Glassy materials such as sulfides, selenides and tellurides (i.e. chalcogenides) of Ge, As, Sb and P have found wide-ranging applications in the areas of photonics, telecommunication, memory storage, alternative energy resources and environmental remote sensing. The atomic structures of these materials are typically characterized by a network of covalently bonded atoms and structure-property relationships in these network chalcogenide glasses have been studied in detail. The physical and chemical characteristics of these networks can be substantially modified upon incorporation of elements such as Ba and Ga. Little, if any, is known about the unique properties of these new materials - they could result in transformative and wide-ranging technological applications. This research project brings together investigators with complementary expertise and common interests from UC Davis and Corning Incorporated (the world's foremost innovator and commercial developer of cutting-edge glass technology) to investigate the fundamental structure-property relationships in these novel chalcogenide materials. This project will finally enable the formulation of predictive models necessary for the optimization of these materials towards improved functionalities for potential commercialization. Students in this research project are learning to investigate problems in the realm of "basic science" that underlies industrial applications. The project is preparing students with powerful experimental skills and research experience in both academic and industrial settings that will open many opportunities for their careers. This project coordinates with the underrepresented minority-serving and other outreach programs at UC Davis to attract and recruit underrepresented graduate students and to increase the awareness of students in the science and technology of glassy materials.
TECHNICAL DETAILS: This project entails studying the structure-property relationships and developing an atomic scale understanding of the structural mechanisms of transport and relaxation near the glass transition in novel modified and compensated network ternary and quaternary chalcogenide bulk glasses, fibers and supercooled liquids in the Ba-Ga-Ge-Se system. Accomplishing this goal involves application of a powerful combination of state-of-the-art techniques of physical property measurement and structural and dynamical characterization including nuclear magnetic resonance (NMR), Raman, optical absorption and fluorescence spectroscopy, high-energy X-ray diffraction and reverse Monte Carlo simulation. The results are being combined to develop predictive models, linking the atomic structure and dynamics with macroscopic physical properties that are crucial for compositional optimization of these materials for a wide range of technological applications. One example is exploring potential applications in photonics where these materials serve as efficient rare earth hosts with low phonon energy and high quantum efficiency. The interdisciplinary nature of this project impacts materials science and engineering, solid-state chemistry and physics and incorporates significant training of graduate students in state-of-the-art spectroscopic, diffraction and simulation techniques. The equipment and expertise at UC Davis, Corning Inc., National High Magnetic Field laboratory and Argonne National Laboratory provide students with a variety of modern research tools and a supportive structure for learning to use them. It continues to foster our longstanding collaborations with scientists in industry, academia and national laboratories and enriches the graduate education and training experience through numerous scientific dialogue and interactions between the collaborating scientists and participating students.
FUNDING: This National Science Foundation project is co-funded by the Engineering Directorate and the Mathematical and Physical Sciences Directorate.