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The use of DC arc optical emission spectroscopy (OES) for quantitative analysis of thin films deposited on graphite electrodes was investigated as a process control tool. Three binary systems were evaluated: nickel-chromium, phosphorous-silicon, and silicon-aluminum. Sampling by direct deposition onto graphite electrodes placed in the deposition chamber with product runs proved to be a rapid, representative, and non-disruptive technique. Standard electrodes were prepared for each system either by evaporation of solutions of known concentration onto the tips of electrodes or by weighing out powdered standards of the appropriate concentrations. Standard curves were then prepared by burning multiple sets of standard electrodes in a DC arc of 15 amperes and obtaining intensity rations of selected analytical line pairs. Comparison of the OES technique with atomic absorption, electron microprobe, or gravimetric analysis of samples from the same deposition showed absolute agreement to within ±3% for the nickel-chromium system, ±0.3% for the phosphorous-silicon system, and ±0.2% for the silicon-aluminum system. Maximum relative percent error for the techniques were 5%, 10%, and 12.5% respectively.

<p>Nanocomposite thin films are materials that have the potential to improve and tune many properties for various applications in electronics, sensors, memory storage, and optics. Materials properties are a consequence of their structure, so being able to manipulate the nanostructure of nanocomposite thin films is important for modifying them for device purposes. One structure that has gained a lot of attention is vertically aligned nanocomposites (VANs) due to the increased vertical coupling between two or more phases of materials and the unique nanostructures achievable through controlling deposition factors. </p> <p>VAN thin film growth involves many factors: diffusion, substrate surface conditions, source material composition, and deposition temperature and rate. The two main approaches to thin film fabrication are bottom-up and top-down. Bottom-up growth focuses on the self-assembly of the nanostructure. This work focuses on the self-assembly of VAN thin film materials through controlling the thermodynamic and kinetic factors involved in thin film growth. The main factors being considered in this work are substrate manipulation, oxygen gas flow during deposition, deposition rate, and composition. The effectiveness of each of these methods is evaluated in comparison to each other and their growth of VAN thin film materials along with the future work needed to refine each nanostructure manipulation method. </p>

Polymer applications have become more demanding as industry continuously turns to more microscopic parts. Due to the interactions of the polymer chains with the supporting surface and the air interface, the thinner films required for such applications have distinctly different properties than those of the well-defined bulk systems. The goal of the current research is to elucidate the behavior of ultrathin films. Two separate studies were performed on thin films supported on silicon wafer substrates: the first focuses on the viscoelastic cooperativity of thin films, and the second concentrates on the morphological behavior of polymer brush films. For the first study, polymethyl methacrylate films were spin coated onto silicon wafers, and the film thickness was determined using ellipsometry. A series of thin films were examined using techniques such as dielectric analysis and thermal mechanical analysis. The theory of cooperativity, which explains polymeric behavior using the intermolecular and intramolecular forces among polymer chains, was employed to understand the behavior of these thin films. Another type of thin film, a polymer brush, was investigated in the second study. Polymer brushes are formed by chemically bonding one end of many polymer chains to a substrate. The other ends of the chains can interact with the surrounding environment creating a brush-like structure. Constraining one end of a polymer chain alters the behavior of such a thin film. Polymer brushes of the di-block copolymer poly(t-butyl methacrylate) and polystyrene were produced on silicon wafers using spin coating techniques. The effects of both grafting density and solvent washes were analyzed using contact angle analysis and atomic force microscopy. In addition, hydrolysis was successfully performed on existing polymer brush samples to produce polymer brushes of the di-block copolymer polymethyl acrylic acid and polystyrene. / Master of Science

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