Bulletin of the American Physical Society
APS March Meeting 2018
Volume 63, Number 1
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session E18: Quantum Wires and 1-Dimensional Nanostructures: Fabrication and Characterization |
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Sponsoring Units: DCMP Chair: Adam Biacchi, National Institute of Standards and Technology (NIST) Room: LACC 306B |
Tuesday, March 6, 2018 8:00AM - 8:12AM |
E18.00001: Single-Step High-Yield Growth of Well Oriented Carbon Nanotubes by Plasma Enhanced Chemical Vapor Deposition Wei-Shiuan Tseng, Wei-Hsiang Lin, Chih I Wu, Nai-Chang Yeh The excellent electrical and mechanical properties of carbon nanotubes (CNTs) have enabled their incorporation in many commercial applications. In order to optimize the performance of CNT-based integrated electronics, it is desirable to develop a growth method that can produce highly-oriented CNTs with large aspect ratios. Here we report a new single-step seeded growth method of well oriented CNTs with high yields (up to 3 mg on ~ 1 cm2 area within 10 minutes) by plasma-enhanced chemical vapor deposition (PECVD) on a substrate consisting of a thin copper layer on top of SiO2/Si. Interestingly, we found that by varying the thickness of the copper layer on the substrate while keeping the same PECVD growth parameters, the carbon nanostructures synthesized ranged from graphene nano-stripes (with the long dimension up to ~ 10 μm on the substrate) to densely packed and vertically oriented CNTs (with the long dimension up to ~ 20 μm perpendicular to the substrate). Systematic studies of the growth parameters and the resulting structural and spectroscopic characteristics of these CNTs (determined by measurements of the Raman spectroscopy, XPS, UPS, SEM, AFM, TEM and EDS) are being carried out to optimize the growth conditions and to help unveil the growth mechanism. |
Tuesday, March 6, 2018 8:12AM - 8:24AM |
E18.00002: Molecular Dynamics Insight in the Tilt Effect of Carbon Nanotubes in Small Assemblies Haoyan Sha, Roland Faller Carbon nanotubes (CNTs) of finite length assembled in small bundles were modeled with molecular dynamics simulations. Instead of the generally considered parallel alignment of CNTs for long sizes and large assemblies, an interesting tilt angle is observed in the small hexagonal 7 CNT bundle, in which the outer 6 CNTs spirally tilt to one direction with respect to the CNT in the center. This effect was characterized with CNTs of different lengths. The tilt angle shows a strong length dependence in the short length regime and disappears at longer lengths. In addition, the tilt angle affected by CNT diameter was analyzed with CNTs of various diameters. Narrower CNTs are more parallel, while thicker ones show larger tilt angles and stronger vibrations. This tilt effect was confirmed for both armchair and zigzag type CNTs. The present work for the first time unveils the tilt effect of small CNT bundles in finite length. |
Tuesday, March 6, 2018 8:24AM - 8:36AM |
E18.00003: A New Directly Placement Method For Individual Carbon Nanotube Devices And Its Applications To The Nanomechanical Resonators Xinhe Wang, Xiaoyang Lin, guangwei deng, dong zhu, jiangtao wang, guoping guo, Kaili Jiang Though carbon nanotube (CNT) is acknowledged as an ideal system for one-dimensional physics, making ultraclean nanotubes with electrical circuits of arbitrary complexity is still a challenge. We develop a new directly deterministic placement technique that allows us to operate each CNT under an optical microscope and ambient conditions. For an individual ultralong few walled CNT, after deposit nanoparticles on the suspended part of it for visualization, we draw the inner shell of the CNT, and transfer it between the two homemade tips, then place it to the target placement on the device chip. The CNTs transferred are perfect clean since they are inner shell of the CNTs and not suffer from any wet process. The way to transfer and placement is so flexible and steerable that the construction of complex multi-nanotube devices can be allowed. Using this technique, we fabricate the CNT electromechanical resonators and study the different types of coupling effects, including the Rabi oscillation of the coherent phonon between the coupling modes and the nonlocal coupling of phonon. Further, we realized the stressed CNT devices for high tunability, high quality factor, single mode GHz resonators. |
Tuesday, March 6, 2018 8:36AM - 8:48AM |
E18.00004: Synthesis of boron-nitride nanostructures in volume plasma longtao Han, Predrag Krstic Computer simulations of syntesis of nanocages, nanotubes, nanoflakes and cubic boron-nitride have been performed by qunatum-classical molecular dynamics. Hydrogen plays a decisive role in transformation of a hexagonal, sp2 hybridized BN structure to the sp3, tetrahedral cBN structure. We determine the optimal size and temeprature for this tranformation. Analysis of the hybridization of the B and N atoms during the transformation and created rings, change of Lindemann index, chnage of formation energy and entropy provide kinetic and thermodynamic picture of these processes of the B-N self-organization. |
Tuesday, March 6, 2018 8:48AM - 9:00AM |
E18.00005: The Interaction of Carbon and Boron Nitride Nanotubes with Metals Christoph Rohmann, Michael Zwolak The interaction of carbon and boron nitride nanotubes with metals is significant for a wide variety of applications. For example, the binding of tubes to transition metal nanoparticles plays a role in their catalytic growth, as well as in their nucleation. Similarly, the strength of nanotube-metal composites crucially depends on the interaction strength between the tube and the metal matrix. We performed quantum chemical calculations to investigate the binding strength and geometry of a variety of metals with carbon and boron nitride nanotubes. We examined both binding by individual metal atoms and the interaction with metallic surfaces, including by graphene and hexagonal boron nitride in addition to tubes. We will discuss the trends in binding energies, as well as the changes in the density of states induced by adsorption. |
Tuesday, March 6, 2018 9:00AM - 9:12AM |
E18.00006: The 1-D Camelback Potential in the Parallel Dipole Line Magnetic Trap: Physics and Applications Oki Gunawan, Yudistira Virgus We recently reported the discovery of a new type of field confinement effect that generates a fascinating 1-D camelback potential trap in a system of two lines of transverse dipoles [1,2]. This effect is the key feature that enables the system to serve as a new type of natural magnetic trap called parallel dipole line (PDL) trap. The trap can be realized with a pair of cylindrical magnets with uniform transverse magnetization and a graphite rod as the trapped object. We show that the camelback potential effect only occurs when the length of the PDL system is beyond certain critical length (LC). We present more detailed experimental and theoretical studies of the finite size effect of the graphite rod and its impact on the stability and oscillation dynamics of the trap. The size (length and radius) of the magnets and the trapped rod determines the frequency and the damping of the oscillator respectively. We also discuss several applications of the trap such as for magnetic susceptometer and gas viscometer. [1] Appl. Phys. Lett. 106, 062407 (2015). [2] J. Appl. Phys. 121, 133902 (2017). |
Tuesday, March 6, 2018 9:12AM - 9:24AM |
E18.00007: Lateral Force Coupling in Piezoelectric GaN Nanorods Grown on Pyramided Si Substrate Chung Lin Wu, Chun-Yeh Lin, Jhih-Wei Chen, Shu-Ju Tsai, Chia-Hao Chen How to efficiently harvesting piezoelectric energy is a critical issue for scavenging ambient mechanical motion for driving compact, low-power, multi-functional electronic devices. Herein, by applying a normal force, we report an innovative structure for harvesting piezoelectric energy from bending the obliquely aligned GaN piezoelectric nanorods (NRs) that are integrated with the vertically integrated nanogenerator (VING) by using plasma-assisted molecular beam epitaxy (PA-MBE) technique. Using conductive atomic force microscope (AFM), a remarkable change in the Schottky barrier height (SBH) between the tip and GaN NR is observed upon bending an oblique-aligned GaN NR. This demonstrates that a remarkably enhanced piezoelectric performance of GaN NRs can be achieved by coupling a lateral force. |
Tuesday, March 6, 2018 9:24AM - 9:36AM |
E18.00008: Template Assisted Electrochemical Deposition on Substrates, Tapes and Wires for Nanotechnology Applications Jason Giuliani, John Cadena, Carlos Monton Anodic aluminum oxide-template-assisted electrochemical deposition (AAO-ED) is a popular technique to fabricate multi composition nanowires (NW) using self-supported AAO membranes. AAO-ED in conjunction with other techniques allows for the fabrication of complex, multi-compositional, core-shell NW architectures which possess physical properties, such as giant magnetoresistance, photonics, thermoelectric, and plasmonics. However, self-supported AAO templates have one main limitation, when the AAO template is removed it leaves a disordered NW distribution. In this work, we introduce a variation of the AAO-ED technique that allows for the growth of multi-compositional NWs on almost any surface and preliminary results show that unlike lithographic techniques, the NWs can even be synthesized on 3D surfaces. We applied this method to synthesize Ni and segmented Ni/Au NWs on Si substrates, flexible Cu tape, and thin Cu wires. This demonstrates that the proposed method can be applied to manufacture complex devices for nanotechnology applications. |
Tuesday, March 6, 2018 9:36AM - 9:48AM |
E18.00009: Design of NbN superconducting nanowire single photon detectors with enhanced infrared photon detection efficiency Qiang Wang, Jelmer Renema, Andreas Engel, Michiel de dood We optimize the design of nanowire superconducting single photon detectors (SNSPD) by accounting for a position dependence in the internal detection efficiency (IDE): wide wires biased at relatively lower currents (~80% of the depairing current) have higher detection efficiency for photons absorbed at the edges compared to the central part. This can be explained by a higher optical absorption for photons at the edges combined with a lower barrier for vortex entry and vortex crossing is the dominant effect in a detection event. |
Tuesday, March 6, 2018 9:48AM - 10:00AM |
E18.00010: Tunable Low Density Palladium Nanowire Foams Dustin Gilbert, Edward Burks, Kai Liu, Sergey Ushakov, Alexandra Navrotsky, Patricia Abellan, Ilke Arslan, Thomas Felter Nanostructured metal foams offer exciting potential for applications in diverse fields such as biomedical, aerospace and chemical engieering. We have fabricated palladium nanowire foams with opportunities in catalysts, fuel cells, and hydrogen storage technologies using a cross-linking and freeze-drying technique. These foams have a tunable density down to 0.1% of the bulk, and a surface area to volume ratio of up-to 1.54×106 :1 m-1. These foams exhibit highly attractive characteristics for hydrogen storage, in terms of loading capacity, rate of absorption and heat of absorption.[1] The hydrogen absorption/desorption process is hysteretic in nature, accompanied by substantial lattice expansion/contraction as the foam converts between Pd and PdHx. |
Tuesday, March 6, 2018 10:00AM - 10:12AM |
E18.00011: Charge Transfer in the Palladium Based Bi-Metallic Nano-Systems PdAg, PdPt and PdAu Carlos Quintanar, Reyna Caballero, Maira Ramos, Elizabeth Chavira, Magali Ugalde, Francisco Espinosa In this work, we aimed to understand the characteristics of non-ideal bi-metallic systems, samples with porous and large surface areas. In doing this we studied in particular, silver-palladium, platinum-palladium and gold-palladium nano surfaces. For that, a variety of experimental methods including sputtering, sol-gel, high resolution transmission electron microscopy and energy dispersive x-ray spectrometry have been combined with density functional theory, for the preparation, characterization and modelling of palladium, silver, platinum, gold, palladium-silver, palladium-platinum and palladium-gold nano systems. |
Tuesday, March 6, 2018 10:12AM - 10:24AM |
E18.00012: Characterization of ZnO in Infiltrated PS-b-PMMA Paris Blaisdell-Pijuan We have characterized the growth of ZnO using sequential infiltration synthesis (SiS) in PS-b-PMMA block copolymers (BCP) of spherical and cylindrical sub-20nm morphologies and studied how the photoluminescence of these nanostructures varies per its seed layer. We report blue-shifted photoemission at 335 nm (3.70 eV), suggesting quantum confinement effects. Infiltrated ZnO prepared with an alumina seed layer showed additional defect state photoemission at 470 nm and 520 nm for spherical and cylindrical BCP morphologies, respectively. Defect photoemission was not observed in samples prepared without a seed layer. No Raman peaks were observed for any samples with less than four cycles of ZnO, implying these ZnO nanostructures are isolated emitters. Samples annealed in air above 500 oC began to coalesce and show photoemission characteristic of bulk ZnO at 370 nm (3.35 eV). Our work demonstrates that ZnO nanostructures grown on PS-b-PMMA via SiS are advantageous in uniformity and size, and exhibit unique fluorescence properties. The nature of PS-b-PMMA as a photoresist allows infiltrated ZnO to be easily manipulated with lithography for on-chip compact light sources, photodetectors, photodiodes, and other various quantum materials and CMOS applications. |
Tuesday, March 6, 2018 10:24AM - 10:36AM |
E18.00013: Synthesis of Single-Crystalline VO2 Nanostructures of Various Shapes and their Structural Phase Transition Mohd Faiyaz, Jung Won Choi, Sung Soo Ha, Hojun Oh, Kangwoo Ahn, Muhammad Ijaz Anwar Mahar, Hyon Chol Kang, Do Young Noh Vanadium dioxide is a strongly correlated oxide material exhibiting first-order metal−insulator transition (MIT) which is accompanied by a structural phase transition from a low T monoclinic to a high T rutile phase at ~68°C in bulk. For potential applications such as catalytic, sensor and thermoelectric devices based on this MIT, controlling the nanoscale morphology and understanding the dependence of MIT on the morphology are important issue. We report a systematic synthesis of VO2 nanostructures with controlled morphology. Twin boundaries played a key role in determining the shape of nanostructures as revealed in SEM and TEM microscopy images. Comprehensive in-situ x-ray scattering experiments were performed and data illustrate that MIT Temperature depends sensitively on the morphology of nanostructures. We tuned the MIT from 64°C to as low as 54°C by changing the shape and size of VO2 nanostructures. We found that MIT temperature decreases as the dimension of nanostructure decreases, which can be attributed to the increased number of heterogeneous nucleation centers such as O2 vacancies. We also present optical microscope images revealing dynamics of the metallic domain growth and reciprocal space map of XRD profile on a single VO2 Nanowire |
Tuesday, March 6, 2018 10:36AM - 10:48AM |
E18.00014: Pulsed laser deposition of In2O3-SnO2: from films to nano-wires Davide Del Gaudio, Erica Mason, Benjamin Serratos, John Heron, Ilan Shalish, Rachel Goldman Metal oxides have been identified as promising materials many devices, such as lithium ion batteries and UV lasers. Furthermore, metal-oxide NWs have been embedded in field-effect transistors, lasers, solar cells, and various chemical sensors. Pulsed-laser deposition (PLD) has emerged as a promising approach for the fabrication of tin-doped indium oxide (ITO), with film or NW growth determined by the choice of a reactive (O2) or inert (N2) atmosphere. However, a mechanistic understanding of the influence of growth parameters on the morphology, composition, and crystal structure of the deposited film is needed. Additionally, PLD of various In2O3-SnO2 mixtures has yet to be considered. We report on PLD of various In2O3 -SnO2 mixtures on sapphire substrates. Using an inert atmosphere, we have identified parameters to obtain pyramid-shaped nano-scale clusters; tapered nano-rods; and high density, vertically oriented NWs. We explain the influence of deposition pressure on the growth mode transition from straight NW to tapered NW to pyramidal nano-clusters. Additionally, we examine the influence of deposition pressure and NW diameter on the NW resistivity, obtained via single-NW IV characteristics measurements. |
Tuesday, March 6, 2018 10:48AM - 11:00AM |
E18.00015: Nanostructuring of Hybrid Halide Perovskites Down to stable Low-Dimensional and Semi-Metallic Allotropes: An ab initio study Muhammad Ejaz Khan, Yong-Hoon Kim Based on density functional theory (DFT) calculations, we studied the nanostructuring of the recently synthesized organic-inorganic trimethylsulfonium lead triiodide (CH3)3SPbI3 perovskite, which showed a high ambient stability and an optical bandgap that extends into the visible range. We find that the two-dimensional (2D) monolayer and one-dimensional (1D) nanowire structures derived from three-dimensional (3D) (CH3)3SPbI3 perovskite are energetically and dynamically stable. Furthermore, it is found that the inorganic 1D face-sharing PbI6 framework prepared by removal of ligands is also structurally stable. Comparison of the electronic band structures of the 3D, 2D and 1D (CH3)3SPbI3 allotropes shows that the band edge-region electronic structures are robustly determined at the 1D level. Most interestingly, we find that the 1D PbI6 becomes semi-metallic, showing the possibility of deriving structurally and electronically diverse stable nanomaterials based on the parental 1D (CH3)3SPbI3 component. We propose that these (CH3)3SPbI3– and PbI6–derived 2D and 1D hybrid perovaskites are promising candidates to be combined with other 2D materials such as transition metal dichalcogenides to achieve novel vertical heterosturctures for advanced electronic and optoelectronic applications. |
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