September 10, 1999

"Small is Beautiful, but Nano is Even Better" aka
"Electron Microscopy of Nanostructured Materials"
Vinayak P. Dravid
Associate Professor, Department of Materials Science & Engineering
Director Electron Probe Instrumentation Center (EPIC)
Northwestern University, Evanston, IL

As modern devices continue to shrink in size, there are urgent needs for techniques and to visualize, analyze and manipulate materials at submicron length scales. Motivation for this is two-fold: a need to look at microstructures with submicron length scale resolution and the emergence of new phenomena and behavior as the materials approach nanometer scale dimensions. This presentation will cover various types of nanostructures (point, line and planar) and the role of electron microscopy in improving the understanding of their order, character and behavior. Examples will range from nanocrystals, nanotubes, thin films to multilayers.

Bio Sketch

Vinayak P. Dravid received his undergraduate B.Tech degree in Metallurgical Engineering from the Indian Institute of Technology (IIT), Bombay - India in 1984, and his Ph.D. in Materials Science & Engineering in the fall of 1990 from Lehigh University. He then gathered his courage to venture into an academic career the same year with the Department of Materials Science & Engineering at Northwestern University. He is now an associate professor and directs the electron probe instrumentation center (EPIC).

Professor Dravid's research and teaching interests revolve around nanoscale phenomena in solids - specifically interfacial phenomena in ceramics and nanostructured materials, and the prudent use of emerging as well as conventional electron microscopy techniques. He has authored over 110 refereed journal publications and holds several patents in these areas. Prof. Dravid is a recipient of various research awards including: NSF Young Investigator Award, Exxon Foundation Fellowship, IBM Faculty Development Award, the Microscopy Society of America (MSA) Burton Medal, the Robert L. Coble award from the American Ceramic Society and the Kurt F.J. Heinrich award from the Microbeam Analysis Society (MAS). He has served the microscopy, microanalysis and materials community in various capacities. One of Prof. Dravidi's passions (and challenges) is to increase societal awareness of science and technology, specifically that in materials science and technology. He enjoys touring and hosting local area high schools, and attempts to convey the beauty, diversity and complexity of materials via electron microscopy and microanalysis.

Report of SMSI meeting of September 10, 1999

The meeting was called to order at 7PM by Bill Mikuska. The featured speaker, Dr. Vinayak Dravid, described his work at Northwestern University as centering on bizarre materials and esoteric techniques. His talk on Electron Microscopy of Nanostructure Materials tended to bear this out. Defined as ~8 microns in diameter, more nanostructure components will fit on a conventional silicon chip than there are people on the earth.

Defined in zero, one, two and three dimensions, nanostructures exist as quantum dots, wire (buckytubes), ultra thin films or membranes and multilayered assembled nanocrystals. The electron microscope has been an essential tool in the discovery of these structures which possess interesting properties. Their large surface area to volume ratio renders them relatively reactive. Research indicates that electronic structure changes at nanophase as opposed to bulk. A nickel particle slide encapsulated by nanoscale graphite is protected even from aqua regia. Nanostructures can exhibit superparamagnetism at low (10K) temperatures, a property which can be used, for example, to attach receptors to molecules to search for pathogens.

Another example of nanostructure research and development during the past 5-10 years revolves around nano cylinders. Tubes fashioned from very thin sheets of graphite can be stuffed with low melting point metals such as tin or lead. At this scale metals also tend to behave differently and technologies such as thin screen television emerge. When two dimensional nanostructures are stacked, barriers arise at interface locations which can effect thermodynamics and chemistry. Van der Waals forces tend to become unusually strong at nano dimensions.

This relatively new field in materials research has already uncovered a wealth of peculiar properties unique to ultra small dimensions and portends another revolutionary round in technology. Dr. Dravid successfully magnified nanostructures in the minds of his audience to reveal their large scale importance for the future.

Report submitted by John Macdonald, Recording Secretary.