Bulletin of the American Physical Society
APS March Meeting 2010
Volume 55, Number 2
Monday–Friday, March 15–19, 2010; Portland, Oregon
Session J20: Focus Session: Carbon Nanotubes: Mechanical properties and Biosensors |
Hide Abstracts |
Sponsoring Units: DMP Chair: Apparao Rao, Clemson University Room: C120-C122 |
Tuesday, March 16, 2010 11:15AM - 11:51AM |
J20.00001: Carbon nanotube mechanical resonators Invited Speaker: Nano-electromechanical systems (NEMS) make use of electrically induced mechanical motion and vice versa. Carbon nanotubes are ideal building blocks of NEMS because of their unique (mechanical) properties and their low mass. This puts them in an unexplored regime of motion which approaches the fundamental detection limit set by quantum mechanics. At room temperature, we use mixing techniques to probe the bending-mode vibration of a suspended carbon nanotube; the gate voltage strains the carbon nanotube and thereby tunes the frequency. At low temperatures, mechanical vibrations are actuated by a nearby antenna and a record high Q-value of 150000 at a resonance frequency of 300 MHz is achieved. Electron tunneling and mechanical motion are strongly coupled resulting in single- electron tuning oscillations of the mechanical frequency and in energy transfer to the electrons causing mechanical damping. Strikingly, we also observe that a d.c. current through the nanotube spontaneously drives the mechanical resonator, exerting a force that is synchronized with the high-frequency vibrations. [Preview Abstract] |
Tuesday, March 16, 2010 11:51AM - 12:03PM |
J20.00002: Bending and Twisting of Suspended Single-Walled Carbon Nanotubes in Solution Arthur Barnard, Ya-Qiong Xu, Paul McEuen We combine suspended, aligned carbon nanotube transistors with optical trapping techniques and scanning photocurrent microscopy to investigate the mechanics of suspended single-walled carbon nanotubes as well as DNA-nanotube systems in solution. We study the movement of nanotubes by monitoring their photocurrent images and measure their thermal fluctuations by imaging microbeads that are tightly attached to nanotubes by single-stranded DNA. By analyzing thermal fluctuations of these microbeads and by using optical tweezers we are able to obtain the torsional and bending stiffness of nanotubes and then calculate their diameters. We can also measure, with subangstrom resolution, the effective attachment point of the microbead to the nanotube. [Preview Abstract] |
Tuesday, March 16, 2010 12:03PM - 12:15PM |
J20.00003: Observation, Modeling and Fabrication of Self-Oscillating Carbon Nanotube-Based NEMS Benjamin Aleman, Jeff Weldon, Allen Sussman, Will Gannett, Alex Zettl Capturing the full potential size, power and performance benefits of NEMS is often precluded by their functional reliance on relatively large, high-power, high-frequency external electronics. In this work, we use Transmission Electron Microscopy (TEM) to observe the controllable self-oscillations of singly-clamped, field-emitting carbon nanotubes that operate with only a single DC bias voltage, and formulate an electromechanical model that predicts the voltage necessary to induce oscillations solely in terms of device geometry and material properties. Furthermore, we use this model to successfully fabricate, for the first time, top-down self-oscillating NEMS amenable to large-scale integration. [Preview Abstract] |
Tuesday, March 16, 2010 12:15PM - 12:27PM |
J20.00004: Altering the Frequency of Nanoscale Mechanical Resonators with Mass Redistribution Kwanpyo Kim, K. Jensen, A. Zettl Using indium mass redistribution on multiwall carbon nanotubes (MWNTs), we demonstrate a new way of tuning MWNT nanomechanical resonators. \textit{In Situ} transmission electron microscope (TEM) studies show that indium mass can be reversibly migrated to different locations along MWNT resonators by electrical currents. Mass redistributions result in nonvolatile resonant frequency shifts, which can be as large as 20 {\%}. The indium migration can take place either on the outer surface of a MWNT, or through the hollow channel of a MWNT. [Preview Abstract] |
Tuesday, March 16, 2010 12:27PM - 12:39PM |
J20.00005: Theory of fundamental detection limits of carbon nanotube mass sensors Johannes Lischner, T. A. Arias Starting from \emph{ab initio} calculations of linear and non-linear elastic constants, we use a quantized continuum elastic theory containing both linear and geometric nonlinearities to compute the intrinsic quality factor of the fundamental flexural mode of a semiconducting single-walled carbon nanotube by means of many-body perturbation theory. We analyze both three- and four-phonon loss channels and present results for the temperature, radius and length dependence of the losses. The intrinsic quality factor imposes a fundamental limit to mass differences that can be resolved by nanotube mass sensors. Our calculations suggest that yoctogram mass resolution, necessary to monitor chemical reactions on the nanotube surface, can be achieved at low temperatures if extrinsic losses are reduced sufficiently. [Preview Abstract] |
Tuesday, March 16, 2010 12:39PM - 12:51PM |
J20.00006: Stability and mechanical properties of partially unzipped carbon nanotubes Chun Tang, Wanlin Guo, Changfeng Chen We have explored the stability and mechanical properties of partially unzipped carbon nanotubes using molecular dynamics simulations. Our results show that due to the presence of dangling bonds created by the unzipping process, the unzipped graphene ribbon region becomes unstable with increasing temperature. The dangling bonds can seamlessly self-heal to form nanotube structure at sufficiently high temperatures. These results suggest that temperature treatment that passivates the dangling bonds could be a useful tool in tailoring these nanoscale structures in nanoelectronic applications. Tensile tests show that the partially unzipped structure has a Young's modulus of 700 GPa, comparable to that of SWCNTs and graphene nanoribbons. Size and chirality effects are also discussed. [Preview Abstract] |
Tuesday, March 16, 2010 12:51PM - 1:03PM |
J20.00007: Electrostatically induced shape transitions in single wall carbon nanotubes Oleg Shklyaev, Vincent Crespi, Eric Mockensturm We investigate a transition of electrically charged single wall carbon nanotubes from a collapsed to an inflated configuration caused by electrostatic repulsion between the tube walls. If the charge on the tube is large enough then Coulombic repulsive forces, together with the elastic forces overcome Van-der-Waals attraction and convert the tube from a collapsed to an inflated configuration. If the radius of the tube is such that the collapsed configuration is metastable and the inflated state is energetically favorable, then the collapsed-to-inflated transition in one tube section will cause successive inflation of the neighboring sections and result in propagation of the transition region along the tube. If the applied voltage is tuned so that the collapsed and inflated configurations are degenerate, then various mechanical response functions diverge. At this point, a single atom encapsulated in a capped carbon tube may substantially shift the collapsed-to-inflated transition region. Thus, we suggest a system which may be tuned to provide a macroscopic response to the presence of a single atom. [Preview Abstract] |
Tuesday, March 16, 2010 1:03PM - 1:15PM |
J20.00008: Uniaxial strain effects on the band structure and effective masses of wurtzite GaAs Tawinan Cheiwchanchamnangij, Walter Lambrecht While GaAs in bulk form has the zincblende structure, recent interest in the wurtzite form of GaAs arises in the context of nanowires. The band structure of wurtzite GaAs is calculated using the full-potential (FP) linearized muffin-tin orbital (LMTO) method within the local density approximation. The relativistic and spin-orbit coupling effects are included when obtaining the conduction and valence band effective mass tensors and related Rashba-Sheka-Pikus Hamiltonian parameters. The effects of {\it c}-axis uniaxial strain on the band structure is investigated and used to determine the relevant strain deformation potentials. It is found that under increasing uniaxial strain, a crossing of the $\Gamma_5$ and $\Gamma_1$ valence band levels occurs first, followed at higher strain by an additional crossing of the $\Gamma_3$ and $\Gamma_1$ conduction bands.. The latter is related to a corresponding direct to indirect ($\Gamma-L$) crossing under uniaxial strain in zinblende. [Preview Abstract] |
Tuesday, March 16, 2010 1:15PM - 1:27PM |
J20.00009: Carbon Nanotube Field Effect Transistor based High Frequency Biosensors Girish Kulkarni, Kai Boon Ee, Zhaohui Zhong The sensitivity of transistor based biosensors suffers from the electrostatic screening due to mobile ions in solution. Here, we use carbon nanotube field effect transistor based high frequency biosensors for detection in high ionic strength solutions. Carbon nanotube transistors are configured as high frequency mixers and the changes in mixing current provides the sensing mechanism. At high frequencies, the ions are unable to follow the AC field and hence, electrostatic screening is minimized. In addition, the high transconductance of the transistor provides intrinsic gain for high frequency sensing. To prove this concept we demonstrate protein detection in $\sim $100mM buffer solution with high sensitivity. The technique will be evaluated against both, low frequency transistor based biosensors and conventional dielectric sensing technique relying on impedance measurement. The result will lead to novel biosensors for point-of-care applications, where electronic sensors functioning directly in physiologically relevant condition are required. [Preview Abstract] |
Tuesday, March 16, 2010 1:27PM - 1:39PM |
J20.00010: The effects of adsorption orientations on transport through a nanotube gas sensor Amir A. Farajian, Arta Sadrzadeh, Olga V. Pupysheva, Boris I. Yakobson We calculate the quantum transport of a nanoelectronic gas sensor for various adsorption orentations of the gas molecules. The nanosensor employs electronic transport properties of a carbon nanotube exposed to NO$_2$ molecules. The calculations are based on ab initio electronic structures, combined with the Green's function formulation of Landauer's transport theory. Our results show that different energetically equivalent orientations of the NO$_2$ molecules result in different details of transport characteristics. The main features of transport modulation, however, are the same for all the orientations. Implications for nanotube-based gas sensors are discussed. [Preview Abstract] |
Tuesday, March 16, 2010 1:39PM - 1:51PM |
J20.00011: Single carbon nanotube based nanofluidic devices for single-stranded DNA translocation Jin He, Di Cao, Pei Pang, Hao Liu, Stuart Lindsay, Haitao Liu, Jinyao Tang, Colin Nuckolls, Predrag Kristic, Sony Joseph We have recently succeeded in fabricating a single carbon nanotube (CNT) based nanofluidic devices in which just one single-walled carbon nanotube (SWCNT) bridges two fluid reservoirs, using careful control experiments to show that fluid flow is through the SWCNT and not via a leakage path. Our device worked as a nanopore device and also contained a field effect transistor (FET) component. We investigated the filling effect of pure water and different salt solutions to individual SWCNT by measuring the electrical transport characteristics. Obvious change in the electrical properties of semiconducting SWCNTs during filling process was observed. We also measured the ionic current of these devices. Electrophoretic transport of short single stranded DNA oligomers through CNT was marked by a large transient increases in ion current and was confirmed by polymerase chain reaction (PCR) analysis. The CNT based nanofluidic device has the potential to act as a single-molecule sensor and new type of nanopore for controlling of DNA translocation. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700