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

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

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

10 Sep 2012

Volume 101, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

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

Chang-Hoon Shim, Shuzo Hirata, Juro Oshima, Tomohiko Edura, Reiji Hattori, and Chihaya Adachi
Enlarge Image | Read More
Page 1 of 5 Pages Next Page | Jump to Page
back to top
RSS Feeds

Generation of high-frequency terahertz waves in periodically poled LiNbO3 based on backward parametric interaction

Ruolin Chen, Guan Sun, Guibao Xu, Yujie J. Ding, and Ioulia B. Zotova

Appl. Phys. Lett. 101, 111101 (2012); http://dx.doi.org/10.1063/1.4751843 (3 pages)

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Backward terahertz pulses at high frequencies are generated in multi-period periodically poled LiNbO3 using ultrafast pulses of a regenerative amplifier. The highest frequencies generated by us are centered at 4.8 THz at the poling period of 7.1 μm, corresponding to the output wavelength of 62.5 μm. Enhancement factors as large as 61 in the output powers are achieved and analyzed due to resonance-enhanced nonlinear optical coefficients.
Show PACS
78.70.Gq Microwave and radio-frequency interactions
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Far field subwavelength imaging of magnetic patterns

Abdelwaheb Ourir, Geoffroy Lerosey, Fabrice Lemoult, Mathias Fink, and Julien de Rosny

Appl. Phys. Lett. 101, 111102 (2012); http://dx.doi.org/10.1063/1.4748974 (4 pages)

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Far field imaging of subwavelength magnetic objects in real time is a very challenging issue. We propose an original solution based on a planar array of closely spaced split ring resonators. Hybridization between the resonators of such metalens induces subwavelength modes with different frequencies. Thanks to these high Q resonating modes, Purcell like effect allows an evanescent source, close to the metalens, to emit waves that can be collected efficiently in the far field. We present the first microwave experimental demonstration of such metalens to image of a subwavelength magnetic pattern. Numerical simulation shows that this approach is still valid at THz frequencies.
Show PACS
42.79.Bh Lenses, prisms and mirrors
02.60.Cb Numerical simulation; solution of equations

Enhanced nonlinear optical response of metal nanocomposite based photonic crystals

Saima Husaini, Huayu Teng, and Vinod M. Menon

Appl. Phys. Lett. 101, 111103 (2012); http://dx.doi.org/10.1063/1.4751840 (4 pages)

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate enhanced nonlinear optical response from a one-dimensional metal nanocomposite based photonic crystal. A three-fold increase in the two photon absorption coefficient was observed for the photonic crystal structure when compared to a single layer of the metal nanocomposite having comparable metal content. The photonic crystal structure also shows a reduction in the optical limiting threshold by a factor of seven. The combination of metal nanoparticles with appropriately designed plasmon resonance in combination with photonic crystal structure provides an attractive approach for developing practical nonlinear optical devices with low thresholds and wide spectral bandwidth.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
78.67.Sc Nanoaggregates; nanocomposites
42.70.Mp Nonlinear optical crystals
61.66.Dk Alloys

Equalizing disordered ferroelectrics for diffraction cancellation

Jacopo Parravicini, Aharon J. Agranat, Claudio Conti, and Eugenio DelRe

Appl. Phys. Lett. 101, 111104 (2012); http://dx.doi.org/10.1063/1.4751847 (4 pages) | Cited 1 time

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show how the cross-over effect of dipolar glasses can be used to observe diffraction cancellation in composite ferroelectric samples independently of composition. We are able to selectively frustrate the dielectric anomaly of different compositionally disordered photorefractive ferroelectrics to achieve scale-free optical propagation at one same temperature.
Show PACS
77.80.B- Phase transitions and Curie point
42.70.Gi Light-sensitive materials
77.84.Ek Niobates and tantalates

Photocarrier lifetime and transport in silicon supersaturated with sulfur

Peter D. Persans, Nathaniel E. Berry, Daniel Recht, David Hutchinson, Hannah Peterson, Jessica Clark, Supakit Charnvanichborikarn, James S. Williams, Anthony DiFranzo, Michael J. Aziz, and Jeffrey M. Warrender

Appl. Phys. Lett. 101, 111105 (2012); http://dx.doi.org/10.1063/1.4746752 (4 pages)

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Doping of silicon-on-insulator layers with sulfur to concentrations far above equilibrium by ion implantation and pulsed laser melting can result in large concentration gradients. Photocarriers generated in and near the impurity gradient can separate into different coplanar transport layers, leading to enhanced photocarrier lifetimes in thin silicon-on-insulator films. The depth from which holes escape the heavily doped region places a lower limit on the minority carrier mobility-lifetime product of 10−8 cm2/V for heavily sulfur doped silicon. We conclude that the cross-section for recombination through S impurities at this concentration is significantly reduced relative to isolated impurities.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.50.Dn Low-field transport and mobility; piezoresistance
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
61.72.uf Ge and Si
72.20.Fr Low-field transport and mobility; piezoresistance

Quasi-monoenergetic electron beams production in a sharp density transition

S. Fourmaux, K. Ta Phuoc, P. Lassonde, S. Corde, G. Lebrun, V. Malka, A. Rousse, and J. C. Kieffer

Appl. Phys. Lett. 101, 111106 (2012); http://dx.doi.org/10.1063/1.4752114 (4 pages) | Cited 1 time

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using a laser plasma accelerator, experiments with a 80 TW and 30 fs laser pulse demonstrated quasi-monoenergetic electron spectra with maximum energy over 0.4 GeV. This is achieved using a supersonic He gas jet and a sharp density ramp generated by a high intensity laser crossing pre-pulse focused 3 ns before the main laser pulse. By adjusting this crossing pre-pulse position inside the gas jet, among the laser shots with electron injection, more than 40% can produce quasi-monoenergetic spectra. This could become a relatively straight forward technique to control laser wakefield electron beams parameters.
Show PACS
29.20.Ej Linear accelerators
41.75.Fr Electron and positron beams
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
42.55.-f Lasers
52.75.-d Plasma devices

Terahertz transmission ellipsometry of vertically aligned multi-walled carbon nanotubes

M. J. Paul, N. A. Kuhta, J. L. Tomaino, A. D. Jameson, L. P. Maizy, T. Sharf, N. L. Rupesinghe, K. B. K. Teo, S. Inampudi, V. A. Podolskiy, E. D. Minot, and Yun-Shik Lee

Appl. Phys. Lett. 101, 111107 (2012); http://dx.doi.org/10.1063/1.4752158 (5 pages) | Cited 1 time

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate time-resolved terahertz transmission ellipsometry of vertically aligned multi-walled carbon nanotubes. The angle-resolved transmission measurements reveal anisotropic characteristics of the terahertz electrodynamics in multi-walled carbon nanotubes. The anisotropy is, however, unexpectedly weak: the ratio of the tube-axis conductivity to the transverse conductivity, σz/σxy ≅ 2.3, is nearly constant over the broad spectral range of 0.4–1.6 THz. The relatively weak anisotropy and the strong transverse electrical conduction indicate that THz fields readily induce electron transport between adjacent shells within multi-walled carbon nanotubes.
Show PACS
78.67.Ch Nanotubes
78.70.Gq Microwave and radio-frequency interactions
73.63.Fg Nanotubes

Terahertz mirage: Deflecting terahertz beams in an inhomogeneous artificial dielectric based on a parallel-plate waveguide

Rajind Mendis, Jingbo Liu, and Daniel M. Mittleman

Appl. Phys. Lett. 101, 111108 (2012); http://dx.doi.org/10.1063/1.4752241 (4 pages)

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The field of metamaterials and the formalism of transformation optics have provided a prescription for constructing artificial dielectrics with unique properties such as light trapping and cloaking. Here, we describe a different approach to creating an inhomogeneous artificial medium, based on waveguide techniques, which does not rely on engineered subwavelength-scale components. We demonstrate a mirage effect in which an object several times larger than the selected wavelength is rendered invisible by bending a beam around it.
Show PACS
42.79.Gn Optical waveguides and couplers
42.70.-a Optical materials

High-power high-efficiency optically pumped semiconductor disk lasers in the green spectral region with a broad tuning range

A. Hein, S. Menzel, and P. Unger

Appl. Phys. Lett. 101, 111109 (2012); http://dx.doi.org/10.1063/1.4751352 (4 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optically pumped semiconductor disk lasers with an infra-red fundamental emission at around 1050 nm are presented. Design and characteristics of the devices are discussed and evaluated. A maximum output power of infra-red radiation of 18 W close to room temperature and rather high slope and differential quantum efficiencies are demonstrated. Utilizing intra-cavity second-harmonic generation in a folded resonator, green optical output powers exceeding 8 W are generated. A maximum total conversion efficiency of 22% and a relatively broad tuning range of 22 nm in the second-harmonic regime are achieved.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.60.Fc Modulation, tuning, and mode locking

Optical absorption in graphene integrated on silicon waveguides

Huan Li, Yoska Anugrah, Steven J. Koester, and Mo Li

Appl. Phys. Lett. 101, 111110 (2012); http://dx.doi.org/10.1063/1.4752435 (5 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To fully utilize graphene's remarkable optical properties for optoelectronic applications, it needs to be integrated in planar photonic systems. Here, we demonstrate integration of graphene on silicon photonic circuits and precise measurement of the optical absorption coefficient in a graphene/waveguide hybrid structure. A method based on Mach-Zehnder interferometry is employed to achieve high measurement precision and consistency, yielding a maximal value of absorption coefficient of 0.2 dB/μm when graphene is located directly on top of the waveguide. The averaged results obtained from a large number of samples agree with theoretical model utilizing the universal ac conductivity in graphene. Our work provides an important guide for the design and optimization of integrated graphene optoelectronic devices.
Show PACS
42.82.Et Waveguides, couplers, and arrays
07.60.Ly Interferometers
42.79.Gn Optical waveguides and couplers
42.15.Eq Optical system design
42.82.Bq Design and performance testing of integrated-optical systems

Propagation of light in serially coupled plasmonic nanowire dimer: Geometry dependence and polarization control

Danveer Singh, Mohit Raghuwanshi, and G. V. Pavan Kumar

Appl. Phys. Lett. 101, 111111 (2012); http://dx.doi.org/10.1063/1.4752718 (5 pages) | Cited 2 times

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We experimentally studied plasmon-polariton-assisted light propagation in serially coupled silver nanowire (Ag-NW) dimers and probed their dependence on bending-angle between the nanowires and polarization of incident light. From the angle-dependence study, we observed that obtuse angles between the nanowires resulted in better transmission than acute angles. From the polarization studies, we inferred that light emission from junction and distal ends of Ag-NW dimers can be systematically controlled. Further, we applied this property to show light routing and polarization beam splitting in obtuse-angled Ag-NW dimer. The studied geometry can be an excellent test-bed for plasmonic circuitry.
Show PACS
81.05.Bx Metals, semimetals, and alloys
81.07.Gf Nanowires
78.67.Uh Nanowires

Optical polarization properties of a nanowire quantum dot probed along perpendicular orientations

Gabriele Bulgarini, Michael E. Reimer, and Val Zwiller

Appl. Phys. Lett. 101, 111112 (2012); http://dx.doi.org/10.1063/1.4752453 (4 pages)

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the optical properties of single quantum dots in nanowires probed along orthogonal directions. We address the same quantum dot from either the nanowire side or along the nanowire axis via reflection on a micro-prism. The collected photoluminescence intensity from nanowires lying on a substrate is improved 3-fold using the prism as compared to usual collection from the top. More importantly, we circumvent the polarizing effect of the nanowire and access the intrinsic polarization properties of the quantum emitter. Our technique is compatible with the design of complex nanowire devices for the development of quantum opto-electronics.
Show PACS
78.67.Hc Quantum dots
81.07.Ta Quantum dots
78.67.Uh Nanowires
81.07.Gf Nanowires
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
back to top
RSS Feeds

Growth of continuous and ultrathin platinum films on tungsten adhesion layers using atomic layer deposition techniques

L. Baker, A. S. Cavanagh, J. Yin, S. M. George, A. Kongkanand, and F. T. Wagner

Appl. Phys. Lett. 101, 111601 (2012); http://dx.doi.org/10.1063/1.4749819 (4 pages) | Cited 2 times

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Continuous and ultrathin platinum (Pt) films were deposited on tungsten (W) adhesion layers using atomic layer deposition (ALD) techniques. Pt ALD films were deposited at 120 °C using MeCpPtMe3 and H2 plasma as the reactants. X-ray reflectivity studies observed the rapid nucleation of the Pt film. X-ray photoelectron results were consistent with layer-by-layer growth suggesting a continuous Pt film at thicknesses ≥1.5 nm. The high surface energy of the W ALD adhesion layer enables the growth of continuous and ultrathin films of lower surface energy metals and should facilitate the use of precious metals for a variety of applications.
Show PACS
68.55.at Other materials
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
65.40.gp Surface energy
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Effect of the polarity of carbon-fluorine bonds on the work function of plasma-fluorinated epitaxial graphene

Sonam D. Sherpa, Galit Levitin, and Dennis W. Hess

Appl. Phys. Lett. 101, 111602 (2012); http://dx.doi.org/10.1063/1.4752443 (4 pages)

Online Publication Date: 12 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Work function engineering of graphene facilitates its application as a transparent electrode material in organic electronic devices. Toward this end, we demonstrate the dependence of the work function of plasma-fluorinated epitaxial graphene on the polarity of carbon-fluorine bonds which is controlled by the nature of chemical bonding (ionic, semi-ionic, or covalent) between fluorine and carbon atoms. The work function of fluorinated graphene was measured using ultraviolet photoelectron spectroscopy and the polarity of carbon-fluorine bonds was established using x-ray photoelectron spectroscopy.
Show PACS
73.30.+y Surface double layers, Schottky barriers, and work functions
78.67.Wj Optical properties of graphene
79.60.Bm Clean metal, semiconductor, and insulator surfaces
61.50.Lt Crystal binding; cohesive energy

Superhydrophobic surfaces cannot reduce ice adhesion

Jing Chen, Jie Liu, Min He, Kaiyong Li, Dapeng Cui, Qiaolan Zhang, Xiping Zeng, Yifan Zhang, Jianjun Wang, and Yanlin Song

Appl. Phys. Lett. 101, 111603 (2012); http://dx.doi.org/10.1063/1.4752436 (3 pages) | Cited 1 time

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Understanding the mechanism of ice adhesion on surfaces is crucial for anti-icing surfaces, and it is not clear if superhydrophobic surfaces could reduce ice adhesion. Here, we investigate ice adhesion on model surfaces with different wettabilities. The results show that the superhydrophobic surface cannot reduce the ice adhesion, and the ice adhesion strength on the superhydrophilic surface and the superhydrophobic one is almost the same. This can be rationalized by the mechanical interlocking between the ice and the surface texture. Moreover, we find that the ice adhesion strength increases linearly with the area fraction of air in contact with liquid.
Show PACS
68.35.Np Adhesion
68.08.Bc Wetting

Modulation doping to control the high-density electron gas at a polar/non-polar oxide interface

Tyler A. Cain, Pouya Moetakef, Clayton A. Jackson, and Susanne Stemmer

Appl. Phys. Lett. 101, 111604 (2012); http://dx.doi.org/10.1063/1.4752439 (4 pages)

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A modulation-doping approach to control the carrier density of the high-density electron gas at a prototype polar/non-polar oxide interface is presented. It is shown that the carrier density of the electron gas at a GdTiO3/SrTiO3 interface can be reduced by up to 20% from its maximum value (∼3 × 1014 cm−2) by alloying the GdTiO3 layer with Sr. The Seebeck coefficient of the two-dimensional electron gas increases concurrently with the decrease in its carrier density. The experimental results provide insight into the origin of charge carriers at oxide interfaces exhibiting a polar discontinuity.
Show PACS
73.40.Ns Metal-nonmetal contacts
72.20.Pa Thermoelectric and thermomagnetic effects

Droplet contact angle behavior on a hybrid surface with hydrophobic and hydrophilic properties

C. W. Yao, T. P. Garvin, J. L. Alvarado, A. M. Jacobi, B. G. Jones, and C. P. Marsh

Appl. Phys. Lett. 101, 111605 (2012); http://dx.doi.org/10.1063/1.4752470 (5 pages) | Cited 1 time

Online Publication Date: 13 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A hybrid surface consisting of an array of hydrophobic and hydrophilic sites was designed and fabricated in an effort to better understand the effects of microscale surface features and chemistry on wettability. A model based on energy minimization was developed to design and predict the wettability of hybrid surfaces. Measured advancing, receding, and equilibrium contact angles fit the proposed model well. Experiments show that a higher degree of hydrophobicity results in higher contact angles and that contact angle hysteresis increases with decreasing micropillar spacing (b/a). Moreover, measured roll-off angle as an indicator of droplet shedding, decreases with b/a.
Show PACS
68.03.Cd Surface tension and related phenomena
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces

Experimental surface-enhanced Raman scattering response of two-dimensional finite arrays of gold nanopatches

M. Grande, G. V. Bianco, M. A. Vincenti, T. Stomeo, D. de Ceglia, M. De Vittorio, V. Petruzzelli, M. Scalora, G. Bruno, and A. D'Orazio

Appl. Phys. Lett. 101, 111606 (2012); http://dx.doi.org/10.1063/1.4752719 (4 pages) | Cited 4 times

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We experimentally investigate the nonlinear response of two-dimensional periodic arrays composed of gold nanopatches on silicon substrate, functionalized by means of a conjugated rigid thiol. The surface-enhanced Raman scattering (SERS) response is empirically evaluated using a laser source operating in the visible spectral range at λ = 633 nm. Nonlinear results are then correlated to optical and structural properties of the samples under investigation. SERS mapping and estimation of the SERS enhancement factor are examined to determine stability and reproducibility of the results, highlighting also the contribution of the plasmonic resonance excited in the two-dimensional periodic array, and the dependence on the numerical aperture of the microscope objective used in the micro-Raman system.
Show PACS
78.30.Er Solid metals and alloys
61.46.-w Structure of nanoscale materials
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.40.Kc Metals, semimetals, and alloys
78.66.Bz Metals and metallic alloys

A photoelectron spectroscopy study of the electronic structure evolution in CuInSe2-related compounds at changing copper content

T. V. Kuznetsova, V. I. Grebennikov, H. Zhao, C. Derks, C. Taubitz, M. Neumann, C. Persson, M. V. Kuznetsov, I. V. Bodnar, R. W. Martin, and M. V. Yakushev

Appl. Phys. Lett. 101, 111607 (2012); http://dx.doi.org/10.1063/1.4752723 (4 pages)

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Evolution of the valence-band structure at gradually increasing copper content has been analysed by x-ray photoelectron spectroscopy (XPS) in In2Se3, CuIn5Se8, CuIn3Se5, and CuInSe2 single crystals. A comparison of these spectra with calculated total and angular-momentum resolved density-of-states (DOS) revealed the main trends of this evolution. The formation of the theoretically predicted gap between the bonding and non-bonding states has been observed in both experimental XPS spectra and theoretical DOS.
Show PACS
79.60.Bm Clean metal, semiconductor, and insulator surfaces
73.20.At Surface states, band structure, electron density of states
71.20.Nr Semiconductor compounds
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)

Scanning internal photoemission microscopy for the identification of hot carrier transport mechanisms

D. Differt, W. Pfeiffer, and D. Diesing

Appl. Phys. Lett. 101, 111608 (2012); http://dx.doi.org/10.1063/1.4752734 (4 pages)

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Linear and nonlinear internal photoemission in a thin-film metal-insulator-metal heterosystem, i.e., a Ta-TaOx-Ag junction, together with surface reflectivity are mapped with a lateral resolution of better than 5 μm. The spatial correlation of the different signals and time-resolved internal photoemission spectroscopy reveal excitation mechanisms and ballistic hot carrier injection. The internal photoemission yield variation with Ag layer thickness is quantitatively explained by above-barrier injection. The hot-spot-like behavior of the two-photon induced internal photoemission observed for short pulse excitation is attributed to local field enhancements because of Ag-film thickness reduction and plasmonic effects at structural defects.
Show PACS
73.40.Rw Metal-insulator-metal structures
78.47.D- Time resolved spectroscopy (>1 psec)
79.60.Jv Interfaces; heterostructures; nanostructures
73.23.Ad Ballistic transport
72.30.+q High-frequency effects; plasma effects
72.20.Ht High-field and nonlinear effects

Analysis of surface plasmon excitation at terahertz frequencies with highly doped graphene sheets via attenuated total reflection

Choon How Gan

Appl. Phys. Lett. 101, 111609 (2012); http://dx.doi.org/10.1063/1.4752465 (4 pages)

Online Publication Date: 14 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Excitation of surface plasmons supported by doped graphene sheets at terahertz frequencies is investigated numerically. To alleviate the momentum mismatch between the highly confined plasmon modes and the incident radiation, it is proposed to increase the surface conductivity of graphene through high doping levels or with few-layer graphene. For currently achievable doping levels, our analysis shows that surface plasmons on monolayer graphene may be excited at operating frequencies up to about 10 THz ( ∼ 41.3 meV) with a high-index coupling prism, and higher frequencies/energies are possible for few-layer graphene. These highly confined surface modes are promising for sensing and waveguiding applications in the terahertz regime.
Show PACS
73.22.Lp Collective excitations
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.68.+m Optical properties of surfaces
78.70.Gq Microwave and radio-frequency interactions
61.72.up Other materials
73.25.+i Surface conductivity and carrier phenomena
back to top
RSS Feeds

Black silicon with controllable macropore array for enhanced photoelectrochemical performance

Xianyu Ao, Xili Tong, Dong Sik Kim, Lianbing Zhang, Mato Knez, Frank Müller, Sailing He, and Volker Schmidt

Appl. Phys. Lett. 101, 111901 (2012); http://dx.doi.org/10.1063/1.4752231 (4 pages)

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Macroporous silicon with multiscale texture for reflection suppression and light trapping was achieved through a controllable electrochemical etching process. It was coated with TiO2 by atomic layer deposition, and used as the photoanode in photocatalytic water splitting. A conformal pn-junction was also built-in in order to split water without external bias. A 45% enhancement in photocurrent density was observed after black silicon etching. In comparison with nano-structured silicon, the etching process here has neither metal contamination nor requirement of vacuum facilities.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
82.45.Fk Electrodes

High pressure phase determination and electronic properties of lithiumamidoborane

M. Ramzan, T. Hussain, and R. Ahuja

Appl. Phys. Lett. 101, 111902 (2012); http://dx.doi.org/10.1063/1.4752237 (4 pages)

Online Publication Date: 10 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this study we report on the high pressure phase of the promising hydrogen storage material lithiumamidoborane (LiNH2BH3), on the basis of density functional theory calculations with generalized gradient approximation. We take the five possible candidate structures, Pbca, Pbcn, Pcca, Pnma, and Pnnm for the high pressure study of LiNH2BH3. The corresponding structures are relaxed with respect to fractional atomic coordinates and cell parameters, with the use of fully self-consistent ab initio electronic structure calculations to get the equilibrium parameters and total energies. Then we compare the energies of these phases and find that Pbcn is the most favorable phase at ≈ 100 GPa. Then we calculate the structural parameters of this phase. Finally, we calculate the density of states, Bader charge analysis, and corresponding electron density of this phase.
Show PACS
62.50.-p High-pressure effects in solids and liquids
88.30.R- Hydrogen storage
71.15.-m Methods of electronic structure calculations
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
71.20.Ps Other inorganic compounds
71.15.Nc Total energy and cohesive energy calculations

Visible photoluminescence in polycrystalline terbium doped aluminum nitride (Tb:AlN) ceramics with high thermal conductivity

A. T. Wieg, Y. Kodera, Z. Wang, T. Imai, C. Dames, and J. E. Garay

Appl. Phys. Lett. 101, 111903 (2012); http://dx.doi.org/10.1063/1.4751856 (5 pages) | Cited 1 time

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermal management continues to be one of the major challenges in the development of high powered light sources such as solid state lasers. In particular, the relatively low thermal conductivity of standard photoluminescent (PL) materials limits the overall power output and/or duty cycle. We present a method based on current activated pressure assisted densification for the fabrication of high thermal conductivity PL materials: rare earth doped polycrystalline bulk aluminum nitride. Specifically, the ceramics are translucent and are doped with Tb3+, allowing for emission in the visible. Remarkably, the ceramics have a room temperature thermal conductivity of 94 W/(m K) which is almost seven times higher than that of the state of the art host material, Nd-doped yttrium aluminum garnet. These light emitting properties coupled with very high thermal conductivity should enable the development of a wide variety of more powerful light sources.
Show PACS
78.55.Cr III-V semiconductors
66.70.Df Metals, alloys, and semiconductors
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
81.05.Ea III-V semiconductors

Strain effect on lattice vibration, heat capacity, and thermal conductivity of graphene

F. Ma, H. B. Zheng, Y. J. Sun, D. Yang, K. W. Xu, and Paul K. Chu

Appl. Phys. Lett. 101, 111904 (2012); http://dx.doi.org/10.1063/1.4752010 (4 pages) | Cited 1 time

Online Publication Date: 11 September 2012

Full Text: Read Online (HTML) | Download PDF

Show Abstract
First-principle calculation based on density functional theory is performed to study the lattice vibration, heat capacity, and thermal conductivity of graphene under strain. Two degenerate optical branches in the phonon dispersion curves split near the G points due to the reduced crystal symmetry, and the frequencies of the optical phonon modes shift down thus inducing more phonon modes at a given temperature. The heat capacity is increased, but the thermal conductivity is reduced because of enhanced Umklapp scattering among more phonons. This phenomenon should be considered when determining the heat management of graphene-based devices.
Show PACS
65.40.Ba Heat capacity
72.80.Vp Electronic transport in graphene
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
63.22.Rc Phonons in graphene
66.70.Lm Other systems such as ionic crystals, molecular crystals, nanotubes, etc.
Page 1 of 5 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close