Michael J. Aziz
Gene and Tracy Sykes Professor of Materials and Energy Technologies
Harvard School of Engineering and Applied Sciences
How often has a scientist or engineer said, "If I could only make this particular material or combine these materials into a certain structure, I bet it would have these wonderful properties that could be used to make this cool device"?
Fig. 1. Paradigm of connections in materials science and engineering.
Our generation is the first in human history to enjoy more than accidental success in this regard, but in general it's a very difficult task that is in many cases still characterized by much empirical laboratory trial-and-error. Examples of such goals in the Aziz group's research include the search for:
• Ways to manipulate the optical activity of silicon for computer telecommunications and enhanced solar cell capabilities;
• A way to use focused ion beams to precisely shape a microscopic optical element out of material with just the right optical absorption properties to enable the imaging of planets orbiting distant stars;
• A way of using ion and photon beams to laterally pattern compound semiconductor band structure through controlling alloy composition, permitting the fabrication of novel optoelectronic devices.
• A way to turn silicon into a ferromagnetic semiconductor, permitting the storage and manipulation of information using carrier spin instead of charge for spintronics.
• A way to efficiently split salt water into acid and base for capture and storage of excess atmospheric greenhouse gases;
• A way to efficiently store electrical energy in reversible fuel cells based on one-electron transfer reactions for load leveling on the electrical grid;
• A way to use ion beams to take the smallest electronic devices that can be readily fabricated by standard methods, and "shrink wrap" them down to molecular dimensions
Many of the modern synthesis and processing techniques employed in these efforts take advantage of processes that occur far from thermodynamic equilibrium to force atoms into positions that are not naturally favored and to prevent them from relaxing to their most favored positions. Professor Aziz studies the mechanisms and rates of atomic rearrangements that underlie modern processing techniques in semiconductors, metals, and insulators. Are there limits to what can be formed by highly nonequilibrium processes? Are there laws of Nature dictating what actually will be formed in a particular process? How do these laws scale as you try to make and stabilize smaller and smaller nanostructures? Can we understand and, better yet, predict structural evolution of materials, and develop a scientific basis to permit the Materials Engineer to fabricate the structure of his/her dreams?
His research group is currently engaged in studies of nonequilibrium materials synthesis and processing methods, and in utilizing the knowledge gained from these studies to develop materials and structures with combinations of properties desirable for several important applications.
©2007 Materials Science Group