Electronic transport in CdSe quantum dot arrays

When an isolated piece of conductor is sufficiently small, the energy to add another electron can be larger than the available thermal energy, and the number of electrons on the island is well-defined. If the island is made still smaller, the quantum confinement energy also becomes large, the electronic states on the dot become discrete, and the island is called a quantum dot, or sometimes an artificial atom. Quantum dots have been a focus of active research for the past decade, both as model systems for exploring physics, and as the ultimate limit in size reduction for conventional transistors. Early quantum dots were made only by lithographic patterning, but more recently the solution-based synthesis of semiconductor nanocrystals, which are much smaller than the lithographic quantum dots, has been developed. The nanocrystals can range in size from 1.5 nm to 8 nm in diameter with a narrow size distribution, and they can form close-packed arrays when deposited from solution, with organic molecules that coat the nanocrystals serving as spacers. These quantum dot arrays have the potential to be model artificial solids, with tunable intersite coupling, site energies, and order. I present results for electronic transport measurements on large arrays of CdSe nanocrystals. In response to a step in the applied voltage, we observe a power-law decay of the current over five orders of magnitude in time and four orders of magnitude in current. Furthermore, we do not observe a steady-state dark current for fields up to 1x106 V/cm and times out to 5 x 104 seconds.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Morgan, Nicole Yen-i, 1971-

Advisor dc:contributor.advisor

• Marc A. Kastner.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8668

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8668