Spacer layer

LB Films of Long-Chain Fatty Acids. LB films of saturated long-chain fatty acids have been studied since the inception of the LB technique. The most stable films of long-chain fatty acids are formed by cadmium arachidate deposited from a buffered CdCl2 subphase. These films, considered to be standards, have been widely used as spacer layers (23) and for examining new analytical techniques. Whereas the chains are tilted - 25° from the surface normal in the arachidic acid, CH2(CH2) gCOOH, films (24), it is nearly perpendicular to the surface in the cadmium arachidate films (25). 

Fuji Peel-Apart Film FP-100. In 1984 Fuji introduced FP-lOO, a peel-apart instant color film rated at ISO 100. The FP-lOO system uses a dye-release process similar to that used in the Fuji integral films. Figure 16b is a schematic cross section of FP-100, and Figure 11b (on the colored plate) is a micrograph of the unprocessed film in cross section. The negative stmcture includes a spacer layer between the red-sensitive layer and the cyan dye-releaser layer that it controls, similar to that shown in the FI-800 stmcture, but there are no spacers between the other emulsions and corresponding dye-releaser layers. 

This method was developed by Johnston et al. in 1991 and well described in Ref. [10], according to which the method is introduced as follows. The principle of optical interference is shown schematically in Fig. 1. A coating of transparent solid, typically silica, of known thickness, is deposited on top of the semi-reflecting layer. This solid thus permanently augments the thickness of any oil film present and is known as a "spacer layer. The destructive interference now obeys the equation ... 

The two limitations of optical interferometry, the one-quarter wavelength of light limit and the low resolution, have been addressed by using a combination of a fixedthickness spacer layer and spectral analysis of the reflected beam. The first of these overcomes the minimum film thickness that can normally be measured and the second addresses the limited resolution of conventional chromatic interferometry. 

The disk was coated with a 20 nm sputtered chromium semi-reflecting layer, a silica spacer layer was sputtered on top of the chromium. This spacer layer varied in thickness in the radial direction, but was approximately constant circumferentially round the disk [10]. 

Fig. 4 —Measured film thickness—thick spacer layer [10],...

When using the thin silica spacer layer, however, it was found that the results from the above-mentioned methods did not agree with the direct measurements from the Taly-surf profilemeter, as shown in Fig. 4(a). This was tentatively ascribed to the effect of penetration of the reflecting beam into the substrate. With a very thin silica layer, the depth of penetration and thus the phase change would depend upon the thickness of the silica spacer layer and also upon that of any oil film present. 

Spherical rollers were machined from AISI 52100 steel, hardened to a Rockwell hardness of Rc 60 and manually polished with diamond paste to RMS surface roughness of 5 nm. Two glass disks with a different thickness of the silica spacer layer are used. For thin film colorimetric interferometry, a spacer layer about 190 nm thick is employed whereas FECO interferometry requires a thicker spacer layer, approximately 500 nm. In both cases, the layer was deposited by the reactive electron beam evaporation process and it covers the entire underside of the glass disk with the exception of a narrow radial strip. The refractive index of the spacer layer was determined by reflection spectroscopy and its value for a wavelength of 550 nm is 1.47. 

Lubricating Films Using Wedged Spacer Layer Optical Interferometry, Proceedings, 14th Leeds-Lyon Symposium on Tribology, Interface Dynamics, Leeds, 1988, pp. 275-279. 

Figure 3 is a schematic representation of a typical CO electrode. A KCI/HCOJ containing electrolyte solution is trapped within a nylon mesh spacer layer whose pH is monitored by a contacting conventional glass pH electrode. A CO permeable membrane isolates the electrolyte layer from the analyte phase. Currently available... 

Schueppel R, Timmreck R, Allinger N, Mueller T, Fumo M, Uhrich C, Leo K, Riede M (2010) Controlled current matching in small molecule organic tandem solar cells using doped spacer layers. J Appl Phys 107 6... 

Balzer E, Bammel K, Rubahn HG (1993) Laser investigation Na atoms deposited via inert spacer layers close metal surfaces. J Chem Phys 98 7625-7635... 

Figure 14 Schematic diagram of simplified one-dimensional band structure for an nHg (top) and Kr (bottom) spacer layer film. (From Ref 232.)...

Figure 8.21 Diagram of a multilayer Langmuir-Bloggett film. F, metal or glass support LI, layer of chromophoric molecules M S, spacer layer L2, layer of quencher molecules...

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