Condensed Matter Physics Seminar
2 p.m., Thursday, November 21, 2002
Room 1201, Physics Building
Exploring the world of CdSe nanocrystals
(Massachusetts Institute of Technology)
Abstract: Between the world of atoms, and the world of large
crystals, there is a world of nanocrystals. Nanocrystals are clusters of about a
thousand atoms, a millionth of a milimeter in size, having the properties of
both atoms and crystals. They can be regarded as artificial atoms whose size and
composition can be tailored. Nanocrystals pack in arrays like oranges in crates
to form artificial solids with new properties. I will present the
electrical transport properties and the electric-force microscopy measurements
of artificial solids composed of chemically synthesized CdSe nanocrystals.
Devices consist of close-packed arrays of nanocrystals, self-assembled on top of
microfabricated electrodes. We can control the tunneling of electrons between
nanocrystals to decrease the inter-dot separation and to lower the barrier for
electron tunneling. The transport properties can also be changed by applying a
gate voltage to change the electron density in the solids. Finally, I will
present experiments in which we have imaged the charge distribution in
nanocrystal solids using electric-force microscopy.
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Host: Williams
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