Substrates surface density

Fig. 11. Displacement of Ca + ions bound to the HPA film by Na+ ions, r = ratio Ca ions/monomers. CNa+ = concentration of Na ions in the substrate. Surface density of COOH groups = 1.85 x lO groups cm-2. ccacia = 2 x lO- M pH = 7.5 (O) pH = 6 (+).

Concurrent bombardment during film growth affects film properties such as the film—substrate adhesion, density, surface area, porosity, surface coverage, residual film stress, index of refraction, and electrical resistivity. In reactive ion plating, the use of concurrent bombardment allows the deposition of stoichiometric, high density films of compounds such as TiN, ZrN, and Zr02 at low substrate temperatures. 

TABLE 6 Surface Density and Area per Molecule of Cytochrome P450scc wild type and Recombinant in LB Film Deposited onto Solid Substrate... 

Fig. 11 The number density of chain atoms vs. distance z from the substrate surface, at the early stage of 12.8 ps (dash), and at the late stage of 1280 ps (solid). The data were obtained at a 50 K, b 100 K, and c 250 K. The layer s true lures are readily noticed at the late stage irrespective of temperature...

Lithography With the STM Nonelectrochemical Methods. The prospect of atomic density information storage has spurred applications of the STM as a surface modification tool. In this application, the anisotropic current density distribution generated by an STM tip is exploited to "write" on a substrate surface. Features with critical dimensions < 5 nm have been written in UHV, in air, and under liquids. 

Lithography With the STM Electrochemical Techniques. The nonuniform current density distribution generated by an STM tip has also been exploited for electrochemical surface modification schemes. These applications are treated in this paper as distinct from true in situ STM imaging because the electrochemical modification of a substrate does not a priori necessitate subsequent imaging with the STM. To date, all electrochemical modification experiments in which the tip has served as the counter electrode, the STM has been operated in a two-electrode mode, with the substrate surface acting as the working electrode. The tip-sample bias is typically adjusted to drive electrochemical reactions at both the sample surface and the STM tip. Because it has as yet been impossible to maintain feedback control of the z-piezo (tip-substrate distance) in the presence of significant faradaic current (vide infra), all electrochemical STM modification experiments to date have been performed in the absence of such feedback control. 

The morphology of alkaline-etched (100) and (110) silicon surfaces varies from rough surfaces that exhibit micron-sized pyramids or ridges [Sc5] to smooth orange peel-like surfaces, depending on the etchant composition and substrate doping density. Mirror-like surfaces can be obtained on (111) crystal planes. 

Bonding density (or surface coverage) for a stationary-phase is calculated from the percent carbon loading, substrate surface area, and estimated relative molecular... 

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