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

16 Mar 2009

Volume 94, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 94, 111101 (2009); http://dx.doi.org/10.1063/1.3097278 (3 pages)

Ling Lu, Adam Mock, Tian Yang, Min Hsiung Shih, Eui Hyun Hwang, Mahmood Bagheri, Andrew Stapleton, Stephen Farrell, John O’Brien, and P. Daniel Dapkus
Enlarge Image | Read More
Page 1 of 4 Pages Next Page | Jump to Page
back to top
RSS Feeds

120 μW peak output power from edge-emitting photonic crystal double-heterostructure nanocavity lasers

Ling Lu, Adam Mock, Tian Yang, Min Hsiung Shih, Eui Hyun Hwang, Mahmood Bagheri, Andrew Stapleton, Stephen Farrell, John O’Brien, and P. Daniel Dapkus

Appl. Phys. Lett. 94, 111101 (2009); http://dx.doi.org/10.1063/1.3097278 (3 pages) | Cited 9 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
As an attempt to collect more in-plane emission power out of wavelength size two-dimensional photonic crystal defect lasers, edge-emitting photonic crystal double-heterostructure quantum well membrane lasers were fabricated by shortening the number of cladding periods on one side. 120 μW peak output power was collected from the facet of the single mode laser at room temperature. Laser efficiencies were analyzed and agree very well with three-dimensional finite-difference time-domain modeling.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems
42.70.Qs Photonic bandgap materials
02.70.Bf Finite-difference methods

A wireless-compatible optics-free fluorescent array reader

M. Anwar, T. Aytur, and P. Matsudaira

Appl. Phys. Lett. 94, 111102 (2009); http://dx.doi.org/10.1063/1.3097008 (3 pages)

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical-based bioassays, particularly fluorescent-based arrays, form the basis for biological detection in both biological and clinical assays, yet their use is restricted by the need for sensitive optical detectors and optics. To address this, we developed an integrated circuit-based fluorescent imaging platform that functions without the use of optics while directly integrating electronics, enabling a low-cost integrated solution. Additionally, we incorporate a wireless interface, enabling optical detection within any biological environment. As a proof of concept, we demonstrate the detection of 20 nM of Streptavidin on an array without the use of optical filters and lenses.
Show PACS
87.80.-y Biophysical techniques (research methods)
42.79.Pw Imaging detectors and sensors
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Deep ultraviolet photoluminescence of Tm-doped AlGaN alloys

N. Nepal, J. M. Zavada, D. S. Lee, A. J. Steckl, A. Sedhain, J. Y. Lin, and H. X. Jiang

Appl. Phys. Lett. 94, 111103 (2009); http://dx.doi.org/10.1063/1.3097808 (3 pages) | Cited 3 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The ultraviolet (UV) photoluminescence (PL) properties of Tm-doped AlxGa1−xN (0.39 ≤ x ≤ 1) alloys grown by solid-source molecular beam epitaxy were probed using above-bandgap excitation from a laser source at 197 nm. The PL spectra show dominant UV emissions at 298 and 358 nm only for samples with x = 1 and 0.81. Temperature dependence of the PL intensities of these emission lines reveals exciton binding energies of 150 and 57 meV, respectively. The quenching of these UV emissions appears related to the thermal activation of the excitons bound to rare-earth structured isovalent (RESI) charge traps, which transfer excitonic energy to Tm3+ ions resulting in the UV emissions. A model of the RESI trap levels in AlGaN alloys is presented.
Show PACS
78.66.Fd III-V semiconductors
71.35.-y Excitons and related phenomena
61.72.U- Doping and impurity implantation
78.55.Cr III-V semiconductors
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Parametric amplification and wavelength conversion in the 1040–1090 nm band by use of a photonic crystal fiber

T. Sylvestre, A. Kudlinski, A. Mussot, J. F. Gleyze, A. Jolly, and H. Maillotte

Appl. Phys. Lett. 94, 111104 (2009); http://dx.doi.org/10.1063/1.3100192 (3 pages) | Cited 7 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly efficient parametric amplification and wavelength conversion have been demonstrated in the 1040–1090 nm band. A nonlinear photonic crystal fiber was used to provide the anomalous dispersion required for phase matching at 1 μm. A 40 dB maximum gain and +35 dB idler conversion efficiency have been achieved in the subnanosecond pulsed regime and by using a spectrally filtered supercontinuum source as a small signal.
Show PACS
42.65.Lm Parametric down conversion and production of entangled photons
42.70.Qs Photonic bandgap materials
42.81.Dp Propagation, scattering, and losses; solitons
42.79.Ci Filters, zone plates, and polarizers
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Focusing surface plasmons to multiple focal spots with a launching diffraction grating

Chenglong Zhao, Jiayuan Wang, Xiaofei Wu, and Jiasen Zhang

Appl. Phys. Lett. 94, 111105 (2009); http://dx.doi.org/10.1063/1.3100195 (3 pages) | Cited 7 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose a surface plasmon launching diffraction grating (SPLDG) to obtain multiple focal spots of SPs with nearly equal intensity. The SPLDG is composed of grooves that are located on concentric arcs, whose projections on the chord form a grating. When the incident plane wave illuminates the grating, SPs launched and diffracted into different directions will be approximately focused to multispots on a circle. Here, we obtain three and five focuses and the numerical simulation agrees well with the experiment.
Show PACS
42.79.Dj Gratings
42.79.Wc Optical coatings
42.86.+b Optical workshop techniques

GaAs0.7Sb0.3/GaAs type-II quantum well with an adjacent InAs quantum-dot stressor layer

You-Ru Lin, Yi-Feng Lai, Chuan-Pu Liu, and Hao-Hsiung Lin

Appl. Phys. Lett. 94, 111106 (2009); http://dx.doi.org/10.1063/1.3100191 (3 pages) | Cited 1 time

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the optical properties of a composite structure comprising a type-II GaAs0.7Sb0.3/GaAs quantum well (QW) and an InAs quantum-dot (QD) layer adjacent to the QW. The low-temperature photoluminescence (PL) of the composite structure with a 5-nm-thick GaAs spacer demonstrates a redshift of 44 meV, as compared with that of GaAs0.7Sb0.3/GaAs single QW at low excitation level. The redshift reveals the existence of local potential minimums, induced by the stress exerted by the adjacent QDs, in the type-II QW. At higher temperature, the composite structure shows stronger PL intensity than the GaAs0.7Sb0.3 QW, indicating the potential of the applications to laser diodes.
Show PACS
78.67.De Quantum wells
78.67.Hc Quantum dots
81.07.Ta Quantum dots
81.07.St Quantum wells
78.55.Cr III-V semiconductors

Submonolayer quantum dot infrared photodetector

David Z.-Y. Ting, Sumith V. Bandara, Sarath D. Gunapala, Jason M. Mumolo, Sam A. Keo, Cory J. Hill, John K. Liu, Edward R. Blazejewski, Sir B. Rafol, and Yia-Chung Chang

Appl. Phys. Lett. 94, 111107 (2009); http://dx.doi.org/10.1063/1.3095812 (3 pages) | Cited 15 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe the concept of the submonolayer quantum dot infrared photodetector (SML QDIP) and report experimental device results on long-wavelength infrared detection. An SML QDIP structure was fabricated into megapixel focal plane arrays, which produced clear infrared images up to 80 K. Detectors in the focal plane showed a responsivity peak at 7.8 μm and noise equivalent temperature difference of 33 mK at 70 K.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Intense multimicrojoule high-order harmonics generated from neutral atoms of In2O3 nanoparticles

L. B. Elouga Bom, R. A. Ganeev, J. Abdul-Hadi, F. Vidal, and T. Ozaki

Appl. Phys. Lett. 94, 111108 (2009); http://dx.doi.org/10.1063/1.3100772 (3 pages) | Cited 6 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We studied high-order harmonic generation from plasma that contains an abundance of indium oxide nanoparticles. We found that harmonics from nanoparticle-containing plasma are considerably more intense than from plasma produced on the In2O3 bulk target, with high-order harmonic energy ranging from 6 μJ (for the ninth harmonic) to 1 μJ (for the 17th harmonic) in the former case. The harmonic cutoff from nanoparticles was at the 21st order, which is lower than that observed using indium oxide solid target. By comparing the harmonic spectra obtained from solid and nanoparticle indium oxide targets, we concluded that intense harmonics in the latter case are dominantly generated from neutral atoms of the In2O3 nanoparticles.
Show PACS
52.38.Dx Laser light absorption in plasmas (collisional, parametric, etc.)
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.27.Lw Dusty or complex plasmas; plasma crystals
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.38.Mf Laser ablation

Internal quantum efficiency and nonradiative recombination coefficient of GaInN/GaN multiple quantum wells with different dislocation densities

Q. Dai, M. F. Schubert, M. H. Kim, J. K. Kim, E. F. Schubert, D. D. Koleske, M. H. Crawford, S. R. Lee, A. J. Fischer, G. Thaler, and M. A. Banas

Appl. Phys. Lett. 94, 111109 (2009); http://dx.doi.org/10.1063/1.3100773 (3 pages) | Cited 42 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Room-temperature photoluminescence (PL) measurements are performed on GaInN/GaN multiple-quantum-well heterostructures grown on GaN-on-sapphire templates with different threading-dislocation densities. The selective optical excitation of quantum wells and the dependence of integrated PL intensity on excitation power allow us to determine the internal quantum efficiency (IQE) as a function of carrier concentration. The measured IQE of the sample with the lowest dislocation density (5.3×108 cm−2) is as high as 64%. The measured nonradiative coefficient A varies from 6×107 to 2×108 s−1 as the dislocation density increases from 5.3×108 to 5.7×109 cm−2, respectively.
Show PACS
78.67.De Quantum wells
81.07.St Quantum wells
73.63.Hs Quantum wells
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

All-chalcogenide glass omnidirectional photonic band gap variable infrared filters

H. Esat Kondakci, Mecit Yaman, Ozlem Koylu, Aykutlu Dana, and Mehmet Bayindir

Appl. Phys. Lett. 94, 111110 (2009); http://dx.doi.org/10.1063/1.3103279 (3 pages) | Cited 7 times

Online Publication Date: 18 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the design, fabrication, and characterization of spatially variable infrared photonic band gap filter that consists of thermally evaporated, high refractive index contrast, amorphous chalcogenide glass multilayers. Due to graded thickness structure, the filter exhibits a position dependent stop band and a cavity mode ranging from 1.8 to 3.4 μm wavelengths. Reflection measurements on the variable filter agree well with theoretical calculations. These results pave the way to low-loss infrared mirrors, filters, spectral imaging, and miniaturized spectrometers at infrared region.
Show PACS
42.79.Ci Filters, zone plates, and polarizers
42.70.Qs Photonic bandgap materials
42.79.Wc Optical coatings

Single photon emission from a site-controlled quantum dot-micropillar cavity system

C. Schneider, T. Heindel, A. Huggenberger, P. Weinmann, C. Kistner, M. Kamp, S. Reitzenstein, S. Höfling, and A. Forchel

Appl. Phys. Lett. 94, 111111 (2009); http://dx.doi.org/10.1063/1.3097016 (3 pages) | Cited 26 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the deterministic integration of single site-controlled quantum dots (SCQDs) into micropillar cavities. Spatial resonance between single positioned QDs and GaAs/AlAs micropillar cavities was achieved using cross markers for precise SCQD-cavity alignment. Cavity effects are clearly reflected in an enhanced photoluminescence intensity when tuning SCQD emission lines through the fundamental cavity resonance. Single photon emission from a spatially and spectrally coupled SCQD-resonator system is confirmed by photon autocorrelation measurements yielding a g(2)(0) value of 0.12.
Show PACS
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors

Slow surface phonon polaritons for sensing in the midinfrared spectrum

Igal Balin, Nir Dahan, Vladimir Kleiner, and Erez Hasman

Appl. Phys. Lett. 94, 111112 (2009); http://dx.doi.org/10.1063/1.3098360 (3 pages) | Cited 11 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a reflection-type sensor in the midinfrared spectra based on resonant excitation of surface phonon polaritons (SPhPs). In this range, SPhPs are characterized by the high density of states associated with slow surface waves that lead to enhanced resonance absorption. Delocalized SPhPs were excited by irradiating TM-polarized light on a one-dimensional grating embedded in a SiC substrate. The sensor response was characterized by changing the refractive index (RI) of a lossless CO2 gas. A detection limit of 2×10−5 RI units was obtained at a wavelength of 11.9 μm.
Show PACS
78.30.-j Infrared and Raman spectra
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
68.35.Ja Surface and interface dynamics and vibrations
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.68.+m Optical properties of surfaces
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Efficient generation of energy-tunable entangled photons in a semiconductor microcavity

Hisaki Oka, Goro Oohata, and Hajime Ishihara

Appl. Phys. Lett. 94, 111113 (2009); http://dx.doi.org/10.1063/1.3103209 (3 pages) | Cited 6 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A scheme is proposed for the generation of polarization- and frequency-entangled photons in a semiconductor planar microcavity. Photon entanglement can be achieved by converting two lower polariton branches with symmetric in-plane momenta into lower and upper polariton branches with zero in-plane momentum via a biexciton state. The phase-matching condition is satisfied for a microcavity with cavity detuning equal to the biexciton binding energy. The generation efficiency and energy control of the entangled photons are demonstrated for a CuCl microcavity as an example.
Show PACS
42.50.-p Quantum optics
03.65.Ud Entanglement and quantum nonlocality (e.g. EPR paradox, Bell's inequalities, GHZ states, etc.)
71.35.-y Excitons and related phenomena
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)
71.45.-d Collective effects

Distributed feedback all-organic microlaser based on holographic polymer dispersed liquid crystals

L. Criante, D. E. Lucchetta, F. Vita, R. Castagna, and F. Simoni

Appl. Phys. Lett. 94, 111114 (2009); http://dx.doi.org/10.1063/1.3103276 (3 pages) | Cited 3 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An optically pumped vertically emitting all-organic laser, based on a holographic polymer dispersed liquid crystal reflection grating operating in a distributed feedback configuration, is presented. The used experimental geometry overcomes the main drawbacks characterizing similar systems, allowing virtually infinite operations and absence of damages associated with the high energy of the optical pumping.
Show PACS
42.55.-f Lasers
42.40.Eq Holographic optical elements; holographic gratings

Strong coupling through optical positioning of a quantum dot in a photonic crystal cavity

Susanna M. Thon, Matthew T. Rakher, Hyochul Kim, Jan Gudat, William T. M. Irvine, Pierre M. Petroff, and Dirk Bouwmeester

Appl. Phys. Lett. 94, 111115 (2009); http://dx.doi.org/10.1063/1.3103885 (3 pages) | Cited 26 times

Online Publication Date: 20 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Single self-assembled InAs quantum dots embedded in GaAs photonic crystal defect cavities are a promising system for cavity quantum electrodynamics experiments and quantum information schemes. Achieving controllable coupling in these small mode volume devices is challenging due to the random nucleation locations of individual quantum dots. We have developed an all optical scheme for locating the position of single dots with sub-10 nm accuracy. Using this method, we are able to deterministically reach the strong coupling regime with a spatial positioning success rate of approximately 70%. This flexible method should be applicable to other microcavity architectures and emitter systems.
Show PACS
78.67.Hc Quantum dots
42.70.Qs Photonic bandgap materials
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
back to top
RSS Feeds

Optical diagnosis of an argon/oxygen needle plasma generated at atmospheric pressure

Shou-Zhe Li, Wen-Tong Huang, Jialiang Zhang, and Dezhen Wang

Appl. Phys. Lett. 94, 111501 (2009); http://dx.doi.org/10.1063/1.3099339 (3 pages) | Cited 13 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An atmospheric-pressure argon/oxygen needle plasma discharge is generated in a long dielectric tube and investigated with respect to its electrical characteristics and the production of oxygen atom by means of optical actinometry. The length of discharge column depends on the operating frequency and applied voltage of power supply, which is interpreted qualitatively with an equivalent circuit model. Moreover it is found that there exists an optimal value of oxygen concentration in the production of oxygen radicals. At last, the oxygen/argon plasma is employed to modify the interior surface of a fine quartz tube to demonstrate its potential applications.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.50.-b Plasma production and heating
52.80.-s Electric discharges
back to top
RSS Feeds

Stranski–Krastanow growth of (11math2)-oriented GaN/AlN quantum dots

L. Lahourcade, S. Valdueza-Felip, T. Kehagias, G. P. Dimitrakopulos, P. Komninou, and E. Monroy

Appl. Phys. Lett. 94, 111901 (2009); http://dx.doi.org/10.1063/1.3095499 (3 pages) | Cited 7 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Semipolar GaN(11math2) deposited on AlN(11math2) by plasma-assisted molecular-beam epitaxy can follow the Frank–Van der Merwe or the Stranski–Krastanow growth mode as a function of the Ga/N ratio. N-rich grown GaN relaxes elastically at a critical thickness but the resulting GaN islands present multiple crystallographic orientations. In contrast, after deposition of a few two-dimensional GaN monolayers under Ga-rich conditions, a growth interruption in vacuum induces (11math2)-oriented islanding. Applying this latter procedure, we have synthesized GaN/AlN quantum dot superlattices with reduced internal electric field.
Show PACS
68.65.Cd Superlattices
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.07.Ta Quantum dots

Effect of atomic ordering on hydrogen dissociation on Ni3Fe surfaces

X. Y. Cheng, Yip-Wah Chung, Bo Zhao, B. Hong, and C. T. Liu

Appl. Phys. Lett. 94, 111902 (2009); http://dx.doi.org/10.1063/1.3089575 (3 pages) | Cited 2 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dissociation of molecular to atomic hydrogen on clean surfaces of Ni3Fe with either an ordered or disordered structure has been directly investigated by thermal desorption studies. Results show that when exposed to an ordered Ni3Fe surface, molecular hydrogen dissociates to produce atomic hydrogen, which desorbs from the surface around 350 K. On the other hand, hydrogen does not dissociate on a disordered Ni3Fe surface. These results indicate that atomic ordering has a marked effect on surface chemical reactivity. Furthermore, our study provides a mechanistic basis to explain the hydrogen-induced embrittlement in ordered Ni3Fe but not in disordered Ni3Fe.
Show PACS
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
68.43.Nr Desorption kinetics
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Localized modes in capped single-walled carbon nanotubes

Alexander V. Savin and Yuri S. Kivshar

Appl. Phys. Lett. 94, 111903 (2009); http://dx.doi.org/10.1063/1.3100199 (3 pages) | Cited 4 times

Online Publication Date: 16 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study numerically small-amplitude oscillations in capped single-walled carbon nanotubes and predict the existence of surface modes localized at capped tips of the nanotubes. These modes are similar to the surface Tamm states found in solids and optics at the edges of truncated lattices.
Show PACS
63.22.Gh Nanotubes and nanowires
68.35.Ja Surface and interface dynamics and vibrations
81.07.De Nanotubes

Photoactive periodic media

Tahar Ben-Messaoud, Jason Riordon, Alexandre Melanson, P. V. Ashrit, and Alain Haché

Appl. Phys. Lett. 94, 111904 (2009); http://dx.doi.org/10.1063/1.3095478 (3 pages) | Cited 3 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Photoactive (photochromic) multilayers of MoO3/SiO2 are studied optically before and after UV excitation. Enhancement in photochromic activity is observed over a wide spectrum and in particular near the photonic band edges where optical changes are up to 25 times greater than in similarly prepared bulk, nonperiodic samples. Applications to light-sensitive devices are discussed.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
68.65.Ac Multilayers

Spatially resolved electron energy loss spectroscopy on n-type ultrananocrystalline diamond films

R. Arenal, O. Stephan, P. Bruno, and D. M. Gruen

Appl. Phys. Lett. 94, 111905 (2009); http://dx.doi.org/10.1063/1.3095663 (3 pages) | Cited 2 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The addition of nitrogen to the synthesis gas during synthesis of ultrananocrystalline-diamond (UNCD) films results in films uniquely exhibiting very high n-type electrical conductivity even at ambient temperatures. This result is due to the formation of nanowires having elongated diamond core nanostructures and a sp2-bonded C sheath surrounding the core. The work presented here provides detailed confirmation of this important result through spatially resolved-electron energy loss spectroscopy. The direct observation of nitrogen incorporated in the sheath has been enabled. The incorporation of this nitrogen provides strong support to a plausible mechanism for the n-type conduction characteristic of the UNCD films.
Show PACS
79.20.Uv Electron energy loss spectroscopy
73.61.-r Electrical properties of specific thin films

UV photovoltaic cells based on conjugated ZnO quantum dot/multiwalled carbon nanotube heterostructures

Fushan Li, Sung Hwan Cho, Dong Ick Son, Tae Whan Kim, Sun-Kyun Lee, Yong-Hoon Cho, and Sungho Jin

Appl. Phys. Lett. 94, 111906 (2009); http://dx.doi.org/10.1063/1.3098400 (3 pages) | Cited 9 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In situ growth of ZnO quantum dots (QDs) on the surface of multiwalled carbon nanotubes (MWCNTs) was realized via a mild solution-process method, which resulted in an improvement in photoinduced charge separation and transport of carriers to the collecting electrode. The charge transfer efficiency was significantly increased by more than 90% due to the conjugation of ZnO QDs with MWCNTs, as confirmed by photoluminescence measurements. Ultraviolet photovoltaic cells based on the charge transfer at the ZnO QD-MWCNT heterostructures were fabricated, and their power conversion efficiency was measured to be above 1%.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.63.Fg Nanotubes
78.67.Ch Nanotubes
84.60.Jt Photoelectric conversion
78.67.Hc Quantum dots
73.63.Kv Quantum dots

Hydrogen diffusion in NaH as derived from isotope exchange experiments

A. Borgschulte, F. Pendolino, R. Gremaud, and A. Züttel

Appl. Phys. Lett. 94, 111907 (2009); http://dx.doi.org/10.1063/1.3103277 (3 pages) | Cited 3 times

Online Publication Date: 17 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on hydrogen-deuterium-exchange experiments on NaH probed by thermogravimetry. From the measurements a diffusion parameter of deuterium in NaH of D = 1.1×10−17 m2/s at 523 K is derived. The activation energy of tracer diffusion of D in NaH is found to be 1.0 eV. The results are hints for a diffusion process mediated by neutral hydrogen vacancies.
Show PACS
66.30.H- Self-diffusion and ionic conduction in nonmetals
61.72.jd Vacancies

Time reversal of continuous-wave, steady-state signals in elastic media

Brian E. Anderson, Robert A. Guyer, Timothy J. Ulrich, and Paul A. Johnson

Appl. Phys. Lett. 94, 111908 (2009); http://dx.doi.org/10.1063/1.3097811 (3 pages) | Cited 3 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Experimental observations of spatial focusing of continuous-wave, steady-state elastic waves in a reverberant elastic cavity using time reversal are reported here. Spatially localized focusing is achieved when multiple channels are employed, while a single channel does not yield such focusing. The amplitude of the energy at the focal location increases as the square of the number of channels used, while the amplitude elsewhere in the medium increases proportionally with the number of channels used. The observation is important in the context of imaging in solid laboratory samples as well as problems involving continuous-wave signals in Earth.
Show PACS
62.30.+d Mechanical and elastic waves; vibrations

Photoluminescence and band gap modulation in graphene oxide

Zhengtang Luo, Patrick M. Vora, Eugene J. Mele, A. T. Charlie Johnson, and James M. Kikkawa

Appl. Phys. Lett. 94, 111909 (2009); http://dx.doi.org/10.1063/1.3098358 (3 pages) | Cited 74 times

Online Publication Date: 19 March 2009

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report broadband visible photoluminescence from solid graphene oxide, and modifications of the emission spectrum by progressive chemical reduction. The data suggest a gapping of the two-dimensional electronic system by removal of π-electrons. We discuss possible gapping mechanisms, and propose that a Kekule pattern of bond distortions may account for the observed behavior.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
81.05.ub Fullerenes and related materials
82.30.-b Specific chemical reactions; reaction mechanisms
71.20.Tx Fullerenes and related materials; intercalation compounds
78.55.Hx Other solid inorganic materials
Page 1 of 4 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close