Kono, Junichiro2011-07-252011-07-252010Booshehri, Layla Goli. "Ultrafast and magneto-optical spectroscopy of excitons and phonons in carbon nanotubes." (2010) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/62157">https://hdl.handle.net/1911/62157</a>.https://hdl.handle.net/1911/62157Understanding how electrons and phonons relax in energy and momentum is one of the current goals in carbon nanotube spectroscopy as well as an important step toward developing novel electronic and optoelectronic devices based on carbon nanotubes. Here, we investigate the polarization anisotropy of coherent phonon (CP) dynamics of radial breathing mode (REM) phonons in highly-aligned single-walled carbon nanotubes (SWNTs). Using CP spectroscopy, we measure REM CPs as a function of angle for two different geometries and in both cases, we observe quenching of the RBM when polarization is perpendicular to the nanotubes. We also make progress in understanding the role of dark excitons in SWNTs at ultralow temperatures. Measuring the magnetic field dependence to 5 T, we obtained an unexpected zero-field photoluminescence (PL) and PL brightening at 50 mK. To explain this contradiction with current theory, we introduced a non-thermal distribution of excitons into current theory.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Condensed matter physicsThesisTHESIS PHYS. 2011 BOOSHEHRI