Center for Excitonics
Seminar Series Announcement
The Center for Excitonics is an Energy Frontier Research Center funded by
the
U.S. Department of Energy, Office of Science and Office of Basic Energy
Sciences
The Center for Excitonics invites you to join us at the next seminar of
the
Spring 2010 series. Please forward this information on to others who
might be
interested in attending this and other center seminars.
Title: Semiconductor nanowires: from LEDs to Solar Cells
Presenter: Silvija Gradečak
Organization: Laboratory for Nanophotonics and electronics
Massachusetts Institute of Technology
Date: May 4, 2010
Time: 3:00 - 4:00pm
Place: Haus Room 36-428
Center URL:
http://www.rle.mit.edu/excitonics
Seminar URL:
http://www.rle.mit.edu/excitonics/gradecak-050410.html
Abstract
Nanostructured materials – including nanowires, nanotubes, and
nanocrystals – have unique and size-tunable properties that depend on the
precise arrangement of their atomic constituents. These nanomaterials
offer solutions to some of the current challenges in science and
engineering, and could potentially lead to improved understanding of the
physical world and to discoveries of new phenomena. However, functionality
of novel nanomaterials and their impact on society will be ultimately
dictated by our understanding and ability to precisely control their
structural properties, size uniformity, and dopant distribution at the
atomic level.
In this talk, I will discuss the growth, doping, and applications of III-V
nanowires and nanowire heterostructures using metalorganic chemical vapor
deposition, as well as advanced electron microscopy techniques for direct
correlation of structural and physical properties with high spatial
resolution. We have demonstrated that the cathodoluminescence (CL)
technique, coupled with scanning transmission electron microscopy (STEM),
effectively bypasses the resolution limit of conventional far-field
photoluminescence spectroscopy and allows direct structure-property
correlation on the nanoscale. The CL-STEM optical studies of single
nanowire heterostructures with spatial resolution of <20 nm will be
discussed. Finally, applications of semiconductor nanowires for LED and
solar cell applications will be described.
Bio
Silvija Gradečak is an Assistant Professor of Materials
Science and Engineering at MIT. She received her Dipl. Ing. degree in
Physics from University of Zagreb,
Croatia, in 1999 and her PhD in Physics from EPFL,
Switzerland, in 2003. Following two years of postdoctoral research at
Harvard University with Prof. Charles
Lieber, Gradečak joined the faculty at MIT in 2006. Prof.
Gradečak’s group at MIT uses interdisciplinary approach to study
semiconductor materials and
low-dimensional systems. She held the Merton C. Flemings
Career Development Chair and is a recipient of the NSF CAREER Award and 3M
Innovation Award.