Optical studies of DNA-wrapped carbon nanotubes

This thesis presents a series of detailed optical studies of phonon-assisted relaxation processes in DNA-wrapped single walled carbon nanotubes. Using resonance Raman spectroscopy (RRS) and photoluminescence spectroscopy (PL), a careful characterization has been carried out on different DNA-wrapped SWNT samples to study the effects of DNA wrapping on the electronic and vibrational structure of SWNTs. Then, by using a DNA-wrapped SWNT sample that is highly enriched in (6, 5) SWNTs, I was able to separately identify the individual phonon-assisted relaxation channels that could not be clearly observed in bulk materials system. In light of the recent developments in the excitonic theory of D systems in general and of 1D carbon nanotubes in particular, the observed phonon-assisted processes are interpreted and examined in terms of excitonic states. An intense up-shifted phonon-assisted transition observed in PL spectra of SWNTs suggests the presence of a strongly coupled exciton-phonon bound state due to the strong 1D confinement condition. The presence of such exciton-phonon bound state confirms the excitonic nature of the optical transitions observed in semiconducting SWNTs.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Chou, Shin Grace

Advisor dc:contributor.advisor

• Mildred S. Dresselhaus.

• Chemistry.

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/1721.1/36252

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36252