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

28 Sep 2009

Volume 95, Issue 13, Articles (13xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 95, 131107 (2009); http://dx.doi.org/10.1063/1.3236752 (3 pages)

Marcus Eichfelder, Wolfgang-Michael Schulz, Matthias Reischle, Michael Wiesner, Robert Roßbach, Michael Jetter, and Peter Michler
Enlarge Image | Read More
Page 3 of 5 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Output power enhancement of light-emitting diodes via two-dimensional hole arrays generated by a monolayer of microspheres

Chia-Hung Hou, Shao-Ze Tseng, Chia-Hua Chan, Tsing-Jen Chen, Hung-Ta Chien, Fu-Li Hsiao, Hua-Kung Chiu, Chien-Chieh Lee, Yen-Ling Tsai, and Chii-Chang Chen

Appl. Phys. Lett. 95, 133105 (2009); http://dx.doi.org/10.1063/1.3238360 (3 pages) | Cited 7 times

Online Publication Date: 28 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The output power enhancement of the GaN-based light-emitting diodes (LEDs) featuring two-dimensional (2D) hole arrays is demonstrated. The 2D air hole arrays were first generated in the photoresist by utilizing the focusing nature of microspheres, and then transferred onto the GaN surface through dry etching. The maximum output power of the surface-textured LEDs was enhanced by 45% compared with the LEDs without surface texturing. The finite-difference time-domain calculation was performed and revealed that the light extraction efficiency of the textured LEDs increased with increasing etching depth.
Show PACS
85.60.Jb Light-emitting devices
85.40.Hp Lithography, masks and pattern transfer
81.16.Nd Micro- and nanolithography
02.70.Bf Finite-difference methods
81.65.Cf Surface cleaning, etching, patterning

In situ studies of Al2O3 and HfO2 dielectrics on graphite

Adam Pirkle, Robert M. Wallace, and Luigi Colombo

Appl. Phys. Lett. 95, 133106 (2009); http://dx.doi.org/10.1063/1.3238560 (3 pages) | Cited 20 times

Online Publication Date: 28 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Deposition of Al2O3 and HfO2 dielectrics on graphite is studied as a route to the formation of a high-κ dielectric on graphene. Electron beam evaporation of metal Al and Hf is followed by a separate oxidation step. Reactive e-beam deposition of HfO2 by introduction of O2 to the deposition chamber is also demonstrated as an alternative to the two-step metal deposition and oxidation approach. We employ in situ x-ray photoelectron spectroscopy to study reactions between the substrate and deposited film and ex situ atomic force microscopy to examine the dielectric film morphology.
Show PACS
77.55.-g Dielectric thin films
68.37.Ps Atomic force microscopy (AFM)
79.60.Dp Adsorbed layers and thin films
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.55.J- Morphology of films
81.65.Mq Oxidation

GaN and InGaN(11math2) surfaces: Group-III adlayers and indium incorporation

John E. Northrup

Appl. Phys. Lett. 95, 133107 (2009); http://dx.doi.org/10.1063/1.3240401 (3 pages) | Cited 19 times

Online Publication Date: 28 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
First-principles calculations for clean and In-rich GaN(11math2) surfaces indicate that indium will, for the same indium chemical potential, incorporate in higher concentrations on the (11math2) surface than on the (10math0) surface. Because In atoms are larger than Ga atoms, there is a strain-induced repulsive interaction between incorporated In atoms on the surface. This interaction is weaker on the (11math2) surface in comparison to the (10math0) surface.
Show PACS
68.43.Bc Ab initio calculations of adsorbate structure and reactions
65.40.G- Other thermodynamical quantities

Structure and photoluminescence of wurtzite/zinc-blende heterostructure GaN nanorods

H. Y. Xu, Z. Liu, Y. Liang, Y. Y. Rao, X. T. Zhang, and S. K. Hark

Appl. Phys. Lett. 95, 133108 (2009); http://dx.doi.org/10.1063/1.3240890 (3 pages) | Cited 4 times

Online Publication Date: 29 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
GaN nanorods with a wurtzite/zinc-blende (WZ/ZB) heterostructure are synthesized by chemical vapor deposition. They have a triangular cross section and grow along the WZ [01math0] direction. The WZ and ZB phases appear alternately along the nanorod’s transverse direction, forming a type-II superlattice structure. Two ultraviolet emission peaks dominate the photoluminescence spectra of the GaN nanorods. One originates from excitonic transitions within the WZ regions. The other shows an anomalous “S-shaped” energy shift with increasing temperature, and is attributed to radiative recombinations of carriers localized at potential fluctuations in ZB regions. The carrier localization also results in high luminescent efficiency of the GaN nanorods.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
81.05.Ea III-V semiconductors
78.55.Cr III-V semiconductors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
78.40.Fy Semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.07.-b Nanoscale materials and structures: fabrication and characterization
71.35.-y Excitons and related phenomena
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Graphene growth on polycrystalline Ru thin films

E. Sutter, P. Albrecht, and P. Sutter

Appl. Phys. Lett. 95, 133109 (2009); http://dx.doi.org/10.1063/1.3224913 (3 pages) | Cited 18 times

Online Publication Date: 29 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monolayer graphene has been grown on polycrystalline Ru thin films on SiO2/Si substrates. The Ru films have columnar structure with strongly aligned grains exposing flat (0001) surface facets. Adjacent grains show small relative tilts of their [0001] axes and variations in in-plane orientation. Graphene layers grown on this template cover the entire surface and have uniform monolayer thickness. Analysis of the graphene/Ru moiré structure shows that monocrystalline graphene domains are coherent across a large number of substrate grains. Hence, the size of monolayer graphene domains is not limited by grain boundaries in the metal template.
Show PACS
68.47.Pe Langmuir-Blodgett films on solids; polymers on surfaces; biological molecules on surfaces
68.55.-a Thin film structure and morphology
81.10.-h Methods of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation
61.72.Mm Grain and twin boundaries
61.48.-c Structure of fullerenes and related hollow and planar molecular structures

Specific surface effect on transport properties of NiO/MgO heterostructured nanowires

Keisuke Oka, Takeshi Yanagida, Kazuki Nagashima, Hidekazu Tanaka, Shu Seki, Yoshihito Honsho, Manabu Ishimaru, Akihiko Hirata, and Tomoji Kawai

Appl. Phys. Lett. 95, 133110 (2009); http://dx.doi.org/10.1063/1.3237176 (3 pages) | Cited 11 times

Online Publication Date: 30 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
NiO heterostructured nanowires are promising building blocks due to the nonvolatile resistive switching in nanoscale. Here, we report on the noncontact transport measurements of single crystalline NiO/MgO heterostructured nanowires by utilizing a microwave conductivity method. We found the substantial discrepancy up to four orders of magnitude between the heterostructured nanowires and heterothin films on the resistivity when the bulk resistivity increased, whereas the reasonable agreement was found for relatively conductive range. The origin of such huge discrepancy was interpreted in terms of both the large specific surface area of nanowires and the surface transport events of insulative NiO.
Show PACS
73.63.-b Electronic transport in nanoscale materials and structures
73.61.Ng Insulators
75.50.Ee Antiferromagnetics

Carbon nanotube pillar arrays for achieving high emission current densities

Jeremy L. Silan, Darrell L. Niemann, Bryan P. Ribaya, Mahmud Rahman, M. Meyyappan, and Cattien V. Nguyen

Appl. Phys. Lett. 95, 133111 (2009); http://dx.doi.org/10.1063/1.3216584 (3 pages) | Cited 9 times

Online Publication Date: 30 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We introduce an innovative geometry carbon nanotube (CNT) field emitter array capable of achieving stable and high current densities. Arrays of toroid CNT pillars were grown directly on bulk metal alloy substrates and on patterned metal catalyst on silicon substrates. Compared to a solid CNT pillar array (CPA), this toroid CPA (tCPA) provides a larger edge area for achieving a higher stable current density of 50 mA/cm2 at an applied dc field of less than 8 V/μm. Electrostatic simulation data confirming the field enhancement at the inner and outer edges of the tCPA are also presented.
Show PACS
85.45.Db Field emitters and arrays, cold electron emitters
85.35.Kt Nanotube devices

Magnetically controllable nanofluid with tunable thermal conductivity and viscosity

P. D. Shima, John Philip, and Baldev Raj

Appl. Phys. Lett. 95, 133112 (2009); http://dx.doi.org/10.1063/1.3238551 (3 pages) | Cited 20 times

Online Publication Date: 30 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the viscosity (η) and thermal conductivity (k) enhancement in a stable magnetic nanofluid containing particles size <10 nm as a function of volume fraction (vol %), shear rate, magnetic field, and time. Without field, the η enhancement of nanoparticle is much larger than that of k. In a nanofluid with 0.078 vol %, the k/η ratio is tunable from 0.725 to 2.35 by controlling the applied field. Our results show that magnetic nanofluids with tunable k/η ratio can be used as multifunctional “smart materials” for miniature cooling cum damping applications.
Show PACS
66.20.Ej Studies of viscosity and rheological properties of specific liquids
62.10.+s Mechanical properties of liquids
66.25.+g Thermal conduction in nonmetallic liquids

Piezoresistive transduction in multilayer polycrystalline silicon resonators

J. D. Cross, B. R. Ilic, M. K. Zalalutdinov, W. Zhou, J. W. Baldwin, B. H. Houston, H. G. Craighead, and J. M. Parpia

Appl. Phys. Lett. 95, 133113 (2009); http://dx.doi.org/10.1063/1.3241077 (3 pages) | Cited 1 time

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate piezoresistive transduction of mechanical motion from out-of-plane flexural micromechanical resonators made from stacked thin films. The resonators are fabricated from two highly doped polycrystalline silicon layers separated by an interlayer dielectric. We examine two interlayer materials: thermal silicon dioxide and stoichiometric silicon nitride. We show that via one-time dielectric breakdown, the film stack functions as a vertical piezoresistor effectively transducing the motion of the resonators. We obtain a gauge factor of ∼ 5, which is sufficient to detect the resonator motion. The simple film stack constitutes a vertically oriented piezoresistor that is readily integrated with micro- and nanoscale resonators.
Show PACS
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)
77.22.Jp Dielectric breakdown and space-charge effects

Graphitic carbon growth on Si(111) using solid source molecular beam epitaxy

J. Hackley, D. Ali, J. DiPasquale, J. D. Demaree, and C. J. K. Richardson

Appl. Phys. Lett. 95, 133114 (2009); http://dx.doi.org/10.1063/1.3242029 (3 pages) | Cited 25 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Solid source molecular beam epitaxy is used to explore the growth of carbon films directly on Si(111). It is shown that graphitic carbon is grown by the implementation of a thin amorphous carbon film that suppresses the formation of SiC precipitates. Raman scattering measurements show the D and G vibrational phonon modes, indicating graphitic ordering in the carbon film. X-ray photoelectron spectroscopy is used to verify the formation of sp2 bonds in the graphitic carbon films and confirms the suppression of SiC.
Show PACS
68.55.A- Nucleation and growth
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials

Ni@B80: A single molecular magnetic switch

J. L. Li and G. W. Yang

Appl. Phys. Lett. 95, 133115 (2009); http://dx.doi.org/10.1063/1.3242362 (3 pages) | Cited 5 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We theoretically performed that the magnetic moment of Ni-encapsulated B80 (Ni@B80) can be greatly tuned by changing the position of Ni atom inside the hollow cage of B80. There are three stable configurations of Ni@B80 with Ni atom located at center, pentagon, and hexagonal-in, respectively. Compared with that of Ni@B80 with Ni atom located at center, all the magnetic moments of Ni@B80’s with Ni atom located at pentagon and hexagon-in in the hollow cage of B80 are zero. These fascinating findings imply that Ni@B80 may be a promising candidate for single molecular magnetic switch.
Show PACS
85.65.+h Molecular electronic devices
75.60.-d Domain effects, magnetization curves, and hysteresis
75.30.Cr Saturation moments and magnetic susceptibilities
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
75.50.Cc Other ferromagnetic metals and alloys
75.50.Xx Molecular magnets

Edge-passivation induced half-metallicity of zigzag zinc oxide nanoribbons

Qian Chen, Liyan Zhu, and Jinlan Wang

Appl. Phys. Lett. 95, 133116 (2009); http://dx.doi.org/10.1063/1.3238561 (3 pages) | Cited 8 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electronic and magnetic properties of zigzag zinc oxide (ZnO) nanoribbons with or without hydrogen passivation are investigated using ab initio calculations. The ribbon is found to be half-metallic ferromagnet when edge zinc atoms are passivated only. Moreover, the half-metallicity only emerges in the ribbons with relatively large width. Besides, the half-metallic ferromagnet can also be achieved when the passivatator H is replaced by CH3 or NH2. These diverse electronic and magnetic properties might open ZnO materials great possibility in future spintronics.
Show PACS
81.65.Rv Passivation
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Pp Magnetic semiconductors
71.15.-m Methods of electronic structure calculations
73.22.-f Electronic structure of nanoscale materials and related systems
72.25.-b Spin polarized transport

Duty ratio-dependent fluorescence enhancement through surface plasmon resonance in Ag-coated gratings

Xiaoqiang Cui, Keiko Tawa, Hironobu Hori, and Junji Nishii

Appl. Phys. Lett. 95, 133117 (2009); http://dx.doi.org/10.1063/1.3238562 (3 pages) | Cited 6 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
One-dimensional gratings with different duty ratios were designed and implemented for enhanced fluorescence detection and imaging. Verified by finite difference time domain simulations, our results showed that the enhancement strongly depended on the duty ratio of the land width to pitch of the grating structure. The maximum enhancement factor was achieved when the duty ratio was equal to 0.50 in our trapezoidal gratings with pitch = 400 nm and depth = 20 nm. Such a facile grating mold will exert a considerable influence on microarray biosensors and fluorescence microscopy.
Show PACS
42.79.Dj Gratings
42.15.Eq Optical system design
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
87.80.-y Biophysical techniques (research methods)
87.15.mq Luminescence

Modification of the conductance of single fullerene molecules by endohedral doping

Anna Stróżecka, Kaliappan Muthukumar, Aneta Dybek, T. John Dennis, J. Andreas Larsson, Josef Mysliveček, and Bert Voigtländer

Appl. Phys. Lett. 95, 133118 (2009); http://dx.doi.org/10.1063/1.3236529 (3 pages) | Cited 7 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We use scanning tunneling microscopy to establish controlled contacts to single molecules of endohedrally doped Ce2@C80 fullerenes with C60 as a reference. The stability of the experimental setup allows for the determination of the conductance of Ce2@C80 relative to the conductance of C60. The endohedral doping reduces the conductance of Ce2@C80 by a factor of about five with respect to C60. Ab initio calculations show that the reason for this reduced conductance is the absence of electron orbitals delocalized over the cage of Ce2@C80 in the energy window of the conductance measurement.
Show PACS
61.72.up Other materials
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
71.15.-m Methods of electronic structure calculations
61.48.-c Structure of fullerenes and related hollow and planar molecular structures

Carbon-coated silicon nanowire array films for high-performance lithium-ion battery anodes

Rui Huang, Xing Fan, Wanci Shen, and Jing Zhu

Appl. Phys. Lett. 95, 133119 (2009); http://dx.doi.org/10.1063/1.3238572 (3 pages) | Cited 25 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Carbon-coated silicon nanowire array films prepared by metal catalytic etching of silicon wafers and pyrolyzing of carbon aerogel were used for lithium-ion battery anodes. The films exhibited an excellent first discharge capacity of 3344 mAh g−1 with a Coulombic efficiency of 84% at a rate of 150 mA g−1 between 2 and 0.02 V and a significantly enhanced cycling performance, i.e., a reversible capacity of 1326 mAh g−1 was retained after 40 cycles. These improvements were attributed to the uniform and continuous carbon coatings, which increased electronic contact and conduction and buffered large volume changes during lithium ion insertion/extraction.
Show PACS
81.16.Hc Catalytic methods
81.07.Vb Quantum wires
81.65.Cf Surface cleaning, etching, patterning
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
82.47.Aa Lithium-ion batteries
68.55.ag Semiconductors
61.46.Km Structure of nanowires and nanorods (long, free or loosely attached, quantum wires and quantum rods, but not gate-isolated embedded quantum wires)
81.05.Cy Elemental semiconductors

Photoluminescence and Raman scattering in axial Si/Ge nanowire heterojunctions

H.-Y. Chang, L. Tsybeskov, S. Sharma, T. I. Kamins, X. Wu, and D. J. Lockwood

Appl. Phys. Lett. 95, 133120 (2009); http://dx.doi.org/10.1063/1.3240595 (3 pages) | Cited 1 time

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In crystalline, dislocation-free, Si/Ge nanowire axial heterojunctions grown using the vapor-liquid-solid technique, photoluminescence and Raman spectroscopy reveal a SiGe alloy transition layer with preferential chemical composition and strain. In addition to the lattice mismatch, strain in Si/Ge nanowires is observed from a temperature dependent study to be affected by the difference in Si and Ge thermal expansion. The conclusions are supported by analytical transmission electron microscopy measurements.
Show PACS
78.55.Hx Other solid inorganic materials
78.66.Li Other semiconductors
78.30.Hv Other nonmetallic inorganics
65.40.De Thermal expansion; thermomechanical effects

Achievement of 6.03% conversion efficiency of dye-sensitized solar cells with single-crystalline rutile TiO2 nanorod photoanode

Weiguang Yang, Farong Wan, Yali Wang, and Chunhua Jiang

Appl. Phys. Lett. 95, 133121 (2009); http://dx.doi.org/10.1063/1.3240870 (3 pages) | Cited 17 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The rutile TiO2 nanorods (RTNs) with the length of 40–130 nm and diameters approximately 8–15 nm, containing some 300–500 nm sized RTN aggregates and 6% of anatase TiO2 nanocrystals, were prepared by surfactant-assisted hydrothermal method. The dye-sensitized solar cell (DSC) based on the RTNs exhibited power conversion efficiency of 6.03%. As compared to P25 TiO2 based DSC, RTNs based DSC shows improved light-harvesting and Brunauer–Emmett–Teller surface area, leading to an increase in short-circuit current (Jsc) by 40.6%.
Show PACS
84.60.Jt Photoelectric conversion
82.50.-m Photochemistry
82.45.Fk Electrodes

The MoS2 nanotube hybrids

M. Remškar, M. Viršek, and A. Mrzel

Appl. Phys. Lett. 95, 133122 (2009); http://dx.doi.org/10.1063/1.3240892 (3 pages) | Cited 8 times

Online Publication Date: 2 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The MoS2 nanotube hybrids represent a family of nanomaterials, where nanotubes serve as nanoreactors and in some cases also as nanocontainers of MoS2 fullerenelike particles, which have in situ grown in a confined geometry of nanotubes. A simple temperature control of morphology, size, and inner structure of nanohybrids leads to a selective morphology such as coaxial nanotubes, “mama”-tubes with encapsulated nano-onions, the growth of MoS2 nanobuds or it facilitates a release of MoS2 nano-onions, which then form weakly bonded self-assemblies. Growth mechanism is discussed based on atomic probe electron microscopy, x-ray diffraction and high-resolution transmission electron microscopy.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
81.16.Dn Self-assembly
68.37.Ps Atomic force microscopy (AFM)
61.46.Fg Nanotubes

Effect of donor-acceptor concentration ratios on nonradiative energy transfer in closely packed CdTe quantum dots

Y. C. Lin, W. J. Wang, H. L. Chung, W. C. Chou, W. K. Chen, W. H. Chang, A. S. Susha, and A. L. Rogach

Appl. Phys. Lett. 95, 133123 (2009); http://dx.doi.org/10.1063/1.3242371 (3 pages) | Cited 3 times

Online Publication Date: 2 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This study investigates the dependence of Förster resonance energy transfer (FRET) on donor-acceptor (D/A) concentration ratios in mixed-size CdTe quantum dots (QDs) films by using photoluminescence (PL) and time-resolved PL spectroscopy. Experimental results indicate that an increasing donor concentration significantly quenches the emission intensity and lifetime in donor QDs and enhances that in acceptor QDs, providing clear evidence of increased FRET efficiency. When D/A ratio exceeds 6, however, the emission intensity and the lifetime of acceptors start to decline, reflecting a decreasing FRET efficiency because of a markedly declining availability of acceptor QDs.
Show PACS
78.67.Hc Quantum dots
78.55.Et II-VI semiconductors
78.66.Hf II-VI semiconductors
78.47.jd Time resolved luminescence

Ultraviolet emission from a ZnO rod homojunction light-emitting diode

X. W. Sun, B. Ling, J. L. Zhao, S. T. Tan, Y. Yang, Y. Q. Shen, Z. L. Dong, and X. C. Li

Appl. Phys. Lett. 95, 133124 (2009); http://dx.doi.org/10.1063/1.3243453 (3 pages) | Cited 31 times

Online Publication Date: 2 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultraviolet electroluminescence was demonstrated at room temperature from a ZnO rod homojunction light-emitting diode array. The p-type doping was realized by phosphorous (P) ion implantation into defect-free ZnO rods followed by annealing. High resolution transmission electron microscopy shows the lattice compression of annealed single crystalline P-doped ZnO rod compared to the as-grown ZnO rod, suggesting atomically incorporation of P into the ZnO wurtzite structure. p-type doping was confirmed by low temperature photoluminescence spectra and single rod current-voltage characterization.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
61.72.uj III-V and II-VI semiconductors
78.55.Et II-VI semiconductors
78.60.Fi Electroluminescence
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.60.Jb Light-emitting devices
61.72.Cc Kinetics of defect formation and annealing

Close-packed hemiellipsoid arrays: A photonic band gap structure patterned by nanosphere lithography

Wai Yuen Fu, Kenneth Kin-Yip Wong, and H. W. Choi

Appl. Phys. Lett. 95, 133125 (2009); http://dx.doi.org/10.1063/1.3238564 (3 pages) | Cited 8 times

Online Publication Date: 2 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A self-assembled hexagonal close-packed hemiellipsoidal photonic crystal structure was fabricated on GaN material. An ordered monolayer silica nanosphere coating served as a hard mask in an inductively coupled plasma etching process. The shape of the arrayed hemiellipsoids can be controlled by adjusting the etch selectivities and durations according to the fabrication model. The existence of a photonic band gap is established through planar transmissivity measurement whereby a transmission dip centered at 440 nm was identified. A threefold enhancement in light extraction was achieved, as determined from the measured angular photoluminescence emission pattern.
Show PACS
42.70.Qs Photonic bandgap materials
81.16.Dn Self-assembly
81.16.Nd Micro- and nanolithography
81.16.Rf Micro- and nanoscale pattern formation
42.82.Cr Fabrication techniques; lithography, pattern transfer
81.65.Cf Surface cleaning, etching, patterning

Ferromagnet-semiconductor nanowire coaxial heterostructures grown by molecular-beam epitaxy

M. Hilse, Y. Takagaki, J. Herfort, M. Ramsteiner, C. Herrmann, S. Breuer, L. Geelhaar, and H. Riechert

Appl. Phys. Lett. 95, 133126 (2009); http://dx.doi.org/10.1063/1.3240405 (3 pages) | Cited 7 times

Online Publication Date: 2 October 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
GaAs–MnAs core-shell structures are grown by molecular-beam epitaxy using wurtzite GaAs nanowires on GaAs(111)B. The nanowire structures curve due to the strain at the heterointerface when the substrate is not rotated during the growth, evidencing the diffusion length in the MnAs overgrowth being less than the perimeter of the columns. The MnAs growth is thus demonstrated to take place by direct deposition on the sidewall. The MnAs envelope is m-plane-oriented with the c-axis along the nanowire axis. The magnetic easy axis hence lies in the surface plane of the substrate, which is confirmed by magnetization measurements and magnetic-force microscopy.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
61.46.Km Structure of nanowires and nanorods (long, free or loosely attached, quantum wires and quantum rods, but not gate-isolated embedded quantum wires)
66.30.Pa Diffusion in nanoscale solids
75.75.-c Magnetic properties of nanostructures
73.63.Nm Quantum wires
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
68.37.Rt Magnetic force microscopy (MFM)
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
back to top
RSS Feeds
FREE

Highly efficient nondoped green organic light-emitting devices based on a substituted triphenylpyridine derivative

Na Li, Shiu-Lun Lai, Pengfei Wang, Feng Teng, Zengtao Liu, Chun-Sing Lee, and Shuit-Tong Lee

Appl. Phys. Lett. 95, 133301 (2009); http://dx.doi.org/10.1063/1.3242000 (3 pages) | Cited 4 times

Online Publication Date: 30 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly efficient nondoped green organic light-emitting devices based on a triphenylpyridine derivative, 4-[4-(dimethylamino)phenyl]-2,6-diphenylnicotinonitrile (NPDPN), were fabricated and characterized. The double-organic-layer device with a structure of ITO/α-napthylphenylbiphenyl diamine /NPDPN/LiF/Al, in which NPDPN was used as both the emitter and the electron transporter, exhibits a green emission with Commission Internationale de L'Eclairage (CIE) coordinates of (0.23,0.52) and a power efficiency of 5.5 lm/W. The result is much better than that of similarly structured device based on tris(8-hydroxyquinoline)aluminum. Furthermore, a high current efficiency of 8.4 cd/A was achieved with an optimized device configuration.
Show PACS
85.60.Jb Light-emitting devices
FREE

Enhancement in current efficiency in organic light-emitting diodes with incorporation of subphthalocyanine

Yu-Hung Chen, Jung-Hung Chang, Guan-Ru Lee, I-Wen Wu, Jheng-Hao Fang, Chih-I Wu, and Tun-Wen Pi

Appl. Phys. Lett. 95, 133302 (2009); http://dx.doi.org/10.1063/1.3237173 (3 pages) | Cited 8 times

Online Publication Date: 30 September 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A highly efficient hole injection material, boron subphthalocyanine chloride (SubPc), was incorporated in organic light-emitting diodes. Device performance is greatly enhanced by inserting an ultrathin layer of SubPc between anodes and N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidene (NPB). Electronic structures and chemical reaction at the interface between NPB and SubPc are also investigated by photoemission spectroscopy with synchrotron radiation sources. Extra states are observed at the forbidden gap of SubPc with deposition of NPB, resulting from the broken bonds between boron and chlorine on SubPc with presence of NPB. These gap states are attributed to the improvement of device performance.
Show PACS
85.60.Jb Light-emitting devices
FREE

Enhancing the photocurrent in poly(3-hexylthiophene)/[6,6]-phenyl C61 butyric acid methyl ester bulk heterojunction solar cells by using poly(3-hexylthiophene) as a buffer layer

Chin-Wei Liang, Wei-Fang Su, and Leeyih Wang

Appl. Phys. Lett. 95, 133303 (2009); http://dx.doi.org/10.1063/1.3242006 (3 pages) | Cited 14 times

Online Publication Date: 1 October 2009

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
This work presents an approach for improving the unfavorable vertical composition gradients of poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in the photoactive layer of bulk heterojunction solar cells. The proposed method involves simply depositing a thin layer of P3HT on top of poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate) (PEDOT:PSS) prior to the P3HT:PCBM blend is spin coated. The results from photoluminescence and photovoltaic measurements indicate that incorporating this P3HT layer significantly enhances the electron blocking ability of PEDOT:PSS, the efficiency of photoinduced electron transfer and the photocurrent of the device, resulting in an improvement of the power conversion efficiency from 3.98% to 5.05%.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
79.60.Bm Clean metal, semiconductor, and insulator surfaces
78.55.Kz Solid organic materials
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
84.60.Jt Photoelectric conversion
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
Page 3 of 5 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close