Layered thin films

In multiple-layer thin films, it is possible that some of the elements may be present simultaneously in two or more layers. XRF analysis of this type of film can be complicated and cannot be made solely from their observed intensities. Additional information, such as the compositions or thickness of some of the layers is needed. The amount of addidonal non-XRF information required depends on the complexity of the film. For example, in the analysis of a FeMn/NiFe double-layer film, the additional information needed can be the composition or thickness of either the FeMn or NiFe layer. Using the composition or thickness of one of the film predetermined from a single-layer film deposited under identical condidons, XRF analysis of the FeMn/NiFe film was successfiil. ... 

In other cases, a thin-film process is used to form the layers. Thin-film processes used in the manufacture of IC s include ... 

Adsorbed layers, thin films of oxides, or other compounds present on the metal surface aggravate the pattern of deactivation of metastable atoms. The adsorption changes the surface energy structure. Besides, dense layers of adsorbate may hamper the approach of metastable atom sufficiently close to the metal to suppress thus the process of resonance ionization. An example can be work [130], in which a transition from a two- to one-electron mechanism during deactivation of He atoms is exemplified by the Co - Pd system (111). The experimental material on the interaction of metastable atoms with an adsorption-coated surface of... 

Membrane-like microstructures are generally several micrometers thick, while the lateral dimensions of the structures and the surrounding package are on the order of a few hundred micrometers. If the layered thin-film structure would be directly transferred to a 3-d geometry model, an enormous number of finite elements would be created, as the smallest structure size determines the mesh density. Averaging the structural information and properties over the different layers in the cross section of the membrane is a good method to avoid such problems. The membrane is, therefore, initially treated as a quasi-two-dimensional object. 

A second reason for the absence of a purple sheen could be damage to the ITO layer. Thin-film indium-tin oxide is stable in most basic solutions unless the pH is extremely high, but in aqueous acidic solutions the tin oxide will leach out to leave a porous honeycomb of indium oxide, which soon collapses and falls off the electrode. This dissolution process is termed etching. 

Wood KC, Boedicker IQ, Lynn DM et al (2005) Tunable drug release from hydrolytically degradable layer-by-layer thin films. Langmuir 21 1603-1609... 

Fig. 1.10. Calculated ratio of the charge in the first u total charge in the conducting channel as a function of gaTe voltage multiplied by insulator capacitance. The ratio is calculated for two-layer and ten-layer thin films.

Reports have shown that multi-layer thin films can be fabricated by an alternating deposition of two kinds of molecules with affinity to each other. This... 

Miyauchi, M., A.K. Nakajima, T. Watanabe and K. Hashimoto (2002). Photoinduced hydrophilic conversion of Ti02/W03 layered thin films. Chemistry of Materials, 14(11), 4714 1720. 

It is also possible to characterize accurately the composition of new thin fihn materials using RBS. RBS analysis of the Sri xCaxCu02 materials demonstrates that the single-phase infinite-layer thin films have the same average composition as the multiphase targets from which they were prepared by laser ablation. These compositional analysis results demonstrate that PLD can be used to prepare readily a specific stoichiometry material even when the target is not single phase. 

Physical deposition Recent disks with glass substrate do not have the Ni(P) underlayer [156]. Thus, the last electroless layer, Ni(P), is eliminated in some products. The underlayers considered currently have complex structures composed of up to three layers. Thin-film magnetic layers are complex and composed of three layers [157], Fig. 50. 

Guan, J. Lee, L.J. Hansford, D.J. Layered thin-film polymer microparticles fabricated by soft lithography. To be submitted to chemistry of marterials. 

Wood KC, Chuang HF, Batten RD, et al. Controlling interlayer diffusion to achieve sustained multiagent delivery from layer-by-layer thin films. Proc Natl Acad Sci U S A 2006 103 10207-10212. 

Simple SQUID devices in a few forms have already been demonstrated to operate in the liquid nitrogen temperature range. Koch et al. (48) successfully operated at 68 K a one-layer thin film dc SQUID with long, granular, weak-link bridges, while Iguchi et al. (49) and Zimmerman et al.(50) successfully operated rf- and dc-SQUIDs, respectively, based on bulk ceramic loops... 

When one views the membrane as a multi-layer thin film device, he begins to understand how the interphases control its electrophysical properties and the reaction rates across its junctions (18) (29). 

Fig. 1-16. Two-layer thin-film model of the air-sea interface, adapted from Liss and Slater (1974). The concentrations at the interface, cgl (gas-phase) and cu (liquid-phase), are related by Henry s law. Material transport across the interface occurs by molecular diffusion within the film layers.

Any ionic polymer with a flexible structure can be used to construct layer-by-layer thin films. Common polyanions are poly(sodium acrylate) and proteins at pH higher than their isoelectric points. Common polycations are protonated polyamines and poly(quaternary ammonium ions) such as poly(4-vinylpyridine hydrochloride) and poly(diallyldimethylammonium chloride). 

The obtained neutron reflectivity profiles from d-PS/h-PS/d-PS three-layered thin films at several temperatures are shown in Fig. 28 and the reflectivity profiles were analyzed with the formula derived by Parratt [66]. The solid lines in Fig. 28... 

Fig. 29 Temperature dependence of the total film thickness and thickness of first, second and third layers for a three-layered thin film. The arrows indicate the evaluated T ...

Zaytsev et al. (1975) have studied the evolution by annealing in air up to 1670 K of two-layer and three-layer thin films of CrY and CrYCr produced by... 

Semiconductor materials are used to manufacture discrete devices and integrated circuits for the electronics industry. Integrated circuits and discrete devices are made of metal-semiconductor, semicondutor-semiconductor, and metal-insulator-semiconductor junctions and layered thin film structures. In general, the electrical properties of a device (IC or discrete) are determined by one or more junctions. The electrical properties of the junction are dependent on the microchemistry at and near the interface. Consequently, it is very important for the device designer/physicist to understand the electronic properties which occur both at semiconductor surfaces and at semiconductor interfaces. The study of the electronic properties of semiconductor surfaces has been accomplished by either cleaving a solid sample in ultrahigh vacuum or... 

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