Thin film/bulk comparison

Thin Film / Bulk Comparison. In all surface fnction studies we observe the position of the glass-transition temperature lowered somewhat compared to bulk dynamic mechanical measurements. This type of thin polymer film behavior is not surprising since thin films are known to vary considerably from bulk polymer (17). This is a result of chain confirmation differences (8), confinement effects (18), as well... 

Up to this point this text has focused primarily on materials themselves and not how to produce them. A major aspect of materials science is the control of the kinetic and thermodynamic conditions under which materials are produced to yield specific properties. This chapter and the ones that follow describe some of the ways semiconductor electronic materials are created as thin films. For comparison, the most popular method of production of bulk materials was covered in Chapter 4. Bulk wafers are useful as substrates but are impractical for many applications, especially where alloys are needed. In current technology, thin films constitute most of the active and passive layers that are used in electronic devices. 

The mechanical properties of the polymers were tested in bulk as well to correlate with the single chain nanomechanical studies. Polymer samples were cast into thin films and subjected to stress-strain analysis. Figure 10.4 shows the comparison of... 

Comparison of the magnetoelastic data for magnetostrictive bulk and thin-film materials... 

The condition in Equation 3 is a potential source of error for thin-film analyses in mineralogy because the abundance of low-Z elements (e.g. F, O, N, H) is usually calculated from stoichiometry or inferred from bulk elemental analyses. However, comparisons within a suite of minerals will remain internally consistent, provided assumptions about low-Z elements are appropriately included in data reduction. 

Fig. 9. Phase diagram ofthe thin film with surface parameters p O.2, g=-0.5 plotted in the plane of variables % 1, for polymers of chain length N=100 and for three choices of film thicknesses D=20 (diamonds), D=60 (crosses) and D=100 (squares). Broken curve shows the bulk phase diagram of the underlying Flory-Huggins model for comparison. Remember that lengths are measured in units of the size b of an effective monomer. From Flebbe et al. [58]...

Figure 3 shows a typical VIS emission CL spectrum from a ZnO microcrystal. An electron microscopy image of the crystal is given in the inset. In comparison to the broad and unstructured VIS emission of thin films or bulk material, VIS emission of the microcrystal is accompanied by a series of comparatively sharp peaks. 

Comparison of the properties of CSD thin films to the analogous bulk material properties has also received great attention because of the need for high dielectric constant materials for DRAM applications.Basceri et ai 134,135 jj yg thoroughly considered the differences between film and bulk properties from a fundamental perspective and have been able to interpret these differences in terms of stresses present in the films, compositional differences, and the impact of these characteristics on the phenomenological behavior of the material as predicted from a Landau-Ginzburg-Devonshire approach. All observed differences between film and bulk properties were explainable using this approach. 

In comparison to bulk WO3, thin films always exhibit a high amount of micro-structural disorder. This can be fiirther influenced by the preparation mode. 

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