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

2 Nov 2009

Volume 95, Issue 18, Articles (18xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 95, 183504 (2009); http://dx.doi.org/10.1063/1.3256223 (3 pages)

Hoon-Sik Kim, Sang Min Won, Young-Geun Ha, Jong-Hyun Ahn, Antonio Facchetti, Tobin J. Marks, and John A. Rogers
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Spiral nucleation of silicon solidified on heterogeneous surface of carbon nanocones

H. Li, Y. F. Li, K. M. Liew, J. X. Zhang, and X. F. Liu

Appl. Phys. Lett. 95, 183101 (2009); http://dx.doi.org/10.1063/1.3258492 (3 pages) | Cited 4 times

Online Publication Date: 3 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Molecular dynamics studies are carried out to examine the spiral nucleation mode of silicon solidified on the surface of carbon nanocones (CNCs). The silicon atoms are concentrated to form magic multilayered nanocones composed of coaxial and equidistant conical shells. Heterogeneous nucleation that occurred on CNCs follows a spiral nucleating mechanism. The structures of so-formed silicon cones show strict structural matching and strong structural relevance with CNCs. The uniform internal potential field around the CNCs is responsible for the formation of the coaxial conical shells.
Show PACS
81.30.Fb Solidification
61.46.-w Structure of nanoscale materials
81.16.-c Methods of micro- and nanofabrication and processing
68.65.Ac Multilayers

Shaping site-controlled uniform arrays of SiGe/Si(001) islands by in situ annealing

J. J. Zhang, A. Rastelli, H. Groiss, J. Tersoff, F. Schäffler, O. G. Schmidt, and G. Bauer

Appl. Phys. Lett. 95, 183102 (2009); http://dx.doi.org/10.1063/1.3258648 (3 pages) | Cited 8 times

Online Publication Date: 3 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the effect of in situ annealing on the shape, size, and chemical composition of ordered SiGe islands grown on pit-patterned Si(001) substrates. In contrast to planar substrates, intermixing with substrate material occurs symmetrically during annealing because the substrate patterning pins the island position and suppresses lateral motion. The results are consistent with surface-mediated intermixing and demonstrate that annealing is an effective method to tune the island properties with no appreciable deterioration of the ensemble homogeneity.
Show PACS
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
81.05.Hd Other semiconductors

First-principles study on the enhancement of lithium storage capacity in boron doped graphene

Xianlong Wang, Zhi Zeng, Hyojun Ahn, and Guoxiu Wang

Appl. Phys. Lett. 95, 183103 (2009); http://dx.doi.org/10.1063/1.3259650 (3 pages) | Cited 16 times

Online Publication Date: 4 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The adsorption of Li ions on boron doped graphene was investigated using a first-principles method. Our results show that, as boron doping turns graphene into an electron-deficient system, more Li ions can be captured around boron doped centers than in pristine graphene. One boron atom doped into graphene (6C ring unit) can adsorb six Li ions, which indicates that boron doped graphene is an efficient Li-ion storage material for lithium batteries. Further investigations show that, under limited conditions, boron doped graphene (BC5) can form Li6BC5 compound after Li-ion adsorption, corresponding to a lithium storage capacity of 2271 mAh/g which is six times that of graphite.
Show PACS
71.15.-m Methods of electronic structure calculations
68.43.Mn Adsorption kinetics
61.72.up Other materials
82.47.Aa Lithium-ion batteries
71.20.Tx Fullerenes and related materials; intercalation compounds

Bifurcation topology tuning of a mixed behavior in nonlinear micromechanical resonators

N. Kacem and S. Hentz

Appl. Phys. Lett. 95, 183104 (2009); http://dx.doi.org/10.1063/1.3258654 (3 pages) | Cited 5 times

Online Publication Date: 4 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the experimental observation of a four-bifurcation-point (or five possible amplitudes for a given frequency) behavior of electrostatically actuated micromechanical resonators, called the mixed (first hardening then softening) behavior. We also demonstrate both analytically and experimentally tuning the bifurcation topology of this behavior via an electrostatic mechanism. An analytical model allows for the qualitative as well as quantitative explanation of the experiments and serves as a simple tool for design of nonlinear micromechanical devices under high drive.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
07.10.Cm Micromechanical devices and systems

All graphene electromechanical switch fabricated by chemical vapor deposition

Kaveh M. Milaninia, Marc A. Baldo, Alfonso Reina, and Jing Kong

Appl. Phys. Lett. 95, 183105 (2009); http://dx.doi.org/10.1063/1.3259415 (3 pages) | Cited 20 times

Online Publication Date: 5 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate an electromechanical switch comprising two polycrystalline graphene films; each deposited using ambient pressure chemical vapor deposition. The top film is pulled into electrical contact with the bottom film by application of approximately 5 V between the layers. Contact is broken by mechanical restoring forces after bias is removed. The device switches several times before tearing. Demonstration of switching at low voltage confirms that graphene is an attractive material for electromechanical switches. Reliability may be improved by scaling the device area to within one crystalline domain of the graphene films.
Show PACS
84.32.Dd Connectors, relays, and switches
85.35.-p Nanoelectronic devices
07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Coupling between even- and oddlike modes in a single asymmetric photonic crystal waveguide

Xiaoyu Mao, Yidong Huang, Wei Zhang, and Jiangde Peng

Appl. Phys. Lett. 95, 183106 (2009); http://dx.doi.org/10.1063/1.3259819 (3 pages) | Cited 1 time

Online Publication Date: 5 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The photonic crystal (PC) is an important structure for realizing optical integrative circuits. Nowadays, most PC based passive devices operate by utilizing the coupling either between several PC waveguides or between PC waveguides and resonance cavities. In this letter, we present a coupling mechanism between even- and oddlike modes in a single asymmetric PC waveguide. Switches based on this coupling phenomenon were validated experimentally. By adjusting the temperature controlled by the thermal resistor, an extinction ratio of 9.1 dB was realized. Our researches provide a potential way of not only guiding but also controlling light in a simple single PC waveguide.
Show PACS
42.79.Gn Optical waveguides and couplers
42.70.Qs Photonic bandgap materials
42.82.Et Waveguides, couplers, and arrays

Thermalization of exciton states in silicon nanocrystals

Brian Julsgaard, Ying-Wei Lu, Peter Balling, and Arne Nylandsted Larsen

Appl. Phys. Lett. 95, 183107 (2009); http://dx.doi.org/10.1063/1.3251783 (3 pages)

Online Publication Date: 5 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Silicon nanocrystals are studied by time-resolved fluorescence spectroscopy. After laser excitation the bright and dark exciton ground state levels are populated at random, but subsequently the decay curves reveal a thermalization between these levels. The characteristic thermalization time is found to be approximately 100 ns for temperatures below 100 K and surprisingly increases for higher temperatures. The decay curves are analyzed using a simple two-state model for the bright and dark exciton ground states.
Show PACS
81.07.Bc Nanocrystalline materials
61.46.Hk Nanocrystals
71.35.-y Excitons and related phenomena
78.55.Ap Elemental semiconductors
81.05.Cy Elemental semiconductors
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.47.jd Time resolved luminescence

Determination and enhancement of the capacitance contributions in carbon nanotube based electrode systems

M. Hoefer and P. R. Bandaru

Appl. Phys. Lett. 95, 183108 (2009); http://dx.doi.org/10.1063/1.3258353 (3 pages) | Cited 11 times

Online Publication Date: 5 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We characterize the methodology of, and a possible way to enhance, the capacitance of carbon nanotube (CNT) electrode based electrochemical capacitors. Argon irradiation was used to controllably incorporate extrinsic defects into CNTs and increase the magnitude of both the pseudocapacitance and double-layer capacitance by as much as 50% and 200%, respectively, compared to untreated electrodes. Our work has implications in analyzing the prospects of CNT based electrochemical capacitors, through investigating ways and means of improving their charge storage capacity and energy density.
Show PACS
61.48.De Structure of carbon nanotubes, boron nanotubes, and other related systems
61.80.-x Physical radiation effects, radiation damage
84.32.Tt Capacitors
82.45.Fk Electrodes

Frequency upconverted lasing of nanocrystal quantum dots in microbeads

Chunfeng Zhang, Fan Zhang, An Cheng, Brian Kimball, Andrew Y. Wang, and Jian Xu

Appl. Phys. Lett. 95, 183109 (2009); http://dx.doi.org/10.1063/1.3242352 (3 pages) | Cited 3 times

Online Publication Date: 6 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Stable, frequency upconverted lasing of semiconductor nanocrystal quantum dots was demonstrated in silica microbeads under two-photon pumping conditions. Upon infrared excitation, the stimulated emission of the nanocrystal-doped microbeads exhibits sharp peaks at λ ∼ 610 nm with narrow line widths of ≤ 1 nm. The lasing action has been attributed to the biexciton gain coupled to the whispering gallery modes in spherical cavities, as confirmed by time-resolved photoluminescence spectra. The lasing lifetime characterized in term of pulse numbers ( ∼ 106 pulses) was two orders of magnitude longer than that of the dye salt-based two-photon lasers.
Show PACS
78.67.Hc Quantum dots
78.55.-m Photoluminescence, properties and materials
78.47.jd Time resolved luminescence
07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
78.45.+h Stimulated emission

Nonequilibrium dynamical ferromagnetism of interacting single-molecule magnets

Gui-Bin Liu and Bang-Gui Liu

Appl. Phys. Lett. 95, 183110 (2009); http://dx.doi.org/10.1063/1.3259784 (3 pages) | Cited 2 times

Online Publication Date: 6 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose a nonequilibrium Monte Carlo (MC) approach to explore nonequilibrium dynamical ferromagnetism of interacting single molecule magnets (SMMs). Both quantum spin tunneling and thermally activated spin reversal are implemented in the same MC simulation framework. Applied to a typical example, this simulation method satisfactorily reproduces experimental magnetization curves with experimental parameters. Our results show that both quantum and classical effects are essential to determine the hysteresis behaviors. This method is effective and reliable to gain deep insights into SMMs.
Show PACS
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Xx Molecular magnets
75.10.-b General theory and models of magnetic ordering

Effects of surface ligands on the charge memory characteristics of CdSe/ZnS nanocrystals in TiO2 thin film

Seung-Hee Kang, Ch. Kiran Kumar, Zonghoon Lee, Velimir Radmilovic, and Eui-Tae Kim

Appl. Phys. Lett. 95, 183111 (2009); http://dx.doi.org/10.1063/1.3259929 (3 pages) | Cited 3 times

Online Publication Date: 6 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Charge memory characteristics have been systematically studied based on colloidal CdSe/ZnS nanocrystal quantum dots (QDs) embedded in ∼ 50 nm-thick TiO2 film. Ligand-capped QDs showed negligible electron charging effect, implying that the electron affinity of QDs was significantly decreased by surface dipole layer surrounding QDs. In contrast, the hole charging was affected by the carrier injection blocking effect of the surface ligands. Efficient electron and hole charging characteristics were realized by removing the surface ligands via H2 plasma treatment.
Show PACS
73.63.Kv Quantum dots
82.70.Dd Colloids
72.20.-i Conductivity phenomena in semiconductors and insulators

High temperature stable monodisperse superparamagnetic core-shell iron-oxide@SnO2 nanoparticles

Xiaobin Xu, Mingyuan Ge, Cen Wang, and J. Z. Jiang

Appl. Phys. Lett. 95, 183112 (2009); http://dx.doi.org/10.1063/1.3261756 (3 pages) | Cited 7 times

Online Publication Date: 6 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monodisperse superparamagnetic SnO2-coated iron-oxide nanoparticles ( ∼ 16.4 nm) have been synthesized via thermal decomposition. The thickness of SnO2 shells can be controlled from 1–5 nm. As-prepared SnO2-coated iron-oxide nanoparticles with high saturation magnetization (18 A m2/kg), are stable up to 600 °C, which can be formed stable ferrofluid. It was suggested that the SnO2 shell acts as a barrier of preventing the growth of γ-Fe2O3 and consequently, avoiding the γ-Fe2O3-to-α-Fe2O3 phase transition at high temperatures.
Show PACS
75.20.Ck Nonmetals
75.50.Tt Fine-particle systems; nanocrystalline materials
75.50.Mm Magnetic liquids
75.75.Jn Dynamics of magnetic nanoparticles

Relationship between band alignment and chemical states upon annealing in HfSiON/SiON stacked films on Si substrates

T. Tanimura, S. Toyoda, H. Kamada, H. Kumigashira, M. Oshima, G. L. Liu, Z. Liu, and K. Ikeda

Appl. Phys. Lett. 95, 183113 (2009); http://dx.doi.org/10.1063/1.3258073 (3 pages) | Cited 3 times

Online Publication Date: 6 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the relationship between band alignment and chemical states in HfSiON/SiON stacked films on Si substrates by photoemission spectroscopy and x-ray absorption spectroscopy. Valence-band maxima mainly derived from N 2p states in HfSiON films are closely related to N–Hf bonding configurations. The valence-band offset for a thick HfSiON film is smaller than that for a thin HfSiON film, due to the amount of N–Hf bonding states. Since N–Hf bonding states decrease upon annealing, thickness dependence of valence-band offset can be eliminated. On the other hand, the conduction-band offset does not depend on either the thickness or annealing.
Show PACS
68.55.jd Thickness
79.60.Dp Adsorbed layers and thin films
81.40.Gh Other heat and thermomechanical treatments
78.70.Dm X-ray absorption spectra
73.20.At Surface states, band structure, electron density of states

Mechanistic investigation of ZnO nanowire growth

Simas Rackauskas, Albert G. Nasibulin, Hua Jiang, Ying Tian, Gintare Statkute, Sergey D. Shandakov, Harri Lipsanen, and Esko I. Kauppinen

Appl. Phys. Lett. 95, 183114 (2009); http://dx.doi.org/10.1063/1.3258074 (3 pages) | Cited 10 times

Online Publication Date: 6 November 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
ZnO nanowire (NW) growth mechanism was investigated in a nonvapor and noncatalytic approach for the controlled NW synthesis in a second time scale. The experimental results showed what ZnO NW growth was determined by migration of zinc interstitials and vacancies in a ZnO layer, which should be also considered in other synthesis techniques and mechanisms. The mechanism of the ZnO NW growth was explained as due to the advantageous diffusion through grain boundaries in ZnO layer and crystal defects in NWs. Additionally, on the basis of photoluminescence measurements, a feasible application of as-produced wires for optoelectronic devices was demonstrated.
Show PACS
81.16.-c Methods of micro- and nanofabrication and processing
61.72.jd Vacancies
61.72.jj Interstitials
66.30.Pa Diffusion in nanoscale solids
61.72.Mm Grain and twin boundaries
78.55.Et II-VI semiconductors
81.05.Dz II-VI semiconductors
81.07.-b Nanoscale materials and structures: fabrication and characterization
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close