Bulletin of the American Physical Society
Annual Meeting of the Four Corners Section of the APS
Volume 59, Number 11
Friday–Saturday, October 17–18, 2014; Orem, Utah
Session D2: Material Science II |
Hide Abstracts |
Chair: Bill Evenson, Utah Valley University Room: Science Building 246 |
Friday, October 17, 2014 1:50PM - 2:02PM |
D2.00001: Ab Initio Study of Graphene Functionalized with Carboxyl Groups and Tetracyanoethylene Oxide Sanjiv Jha, Igor Vasiliev, Igor Magedov, Liliya Frolova, Nikolai Kalugin The electronic and structural properties of carbon nanomaterials can be affected by chemical functionalization. We applied {\it ab initio} computational methods based on density functional theory to study the covalent functionalization of graphene with carboxyl (COOH) groups and tetracyanoethylene oxide (TCNEO). Our calculations were carried out using the SIESTA and Quantum Espresso electronic structure codes combined with the generalized gradient approximation and local density approximation for the exchange correlation functional. The calculated binding energies and vibrational spectra of functionalized graphene surface and H-terminated graphene edge were compared with the available experimental data. Our calculation showed that the reaction of cycloaddition of TCNEO to graphene was endothermic for the surface of pristine graphene and exothermic for the edge of H-terminated graphene sheet. The simulated Raman and IR spectra of graphene functionalized with TCNEO were consistent with the experimental results. The computed vibrational spectra of graphene functionalized with COOH groups showed that the presence of point defects near the functionalization site affects the Raman and IR spectroscopic signatures of functionalized graphene. [Preview Abstract] |
Friday, October 17, 2014 2:02PM - 2:14PM |
D2.00002: Modeling Optical Properties of Carbon Nanotube Forests by Waveguides B.D. Wood, T.C. Shen, J.S. Dyer, V.A. Thurgood, N.A. Tomlin, J.H. Lehman Carbon Nanotube (CNT) Forests are vertically grown carbon nanotubes. They have been reported to be the blackest man-made materials- desirable not only for optical calibration but also for energy conversion, antireflection, and radiometry. Effective medium theory (EMT) has been proposed to explain the behavior of optical transmission and reflection in the mid-IR region. However, by varying CNT density and forest height, we find EMT either cannot fit the transmittance spectra or can fit a single spectrum with a large fill factor and alignment uncertainty. Further, the near unity index of refraction generated by EMT cannot fit the observed interference pattern of reflectance. Here we demonstrate that the optical transmission and reflection of the CNT forests can be modeled by cylindrical waveguides. Using the dielectric functions and a reduced conductivity of graphite, we find that all transmittance curves fit this model. CNT density can be correlated to the effective radius of the waveguide which provides a length scale dictating the onset of reflection from CNT forests, an important factor for applications. Transmittance and reflectance data from CNT forests grown on Al and Nb coated Si substrates will be discussed. [Preview Abstract] |
Friday, October 17, 2014 2:14PM - 2:26PM |
D2.00003: Electronic and Transport Properties of Waved Graphene Nanoribbons Mahmoud Hammouri, Igor Vasiliev First principles {\it ab-initio} calculations are employed to study the electronic and transport properties of waved graphene nanoribbons. Our calculations are performed using the SIESTA and TRANSIESTA density functional electronic structure codes. We find that the band gaps of graphene nanoribbons with symmetrical edges change very slightly with the increasing compression, whereas the band gaps of nanoribbons with asymmetrical edges change dramatically. The computed IV-characteristics of the waved graphene nanoribbons with different compression ratios reveal the effect of compression on the transport characteristics of graphene nanoribbons. [Preview Abstract] |
Friday, October 17, 2014 2:26PM - 2:38PM |
D2.00004: Modeling the Energy Dependent Cathodoluminescent Intensity of a Carbon Composite Material Justin Christensen, Kelby Peterson, Justin Dekany, JR Dennison The energy dependent spectral radiance from a carbon composite material under energetic (0.5-30 keV) electron bombardment was measured using visible-NIR cameras. Observed trends could not be accurately modeled using either a thin-film (penetrating electron) model which decreases with increasing electron energies or a bulk (non-penetrating electron) model which increases with increasing energies. However a linear combination of the two models, modeling thick and thin regions of luminescent polyimide above carbon particles was found to fit observed results much better. Electron microscope images of the sample were analyzed to independently determine the ratio of thick/thin sample areas which was found to reasonably match the ratio predicted by the cathodoluminescent model. A potentially more accurate model is also discussed, which uses distributions of dielectric thicknesses and incident electron energies. [Preview Abstract] |
Friday, October 17, 2014 2:38PM - 2:50PM |
D2.00005: Bulge Testing for Mechanical Characterization of sp$^{2}$/sp$^{3}$ Carbon Thin Films Joseph Rowley Bulge testing is a technique employed to measure material properties of thin films. Pressurized gas is applied to one side of a film and it's subsequent deformation measured. In many cases, thin films are fragile and therefore difficult to handle. Bulge testing has the advantage of requiring much less handling than other methods, resulting in fewer samples lost to error or accident. Carbon membranes have a wide range of characteristics, depending on their bonding and nano-structure. They can have very desirable properties such as: being chemically inert, high wear resistance and low friction, and high hardness and/or strength. In this work, reactively sputtered sp$^{2}$ carbon, diamondlike carbon from a pulsed laser deposition process, and a carbon nanotube reinforced polymer were characterized. PEELS and Raman Spectroscopy were used to determine sp$^{3}$/sp$^{2}$ ratios and density, CHN testing was used to determine hydrogen content, measuring the resonant frequency was a measure to check stiffness, and bulge testing was used to obtain the Young's Modulus and tensile strength. [Preview Abstract] |
Friday, October 17, 2014 2:50PM - 3:02PM |
D2.00006: Properties of Carbon Nanofuses for Permanent Data Storage Kevin Laughlin The amount of digital data being stored is increasing every year, so the needs for digital data storage have never been greater then today. The problem is that digital data is usually stored on devices that will last less than a decade, so the data needs to be migrated from device to device every couple years. An answer to this problem is a permanent data storage device that will hold data without the data corrupting for hundreds of years. I have been part of a group that has been working on a solid-state permanent data storage device that uses carbon nanofuses as the data cell. When a voltage bias is placed a carbon nanofuse, if it is intact a current will flow corresponding to a 1 bit. If the nanofuse is blown, no current will be allowed to flow across it, corresponding to a 0. Once a fuse is blown, it will remain in that state because it is a physical change that can't be undone under normal operating conditions. I have been working on understanding the physical properties of the carbon that is used to make these fuses including the resistances of the nanofuses with differing widths and thicknesses, the current required to blow the nanofuses, and the time it takes for the nanofuses to blow. [Preview Abstract] |
Friday, October 17, 2014 3:02PM - 3:14PM |
D2.00007: Discovering new thermal and mechanical properties of nanostructured systems Jorge N. Hernandez-Charpak, Kathleen Hoogeboom-Pot, Travis Frazer, Damiano Nardi, Emrah Turgut, Erik Anderson, Xiaokun Gu, Ronggui Yang, Justin Shaw, Henry Kapteyn, Margaret Murnane How is thermal transport affected by spatial confinement in nanoscale systems? How do elastic properties of materials evolve as nanostructures build up layer by layer? A host of applications in nanoscience and nanotechnology rely on an answer to these questions but our ability to probe the dynamics of nano-systems is still limited. With tabletop high harmonic generation (HHG), we overcome these limitations by extending non-destructive photoacoustic and photothermal techniques to extreme ultraviolet (EUV) wavelengths. The short wavelength and pulse duration of coherent EUV beams from HHG sources offer revolutionary capabilities for observing nano-systems on their intrinsic length and time scales. By generating and directly monitoring hypersonic acoustic waves in nano-systems, we characterize the mechanical properties of sub-10nm layers. Here we find that the density of ultrathin layers remains close to their bulk material value, while their elastic properties are significantly modified. Moreover, with the same technique, we follow the heat dissipation dynamics from 30-750nm heat sources uncovering a new thermal transport regime that dominates for closely-spaced nanoscale sources. Surprisingly, in this regime heat sources can cool more efficiently than widely-spaced sources of the same size. [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