The objective of the proposed research is to develop epitaxial buffer layers grown by chemical vapor deposition (CVD) that will provide both a diffusion/reaction barrier and a transition in crystal structure and lattice parameter between a low loss single crystal substrate and an epitaxial, single crystal high temperature superconducting film. Phase I will establish proof of concept via homoepitaxy. For example magnesium oxide films will be grown on sing crystal magnesium oxide substrates and lanthanum aluminum oxide films will be grown on single lanthanum aluminum oxide substrates. The films will be evaluated for crystal quality, surface smoothness and uniformity, and process conditions will be adjusted to optimize film properties. In Phase II the process will be extended to heteroepitaxy, with the goal of providing epitaxial buffer layers for superconducting films on substrates such as single crystal aluminum oxide (sapphire) that are high desirable for microwave applications.
