APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

10 Sep 2012

Volume 101, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 101, 113302 (2012); http://dx.doi.org/10.1063/1.4749791 (4 pages)

Chang-Hoon Shim, Shuzo Hirata, Juro Oshima, Tomohiko Edura, Reiji Hattori, and Chihaya Adachi
Enlarge Image | Read More
Page 3 of 5 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Evaluation of vortex pinning across low angle grain boundary in YBa2Cu3O7 film

Tomoya Horide and Kaname Matsumoto

Appl. Phys. Lett. 101, 112604 (2012); http://dx.doi.org/10.1063/1.4752462 (4 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Vortex pinning potential across a 5° tilt low angle grain boundary (GB) was evaluated by measuring angular dependences of critical current density in a bicrystal YBa2Cu3O7 film under the variable Lorentz force configuration. Trapping angles of the GB depend on directions in the GB plane (70°–80° and 15°–45° for the c-axis direction and the ab plane one, respectively), due to anisotropic pinning of GB dislocations. Pinning potential across a GB is as large as that of heavy ion irradiated columnar defects, indicating that density and distribution of GBs should be controlled to improve vortex pinning in coated conductors.
Show PACS
74.25.Wx Vortex pinning (includes mechanisms and flux creep)
61.72.Mm Grain and twin boundaries
74.72.-h Cuprate superconductors
74.25.Sv Critical currents
61.80.Jh Ion radiation effects
74.78.-w Superconducting films and low-dimensional structures
back to top
RSS Feeds

Effects of lateral and substrate constraint on the piezoresponse of ferroelectric nanostructures

A. Bernal, A. Tselev, Sergei Kalinin, and Nazanin Bassiri-Gharb

Appl. Phys. Lett. 101, 112901 (2012); http://dx.doi.org/10.1063/1.4751343 (4 pages)

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of lateral constraint and substrate clamping on piezoresponse of ferroelectric materials at small scale are quantitatively evaluated in PbZr0.52Ti0.48O3 nanotubes. Lateral clamping results in a reduction of the extrinsic contributions to the piezoresponse by almost an order of magnitude at low and intermediate fields. Similarly, at aspect ratios below 3:1 (height to width), constraint to the substrate leads to a drastic reduction of the extrinsic contributions to the piezoelectric response of the ferroelectric nanostructures. Both behaviors can be explained by an increased energy requirement for formation and motion of the ferroelastic non-180° domain walls in mechanically constrained systems.
Show PACS
77.80.-e Ferroelectricity and antiferroelectricity
61.46.Fg Nanotubes
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
77.65.-j Piezoelectricity and electromechanical effects

Experimental and theoretical investigation of the effect of SiO2 content in gate dielectrics on work function shift induced by nanoscale capping layers

J. A. Caraveo-Frescas, H. Wang, U. Schwingenschlögl, and H. N. Alshareef

Appl. Phys. Lett. 101, 112902 (2012); http://dx.doi.org/10.1063/1.4747805 (4 pages) | Cited 1 time

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The impact of SiO2 content in ultrathin gate dielectrics on the magnitude of the effective work function (EWF) shift induced by nanoscale capping layers has been investigated experimentally and theoretically. The magnitude of the effective work function shift for four different capping layers (AlN, Al2O3, La2O3, and Gd2O3) is measured as a function of SiO2 content in the gate dielectric. A nearly linear increase of this shift with SiO2 content is observed for all capping layers. The origin of this dependence is explained using density functional theory simulations.
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

The structural and piezoresponse properties of c-axis-oriented Aurivillius phase Bi5Ti3FeO15 thin films deposited by atomic vapor deposition

P. F. Zhang, N. Deepak, L. Keeney, M. E. Pemble, and R. W. Whatmore

Appl. Phys. Lett. 101, 112903 (2012); http://dx.doi.org/10.1063/1.4752007 (4 pages) | Cited 1 time

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The deposition by atomic vapor deposition of highly c-axis-oriented Aurivillius phase Bi5Ti3FeO15 (BTFO) thin films on (100) Si substrates is reported. Partially crystallized BTFO films with c-axis perpendicular to the substrate surface were first deposited at 610 °C (8% excess Bi), and subsequently annealed at 820 °C to get stoichiometric composition. After annealing, the films were highly c-axis-oriented, showing only (00l) peaks in x-ray diffraction (XRD), up to (0024). Transmission electron microscopy (TEM) confirms the BTFO film has a clear layered structure, and the bismuth oxide layer interleaves the four-block pseudoperovskite layer, indicating the n = 4 Aurivillius phase structure. Piezoresponse force microscopy measurements indicate strong in-plane piezoelectric response, consistent with the c-axis layered structure, shown by XRD and TEM.
Show PACS
77.65.-j Piezoelectricity and electromechanical effects
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.hn Other piezoelectric or electrostrictive films
81.40.Gh Other heat and thermomechanical treatments
61.66.Bi Elemental solids
61.66.Dk Alloys
68.55.aj Insulators

Defect mechanisms in high resistivity BaTiO3–Bi(Zn1/2Ti1/2)O3 ceramics

Natthaphon Raengthon, Victoria J. DeRose, Geoffrey L. Brennecka, and David P. Cann

Appl. Phys. Lett. 101, 112904 (2012); http://dx.doi.org/10.1063/1.4752452 (5 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF


See Also: Publisher's Note

Show Abstract
The defect mechanisms that underpin the high energy density dielectric 0.8BaTiO3–0.2Bi(Zn1/2Ti1/2)O3 were investigated. Characterization of the nominally stoichiometric composition revealed the presence of a Ti3+-related defect center, which is correlated with lower resistivities and an electrically heterogeneous microstructure. In compositions with 2 mol. % Ba-deficiency, a barium vacancy-oxygen vacancy pair (VBa−VO), acted as an electron-trapping site. This defect was responsible for a significant change in the transport behavior with a high resistivity and an electrically homogeneous microstructure.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
61.72.jd Vacancies
61.72.-y Defects and impurities in crystals; microstructure
61.66.Bi Elemental solids
61.66.Dk Alloys
77.65.-j Piezoelectricity and electromechanical effects
77.84.Cg PZT ceramics and other titanates

Effect of electrode materials on the scaling behavior of energy density in Pb(Zr0.96Ti0.03)Nb0.01O3 antiferroelectric films

Jun Ge, Gang Pan, Denis Remiens, Ying Chen, Fei Cao, Xianlin Dong, and Genshui Wang

Appl. Phys. Lett. 101, 112905 (2012); http://dx.doi.org/10.1063/1.4752726 (3 pages) | Cited 4 times

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Antiferroelectric Pb(Zr, Nb, Ti)O3 (PZNT) films were deposited via a sol-gel process on Pt(111)/Ti/SiO2/Si, LaNiO3- and La0.5Sr0.5CoO3-buffered Si substrate. The scaling behavior of the energy density W of antiferroelectric films was investigated. The scaling behavior of W against frequency f of PZNT on LaNiO3-buffered Si takes the form of W ∝ f0.08, which differs significantly from that form of W ∝ f−0.14 of PZNT on La0.5Sr0.5CoO3-buffered Si. This indicates that the scaling relations of W vary substantially as bottom electrodes change and might be closely related to the variation of nonuniform strain field and depolarization field within the AFE films.
Show PACS
77.55.hn Other piezoelectric or electrostrictive films
77.80.bj Scaling effects
77.84.Ek Niobates and tantalates

Dehydroxyl effect of Sn-doped silicon oxide resistance random access memory with supercritical CO2 fluid treatment

Tsung-Ming Tsai, Kuan-Chang Chang, Ting-Chang Chang, Yong-En Syu, Kuo-Hsiao Liao, Bae-Heng Tseng, and Simon M. Sze

Appl. Phys. Lett. 101, 112906 (2012); http://dx.doi.org/10.1063/1.4750235 (4 pages) | Cited 3 times

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The tin-doped can supply conduction path to induce resistance switching behavior. However, the defect of tin-doped silicon oxide (Sn:SiOx) increased the extra leakage path lead to power consumption and joule heating degradation. In the study, supercritical CO2 fluids treatment was used to improve resistive switching property. The current conduction of high resistant state in post-treated Sn:SiOx film was transferred to Schottky emission from Frenkel-Poole due to the passivation effect. The molecular reaction model is proposed that the defect was passivated through dehydroxyl effect of supercritical fluid technology, verified by material analyses of x-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.
Show PACS
84.30.Sk Pulse and digital circuits
back to top
RSS Feeds

Correlating stress generation and sheet resistance in InAlN/GaN nanoribbon high electron mobility transistors

Eric J. Jones, Mohamed Azize, Matthew J. Smith, Tomás Palacios, and Silvija Gradečak

Appl. Phys. Lett. 101, 113101 (2012); http://dx.doi.org/10.1063/1.4752160 (5 pages)

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the nanoscale characterization of the mechanical stress in InAlN/GaN nanoribbon-structured high electron mobility transistors (HEMTs) through the combined use of convergent beam electron diffraction (CBED) and elastic mechanical modeling. The splitting of higher order Laue zone lines in CBED patterns obtained along the [540] zone axis indicates the existence of a large strain gradient in the c-direction in both the planar and nanoribbon samples. Finite element models were used to confirm these observations and show that a passivating layer of Al2O3 can induce a tensile stress in the active HEMT layer whose magnitude is dependent on the oxide layer thickness, thus, providing important ramifications for device design and fabrication.
Show PACS
85.75.Hh Spin polarized field effect transistors
Author Select

Growth and stability of Pt on Au nanorods

D. S. He, Y. Han, J. Fennell, S. L. Horswell, and Z. Y. Li

Appl. Phys. Lett. 101, 113102 (2012); http://dx.doi.org/10.1063/1.4751288 (4 pages) | Cited 1 time

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a systematic study of Pt overgrowth on Au nanorods via a wet chemistry approach. The atomic resolved imaging provides direct evidence of initial epitaxial growth of Pt on the surface of Au nanorods, with a preferential deposition occurring at the rod ends. Over a period of one and half years, the carbon-supported nanorods are shown to have undergone a structural transformation when they are kept at ambient conditions, in contrast to the rods kept in solutions whose structure remains stable. Further controlled experiments show morphological changes of the nanorods upon annealing. We discuss the results in terms of the role that kinetics vs. thermodynamics plays in the observed phenomena.
Show PACS
81.07.Bc Nanocrystalline materials
61.46.-w Structure of nanoscale materials
81.16.Be Chemical synthesis methods
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
81.40.Gh Other heat and thermomechanical treatments
64.70.kd Metals and alloys

Anisotropic optical absorption of organic rubrene single nanoplates and thin films studied by μ-mapping absorption spectroscopy

Hyunsoo Lee, Ji Hyun Kim, Krishna P. Dhakal, Jin Woo Lee, Jin Sun Jung, Jinsoo Joo, and Jeongyong Kim

Appl. Phys. Lett. 101, 113103 (2012); http://dx.doi.org/10.1063/1.4751981 (4 pages)

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Local absorption spectra and absorption coefficients were obtained from organic rubrene single nanoplates. Absorption along the b-axis was higher than along the a-axis for polarized illumination on an ab-faced single-crystal rubrene nanoplate, and the lowest crystal transition peak (∼530 nm) relatively increased in size with an increasing incidence angle due to the anisotropic absorption strength along the crystal axes. Rubrene thin films grown by organic molecular beam deposition displayed microscopically varying absorption spectra; the relative peak height of the M-polarized band and the overall absorption strength were strongest with polarized illumination along the c-axis.
Show PACS
78.66.Qn Polymers; organic compounds
78.55.Kz Solid organic materials
78.40.Me Organic compounds and polymers
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
81.16.-c Methods of micro- and nanofabrication and processing
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Superlattice-like electrode for low-power phase-change random access memory

Yegang Lu, Sannian Song, Zhitang Song, Liangcai Wu, Aodong He, Yuefeng Gong, Feng Rao, and Bo Liu

Appl. Phys. Lett. 101, 113104 (2012); http://dx.doi.org/10.1063/1.4751258 (4 pages)

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Superlattice-like top electrode formed alternately by TiN and W was embedded into phase-change random access memory (PCRAM) with the aim of reducing the power. Ga2Sb4Te3 film is employed as phase change layer. The minimum reset voltage of PCRAM based on superlattice-like electrode was significantly lower than that of one based on the conventional electrode. The set operation can be completed by an electric pulse as short as 5 ns. The superlattice-like-electrode-based PCRAM can be normally operated at 120 °C with endurance up to 1 × 106 cycles. The low thermal conductivity of superlattice-like electrode is responsible for the performance improvement of PCRAM.
Show PACS
84.30.Sk Pulse and digital circuits
85.40.Sz Deposition technology

Stochastic simulation of tip-sample interactions in atomic force microscopy

Aleksander Labuda, Martin Lysy, and Peter Grütter

Appl. Phys. Lett. 101, 113105 (2012); http://dx.doi.org/10.1063/1.4745781 (4 pages) | Cited 3 times

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Atomic force microscopy (AFM) simulators, which are used to gain insight into tip-sample physics and data interpretation, so far have been optimized for modeling deterministic cantilever dynamics. In this article, we demonstrate a method for semi-empirical simulation of the stochastic dynamics of tip-sample interactions. The detection, force, and displacement noises are separately generated directly from their numerically defined power spectral densities and used to simulate a force spectroscopy experiment in water at the mica interface. Mechanical noise of the AFM is shown to dominate over thermal noise of the cantilever upon interaction with the last two hydration layers.
Show PACS
07.79.Lh Atomic force microscopes
02.50.Ey Stochastic processes
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion

Single-mode lasing of GaN nanowire-pairs

Huiwen Xu, Jeremy B. Wright, Ting-Shan Luk, Jeffery J. Figiel, Karen Cross, Luke F. Lester, Ganesh Balakrishnan, George T. Wang, Igal Brener, and Qiming Li

Appl. Phys. Lett. 101, 113106 (2012); http://dx.doi.org/10.1063/1.4751862 (4 pages) | Cited 1 time

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Stable single-mode lasing operation from a pair of coupled GaN nanowires is demonstrated through optical pumping. GaN nanowires with different lengths were placed side-by-side in contact to form a coupled cavity through nanoprobe manipulation. Unlike individual nanowire lasers, which operate in a combined multiple transverse and multiple longitude mode oscillation, a coupled nanowire-pair provides a mode selection mechanism through the Vernier effect, which can strongly enhance the free spectrum range between adjacent resonant modes and generate a stable single-mode operation with a high side-mode suppression ratio.
Show PACS
42.60.-v Laser optical systems: design and operation
42.55.-f Lasers
42.79.-e Optical elements, devices, and systems

Prediction of strong ground state electron and hole wave function spatial overlap in nonpolar GaN/AlN quantum dots

S. Schulz, M. A. Caro, and E. P. O'Reilly

Appl. Phys. Lett. 101, 113107 (2012); http://dx.doi.org/10.1063/1.4752108 (4 pages)

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a detailed analysis of the electrostatic built-in field, the electronic structure, and the optical properties of a-plane GaN/AlN quantum dots with an arrowhead-shaped geometry. This geometry is based on extensive experimental analysis given in the literature. Our results indicate that the spatial overlap of electron and hole ground state wave functions is significantly increased, compared to that of a c-plane system, when taking the experimentally suggested trapezoid-shaped dot base into account. This finding is in agreement with experimental data on the optical properties of a-plane GaN/AlN quantum dots.
Show PACS
71.20.Nr Semiconductor compounds
73.21.La Quantum dots
78.67.Hc Quantum dots

Photoluminescence from GaAs nanodisks fabricated by using combination of neutral beam etching and atomic hydrogen-assisted molecular beam epitaxy regrowth

Toshiyuki Kaizu, Yosuke Tamura, Makoto Igarashi, Weiguo Hu, Rikako Tsukamoto, Ichiro Yamashita, Seiji Samukawa, and Yoshitaka Okada

Appl. Phys. Lett. 101, 113108 (2012); http://dx.doi.org/10.1063/1.4752233 (4 pages)

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have fabricated GaAs nanodisk (ND) structures by using a combination of neutral beam etching process and atomic hydrogen-assisted molecular beam epitaxy regrowth. We have observed clear photoluminescence (PL) emissions from GaAs NDs. The peak energy showed a blueshift due to the quantum confinement in three spatial dimensions, and it agreed with the theoretically estimated transition energy. The PL results also showed that the cap-layer disks act as radiative recombination centers. We have confirmed that the PL emission originates from the GaAs NDs, and our approach is effective for the fabrication of high quality ND structures.
Show PACS
81.16.Rf Micro- and nanoscale pattern formation
78.55.Cr III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.07.Ta Quantum dots
81.65.Cf Surface cleaning, etching, patterning
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures

Photoconduction efficiencies and dynamics in GaN nanowires grown by chemical vapor deposition and molecular beam epitaxy: A comparison study

R. S. Chen, H. Y. Tsai, Y. S. Huang, Y. T. Chen, L. C. Chen, and K. H. Chen

Appl. Phys. Lett. 101, 113109 (2012); http://dx.doi.org/10.1063/1.4752230 (4 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The normalized gains, which determines the intrinsic photoconduction (PC) efficiencies, have been defined and compared for the gallium nitride (GaN) nanowires (NWs) grown by chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). By excluding the contributions of experimental parameters and under the same light intensity, the CVD-grown GaN NWs exhibit the normalized gain which is near two orders of magnitude higher than that of the MBE-ones. The temperature-dependent time-resolved photocurrent measurement further indicates that the higher photoconduction efficiency in the CVD-GaN NWs is originated from the longer carrier lifetime induced by the higher barrier height (ϕB = 160 ± 30 mV) of surface band bending. In addition, the experimentally estimated barrier height at 20 ± 2 mV for the MBE-GaN NWs, which is much lower than the theoretical value, is inferred to be resulted from the lower density of charged surface states on the non-polar side walls.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
78.67.Uh Nanowires
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
79.60.Bm Clean metal, semiconductor, and insulator surfaces
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Transition between ballistic and diffusive heat transport regimes in silicon materials

Martin Maldovan

Appl. Phys. Lett. 101, 113110 (2012); http://dx.doi.org/10.1063/1.4752234 (5 pages) | Cited 1 time

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the extent of ballistic and diffusive thermal transport and the range of application of the Casimir and Fourier theories in semiconductor materials by using a theoretical model based on the Boltzmann transport equation. We show that combined effects of length scale, temperature, and boundary roughness are responsible for thermal transport transitions in silicon nanowires and thin films. We also introduce a more accurate principle for ballistic transport that considers the balance between internal and surface scattering. Phonon quantum confinement effects as well as the conditions for phonon wave interference in nanoscale heat transport are discussed.
Show PACS
73.23.Ad Ballistic transport
73.61.Cw Elemental semiconductors
72.10.Fk Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect)
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
72.20.Ht High-field and nonlinear effects

Phonon engineering in nanostructures: Controlling interfacial thermal resistance in multilayer-graphene/dielectric heterojunctions

R. Mao, B. D. Kong, K. W. Kim, T. Jayasekera, A. Calzolari, and M. Buongiorno Nardelli

Appl. Phys. Lett. 101, 113111 (2012); http://dx.doi.org/10.1063/1.4752437 (4 pages) | Cited 2 times

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using calculations from first principles and the Landauer approach for phonon transport, we study the Kapitza resistance in selected multilayer graphene/dielectric heterojunctions (hexagonal BN and wurtzite SiC) and demonstrate (i) the resistance variability ( ∼ 50−700×10−10 m2K/W) induced by vertical coupling, dimensionality, and atomistic structure of the system and (ii) the ability of understanding the intensity of the thermal transmittance in terms of the phonon distribution at the interface. Our results pave the way to the fundamental understanding of active phonon engineering by microscopic geometry design.
Show PACS
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
68.35.Ct Interface structure and roughness
68.35.Ja Surface and interface dynamics and vibrations

Electrical transport properties of individual WS2 nanotubes and their dependence on water and oxygen absorption

Chaoying Zhang, Zhiyuan Ning, Yang Liu, Tingting Xu, Yao Guo, Alla Zak, Zhiyong Zhang, Sheng Wang, Reshef Tenne, and Qing Chen

Appl. Phys. Lett. 101, 113112 (2012); http://dx.doi.org/10.1063/1.4752440 (5 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electrical properties of WS2 nanotubes (NTs) were studied through measuring 59 devices. Important electrical parameters, such as the carrier concentration, mobility, and effective barrier height at the contacts, were obtained through fitting experimental non-linear I-V curves using a metal-semiconductor-metal model. The carrier mobility was found to be several orders of magnitude higher than that have been reported previously for WS2 NTs. Water absorption was found to decrease the conductivity and carrier mobility of the NTs, and could be removed when the sample was dried. Oxygen absorption also slightly decreased the conductivity of WS2 NTs.
Show PACS
73.63.Fg Nanotubes
73.30.+y Surface double layers, Schottky barriers, and work functions
72.20.Fr Low-field transport and mobility; piezoresistance

Flat bands near Fermi level of topological line defects on graphite

Lei Feng, Xianqing Lin, Lan Meng, Jia-Cai Nie, Jun Ni, and Lin He

Appl. Phys. Lett. 101, 113113 (2012); http://dx.doi.org/10.1063/1.4752441 (4 pages) | Cited 1 time

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Here, we report direct experimental evidence for the presence of flat bands, close to the Fermi level, in one-dimensional topological defects of graphite. The flat bands are manifested by a pronounced peak in the tunnelling density of states. Our ab initio calculations indicate that the flat bands with vanishing Fermi velocity originate from sp2 dangling bonds (with antibonding nature) of undercoordinated carbon atoms at the edges of the defects. We further demonstrate that the presence of flat bands could be an inevitable behavior of 1D defects of graphene/graphite with undercoordinated carbon atoms at the edges of the defects.
Show PACS
71.55.Ht Other nonmetals
71.20.Tx Fullerenes and related materials; intercalation compounds
73.40.Gk Tunneling
71.15.-m Methods of electronic structure calculations

AlInP-based rolled-up microtube resonators with colloidal nanocrystals operating in the visible spectral range

Ch. Strelow, S. Kietzmann, A. Schramm, R. Seher, J.-P. Penttinen, T. V. Hakkarainen, A. Mews, and T. Kipp

Appl. Phys. Lett. 101, 113114 (2012); http://dx.doi.org/10.1063/1.4752449 (5 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the realization of AlInP rolled-up microtubes that can be used as high refractive index optical resonators operating in the visible spectral range down to a wavelength of at least 530 nm. Furthermore, colloidal CdSe/CdS/ZnS core-shell-shell nanocrystals were deposited close to the microtube wall by fluid filling of the microtube and subsequent evaporation of the solvent. The optical modes of the microtube resonator are excited via coupling of the nanocrystals to the evanescent fields of the modes. By embedding the nanocrystal emitters in a polymer film, an enhanced nanocrystal stability is obtained. The film is studied by the built-in refractometer of the microtube.
Show PACS
07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Nano-hillock formation in diamond-like carbon induced by swift heavy projectiles in the electronic stopping regime: Experiments and atomistic simulations

D. Schwen, E. Bringa, J. Krauser, A. Weidinger, C. Trautmann, and H. Hofsäss

Appl. Phys. Lett. 101, 113115 (2012); http://dx.doi.org/10.1063/1.4752455 (4 pages) | Cited 2 times

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The formation of surface hillocks in diamond-like carbon is studied experimentally and by means of large-scale molecular dynamics simulations with 5 × 106 atoms combined with a thermal spike model. The irradiation experiments with swift heavy ions cover a large electronic stopping range between ∼12 and 72 keV/nm. Both experiments and simulations show that beyond a stopping power threshold, the hillock height increases linearly with the electronic stopping, and agree extremely well assuming an efficiency of approximately 20% in the transfer of electronic energy to the lattice. The simulations also show a transition of sp3 to sp2 bonding along the tracks with the hillocks containing almost no sp3 contribution.
Show PACS
61.46.-w Structure of nanoscale materials
73.20.At Surface states, band structure, electron density of states
68.35.bp Fullerenes
71.15.Pd Molecular dynamics calculations (Car-Parrinello) and other numerical simulations
61.80.Jh Ion radiation effects

Near-field enhanced ultraviolet resonance Raman spectroscopy using aluminum bow-tie nano-antenna

Ling Li, Shuang Fang Lim, Alexander A. Puretzky, Robert Riehn, and H. D. Hallen

Appl. Phys. Lett. 101, 113116 (2012); http://dx.doi.org/10.1063/1.4746747 (4 pages) | Cited 1 time

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An aluminum bow-tie nano-antenna is combined with the resonance Raman effect in the deep ultraviolet to dramatically increase the sensitivity of Raman spectra to a small volume of material, such as benzene used here. We further demonstrate gradient-field Raman peaks for several strong infrared modes. We achieve a gain of ∼ 105 in signal intensity from the near field enhancement due to the surface plasmon resonance in the aluminum nanostructure. The on-line resonance enhancement contributes another factor of several thousands, limited by the laser line width. Thus, an overall gain of hundreds of million is achieved.
Show PACS
78.30.-j Infrared and Raman spectra
07.60.Rd Visible and ultraviolet spectrometers
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
Author Select

Low-energy electron transmission imaging of clusters on free-standing graphene

Jean-Nicolas Longchamp, Tatiana Latychevskaia, Conrad Escher, and Hans-Werner Fink

Appl. Phys. Lett. 101, 113117 (2012); http://dx.doi.org/10.1063/1.4752717 (4 pages) | Cited 4 times

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated the utility of free-standing graphene as a transparent sample carrier for imaging nanometer-sized objects by means of low-energy electron holography. The sample preparation for obtaining contamination-free graphene as well as the experimental setup and findings are discussed. For incoming electrons with 66 eV kinetic energy, graphene exhibits 27% opacity per layer. Hence, electron holograms of nanometer-sized objects adsorbed on free-standing graphene can be recorded and numerically reconstructed to reveal the object's shapes and distribution. Furthermore, a Moiré effect has been observed with free-standing graphene multi-layers.
Show PACS
61.48.Gh Structure of graphene
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
68.35.B- Structure of clean surfaces (and surface reconstruction)
78.67.Wj Optical properties of graphene

Temperature dependent graphene suspension due to thermal Casimir interaction

Anh D. Phan, Lilia M. Woods, D. Drosdoff, I. V. Bondarev, and N. A. Viet

Appl. Phys. Lett. 101, 113118 (2012); http://dx.doi.org/10.1063/1.4752745 (4 pages)

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermal effects contributing to the Casimir interaction between objects are usually small at room temperature, and they are difficult to separate from quantum mechanical contributions. We propose that the thermal Casimir force effect can be observed for a graphene flake suspended in a fluid between substrates at the room temperature regime. The properly chosen materials for the substrates and fluid induce a Casimir repulsion. The balance with the other forces, such as gravity and buoyancy, results in a stable temperature dependent equilibrium separation. The suspended graphene is a promising system due to its potential for observing thermal Casimir effects at room temperature.
Show PACS
82.70.Kj Emulsions and suspensions
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
Page 3 of 5 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close