Bulletin of the American Physical Society
Fall 2014 Joint Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 59, Number 12
Friday–Sunday, October 17–19, 2014; College Station, Texas
Session B5: Nanoscience/Condensed Matter |
Hide Abstracts |
Chair: Joseph Ross, Texas A&M University Room: MPHY 334 |
Saturday, October 18, 2014 10:35AM - 10:47AM |
B5.00001: Luminescence of La$_{0.2}$Y$_{1.8}$O$_{3}$ ceramic scintillator Sunil Sahi, Wei Chen, Rasool Kenarangui Inorganic single crystals and organic (plastic and liquid) scintillators are the two important types of scintillators. Both of these scintillators have their own drawbacks. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, some efficient inorganic scintillator such as NaI and CsI are not environmental friendly. But on the other hand, organic scintillators have low density and hence poor energy resolution which limits their use in gamma spectroscopy. Ceramic scintillator can be a cost effective alternative to inorganic single crystal. Here we have studied the luminescence of La$_{0.2}$Y$_{1.8}$O$_{3}$ ceramic scintillator. We have fabricated La$_{0.2}$Y$_{1.8}$O$_{3}$ ceramic and characterized structurally using XRD and TEM. Photoluminescence and radioluminescence studies were done using UV and X-ray as an excitation source. We have used gamma isotopes with different energy to studies the scintillation properties of La$_{0.2}$Y$_{1.8}$O$_{3}$ scintillator. Preliminary studies of La$_{0.2}$Y$_{1.8}$O$_{3}$ scintillator shows promising result with energy resolution comparable to that of NaI and CsI. [Preview Abstract] |
Saturday, October 18, 2014 10:47AM - 10:59AM |
B5.00002: Correlation Between Optical Properties and Charge Carrier Mobility in Regioregular Poly (3-hexylthiophene) Thin Films Aaron Mebane, Xin Xu, Seohee Kim, Ananth Dodabalapur The ability to efficiently and accurately determine the charge carrier mobility (CCM) in poly (3-hexylthiophene-2,5-diyl) (P3HT) thin films is important for measurements of quality in P3HT based electronic devices. P3HT is an important semiconducting organic polymer that is one of the leading candidates for use in organic thin-film and, flexible electronics. CCM is routinely determined using methods such as field effect mobility measurements; however, this requires the devices fabrication to be completed in addition to a process of probing the device for current vs voltage readings. Because of these requirements a non-contact optical method was investigated to efficiently predict the CCM of P3HT thin films. Ellipsometric methods were used to examine the anisotropic nature of P3HT with a goal of determining the overall order of the polymer chains in the film and thereby predicting CCM. Results indicate that P3HT chains easily adopt a preferred order in the film, that charge transport is two dimensional, and that annealing temperature does not affect the anisotropic nature of P3HT but does increase the size of the crystallites. These findings will be discussed in detail. [Preview Abstract] |
Saturday, October 18, 2014 10:59AM - 11:11AM |
B5.00003: Photo-Induced Typography with Vanadium Dioxide Thin Films Sanchari Sen, Md Nadim Ferdous Hoque, Luis Grave De Peralta, Zhaoyang Fan, Ayrton Bernussi We report photo-induced insulator-metal phase transition studies of vanadium dioxide (VO$_2$) thin films to generate rewritable patterns in the NIR using a combination of pump-probe technique, a scanning mirror and an IR camera. The structures consisted of VO$_2$ $\sim$150 nm thick films deposited on both sides of c-plane oriented sapphire substrates which temperature was controlled by a thermoelectric heater/cooler stage. Light from a CW high-power laser was deflected by the scanning mirror towards one of the sides of the sample to produce the desired patterns. An IR probe light source was used to illuminate the VO$_2$ samples and the images were obtained with an IR camera. The high power laser optically triggers the VO$_2$ insulator to metal phase transition and the scanned region becomes opaque to the IR irradiation. Clear and high contrast images with different shapes and sizes were demonstrated with the proposed technique. The characteristics of the generated patterns were controlled by the vibration amplitude of the scanning mirror. We anticipate that the developed approach can be prospectively used to realize reconfigurable Fresnel lenses, spatial light modulators, and optical equalizers operating in the NIR. [Preview Abstract] |
Saturday, October 18, 2014 11:11AM - 11:23AM |
B5.00004: Two Color Fluorescence Enhancement Using Gold Nanogratings Robert Hure, Samuel Simoneau, Jennifer Steele We demonstrate directional enhanced fluorescence emission from two fluorophores using a gold wire grating with a period of 500 nm. The dominant enhancement mechanism was found to be fluorophores decaying back to the ground state by exciting a surface plasmon mode, which can then radiate via the periodicity of the grating. Gratings were manufactured with soft lithography using silicon master gratings and polydimethylsiloxane (PDMS) molds. Fluorescent enhancement from the gold gratings corresponds to surface plasmons observed by measuring the transmission of white light through the gratings as a function of incident angle. Fluorescent enhancement of two fluorophores on one grating was observed using two different excitation lasers, producing similar enhancements. Fluorescent measurements were recorded by fixing the angle of a laser incident on the grating and varying the detector angle relative to the sample. [Preview Abstract] |
Saturday, October 18, 2014 11:23AM - 11:35AM |
B5.00005: DNA in Nanoscale Electronics Jason Slinker Functional nanowires and nanoelectronics are sought for their use in next generation integrated circuits, but several challenges limit the use of most nanoscale devices on large scales. DNA has great potential for use as a molecular wire due to high yield synthesis, near-unity purification, and nanoscale self-organization. Nonetheless, a thorough understanding of ground state DNA CT in electronic configurations under biologically relevant conditions, where the fully base-paired, double-helical structure is preserved, is lacking. We explored the fundamentals of charge transport (CT) through double-stranded DNA monolayers on gold by assessing 17 base pair bridges at discrete points with a redox active probe conjugated to a modified thymine. This assessment is performed under temperature-controlled and biologically relevant conditions with cyclic and square wave voltammetry, analyzing the redox peaks to assess transfer rate and yield. We demonstrate that the yield of transport is strongly tied to the stability of the duplex, linearly correlating with the melting temperature. Transfer rate is found to be temperature-activated and to follow inverse distance dependence, consistent with a hopping mechanism of transport. These results establish the governing factors of charge transfer speed and throughput in DNA molecular wires for device configurations, guiding subsequent application for nanoscale electronics. [Preview Abstract] |
Saturday, October 18, 2014 11:35AM - 11:47AM |
B5.00006: Transport Properties of Ferromagnet-Superconductor Hybrids near the Superconducting Transition Temperature Wonbae Bang, K.D.D. Rathnayaka, I.F. Lyuksyutov, W. Teizer, D.G. Naugle We have studied the transport properties of Ferromagnet-Superconductor Hybrids (FSH) near their superconducting transition temperature. The FSH was composed from periodic arrays of nanosized Ni stripes on the top of 100 nm thin Sn films. Electron-Beam Lithography was used to pattern the Sn films and the periodic arrays of Ni nanostripes on SiO$_{2}$ substrate. The Sn films and Ni nanostripes were deposited by thermal quench condensation at liquid nitrogen temperature. A thermally evaporated Germanium (Ge) thin film on top of the Sn films served as an insulating barrier between the Sn and Ni structures. We have studied dependence of resistivity and critical current on temperature and magnetic field normal to the film. We have observed strong hysteresis of resistivity and critical current in magnetic field. We have observed an anisotropy in the critical current depending on the current direction being parallel or perpendicular to the Ni nanostripes. [Preview Abstract] |
Saturday, October 18, 2014 11:47AM - 11:59AM |
B5.00007: Studies of Mn$_{12}$-Ph Single Molecule Magnets by LTSTS K. Reaves, P. Han, K. Iwaya, T. Hitosugi, D. Packwood, H.G. Katzgraber, H. Zhao, K.R. Dunbar, K. Kim, W. Teizer We study Mn$_{12}$O$_{12}$(C$_6$H$_5$COO)$_{16}$(H$_2$O)$_4$ (Mn$_{12}$-Ph) single-molecule magnets on a Cu(111) surface using scanning tunneling microscopy and scanning tunneling spectroscopy (LT-STS). We report the observation of Mn$_{12}$-Ph in isolation and in thin films, deposited through vacuum spray deposition onto clean Cu(111). The local tunneling current observed within the molecular structure shows a strong bias voltage dependency, which is distinct from that of the Cu surface. We will explore these I vs. V curves in detail and present a phenomenological explanation for the observed behavior. [Preview Abstract] |
Saturday, October 18, 2014 11:59AM - 12:11PM |
B5.00008: STM Tip-Induced Growth of Silver Islands Blake Birmingham, Yaobiao Xia, Dmitri V. Voronine, Kenneth T. Park, Zhenrong Zhang, Marlan O. Scully Nanomanipulation of coinage metal islands growth is important for the preparation of surface-enhanced Raman scattering substrates. In this study, the growth of large scale island features on Ag(111) was observed at room temperature via Scanning Tunneling Microscope (STM). This island growth is attributed to tip-induced dynamic diffusion of the surface Ag atoms between terraces and was observed with tungsten and silver tips. The growth is induced in regions where the Ag(111) has been scanned. The rate of diffusion directly relates to the number of times an area has been scanned. This phenomenon was investigated by varying the size and the depth of the initial islands and by controlling tip condition. [Preview Abstract] |
Saturday, October 18, 2014 12:11PM - 12:23PM |
B5.00009: One Step Microwave Synthesis of Size Controlled Monodisperse Noble Metal and Bimetallic Nanoparticles using Polymers Jewell Anne Hartman, Kim Hart, Bryce Brownfield, Kyle Culhane, Justin Case, Andrew Ballast, Ke Jiang, Anatoliy Pinchuk The size controlled synthesis of near monodisperse and stable noble metal and bimetallic nanoparticles was achieved through the development of one-step microwave assisted polymer stabilized techniques. Two synthetic techniques are presented. The first is a dendrimer assisted technique that uses the dendrimer polyethelenimine (PEI) as both a reducing and stabilizing agent for the synthesis of stable, size controlled noble metal and bimetallic alloy nanoparticles. Size control was achieved through a dual-faceted process by modifying the mass ratio of metal salt to dendrimer or maintaining the mass ratio and modifying the temperature. PEI was chosen since nanoparticles encapsulated with PEI have exhibited stability and antibacterial properties. The microwave parameters were optimized for reaction yield using the Box-Benhken design in terms of time, temperature, and pressure. The second is a green chemistry synthesis technique using the reducing sugar mannose for the synthesis of noble metal nanoparticles. Nanoparticles sizes were estimated using UV/Visible Absorption Spectroscopy, dynamic light scattering and scanning electron microscopy. Mie theory calculations of the extinction spectra for an identical size nanoparticle are also presented. [Preview Abstract] |
Saturday, October 18, 2014 12:23PM - 12:35PM |
B5.00010: Solid Propellant Microthrusters based on Nanoenergetic Gas Generators Mkhitar Hobosyan, Ivan Puchades, Lynn Fuller, Sergey Lyshevski, Karen Martirosyan Space flight propulsion systems for microsatellites (20-100kg) and nanosatellites (less than 20kg) require microthrusters to enable to control a small adjustment in flight mission such as payload delivery, stabilization, guidance, navigation, etc. In this work, we examine high-energy-density nano-energetic materials integrated with Microelectromechanical Systems (MEMS) for application of specific flight purposes. From wide variety of possible nano-energetic systems, Al-I$_{2}$O$_{5}$ and Al-Bi$_{2}$O$_{3}$ were chosen due to their superior energetic performance compared to other systems. The nano-energetic materials represent higher energy density per volume and pressure discharge values compared to traditional propellants. These advantages guarantee to enhance the thrust-to-weight and thrust-to-power ratios, specific impulse, effective exhaust velocity, thrust, energy density, controlled combustion, etc. The application-specific thrust profiles can be ensured by microthrusters and their arrays. We present experimental substantiation, evaluation and characterization of fabricated proof-of-concept devices with nanoenergetic propellants. [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. |
© 2025 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