Bulletin of the American Physical Society
2005 72nd Annual Meeting of the Southeastern Section of the APS
Thursday–Saturday, November 10–12, 2005; Gainesville, FL
Session HD: Nanoscience II |
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Chair: Ho Bun Chan, University of Florida Room: Hilton Hickory |
Friday, November 11, 2005 2:00PM - 2:12PM |
HD.00001: NEXAFS and UPS studies of aligned single-walled carbon nanotubes on Si(100) substrates Jack Rowe, S.-J. Oh, Otto Zhou, Les Fleming, Marc Ulrich We report near-edge absorption fine structure (NEXAFS) and ultraviolet photoemission spectroscopy (UPS) studies of aligned single-walled carbon nanotube films on Si(100) substrates. Polarization dependent data show very clear anisotropies due to the aligned nature of these films. We find different polarization dependent oscillator strengths for the $\pi ^{\ast }$-core exciton and the $\sigma ^{\ast }$-core exciton. From our data one can thus determine the orientation of the films using the NEXAFS spectra, with the intensity of the $\pi ^{\ast }$-core exciton at 284.4 eV showing a strong dependence on nanotube alignment with respect to the polarization of the incident radiation. At lower angles of incidence, the intensity of the $\pi ^{\ast }$ peak was higher for all orientations, which we attribute to the greater accessibility of the $\pi ^{\ast }$ orbitals. UPS spectra of the films showed little angular dependence and included features consistent with the total density of states of graphite. As a result of the nanotube curvature and the distribution of nanotube chiralities, the UPS spectra are similar to angle-integrated graphite spectra. [Preview Abstract] |
Friday, November 11, 2005 2:12PM - 2:24PM |
HD.00002: Nanowire Transistors, Gate Electrodes, and Their Directed Self-Assembly K. Skinner, R.L. Carroll, Sean Washburn, C. Dwyer Lithographic processes used in the fabrication of current CMOS technology for microprocessors are rapidly approaching both fundamental and practical limitations. Nanowires capable of acting as either transistors or interconnects are one set of resources currently undergoing heavy research as a possible alternative for lithographic limitations. We present a method for the fabrication of multi-material, segmented nanowires composed of Au and CdSe that display non-linear current-voltage characteristics, and the selective functionalization of these nanowires with DNA by first blocking the Au sites we wish to be non-reactive with 6-mercapto 1-hexanol. Single material, conductive nanowires were then selectively functionalized at only the ends with complementary strands of DNA and were directed to self-assemble with the bound DNA on the segmented nanowires to serve as gate electrodes for the transistors. [Preview Abstract] |
Friday, November 11, 2005 2:24PM - 2:36PM |
HD.00003: A Carbon Nanotube NEMS Switching Device Lamar Mair, Adam Hall, Dmitry Spivak, Michael Falvo, Richard Superfine, Sean Washburn Attempts are underway to fabricate an electrostatically actuated device which uses the overlaying nanotube of a MWNT junction as the dynamic member. The underlying MWNT behaves as a stationary rail on which the top nanotube rests and, during actuation, will slide. The overlaying nanotube is clamped at one end and simply supported by the underlying MWNT, creating a situation of mixed support. Electron beam lithography is used to create sub-micron device features. Controlled manipulation and switching of this device could have impacts in the area of NEMS. [Preview Abstract] |
Friday, November 11, 2005 2:36PM - 2:48PM |
HD.00004: Singlewall Carbon Nanotubes As Springs In A Nanotorsional Device Adam Hall, Michael Falvo, Richard Superfine, Sean Washburn We present on the fabrication and characterization of a nanoelectromechanical device incorporating an individual single wall carbon nanotube as a support for a small, lithographically defined and fully suspended metal platform. The device can be actuated electrostatically through the use of a back gate, causing a concomitant twist in the nanotube. We discuss future potential of such a nanoelectromechanical system. [Preview Abstract] |
Friday, November 11, 2005 2:48PM - 3:00PM |
HD.00005: Single Walled Carbon Nanotube/Silicon Heterojunctions Zhuangchun Wu, Andrew G. Rinzler Characterization of the electrical heterojunction between single walled carbon nanotubes (SWNTs) and semiconductors is important for an array of potential applications. Thin, homogeneous, transparent, films of 100{\%} SWNTs exhibiting good electrical conductivity [1] have already been demonstrated as the hole injection electrode in GaN light emitting diodes [2]. The simultaneous transparency and high electrical conductivity of these films makes them similarly promising for the light transmissive electrode in photovoltaic devices. SWNTs have moreover long been proposed as on-chip, device interconnects. To understand the electrical coupling between the nanotubes and semiconductors, likely to have relevance in such devices, we have begun a systematic exploration of the electrical properties of SWNT/silicon hetrojunctions. We will discuss findings as well as a novel test method made possible by the unique morphology of the nanotubes. 1. Z. Wu, Z. Chen, X. Du, J. M. Logan, J. Sippel, M. Nikolou, K. Kamaras, J. R. Reynolds, D. B. Tanner, A. F. Hebard, A. G. Rinzler, Science 305, 1273 (2004) 2. K. Lee, Z. Wu, Z. Chen, F. Ren, S. J. Pearton, A. G. Rinzler, Nano Lett. \textbf{4}, 911 (2004) [Preview Abstract] |
Friday, November 11, 2005 3:00PM - 3:12PM |
HD.00006: Effect of Magnetic Field in Carbon Nanotubes Andrew Kinchen, Russell Selva, Yuriy Malozovsky We study the effect of longitudinal magnetic in the armchair carbon nanotubes (CNT). We model the carbon nanotube as a tubule with electrons confined to the surface of the tubule by an attractive delta-function potential. We derived the dynamic pair interaction potential between two electrons in the tubule in the presence of magnetic field. Dispersion of plasmon modes at different values of angular momentum, and single-particle excitations in the presence of the magnetic field are derived as well. We also evaluate the self-energy part due to the interaction of an electron with plasma modes in magnetic field. [Preview Abstract] |
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