Imaging Surface preparation

Figure 5. Sorbic acid molecules on HOPG as reported by Smith et. al. (10). This surface was prepared by spin-coating a dilute sorbic acid-benzene solution onto a freshly cleaved HOPG substrate. Images of the surface were obtained in liquid helium. The elongated structure shown was representative of those present on surfaces prepared with this procedure.

Fig. 20.1. MAC Mode AFM three-dimensional images in air of (A) clean HOPG electrode (B) thin-film dsDNA-biosensor surface, prepared onto HOPG by 3 min free adsorption from 60 pg/mL dsDNA in pH 4.5 0.1 M acetate buffer (C) multi-layer film dsDNA biosensor, prepared onto HOPG by evaporation of three consecutive drops each containing 5pL of 50 pg/mL dsDNA in pH 4.5 0.1 M acetate buffer (D) thick-film dsDNA biosensor, prepared onto HOPG by evaporation from 37.5mg/mL dsDNA in pH 4.5 0.1M acetate buffer. With permission from Refs. [28,29].

Fig. 7 Atomic force microscopy image illustrating defect structures in wrinkled surfaces prepared by plasma treatment of stretched PDMS and subsequent relaxation...

Generally any deviation from a perfect surface is considered a defect and can originate from several sources, those that occur naturally on the clean surface or from contaminants. It is useful to understand the most common types of defect on the surface in order to interpret STM images of deposited adsorbates. It is also important to minimize these surface defects, especially from the perspective of nanoscale device construction on Si [17,18] where defects could alter device performance. A surface, prepared using standard annealing techniques in UHV, will typically contain a defect density of a few percent. 

In the case of a photoresist, the ultimate definable feature size together with the ability of the material to withstand either chemical etchants or plasma environments determines the domain of utility. The feature size is in turn determined by the wavelength required for exposure, the sensitivity and contrast of the resist, and the dimensional stability of the material during exposure, development, and subsequent processing. Adhesion of the resist to the substrate is critical both for patterning and use, and adhesion can be affected by surface preparations, and by residual stresses developed during deposition and cure. While photo-imagable polyimides have been introduced, their principal intended application is as a component of the finished part, either as passivant or interlevel dielectric (see below). 

None of the smooth surfaces prepared by the depositing of plasma polymer on the smooth surface of Silastic tubing showed detectable thrombus formation by gamma camera imaging. Therefore, they were evaluated by measurement of relative rates of platelet consumption. Table 35.7 shows the results obtained using the plasma polymers described previously [5]. 

Fig. 13. (a) An atomically resolved STM image (150 A x 150 A) of a surface prepared as in Fig. lie. Small (1x1) terminated islands and patches of connected pseudohexagonal rosettes are seen, (b) Atomic model (top and side view) for the oxygen-induced structure observed in (a). A bulk-terminated (1x1) island is shown on the right side and the unit cell is indicated. Small white balls are Ti atoms. Shadowed large balls represent oxygen atoms darker shading indicates higher z-positions. The rectangle indicates the unit cell of the (1x1) structure. The network patch ( R ) on the left side consists of an incomplete Ti02(l 10)(lxl) layer and contains only atoms at bulk position. The strands probably have a structure similar to the added Ti203 model in Fig. 1 Ic. From ref. [102].

Figure 24. Electron micrograph showing the relatively featureless surface and the fractured interior of a water-in-oil emulsion. This image was prepared with a metal-coated frozen sample, a modification of direct observation in which the sample is coated sufficiently to prevent sample charging but not enough to produce a replica. This technique still requires an electron microscope with...

Figure 2.10 In situ STM images of mixed gramicidine/DMPC film (a) pureAu(lll) electrode surface (b) DMPC monolayer on the surface (prepared differently from the layer shown in Figure 2.9) (c) mixed gramicidine/DMPC monolayer. The dark cavities are gramicidine molecules embedded...

FIGURE 6.12 SEM image of the imprints of anodic films of Al surface prepared in oxalic acid baths. (From Patermarakis et al., 2007. J. Solid State Electrochem. 11, 1191-1204, with permission.)... 

Various approaches have been used to estimate the effect of the wafer downforce on the asperities,123 including the use of elastic force response and volumetric displacement. Whereas the use of SEMs and other high-mag-nification metrology tools to image surface contours is a big step in understanding what the initial surface characteristics are, one must be prepared... 

Figure 13.5.1 Scanning tunneling microscope image of a 23 A X 23 A region of an Au (111) surface prepared by evaporation of Au on a mica substrate. [Reprinted with permission from Y.-T. Kim, R. L. McCarley, and A. J. Bard, J. Phys. Chem., 96, 7416 (1992). Copyright 1992, American Chemical Society.]...

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