NOTE: NANO@TECH WILL TAKE PLACE IN THE PETTIT/MIRC BUILDING IN ROOM 102

Speaker for October 11 (Friday): Jeff Davis, Georgia Tech School of Electrical and Computer Engineering

Anomalous Electrical Properties of Nanocomposite Materials
with Applications to High Energy Density Capacitors
Abstract:  Developing new materials and devices that have extremely long life cycles and deliver high bursts of energy would help to advance a variety of applications that range from mobile storage systems (e.g. for mobile computing or electric vehicles) to pulsed power technologies (e.g. for railguns or laser systems) to larger storage facilities for alternative energy generation (e.g. for wind or solar power stations).  This research effort combines both nanofabrication and numerical simulation to study the polarizability and electric field strength of material interfaces in unique composite configurations.  This investigation is predicated on a variety of observations over the past 20 years during which numerous experiments have revealed a large increase in the low-frequency capacitance of devices constructed from metal-insulator or multi-insulator composite materials.  These capacitive increases are typically reported as dramatic increases in the effective relative dielectric constants of the nanocomposite material.  A class of these metal-insulator composites that have metal particle concentrations near the percolation threshold have been shown to have a dramatic increase in the effective dielectric constant ranging from 3-8 orders of magnitude.   Multi-insulator (e.g. SiO2, Si3N4, Al2O3, and TiO2) nanocomposites have also been shown to increase the permittivity at low frequencies from 1-2 orders of magnitude. To date, there are many competing theories to explain the phenomenon behind these anomalous increases in low frequency dielectric behavior, which range from the Gor’kov-Eliashberg effect to the Maxwell-Wagner effect to percolation theory of metal-insulator transitions.   In addition to giving an overview of these current experiments and associated theories, this seminar will include a presentation of preliminary simulation and measurement results of various test structures that were fabricated at Georgia Tech in the Institute of Electronics and Nanotechnology.

Dr. Jeff Davis received the B.E.E., M.S.E.E., and Ph.D. degrees from the Georgia Institute of Technology. He is currently an Associate Professor in the School of Electrical and Computer Engineering here at Georgia Tech. In addition to receiving an NSF CAREER Award, he has coauthored over 70 refereed journal, conference, and workshop publications.  He has also co-edited and co-written a book entitled Interconnect Technology and Design for Gigascale Integration.  While at Georgia Tech, Dr. Davis has been the recipient of the Outstanding ECE Junior Faculty Award, the ECE Outreach Award, the Class of 1940 W. Roane Beard Outstanding Teacher Award, and the CETL Educational Partnership Award.  Dr. Davis has recently been heavily involved in outreach efforts to promote STEM concepts in K-12 education, which includes the creation of a statewide robotic tournament for middle school students. His current research is focused on using nanofabrication and numerical simulation to explore the electrical properties of metal-insulator and multi-insulator nanocomposite materials for use in high energy density (HED) capacitor applications.

Nano@Tech

Sharing Our Knowledge, Shaping the Future

Nano@Tech is an organization comprised of professors, graduate students and undergraduate students from the Georgia Tech and Emory campuses and professionals from the corresponding scientific community who are interested in Nanotechnology. Meetings are held on the second and fourth Tuesday of the month at noon, during the academic year. Each meeting is held in the Marcus Nanotechnology Building conference rooms (rooms 1116-1118).