Title:

Quantitative In Situ Characterization of Metallic Nanowires

Speaker:

Dr. Jun Lou

Affiliation:

Department of Mechanical Engineering and Materials Science, Rice University

When:

Wednesday, May 5, 2010 at 11:00:00 AM   Add to Calendar

Where:

MARC Building, Room 114

Host:

Ting Zhu
ting.zhu@me.gatech.edu
404-894-6597

Abstract

Metallic nanowires are of great technological importance due to their current and potential applications in miniaturized electronic, optical, thermal and electromechanical systems. In addition, one-dimensional metallic nanomaterials provide a unique opportunity to investigate fundamental mechanisms in materials science governing the origin and transitions of size dependent mechanical behavior for metals. This talk presents some of our recent efforts to study the size dependent mechanical behaviors of metallic nanowires. We have developed a simple micro-device that allows in situ quantitative mechanical characterization of metallic nanowires, in scanning electron microscope (SEM) or transmission electron microscope (TEM) chamber equipped with a quantitative nanoindenter. The unique design of this device makes it possible to convert compression from nanoindentation to uni-axial tension at the sample stages. Fabrication of the micro-device is successfully demonstrated using established micro-fabrication processes. Finite element analysis (FEA) is employed to model the device behavior under mechanical loading and compared with experiments. Finally, some in situ results on deformation and fracture behavior of Ni and Au nanowires will be discussed. Also in this work, we will demonstrate that at near room temperature, individual <111> single crystalline gold nanowires with 3-10 nanometers in diameter can be welded together within seconds by only making mechanical contact without any local heating process. Subsequent quantitative in situ tensile and electrical measurements confirmed that the strength of the as-welded nanowire was very close to that of the original nanowire, and the electrical properties of as-welded nanowires had little change for each successful welding. The implication of the “cold welding” for bottom-up assembly at the nanoscale will be discussed.

Biography

Jun Lou obtained B.E. and M.S. degrees in Materials Science and Engineering from Tsinghua University and Ohio State University, respectively, and his Ph.D. degree from the Department of Mechanical and Aerospace Engineering and Princeton Materials Institute at Princeton University. After a brief postdoc at Brown University he joined Rice University as an assistant professor in the Department of Mechanical Engineering and Materials Science. He is a recipient of the Air Force Office of Scientific Research Young Investigator Award and the ORAU Ralph E. Powe Junior Faculty Enhancement Award. His research interests include nanomaterial synthesis, nanomechanical characterization and nanodevice fabrication for energy and biomedical applications.

Notes

Refreshments will be served.