxygen. Also the direct interaction of oxygen with this organic material is investigated by photoelectron spectroscopy.

Properties of Very Thin Aluminum Films

1971 ◽  
Vol 42 (1) ◽  
pp. 51-53 ◽  
Author(s):  
R. Meservey ◽  
P. M. Tedrow
Keyword(s):  
Aluminum Films ◽  
Thin Aluminum
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