Evaporated intermediate layers

The separating layer optical thicknesses were fixed (Fig. 3) about or AqU, where corresponds to the plasmon absorption maximum of a metallic nanoparticle monolayer in the KCl environment. These multilayer structures were fabricated by the thermal evaporation technique followed by deposition of metal and dielectric materials without breaking the vacuum between the evaporation steps. The structures grown by this technique are realized as a sequence of Ag island films separated by KCl intermediate layers of a subwavelength thickness. These data... 

Figure 18.15 shows the schematic of the fabrication process. After oxidation of the double-side polished silicon substrate wafer, a first lower poly-Si layer with a thickness of 45 pm is deposited by means of an epi-poly process. In order to remove spikes and obtain a smooth surface, 5 pm of poly-Si has to be removed by poly-Si CMP. This polishing is a two-step process, consisting of a 5 pm bulk removal by means of a fiimed-silica slurry and a subsequent final polish of several 10 nm with a haze-firee slurry. After deposition and stmcturing of some intermediate layers, a second upper poly-Si layer, again with a thickness of 45 pm, is deposited and subsequendy polished with the same two-step poly-Si CMP process. As this will be the surface of the evaporated silver mirror, a smooth as well as flat surface has to be achieved. After a backside silicon etch and the removal of the sacrificial layer, the scanning mirror device is released, see Figure 18.16(a) and (b). 

Very similar results were obtained in diffusion bilayer solar cells using pyridyl-substituted pyrrolidinofullerenes (PyFs) as electron acceptor components in combination with ZnPc. To fabricate such cells, a concentrated PyF solution was spin coated on top of the evaporated ZnPc layer. Investigation of the obtained bicomponent systems showed that ZnPc becomes partially dissolved under the fabrication conditions. This results in the formation of a diffusion bilayer architecture with the intermediate layer composed of coordination complexes PyF- -ZnPc arranged in between the layers of pristine PyF and ZnPc materials (Figure 41a). Molecular structure of similar coordination complexes of PyFs was proven by X-ray single crystal diffraction. On the contrary, the reference material PCBM does not dissolve phthalocyanine underlayer and does not form any coordination complexes with ZnPc. Therefore, solution deposition of PCBM on the top of ZnPc gives a truly bilayer device. 

GREEN Have you tried evaporated silver contacts in order to determine in conjunction with your other work, the influence of contact pressure, contact contamination Ce.g. an intermediate layer of oxide), contact crystallography on the polarization data for silver deposition at the Ag/RbAg4l5 interface ... 

In the heat-treatment process, three distinct layers develop after there is water loss of approximately 12 percent through evaporation.The top layer consists of reusable oil, amounting to approximately 24 percent of the original scum volume the middle layer, containing approximately 16 percent of the scum, is called the rag layer and consists of flocculated particulate matter the bottom layer contains approximately 48 percent of the total scum and appears as relatively clear water. This bottom water layer is returned to the spent-coolant holding tanks for retreatment, and the rag, or intermediate, layer is combined with the swarf-ing dust and other heavy soUds for removal by haulage. 

A solution of 2-aminobenzophenone (98 g, 0.50 mol) and methyl 2-(methyl-thio)propanoate (74 g, 0,50 mol) in CH Clj (21) was cooled to —70 C and 95% 7-butyl hypochlorite (56 g, 0.5 mol) was added dropwise at such a rate that the temperature did not rise above — 65 C. One hour after the addition was complete, EtjN was added and the mixture was allowed to come to room temperature. The solution w as mixed with 3 N HCl (800 ml) and stirred for 1 h. The organic layer was separated, dried (Na2S04 ) and filtered. The solution was evaporated in vacuo and the residue triturated with ether. Filtration gave the 3-(methylthio)oxindole intermediate (92 g) in 62% yield. 

Ethyl 4,5-Dlbenzamldopent-4-enoate (2) Ethyl 3-lmidazol-4(5)-ylpropanoale 1 (9.2 g, 54 mmol) In ElOAc (140 mL) was treated with benzoyl chloride (15 7 g, 112 mmol) In ElOAc (40 mL) and 1M NaHCOa (380 mL) added simultaneously In 1 h under Ice-cooling. The reaction mixture was stirred for 1 h, then a further portion of benzoyl chloride (IS 7 g, 112 mmol) in ElOAc) and iM NaHCOa (280 mL) was added m the same manner, followed by an additional portion o( 1M NaHCOa (200 mL) The reaction mixture was stirred for 24 h, then the organic layer was separated, concentrated, and the residue dissolved in THF (300 mL) The THF solution was stirred with 10% NaHCOa (600 mL) for 24 h to decompose any N-lormyl intermediate and to remove benzoic acxl Extraction with EtOAc, drying (Na2S04), solvent evaporation and recrystallization of the residue from EtOAc hexane afforded 16 24 g of 2 (84%), mp 128-129°C... 

Figure 13.30. Molecular distillation and related kinds of equipment, (a) Principle of the operation of the falling film still (Chemical Engineers Handbook, McGraw-Hill, New York, 1973). (b) Thin-layer evaporator with rigid wiper blades (Luwa Co., Switzerland), (c) The Liprotherm rotating thin film evaporator, for performance intermediate to those of film evaporators and molecular stills (Sibtec Co., Stockholm), (d) Centrifugal molecular still [Hickman, Ind. Eng. Chem. 39, 686 (1947)].

In many cases, particularly with evaporation and sputtering methods, adhesion of the deposited film to the substrate may be inherently poor. It is extremely desirable in such cases to deposit a thin layer of an intermediate material that has better adhesion to the substrate. Examples of appropriate adhesion layers are discussed after presentation of evaporation and sputtering techniques. 

B. (E)-7,11-Dimethyl-6,10-dodecadien-2-yn-1-ol. To the suspension containing the acetylide intermediate 2, as prepared in part A, is added 14 g (460 mmol) of paraformaldehyde (Note 12) in portions (Note 13) over 10 min (Note 14). After stirrinj the mixture for 24 hr, the resulting suspension is poured into 450 mL of ice-cold watei (Note 15), the aqueous layer is saturated with sodium chloride, and the product is extracted with four 100-mL portions of ether. The combined organic extracts are dried over magnesium sulfate, the drying agent is removed by filtration, and the solvent is removed at room temperature on a rotary evaporator. The residue is distilled through a short-path distillation apparatus to provide a forerun of 2-butyn-1 -ol (bp 42-46°C, 6 mm), followed by 10.5 g (68% yield) of (E)-7,11 -dimethyl-6,10-dodecadien-2-yn-1-ol as a colorless liquid, bp 120-124°C (0.5 mm) (Note 16). 

The processes of infiltration and evaporation of ground water depend strongly on the vertical profile of the soil layer. The following soil layers can be selected saturated and unsaturated. The saturated layer usually covers depths >lm. The upper unsaturated layer includes soil moisture around plants roots, the intermediate level, and the level of capillary water. Water motion through these layers can be described by the Darcy (1856) law, and the gravitation term KZ(P) in Equation (4.31) can be calculated by the equation ... 

A solution of 2.0 g of t-butyl alanine (S-form) and 3.78 g of ethyl 2-bromo-4-phenylbutanoate in 25 ml of dimethylformamide was treated with 1.8 ml of triethylamine and the solution was heated at 70°C for 18 h. The solvent was removed at reduced pressure and the residue was mixed with water and extracted with ethyl ether. The organic layer was washed with water and dried over magnesium sulfate. Concentration of the solvent at reduced pressure gave the oily t-butyl ester of the intermediate which was found to be sufficiently pure by gas liquid chromatography for further use. A solution of 143.7 g of this t-butyl ester in 630 ml of trifluoroacetic acid was stirred at room temperature for one hour. The solvent was removed at reduced pressure and the residue was dissolved in ethyl ether and again evaporated. This operation was repeated. Then the ether solution was treated dropwise with a solution of hydrogen chloride gas in ethyl ether until precipitation ceased. The solid, collected by filtration, was a mixture of diastereoisomers, melting point 153°-165°C. 

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