This project seeks new knowledge and greater fundamental understanding of the optical and electronic properties of crystalline and amorphous states of Ge-Sb-Te materials, including characterizations of the bandgap, energy distribution of electronic band tail and defect states, and other properties. Structural investigations, including the use of fluctuation electron microscopy, aim for detailed nanostructural description of the different amorphous states (as-deposited, partially annealed, and melt- quenched), and their role in phase change kinetics. The project will also explore the nanometer-scale size limit (spatial resolution) of the phase change process with a goal of fabricating quantum devices. %%% The project addresses basic research issues in a topical area of materials science having high technological relevance. The research will contribute basic materials science knowledge at a fundamental level to new understanding and capabilities in electronics/photonics. The research is relevant to applications such as rewritable CD/DVD and the PRAM nonvolatile memory technologies. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. The program will support two graduate students and recruit one or two undergraduates per year to carry out portions of this work as their senior theses. This project will thus contribute to the education and training of B.S., M.S., and Ph.D. graduates. Qualified students will be identified through the SURGE (Support of Under-represented Groups in Engineering) and WISE (Women in Science and Engineering) programs which are in place at UIUC. Research results will be broadly disseminated by presentations at international conferences and by publication in scientific journals. ***
