Elucidation of the Chemistry of Film Formation

Local Structure and Inhomogeneity of Amorphous Thin Films

A distinct feature of the films prepared from our aqueous precursors is that they remain chemically reactive, exchanging water and ions with solutions and reacting internally as condensation occurs with loss of water. Chemical analysis on thin films has historically been difficult with perhaps the most informative results coming from surface analytical techniques extrapolated into the bulk of the film via sputter depth profiling experiments in spite of the artifacts this approach may create.  Understanding the mechanism of formation, diffusion processes, and overall structural evolution of these films will help improve the synthesis of thin films or even lead to the discovery of new materials.

PROJECT: Fundamental film chemistry of solution processed nanolaminates towards new materials and advanced applications. The goal of this project is to develop methods to probe the evolution of local and extended bonding in thin films and nanolaminates as a function of annealing and chemical treatments by incorporating the use of differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR), solid state nuclear magnetic resonance (NMR), pair distribution function analysis (PDF), high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), and a variety of X-ray diffraction (XRD) techniques.  Current emphasis is placed on understanding ion exchange in Hf systems and near-surface compositions across a range of solution-processed compositionally complex films.