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

26 Feb 2007

Volume 90, Issue 9, Articles (09xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 90, 093127 (2007); http://dx.doi.org/10.1063/1.2710743 (3 pages)

Y. Q. Li, J. X. Tang, H. Wang, J. A. Zapien, Y. Y. Shan, and S. T. Lee
Enlarge Image | Read More
Page 1 of 2 Pages Return to All Sections Next Page
back to top
RSS Feeds

Room temperature fast synthesis of zinc oxide nanowires by inductive heating

Lei Luo, Brian D. Sosnowchik, and Liwei Lin

Appl. Phys. Lett. 90, 093101 (2007); http://dx.doi.org/10.1063/1.2709618 (3 pages) | Cited 20 times

Online Publication Date: 26 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
ZnO nanowires have been rapidly synthesized using inductive heating in a room temperature environment. Nanowires with random and aligned orientations were grown on silicon and 4H-SiC (0001) substrates in less than 5 min, respectively, using ZnO/graphite as the solid source powder. Scanning electron microscopy showed nanowire diameters of 20–120 nm and lengths up to 5 μm, and transmission electron microscopy verified the single-crystalline lattice of the nanowires. Electrical properties were studied by connecting a single ZnO nanowire in the field-effect transistor configuration. This demonstration further illustrates the feasibility of a simple and fast nanoscale synthesis using inductive heating for nanomaterial synthesis.
Show PACS
81.05.Dz II-VI semiconductors
81.07.Vb Quantum wires
68.37.Lp Transmission electron microscopy (TEM)
73.63.Nm Quantum wires

Holographic three-dimensional polymeric photonic crystals operating in the 1550 nm window

Jiaqi Chen, Wei Jiang, Xiaonan Chen, Li Wang, Sasa Zhang, and Ray T. Chen

Appl. Phys. Lett. 90, 093102 (2007); http://dx.doi.org/10.1063/1.2709641 (3 pages) | Cited 13 times

Online Publication Date: 26 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A polygonal prism based holographic fabrication method has been demonstrated for a three-dimensional face-centered-cubic-type submicron polymer photonic crystal using both positive and negative photoresists. Special fabrication treatments have been introduced to ensure the survivability of the fabricated large area ( ∼ 1 cm2) nanostructures. Scanning electron microscopy and diffraction results proved the good uniformity of the fabricated structures. With the proper design of the refraction prism the authors have achieved the required band gap for S+C bands (1460–1565 nm) in the [111] direction. The transmission and reflection spectra obtained by Fourier transform infrared spectroscopy are in good agreement with simulated band structure.
Show PACS
42.70.Qs Photonic bandgap materials
42.70.Jk Polymers and organics
42.40.My Applications
42.86.+b Optical workshop techniques
81.16.Nd Micro- and nanolithography
78.40.-q Absorption and reflection spectra: visible and ultraviolet

Growth competition during glancing angle deposition of nanorod honeycomb arrays

C. M. Zhou and D. Gall

Appl. Phys. Lett. 90, 093103 (2007); http://dx.doi.org/10.1063/1.2709929 (3 pages) | Cited 23 times

Online Publication Date: 26 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Arrays of Ta nanorods were grown by glancing angle deposition (GLAD) onto honeycomb Cr nanodot patterns that were evaporated onto Si substrates through a self-assembled monolayer of SiO2 nanospheres. Statistical size analyses from arrays of rods with variable average length l and width w, with 210 nm ⩽ l ⩽ 650 nm and 109 nm ⩽ w ⩽ 304 nm, show that the distribution in w broadens with increasing l and decreasing w, but remains approximately constant with a fixed l/w ratio. This is attributed to an intercolumnar growth competition that exacerbates nanorod size fluctuations but scales with rod size. These results suggest that the overall nanostructure shapes during low-temperature GLAD are independent of material-specific length scales and are, therefore, completely controlled by the geometric shadowing.
Show PACS
81.07.Bc Nanocrystalline materials
81.16.Dn Self-assembly
81.16.Nd Micro- and nanolithography
81.16.Rf Micro- and nanoscale pattern formation
61.46.-w Structure of nanoscale materials

Temperature effects on the spectral properties of colloidal CdSe nanodots, nanorods, and tetrapods

A. Al Salman, A. Tortschanoff, M. B. Mohamed, D. Tonti, F. van Mourik, and M. Chergui

Appl. Phys. Lett. 90, 093104 (2007); http://dx.doi.org/10.1063/1.2696687 (3 pages) | Cited 24 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temperature dependence of the absorption and fluorescence spectra of colloidal CdSe nanocrystals was compared for three different shapes (dots, rods, and tetrapods) in the range of 4–300 K. While the shift of the fluorescence maximum indicates little dependence on the shape, the authors find that the broadening of the emission spectrum behaves very differently for dots and rods, indicating major differences in the broadening mechanisms for different shapes. Tetrapods behave more similarly to dots, which suggests that the lowest exciton state is centered at the core.
Show PACS
78.67.Hc Quantum dots
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.55.Et II-VI semiconductors
78.60.-b Other luminescence and radiative recombination

Enhanced plasmon coupling in crossed dielectric/metal nanowire composite geometries and applications to surface-enhanced Raman spectroscopy

S. M. Prokes, O. J. Glembocki, R. W. Rendell, and M. G. Ancona

Appl. Phys. Lett. 90, 093105 (2007); http://dx.doi.org/10.1063/1.2709996 (3 pages) | Cited 31 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Surface-enhanced Raman spectroscopy (SERS) was performed on Ga2O3/Ag and ZnO/Ag nanowires, which were arranged in either a crossover or noncrossing geometry. Results indicate a high SERS sensitivity (near 0.2 pg) for nanowires arranged in a crossing geometry. It is suggested that this is due to the dielectric core/metal shell structure, as well as to the nanowire crossings, which are regions of very high electric fields. Finite element simulations of the electric field near two crossed wires confirm an enhanced plasmon resonance in the vicinity of the crossing, which extends spatially in the crossings and around the nanowires.
Show PACS
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
78.30.-j Infrared and Raman spectra
73.22.Lp Collective excitations

High temperature rapid thermal annealing of phosphorous ion implanted InAs/InP quantum dots

S. Barik, H. H. Tan, and C. Jagadish

Appl. Phys. Lett. 90, 093106 (2007); http://dx.doi.org/10.1063/1.2710006 (3 pages) | Cited 7 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of high temperature annealing of the InAs/InP quantum dots (QDs) containing a thin GaAs interlayer is investigated. The QDs are rapid thermally annealed at 750, 800, 850, and 900 °C for 30 s. The QDs with the GaAs interlayer show good thermal stability up to 850 °C as well as enhanced integrated photoluminescence (PL) intensity and reduced PL linewidth. The effect of high energy (450 keV) phosphorous ion implantation at room temperature with doses of 5×1011–5×1013 ions/cm2 with subsequent high temperature (750–850 °C) rapid thermal annealing is also studied. A large implantation-induced energy shift of up to 309 meV (400 nm) is observed. The implanted samples annealed at 850 °C show reduced PL linewidth and enhanced integrated PL intensity compared to the implanted samples annealed at 750 °C.
Show PACS
61.72.Cc Kinetics of defect formation and annealing
61.72.uj III-V and II-VI semiconductors
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors

Effect of photon irradiation on conductivity of nanoscale yttria-doped zirconia thin films

Annamalai Karthikeyan and Shriram Ramanathan

Appl. Phys. Lett. 90, 093107 (2007); http://dx.doi.org/10.1063/1.2709990 (3 pages)

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of photon irradiation on high temperature conductivity of nanoscale yttria-doped zirconia thin films is reported. Nanoscale films show substantial decrease in total conductivity (as high as ∼ 40%) during ultraviolet (UV) irradiation, while the conductivity of bulk single crystals shows negligible changes. The UV induced conductivity changes are rapid and reversible and activation energies for ion migration remain unaffected. The reduction in conductivity may arise from changes in effective oxygen vacancy concentration. Such UV-influenced alteration of electrical properties offers an elegant route to tailor surface catalytic activity of oxygen ion and mixed conductors used in various solid-state devices.
Show PACS
73.61.Ng Insulators
66.30.H- Self-diffusion and ionic conduction in nonmetals
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
61.80.-x Physical radiation effects, radiation damage

Near-infrared to visible light optical upconversion by direct tandem integration of organic light-emitting diode and inorganic photodetector

D. Ban, S. Han, Z. H. Lu, T. Oogarah, A. J. SpringThorpe, and H. C. Liu

Appl. Phys. Lett. 90, 093108 (2007); http://dx.doi.org/10.1063/1.2710003 (3 pages) | Cited 18 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report a hybrid organic/inorganic optical upconversion device that converts 1.5 μm infrared light to ∼ 520 nm visible light. The device was made by direct tandem integration of an inorganic InGaAs/InP photodetector with an organic light-emitting diode (OLED). Optical upconversion with an external efficiency of 0.7% W/W at room temperature has been achieved. Interfacial structure at the inorganic-organic interface was found to play a vital role in enabling the integration of the hybrid tandem upconverter. Both sulfur-terminated InP surface and nanocarbon fullerene interlayer were found crucial to form a good interface contact, permitting continuous flow of photocarriers from the inorganic detector into the OLED.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
85.60.Jb Light-emitting devices
42.82.Gw Other integrated-optical elements and systems
85.60.Gz Photodetectors (including infrared and CCD detectors)

Enhancement-mode metal-semiconductor field-effect transistors based on single n-CdS nanowires

R. M. Ma, L. Dai, and G. G. Qin

Appl. Phys. Lett. 90, 093109 (2007); http://dx.doi.org/10.1063/1.2710004 (3 pages) | Cited 26 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Enhancement-mode (E-mode) metal-semiconductor field-effect transistors (MESFETs) based on single nanowires (NWs) were reported. The single NW used is n-CdS NW. Source-drain channel of the nano-MESFET is pinched off by the top surrounding Schottky gate at zero bias. When Schottky gate voltage (VG) changes from 0 to 0.25 V, the source-drain current increases exponentially with VG, and an on/off current ratio of 5×103 is obtained. The maximum transconductance is 14.6 nA/V, and the gate leakage current is lower than source-drain current by more than two orders of magnitude. Their results suggest a way of fabricating E-mode nano-field-effect transistors.
Show PACS
85.30.Tv Field effect devices
85.30.De Semiconductor-device characterization, design, and modeling

Spin injection into a single self-assembled quantum dot in a p-i-n II-VI/III-V structure

M. Ghali, R. Arians, T. Kümmell, G. Bacher, J. Wenisch, S. Mahapatra, and K. Brunner

Appl. Phys. Lett. 90, 093110 (2007); http://dx.doi.org/10.1063/1.2710078 (3 pages) | Cited 5 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on efficient spin injection from a n-Zn0.96Mn0.04Se layer into an InAs single quantum dot (SQD) in a p-i-n diode structure using magnetomicrophotoluminescence experiments. A circular polarization degree of up to 60% at B = 5 T is obtained from the InAs single dot emission while no polarized light is observed in a structure with no electrical doping of any of its layers. A pronounced dependence of the spin injection efficiency on the external bias is found resulting in a strong decrease of the SQD circular polarization degree when the biasing is applied in the forward direction. The experiments emphasize the impact of excess energy and current flow on the spin injection efficiency in a SQD.
Show PACS
73.63.Kv Quantum dots
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.25.Dc Spin polarized transport in semiconductors
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
78.55.Et II-VI semiconductors

Three-dimensional imaging of stacked Pd nanoparticles by electron tomography

Jong-Bong Park, Jun Ho Lee, and Hye-Ran Choi

Appl. Phys. Lett. 90, 093111 (2007); http://dx.doi.org/10.1063/1.2710172 (3 pages) | Cited 4 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spatial distributed quantum-sized nanocrystals (<10 nm) have considerable potential for various engineering applications, such as flash memory devices due to their charge-trap properties, efficient displays, solar cells, and biosensors. In the present study, stacked Pd nanoparticle (5–6 nm in diameter) arrays were examined by different imaging techniques, including bright-field transmission electron microscopy, high-angle annular-dark-field scanning transmission electron microscopy, and three-dimensional (3D) electron tomography. Notably, the authors reliably found both the distribution and the location of the stacked Pd nanoparticles using 3D electron tomography. The authors’ approach offers potential solutions to the problem of enhancing the physicochemical properties of the applications.
Show PACS
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)

Scanning tunneling microscopy study of interfacial structure of InAs quantum dots on InP(001) grown by a double-cap method

Y. Akanuma, I. Yamakawa, Y. Sakuma, T. Usuki, and A. Nakamura

Appl. Phys. Lett. 90, 093112 (2007); http://dx.doi.org/10.1063/1.2710470 (3 pages) | Cited 9 times

Online Publication Date: 27 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The interfacial properties of InAs self-assembled quantum dots (QDs) on InP(001) grown by the double-capped method by metal-organic chemical-vapor deposition have been investigated by means of cross-sectional scanning tunneling microscopy (STM). Truncated pyramidal QDs with a monolayer-step height in the range of 6–14 ML are observed in the STM images, and their top and bottom interfaces are extremely sharp. On the side of the QDs, however, segregation of As atoms is observed, which suggests that the migration of As atoms from the QDs takes place by As/P exchange during the cap and etching processes in the double-cap procedure.
Show PACS
68.65.Hb Quantum dots (patterned in quantum wells)
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.35.Ct Interface structure and roughness
64.75.-g Phase equilibria
68.35.Fx Diffusion; interface formation

Nanostenciling for fabrication and interconnection of nanopatterns and microelectrodes

Haiming Guo, David Martrou, Tomaso Zambelli, Jérôme Polesel-Maris, Agnès Piednoir, Erik Dujardin, Sébastien Gauthier, Marc A. F. van den Boogaart, Lianne M. Doeswijk, and Jürgen Brugger

Appl. Phys. Lett. 90, 093113 (2007); http://dx.doi.org/10.1063/1.2710473 (3 pages) | Cited 11 times

Online Publication Date: 28 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Stencil lithography is used for patterning and connecting nanostructures with metallic microelectrodes in ultrahigh vacuum. Microelectrodes are fabricated by static stencil deposition through a thin silicon nitride membrane. Arbitrary nanoscale patterns are then deposited at a predefined position relative to the microelectrodes, using as a movable stencil mask an atomic force microscopy (AFM) cantilever in which apertures have been drilled by focused ion beam. Large scale AFM imaging, combined with the use of a high precision positioning table, allows inspecting the microelectrodes and positioning the nanoscale pattern with accuracy better than 100 nm.
Show PACS
81.16.Rf Micro- and nanoscale pattern formation
81.16.Nd Micro- and nanolithography

Near-field second harmonic generation by using uncoated silicon tips

M. Breit, S. Malkmus, J. Feldmann, and H. U. Danzebrink

Appl. Phys. Lett. 90, 093114 (2007); http://dx.doi.org/10.1063/1.2709941 (3 pages) | Cited 9 times

Online Publication Date: 28 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors present a concept of a scanning near-field optical microscope for second harmonic imaging. The microscope is based on uncoated silicon atomic force microscope tips, which provide high intensity transmission in the midinfrared spectral range. An approximately three times larger contrast was found for the second harmonic compared to the linear signal. By using a lithographically designed sample of an array of gold nanoparticles the capability of imaging structures much smaller than the fundamental and second harmonic wavelength is demonstrated.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
07.79.Fc Near-field scanning optical microscopes
68.37.Uv Near-field scanning microscopy and spectroscopy
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters

Controlled formation of multiple Taylor cones in electrospinning process

A. Vaseashta

Appl. Phys. Lett. 90, 093115 (2007); http://dx.doi.org/10.1063/1.2709958 (3 pages) | Cited 6 times

Online Publication Date: 28 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electrospinning is a versatile technique for preparation of micro- and nanoscale fibers using polymer solutions. The study presented here describes an observation of multiple Taylor cones in electrospinning processes. Plausible physical models explaining the formation and modeling of multiple Taylor cones in terms of the process and polymer solution parameters are presented. A thorough understanding of the process will lead to the preparation of fibers by design, system on fibers, and e-textiles having applications ranging from biomedical devices, environmental pollution and prevention, to global security and defense.
Show PACS
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.20.-n Methods of materials synthesis and materials processing

Efficient electrothermal actuation of multiple modes of high-frequency nanoelectromechanical resonators

I. Bargatin, I. Kozinsky, and M. L. Roukes

Appl. Phys. Lett. 90, 093116 (2007); http://dx.doi.org/10.1063/1.2709620 (3 pages) | Cited 21 times

Online Publication Date: 28 February 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors observed resonances from multiple vibrational modes of individual silicon-carbide-based nanomechanical resonators, covering a broad frequency range from several megahertz to over a gigahertz. The devices are actuated thermoelastically in vacuum at room temperature using localized Joule heating in a device-integrated metal loop. Their motion is detected piezoresistively using signal downmixing in a similarly integrated metal piezoresistor. The frequencies and amplitudes of the observed resonant peaks are in good agreement with the results from theoretical modeling and finite-element simulations.
Show PACS
07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Arrays of magnetic nanoindentations with perpendicular anisotropy

D. Makarov, L. Baraban, I. L. Guhr, J. Boneberg, H. Schift, J. Gobrecht, G. Schatz, P. Leiderer, and M. Albrecht

Appl. Phys. Lett. 90, 093117 (2007); http://dx.doi.org/10.1063/1.2709513 (3 pages) | Cited 12 times

Online Publication Date: 1 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report an approach to the fabrication of periodic magnetic patterns using spherical indentations. These troughs are shaped by an imprint technique, employing a self-assembled monolayer of particles. Well-defined structures with perpendicular magnetic anisotropy are obtained by deposition of Co/Pd multilayer films onto the topographic array. The structures formed in the indentations can be magnetically exchange decoupled from their neighbors depending critically on their specific shape. The presented concept leads to a realization of a magnetic nanostructure medium, which offers advances in achieving high pattern densities combining a low cost nanoimprint approach with material functionalization.
Show PACS
81.07.Bc Nanocrystalline materials
81.16.Nd Micro- and nanolithography
81.16.Rf Micro- and nanoscale pattern formation
81.16.Dn Self-assembly
75.50.Tt Fine-particle systems; nanocrystalline materials
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)

Assembly of ordered carbon shells on GaN nanowires

Eli Sutter, Peter Sutter, Raffaella Calarco, Toma Stoica, and Ralph Meijers

Appl. Phys. Lett. 90, 093118 (2007); http://dx.doi.org/10.1063/1.2710189 (3 pages) | Cited 8 times

Online Publication Date: 1 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In situ annealing experiments on individual group III-nitride nanowires (NWs) in a transmission electron microscope demonstrate the encapsulation of GaN wires in crystalline carbon shells in the presence of C at moderate temperatures. The complete encapsulation of GaN wires in carbon shells can be achieved when small indium metal clusters are introduced on the wire surface. No encapsulation is observed on pure GaN wires under the same conditions. The observations suggest a general processing route for the formation of semiconductor core/C-shell NW structures based on surface decoration with small metal clusters.
Show PACS
81.05.Ea III-V semiconductors
81.07.Bc Nanocrystalline materials
81.65.Ps Polishing, grinding, surface finishing
61.46.Hk Nanocrystals
61.72.Cc Kinetics of defect formation and annealing

Room-temperature observation of a Coulomb blockade phenomenon in aluminum nanodots fabricated by an electrochemical process

Yasuo Kimura, Kazumasa Itoh, Ryo-taro Yamaguchi, Ken-ichi Ishibashi, Kingo Itaya, and Michio Niwano

Appl. Phys. Lett. 90, 093119 (2007); http://dx.doi.org/10.1063/1.2475419 (3 pages) | Cited 8 times

Online Publication Date: 1 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An aluminum nanodot was self-organized between two electrodes using the anodization process of an aluminum microelectrode of 3 μm in width. The authors observed a clear Coulomb staircase with a very large Coulomb energy of about 2 eV at room temperature. This very large Coulomb energy is attributed to the device structure which depends strongly on the aluminum nanodot formation mechanism. The authors’ results indicate that a single electron transistor operating at room temperature can be fabricated at an appropriate position using both bottom-up and top-down processes.
Show PACS
85.35.Gv Single electron devices

Oscillatory thermal expansion of Pb thin films modulated by quantum size effects

Yan-Feng Zhang, Zhe Tang, Tie-Zhu Han, Xu-Cun Ma, Jin-Feng Jia, Qi-Kun Xue, Kun Xun, and Si-Cheng Wu

Appl. Phys. Lett. 90, 093120 (2007); http://dx.doi.org/10.1063/1.2710223 (3 pages) | Cited 9 times

Online Publication Date: 1 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Varied temperature photoemission study is performed to investigate the quantum size effects on the thermal property of atomically flat Pb films grown on Si(111). The binding energies of the quantum well states for the films with thicknesses from 10 to 24 ML exhibit a linear increase with increasing temperature from 75 to 270 K. Under free electron approximation, thermal expansion coefficients of the thin films are determined, which manifest a large enhancement and oscillation behavior. The large enhancement is interpreted by a model based on the quantum confinement along the film normal direction. The oscillation is shown to be closely related to the structural instability and is a result of the formation of the quantized electronic states in thin films.
Show PACS
65.40.De Thermal expansion; thermomechanical effects
79.60.Bm Clean metal, semiconductor, and insulator surfaces
73.21.Fg Quantum wells

Fabrication of ultrathin magnetic structures by nanostencil lithography in dynamic mode

L. Gross, R. R. Schlittler, G. Meyer, A. Vanhaverbeke, and R. Allenspach

Appl. Phys. Lett. 90, 093121 (2007); http://dx.doi.org/10.1063/1.2710202 (3 pages) | Cited 8 times

Online Publication Date: 1 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The fabrication of magnetic elements containing constrictions is demonstrated using nanostencil lithography in dynamic mode, i.e., by a continuous translation of a shadow mask with respect to the sample. The authors quantify the current resolution limits of this technique, demonstrating edge profile widths of 120 nm and thickness variations of 10%, and discuss prospects and challenges of dynamic nanostencil lithography.
Show PACS
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.Nd Micro- and nanolithography
75.50.Tt Fine-particle systems; nanocrystalline materials

Fabrication and magnetic characteristics of hybrid double walled nanotube of ferromagnetic nickel encapsulated conducting polypyrrole

D. H. Park, Y. B. Lee, M. Y. Cho, B. H. Kim, S. H. Lee, Y. K. Hong, J. Joo, H. C. Cheong, and S. R. Lee

Appl. Phys. Lett. 90, 093122 (2007); http://dx.doi.org/10.1063/1.2710748 (3 pages) | Cited 8 times

Online Publication Date: 1 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter is a report on hybrid double walled nanotubes (HDWNTs) of crystalline ferromagnetic nickel (Ni) nanotubes encapsulated conducting polypyrrole (PPy) nanotubes through a sequentially electrochemical synthetic method. Ferromagnetic Ni nanotubes were fabricated by an electrochemical deposition method outside the wall of the conducting PPy nanotubes. The formation and structure of HDWNTs of conducting PPy nanotubes and ferromagnetic Ni nanotubes were confirmed by transmission electron microscopy, high-resolution transmission electron microscopy, and elementary analysis. From the angular dependences of the magnetic hysteresis curves of the HDWNTs, the authors observed that the Ni nanotubes of the HDWNT systems had an anisotropic ferromagnetic nature with the maximum of coercivity and remanent-saturation magnetization when applying a magnetic field along the parallel direction of the tubes.
Show PACS
81.07.Pr Organic-inorganic hybrid nanostructures
81.07.De Nanotubes
81.15.Pq Electrodeposition, electroplating
75.50.Dd Nonmetallic ferromagnetic materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy

Optical spectroscopy and confocal fluorescence imaging of upconverting Er3+-doped CaF2 nanocrystals

G. A. Kumar, C. W. Chen, and R. E. Riman

Appl. Phys. Lett. 90, 093123 (2007); http://dx.doi.org/10.1063/1.2392284 (3 pages) | Cited 10 times

Online Publication Date: 2 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Up-conversion emission and confocal fluorescence imaging of Er3+-doped CaF2 nanocrystals were investigated using infrared excitation. At Er3+ concentrations less than 2.8 mol %, green emission was dominant while red prevailed at higher concentrations. The simultaneous green and red emission and change in relative intensities is explained with a mechanism utilizing concepts of TPA, ESA, ET, and CR processes.
Show PACS
78.55.Hx Other solid inorganic materials
42.70.-a Optical materials

Electrowetting devices with transparent single-walled carbon nanotube electrodes

Liangbing Hu, George Gruner, Jian Gong, Chang-Jin “CJ” Kim, and Bjoern Hornbostel

Appl. Phys. Lett. 90, 093124 (2007); http://dx.doi.org/10.1063/1.2561032 (3 pages) | Cited 17 times

Online Publication Date: 2 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Microfluidic devices based on the electrowetting principle, more specifically electrowetting on dielectric, were fabricated using transparent single-walled carbon nanotube films as electrodes. The films were spray coated on glass and polyethylene terephalate substrates. The transmittance and sheet resistance remain unchanged after patterning the films using typical photolithography and plasma etching. Operation of water droplets over the patterned nanotube electrodes was demonstrated, and the performance was found to be comparable to that over the usual metal electrodes. The requirement of transparent electrodes is estimated for displays based on electrowetting machanism, and nanotube films indicate promise for such a type of devices.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
47.85.Np Fluidics
73.63.Fg Nanotubes
78.67.Ch Nanotubes
81.16.Nd Micro- and nanolithography
81.16.Rf Micro- and nanoscale pattern formation

Enhanced thermal conductivity of carbon fiber/phenolic resin composites by the introduction of carbon nanotubes

Y. A. Kim, S. Kamio, T. Tajiri, T. Hayashi, S. M. Song, M. Endo, M. Terrones, and M. S. Dresselhaus

Appl. Phys. Lett. 90, 093125 (2007); http://dx.doi.org/10.1063/1.2710778 (3 pages) | Cited 19 times

Online Publication Date: 2 March 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report a significant enhancement in the thermal conductivity of a conventional carbon fiber/phenolic resin composite system when adding highly crystalline multiwalled carbon nanotubes. They demonstrate that 7 wt % of carbon nanotubes dispersed homogeneously in a phenolic resin acted as an effective thermal bridge between adjacent carbon fibers and resulted in an enhancement of the thermal conductivity (e.g., from 250 to 393 W/m K). These results indicate that highly crystalline carbon nanotubes can be used as a multifunctional filler to enhance simultaneously the mechanical and thermal properties of the carbon fiber/phenolic resin composites.
Show PACS
81.05.Qk Reinforced polymers and polymer-based composites
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
81.40.-z Treatment of materials and its effects on microstructure, nanostructure, and properties
62.20.-x Mechanical properties of solids
Page 1 of 2 Pages Return to All Sections Next Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close