Technical Description: This computational and experimental research project aims to answer several fundamental questions in the Au-catalyzed vapor-liquid-solid growth of Ge and Si nanowires. In particular, what mechanisms control kinking of nanowires and how does metastable hexagonal-close packed Au form when growth terminates? A three-dimensional continuum phase field model connects atomistic simulations and experimental observations, which use both ex-situ and in-situ characterization methods, and a rapid thermal chemical vapor deposition system. The project also investigates methods of controlling growth to avoid defects and to facilitate synthesis of abrupt doped junctions and axial Si-Ge heterostructures.
Non-technical Description: This project has a broader impact on a wide range of materials research problems in which a close connection between atomistic modeling and experiments is desirable. Results of this project provide lecture materials on atomistic simulations, thermodynamics and kinetic processes in materials synthesis. The project engages undergraduates through summer research. The science education outreach activity introduces San Jose-area high-school students to crystal growth concepts through interactive Android Apps based on a two-dimensional phase field model.
