This project seeks to further the development of a new class of optical materials by atomic-layer engineering and to understand the effects and mechanisms of incorporating atomic-layer doping of oxide materials that are transparent in the visible light. The research is designed to expand the space of opportunities in materials science by providing a new class of optical materials that are highly transparent in the visible light, have unusually strong dielectric responses and opaque in the infrared light, and are highly anisotropic in optical properties over a broad spectrum. The research project provides a comprehensive training to young researchers from material synthesis to analysis and applications, especially when the materials are new and "beyond" what can be found in nature. It fosters a stronger collaboration with leading research teams in France and Korea.
To accomplish the goal of atomic-layer engineering of the material structure and composition to acquire previously unavailable properties, transparent oxide superlattice structures are designed, synthesized by atomic layer deposition (ALD), and characterized. In superlattices of AlOx/ZnO, TiOx/ZnO, GaOx/ZnO, and InOx/ZnO, individual dopant atomic-layers are inserted into a host transparent oxide (e.g. ZnO), either periodically or with a variable spacing, resulting in an alternating stacking of 2D "doping-layer" and oxide "spacer-layer." The atomic-layer "doping" approach opens possibilities for achieving and controllably varying electro-optical properties that were previously unavailable, and for realizing anisotropic and hyperbolic dispersions by design. Extraordinary structural/electro-optical properties, such as high electron densities, high electron conductivities, high transparency in the visible, and strong plasmonic resonance in the infrared, are expected for these novel materials.
