MSE Fall Seminar Series: James Im, Columbia University

Description

"Discontinuous Phase Transitions in Condensed Systems; some insights gleaned from

studying laser annealing of Si films for AMOLED displays"

James Im, Columbia University

Melting of elemental solids can be identified and appreciated as a particularly simple example of discontinuous phase transitions involving condensed phases. Motivated, on the one hand, by the need to improve the microstructural quality of laser-crystallized columnar-grained polycrystalline Si films for manufacturing advanced AMOLED displays, as well as an opportunity, on the other hand, to investigate the fundamental details associated with phase transformations transpiring in condensed systems, we are in the process of conceptually, experimentally, and theoretically examining (particularly the initial phase of) melting and solidification in thin films with various simple polycrystalline microstructures. Preliminary results from our work, which includes an interface-curvature analysis of the system undergoing melt initiation and propagation, indicate that there are a number of overlooked or unrecognized transformation-affecting details and phenomena.  We will discuss in this talk how, in fact, many of the findings are relevant and useful for understanding discontinuous phase transitions, in general, and can be particularly so for small, confined, and embedded systems that are increasingly being utilized in modern technologies.