niques were prepared using pentane as the solvent. Similar methods were used in preparing calibration samples with the mold release, solder flux, and hydraulic oil samples. All contaminated coupons were gentl y heated in an oven at 50°C for several days to remove both semi-volatile and volatile components. This served to stabi-lize the contaminants, allowing for quantification by weighing. Once the weights became stable, the coupons were cooled and weighed to determine the amount of contaminant present on the surface. When not being weighed or examined, the coupons were kept in a desiccator. 3. RESULTS AND DISCUSSION Grazing-angle incidence reflectance spectroscopy acts to enhance the detection sensitivity for thin layers of residue predominantly through improved coupling of th e electric field intensity of the incident beam with the vibrating dipoles of the surface contaminant layer perpendicular to the metallic surface. Some additional enhancement of the infrared absorption spectrum will also occur due to a length-ening of the effective path length through the absorbing thin film layer [4-6]. If the optical properties of both thin film and substrate are known (or can be de-termined), the reflection-absorption spectrum can be calculated as a function of film thickness and angle of incidence. This capability is particularly useful for in-terpreting experimental data and designing optical instrumentation. Computer codes written at Sandia [7] performed these calculations for a variety of materials. 3.1. FTIR measurements FTIR reflectance data for the full drawing-agent sample set were obtained at NFESC and Sandia using angles of incidence of 75 and 60° for average film thickness ranging from 0.1 to 1 |im, and aluminum substrates with surface finish ranging from 600 to 80 grit. Since the surface finishing operation produced a highly directional roughness, measurements were made both longitudinally and transversely with respect to the polishing grooves. R values were determined at

2003 ◽  
pp. 17-20
Keyword(s):  
Thin Film ◽  
Absorption Spectrum ◽  
Film Thickness ◽  
Infrared Absorption Spectrum ◽  
Grazing Angle ◽  
Incident Beam ◽  
Detection Sensitivity ◽  
Angle Of Incidence ◽  
Solder Flux ◽  
Layer 4

Low-Energy Electron Diffraction from Ag(111): Intensity-versus-Energy Curves and Absolute Intensity of the (00) Beam

1970 ◽  
Vol 25 (11) ◽  
pp. 1567-1578 ◽  
Author(s):  
Max G. Lagally
Keyword(s):  
Geometric Model ◽  
Surface Condition ◽  
Grazing Angle ◽  
Surface Preparation ◽  
Incident Beam ◽  
Absolute Intensity ◽  
Angle Of Incidence ◽  
Faraday Cage ◽  
Scattering Correction ◽  
Low Energies

The intensity of the (00) beam of a (111) surface of Ag has been measured with a Faraday cage as a function of the energy of the incident beam (10 < E < 280 eV), the grazing angle of incidence (46.5° < φ < 83.5°), two azimuths differing by 180°, and the temperature. The I vs E curves, when compared with data for Ag ( 111 ) of other workers who have used different methods of surface preparation, show good agreement in the structure over the whole range of incident angles, indicating that LEED is not strongly sensitive to surface condition. The I vs E curves for the two azimuths are identical, a necessary result of the reciprocity theorem. For comparison with the I vs E structure, a complete 3-beam geometric model is used. This differs from a simple Ewald construction in that it considers also the Bragg conditions between intermediate beams and the final beam. It also requires that there be no difference in the effect of intermediate forward and backward scattered beams. It is shown that the number of possible beams is much too large even at low energies to make positive identification of any structure in the I vs E curves. A comparison with a rigorous multiple-scattering theory yields agreement in the number and position of peaks, but not in heights and widths of peaks. The possibility of comparison of absolute intensities in theory and experiment is investigated and an attempt is made to remove the major differences. Intensity vs temperature measurements are made at closely spaced energies in order to extract the rigid-lattice scattering. Correction of this intensity for surface plasma losses leads finally to maximum scattered intensities of 2% at 100 eV, 10% at 60 eV, and up to 40% at energies below 20 eV.

The nonlinear dynamics of pendent drops on a thin film coating the underside of a ceiling

2010 ◽  
Vol 647 ◽  
pp. 239-264 ◽  
Author(s):  
JOHN R. LISTER ◽  
JOHN M. RALLISON ◽  
SIMON J. REES
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Gravitational Instability ◽  
Initial Perturbation ◽  
Film Coating ◽  
Gravitational Potential Energy ◽  
Angle Of Incidence ◽  
Capillary Length ◽  
Rigid Boundary ◽  
Drain Fluid

This paper considers the dynamics of a thin film of viscous liquid of density ρ coating the underside of a horizontal rigid boundary under the action of surface tension σ and gravity g, and in the lubrication limit. Gravitational instability for inverse wavenumbers larger than the capillary length ℓ = (σ/ρg)1/2) leads to the formation of quasi-static pendent drops of radius ≈3.83ℓ. If the boundary conditions are such as to pin the positions of the drops then the drops slowly drain fluid from the regions between them through thin annular trenches around each drop. A similarity solution is derived and verified numerically in which the film thickness in the intervening regions scales like t−1/4 and that in the trenches like t−1/2. A single drop placed far from boundaries on an otherwise uniform film, and given an initial perturbation, undergoes self-induced quasi-steady translation during which it grows slowly in amplitude by leaving a wake where the film thickness is reduced by an average of 90. It is driven by release of gravitational potential energy as fluid is collected from the film into the lower lying drop. Analysis of Landau–Levich regions around the perimeter of the translating drop predicts its speed and the profile of the wake. Two translating drops may coalesce if they collide, in contrast with the non-coalescence of colliding collars in the analogous one-dimensional problem (Lister et al., J. Fluid Mech. vol. 552, 2006b, p. 311). Colliding drops may also bounce off each other, the outcome depending on the angle of incidence through complex interactions between their surrounding capillary wave fields.

Electron-Channelling Patterns: Principles and Techniques

1976 ◽  
Vol 34 ◽  
pp. 400-401
Author(s):  
David C. Joy
Keyword(s):  
Crystal Structure ◽  
Electron Flux ◽  
Lattice Structure ◽  
Incident Beam ◽  
Bloch Wave ◽  
Crystalline Solid ◽  
Angle Of Incidence ◽  
Electron Channelling ◽  
Regular Arrangement ◽  
Backscattered Signals

In a crystalline solid the regular arrangement of the lattice structure influences the interaction of the incident beam with the specimen, leading to changes in both the transmitted and backscattered signals when the angle of incidence of the beam to the specimen is changed. For the simplest case the electron flux inside the specimen can be visualized as the sum of two, standing wave distributions of electrons (Fig. 1). Bloch wave 1 is concentrated mainly between the atom rows and so only interacts weakly with them. It is therefore transmitted well and backscattered weakly. Bloch wave 2 is concentrated on the line of atom centers and is therefore transmitted poorly and backscattered strongly. The ratio of the excitation of wave 1 to wave 2 varies with the angle between the incident beam and the crystal structure.

Organic thin film thickness-dependent photocurrents polarity in graphene heterojunction phototransistor

Carbon ◽  
2021 ◽  
Vol 178 ◽  
pp. 506-514
Author(s):  
Meiyu He ◽  
Jiayue Han ◽  
Xingwei Han ◽  
Jun Gou ◽  
Ming Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Organic Thin Film ◽  
Thin Film Thickness

scholarly journals Experimental Study on the Thickness-Dependent Hardness of SiO2 Thin Films Using Nanoindentation

Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 23
Author(s):  
Weiguang Zhang ◽  
Jijun Li ◽  
Yongming Xing ◽  
Xiaomeng Nie ◽  
Fengchao Lang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Grain Size ◽  
Integrated Circuits ◽  
Film Thickness ◽  
Depth Range ◽  
Micro Electro Mechanical Systems ◽  
Si Substrates ◽  
Sio2 Thin Film ◽  
Average Grain Size

SiO2 thin films are widely used in micro-electro-mechanical systems, integrated circuits and optical thin film devices. Tremendous efforts have been devoted to studying the preparation technology and optical properties of SiO2 thin films, but little attention has been paid to their mechanical properties. Herein, the surface morphology of the 500-nm-thick, 1000-nm-thick and 2000-nm-thick SiO2 thin films on the Si substrates was observed by atomic force microscopy. The hardnesses of the three SiO2 thin films with different thicknesses were investigated by nanoindentation technique, and the dependence of the hardness of the SiO2 thin film with its thickness was analyzed. The results showed that the average grain size of SiO2 thin film increased with increasing film thickness. For the three SiO2 thin films with different thicknesses, the same relative penetration depth range of ~0.4–0.5 existed, above which the intrinsic hardness without substrate influence can be determined. The average intrinsic hardness of the SiO2 thin film decreased with the increasing film thickness and average grain size, which showed the similar trend with the Hall-Petch type relationship.

scholarly journals Precise control of Jeff=12 magnetic properties in Sr2IrO4 epitaxial thin films by variation of strain and thin film thickness

2020 ◽  
Vol 102 (21) ◽  
Author(s):  
Stephan Geprägs ◽  
Björn Erik Skovdal ◽  
Monika Scheufele ◽  
Matthias Opel ◽  
Didier Wermeille ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Film Thickness ◽  
Epitaxial Thin Films ◽  
Thin Film Thickness ◽  
Precise Control

scholarly journals Optimization of Fiber Bragg Gratings Inscribed in Thin Films Deposited on D-Shaped Optical Fibers

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4056
Author(s):  
José Javier Imas ◽  
Carlos R. Zamarreño ◽  
Ignacio del Villar ◽  
Ignacio R. Matías
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Optical Fibers ◽  
Flat Surface ◽  
Sno2 Thin Film ◽  
Thin Film Thickness ◽  
A Value ◽  
Surrounding Refractive Index ◽  
Reflected Power ◽  
Fabrication Parameters

A fiber Bragg grating patterned on a SnO2 thin film deposited on the flat surface of a D-shaped polished optical fiber is studied in this work. The fabrication parameters of this structure were optimized to achieve a trade-off among reflected power, full width half maximum (FWHM), sensitivity to the surrounding refractive index (SRI), and figure of merit (FOM). In the first place, the influence of the thin film thickness, the cladding thickness between the core and the flat surface of the D-shaped fiber (neck), and the length of the D-shaped zone over the reflected power and the FWHM were assessed. Reflected peak powers in the range from −2 dB to −10 dB can be easily achieved with FWHM below 100 pm. In the second place, the sensitivity to the SRI, the FWHM, and the FOM were analyzed for variations of the SRI in the 1.33–1.4 range, the neck, and the thin-film thickness. The best sensitivities theoretically achieved for this device are next to 40 nm/RIU, while the best FOM has a value of 114 RIU−1.

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