Search

Your search keyword '"Shaver, Jonah"' showing total 35 results
Start Over Author "Shaver, Jonah"
35 results on '"Shaver, Jonah"'

1. Biexciton, single carrier, and trion generation dynamics in single-walled carbon nanotubes

Author

Yuma, Bertrand, Berciaud, Stéphane, Besbas, Jean, Shaver, Jonah, Santos, Silvia M., Gosh, Saunab, Weisman, R. Bruce, Cognet, Laurent, Gallart, Mathieu, Ziegler, Marc, Hönerlage, Bernd, Lounis, Brahim, and Gilliot, Pierre

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present a study of free carrier photo-generation and multi-carrier bound states, such as biexcitons and trions (ionized excitons), in semiconducting single-walled carbon nanotubes. Pump-and-probe measurements performed with fs pulses reveal the effects of strong Coulomb interactions between carriers on their dynamics. Biexciton formation by optical transition from exciton population results in an induced absorption line (binding energy 130 meV). Exciton-exciton annihilation process is shown to evolve at high densities towards an Auger process that can expel carriers from nanotubes. The remaining carriers give rise to an induced absorption due to trion formation (binding energy 190 meV). These features show the dynamics of exciton and free carriers populations., Comment: 9 Pages, 7 figures

Published
2013
Full Text
View/download PDF

2. All-optical trion generation in single walled carbon nanotubes

Author

Santos, Silvia, Yuma, Bertrand, Berciaud, Stéphane, Shaver, Jonah, Gallart, Mathieu, Gilliot, Pierre, Cognet, Laurent, and Lounis, Brahim

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present evidence of all optical trion generation and emission in undoped single walled carbon nanotubes (SWCNTs). Luminescence spectra, recorded on individual SWCNTs over a large CW excitation intensity range, show trion emission peaks red-shifted with respect to the bright exciton peak. Clear chirality dependence is observed for 22 separate SWCNT species, allowing for determination of electron-hole exchange interaction and trion binding energy contributions. Luminescence data together with ultrafast pump probe experiments on chirality sorted bulk samples suggest that exciton-exciton annihilation processes generate dissociated carriers that allow for trion creation upon a subsequent photon absorption event., Comment: 13 pages, 4 figures

Published
2011
Full Text
View/download PDF

6. Cutting of single-walled carbon nanotubes by ozonolysis

Author

Zheyi Chen, Ziegler, Kirk J., Shaver, Jonah, Hauge, Robert H., and Smalley, Richard E.

Subjects
Nanotubes -- Chemical properties, Glycol ethers -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

A new cutting method for single walled carbon nanotubes (SWNT) using perfluoropolyether as reactant medium is described. This method uses extensive ozonolysis at room temperature and SWNT was found to be extensively cut after an ozone treatment with a yield of ~80% of the original carbon.

Published
2006

10. Multimodal Photodiode and Phototransistor Device Based on Two-Dimensional Materials

Author

Namgung, Seon, Shaver, Jonah, Oh, Sang-Hyun, and Koester, Steven J.

Abstract

With strong light–matter interaction in their atomically thin layered structures, two-dimensional (2D) materials have been widely investigated for optoelectronic applications such as photodetectors and photovoltaic devices. Depending on the aim of optoelectronic applications, different device structures have been employed. Lateral phototransistor structures have been employed for high optical gain, while vertical photodiode structures have been employed for fast response and low power operation. Herein, we demonstrate a multimodal photodetector platform based on 2D materials, combining both a phototransistor and a photodiode and taking the corresponding desirable characteristics from each structure within a single device. In this platform, a multilayered transition-metal dichalcogenide flake is transferred on top of metal electrodes, and a transparent gate electrode is employed. The channel region of the flake between electrodes operates as a phototransistor providing a high gain mode, while the electrode region in the same flake operates as a vertical Schottky photodiode providing a fast response mode. These modes can be dynamically selected by controlling the drain voltage and gate voltage.

Published
2024
Full Text
View/download PDF

15. A natural human IgM that binds to gangliosides is therapeutic in murine models of amyotrophic lateral sclerosis

Author

Xu, Xiaohua, primary, Denic, Aleksandar, additional, Jordan, Luke R., additional, Wittenberg, Nathan J., additional, Warrington, Arthur E., additional, Wootla, Bharath, additional, Papke, Louisa M., additional, Zoecklein, Laurie J., additional, Yoo, Daehan, additional, Shaver, Jonah, additional, Oh, Sang-Hyun, additional, Pease, Larry R., additional, and Rodriguez, Moses, additional

Published
2015
Full Text
View/download PDF

19. Nanoscale Block Copolymer Ordering Induced by Visible Interferometric Micropatterning: A Route towards Large Scale Block Copolymer 2D Crystals

Author

Aissou, Karim, primary, Shaver, Jonah, additional, Fleury, Guillaume, additional, Pécastaings, Gilles, additional, Brochon, Cyril, additional, Navarro, Christophe, additional, Grauby, Stéphane, additional, Rampnoux, Jean‐Michel, additional, Dilhaire, Stefan, additional, and Hadziioannou, Georges, additional

Published
2012
Full Text
View/download PDF

29. Cutting single-walled carbon nanotubes

Author

Ziegler, Kirk J, primary, Gu, Zhenning, additional, Shaver, Jonah, additional, Chen, Zheyi, additional, Flor, Erica L, additional, Schmidt, Daniel J, additional, Chan, Candace, additional, Hauge, Robert H, additional, and Smalley, Richard E, additional

Published
2005
Full Text
View/download PDF

32. Squeezing Millimeter Waves through a Single, Nanometer-wide, Centimeter-long Slit.

Author

Xiaoshu Chen, Hyeong-Ryeol Park, Lindquist, Nathan C., Shaver, Jonah, Pelton, Matthew, and Sang-Hyun Oh

Subjects
SUBMILLIMETER waves, ELECTROMAGNETIC waves, ELECTRIC fields, ELECTROMAGNETIC interference, SIGNAL-to-noise ratio, ELECTRON tunneling
Abstract

We demonstrate broadband non-resonant squeezing of terahertz (THz) waves through an isolated 2-nm-wide, 2-cm-long slit (aspect ratio of 107), representing a maximum intensity enhancement factor of one million. Unlike resonant nanogap structures, a single, effectively infinitely-long slit passes incident electromagnetic waves with no cutoff, enhances the electric field within the gap with a broad 1/f spectral response, and eliminates interference effects due to finite sample boundaries and adjacent elements. To construct such a uniform, isolated slit that is much longer than the millimeter-scale spot of a THz beam, we use atomic layer lithography to pattern vertical nanogaps in a metal film over an entire 4-inch wafer. We observe an increasing field enhancement as the slit width decreases from 20 nm to 2 nm, in agreement with numerical calculations. [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

34. Alignment Dynamics of Single-Walled Carbon Nanotubes in Pulsed Ultrahigh Magnetic Fields

Author

Shaver, Jonah, Parra-Vasquez, A. Nicholas G., Hansel, Stefan, Portugall, Oliver, Mielke, Charles H., von Ortenberg, Michael, Hauge, Robert H., Pasquali, Matteo, and Kono, Junichiro

Abstract

We have measured the dynamic alignment properties of single-walled carbon nanotube (SWNT) suspensions in pulsed high magnetic fields through linear dichroism spectroscopy. Millisecond-duration pulsed high magnetic fields up to 56 T as well as microsecond-duration pulsed ultrahigh magnetic fields up to 166 T were used. Because of their anisotropic magnetic properties, SWNTs align in an applied magnetic field, and because of their anisotropic optical properties, aligned SWNTs show linear dichroism. The characteristics of their overall alignment depend on several factors, including the viscosity and temperature of the suspending solvent, the degree of anisotropy of nanotube magnetic susceptibilities, the nanotube length distribution, the degree of nanotube bundling, and the strength and duration of the applied magnetic field. To explain our data, we have developed a theoretical model based on the Smoluchowski equation for rigid rods that accurately reproduces the salient features of the experimental data.

Published
2009
Full Text
View/download PDF

35. Optical Signatures of the Aharonov-Bohm Phase inSingle-Walled Carbon Nanotubes.

Author

Zaric, Sasa, Ostojic, Gordana N., Kono, Junichiro, Shaver, Jonah, Moore, Valerie C., Strano, Michael S., Hauge, Robert H., Smalley, Richard E., and Wei, Xing

Subjects
*CARBON spectra, *SPECTRUM analysis, *PHOTOLUMINESCENCE, *ASTROPHYSICS, *OPTICAL spectrometers, *NANOTUBES
Abstract

We report interband magneto-optical spectra for single-walled carbon nanotubes in high magnetic fields up to 45 tesla, confirming theoretical predictions that the band structure of a single-walled carbon nanotube is dependent on the magnetic flux Φ threading the tube. We have observed field-induced optical anisotropy as well as red shifts and splittings of absorption and photoluminescence peaks. The amounts of shifts and splittings depend on the value of Φ/Φ[sub0] and are quantitatively consistent with theories based on the Aharonov-Bohm effect These results represent evidence of the influence of the Aharonov-Bohm phase on the band gap of a solid. [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results