Now showing items 1-6 of 6

    • Collective antenna effects in the terahertz and infrared response of highly aligned carbon nanotube arrays 

      Ren, L.; Zhang, Q.; Pint, C.L.; Wójcik, A.K.; Bunney, M. Jr; (2013)
      We study macroscopically aligned single-wall carbon nanotube arrays with uniform lengths via polarization-dependent terahertz and infrared transmission spectroscopy. Polarization anisotropy is extreme at frequencies less than ∼100 cm−1 with no sign of attenuation when the polarization is perpendicular to the alignment direction. The attenuation for ...
    • Excitonic effects on coherent phonon dynamics in single-wall carbon nanotubes 

      Nugraha, A.R.T.; Rosenthal, E.I.; Hasdeo, E.H.; Sanders, G.D.; Stanton, C.J.; (2013)
      We discuss how excitons can affect the generation of coherent radial breathing modes in the ultrafast spectroscopy of single-wall carbon nanotubes. Photoexcited excitons can be localized spatially and give rise to a spatially distributed driving force in real space which involves many phonon wave vectors of the exciton-phonon interaction. The equation ...
    • GR-FET application for high-frequency detection device 

      Mahjoub, Akram M.; Nicol, Alec; Abe, Takuto; Ouchi, Takahiro; Iso, Yuhei; (2013)
      A small forbidden gap matched to low-energy photons (meV) and a quasi-Dirac electron system are both definitive characteristics of bilayer graphene (GR) that has gained it considerable interest in realizing a broadly tunable sensor for application in the microwave region around gigahertz (GHz) and terahertz (THz) regimes. In this work, a systematic ...
    • Imaging molecular adsorption and desorption dynamics on graphene using terahertz emission spectroscopy 

      (2014)
      Being an atomically thin material, graphene is known to be extremely susceptible to its environment, including defects and phonons in the substrate on which it is placed as well as gas molecules that surround it. Thus, any device design using graphene has to take into consideration all surrounding components, and device performance needs to be evaluated ...
    • Macroscopic Ensembles of Aligned Carbon Nanotubes in Bubble Imprints Studied by Polarized Raman Microscopy 

      (2014)
      We study the alignment of single-wall carbon nanotubes (SWCNTs) in bubble imprints through polarized Raman microscopy. A hemispherical bubble containing SWCNTs is pressed against a glass substrate, resulting in an imprint of the bubble membrane with a coffee ring on the substrate. We find that macroscopic ensembles of aligned SWCNTs are obtained in ...
    • Photoluminescence sidebands of carbon nanotubes below the bright singlet excitonic levels 

      Murakami, Yoichi; Lu, Benjamin; Kazaoui, Said; Minami, Nobutsugu; Okubo, Tatsuya; (2009)
      We performed detailed photoluminescence (PL) spectroscopy studies of three different types of single-walled carbon nanotubes (SWNTs) by using samples that contain essentially only one chiral type of SWNT, (6,5), (7,5), or (10,5). The observed PL spectra unambiguously show the existence of an emission sideband at ∼140 meV below the lowest singlet ...