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

22 Aug 2011

Volume 99, Issue 8, Articles (08xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 99, 083104 (2011); http://dx.doi.org/10.1063/1.3625926 (3 pages)

E. Detsi, Z. G. Chen, W. P. Vellinga, P. R. Onck, and J. T. M. De Hosson
Enlarge Image | Read More
Page 1 of 4 Pages Next Page | Jump to Page
back to top
RSS Feeds

Generation of multi-color attosecond x-ray radiation through modulation compression

Ji Qiang and Juhao Wu

Appl. Phys. Lett. 99, 081101 (2011); http://dx.doi.org/10.1063/1.3629769 (3 pages) | Cited 1 time

Online Publication Date: 22 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper, we propose a scheme to generate tunable multi-color attosecond coherent x-ray radiation. This scheme uses a modulation compression method to generate a multi-spike prebunched kilo-ampere peak current electron beam from a few tens ampere electron beam out of a linac. Such a beam transporting through a series of undulator radiators and bunch compressors generates multi-color coherent x-ray radiation. As an illustration, we present an example to generate two attosecond pulses with 2.2 nm and 3 nm coherent x-ray radiation wavelength and more than 200 MW peak power using a 50 A 200 nm laser seeded electron beam.
Show PACS
29.27.Eg Beam handling; beam transport
29.20.Ej Linear accelerators
41.60.Cr Free-electron lasers
07.77.Ka Charged-particle beam sources and detectors
41.75.Fr Electron and positron beams

Third-order nonlinearity in silicon beyond 2350 nm

Faezeh Gholami, Sanja Zlatanovic, Aleksandar Simic, Lan Liu, David Borlaug, Nikola Alic, Maziar P. Nezhad, Yeshaiahu Fainman, and Stojan Radic

Appl. Phys. Lett. 99, 081102 (2011); http://dx.doi.org/10.1063/1.3630130 (3 pages) | Cited 1 time

Online Publication Date: 22 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Measurement of the Kerr nonlinearity in silicon is reported in the 2350 nm to 2750 nm wavelength range, where three-photon absorption effect is present. The measurements confirm that the Kerr interaction strength is comparable to that in the near-infrared. The measured dispersion trend for the Kerr coefficient is consistent with that obtained using Kramers-Krönig relations. Three-photon absorption was measured, and its effect on the nonlinear figure of merit in silicon appears not to be as restrictive as that of two-photon absorption. The results identify silicon as a promising platform for parametric processes in mid-infrared spectral region.
Show PACS
78.30.Am Elemental semiconductors and insulators
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation

Near-infrared photodetector with CuIn1−x AlxSe2 thin film

Ruo-Ping Chang and Dung-Ching Perng

Appl. Phys. Lett. 99, 081103 (2011); http://dx.doi.org/10.1063/1.3627185 (3 pages) | Cited 3 times

Online Publication Date: 22 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Application of the CuInSe2-based thin film for a near-infrared (NIR) photodetector (PD) has been demonstrated. The Cu(In,Al)Se2 (CIAS) was used as an absorption layer for NIR PD with comb-structured Al electrodes. X-ray diffraction spectrum and scanning electron microscope (SEM) micrographs show that the CIAS film is a single phased polycrystalline film with smooth surface and super large (2–5 μm) grains. Low temperature photoluminescence analysis indicates that the CIAS has a strong NIR excitation emission peak. The CIAS PDs are highly sensitive to the NIR spectrum with cut-off frequency near 790 nm and demonstrate four-orders of magnitude in photocurrent amplification.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)

Investigation of fast and slow decays in InGaN/GaN quantum wells

Guan Sun, Guibao Xu, Yujie J. Ding, Hongping Zhao, Guangyu Liu, Jing Zhang, and Nelson Tansu

Appl. Phys. Lett. 99, 081104 (2011); http://dx.doi.org/10.1063/1.3627166 (3 pages) | Cited 7 times

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have measured and analyzed the photoluminescence spectra from InGaN/GaN multiple quantum wells. Emission peaks due to recombination of the photogenerated carriers occupying localized states and extended states within quantum wells have been identified through temperature-dependent photoluminescence. Fast and slow decays have been attributed to recombination of carriers in extended states and localized states, respectively, based on time-resolved pump-probe differential photoluminescence.
Show PACS
78.55.Cr III-V semiconductors
78.67.De Quantum wells

GaSe1−xSx and GaSe1−xTex thick crystals for broadband terahertz pulses generation

M. M. Nazarov, S. Yu. Sarkisov, A. P. Shkurinov, and O. P. Tolbanov

Appl. Phys. Lett. 99, 081105 (2011); http://dx.doi.org/10.1063/1.3617438 (3 pages) | Cited 3 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the possibility of broadband THz pulse generation in mixed GaSe1−xSx and GaSe1−xTex crystals. The ordinary and extraordinary refractive indices of the crystals have been measured by the terahertz time-domain spectroscopy method, those values strongly influence the efficiency of THz generation process. The high birefringence and transparency of pure GaSe and mixed crystals allow optical rectification of femtosecond laser pulses in the several millimeters thick crystal using the еее interaction process (with two pumping waves and generated THz wave all having extraordinary polarization in the crystal).
Show PACS
81.05.Hd Other semiconductors
78.47.J- Ultrafast spectroscopy (<1 psec)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.20.Fm Birefringence
78.70.Gq Microwave and radio-frequency interactions

Light extraction beyond total internal reflection using one-dimensional plasmonic crystals

R. McCarron, D. O'Connor, J.-S. Bouillard, W. Dickson, and A. V. Zayats

Appl. Phys. Lett. 99, 081106 (2011); http://dx.doi.org/10.1063/1.3628330 (3 pages) | Cited 2 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the application of plasmonic crystals for extracting light trapped in the substrate due to total internal reflection (TIR). The broadband transmission properties of one-dimensional plasmonic crystals have been investigated, both experimentally and numerically, beyond the TIR critical angle in order to reveal the role of plasmonic modes in this process. Through optimisation of the traditional square slit unit cell geometry of the crystals, transmission coefficients of up to 47% were obtained in the TIR regime. An U-shaped cell geometry with a few nm thick continuous film was found to significantly modify the plasmonic modes of the crystal in addition to exhibiting highly tuneable, structurally dispersive transmission peaks, further increasing transmission in the TIR regime up to 56%. Such structures exhibit better than glass transparency at the design wavelength when integrated over all incident angles.
Show PACS
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Fano resonances in active plasmonic resonators consisting of a nanorod dimer and a nano-emitter

Zhong-Jian Yang, Zong-Suo Zhang, Zhong-Hua Hao, and Qu-Quan Wang

Appl. Phys. Lett. 99, 081107 (2011); http://dx.doi.org/10.1063/1.3628333 (3 pages) | Cited 4 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical emission response of a single nano-emitter coupled with a plasmonic nanorod dimer is investigated, where the short and long nanorods in the dimer support dipolar and quadrupolar plasmon resonance, repsectively. Fano resonances are observed with a nano-emitter being placed at either apex of the dimer. However, no Fano resonance is seen when the nano-emitter is placed in the gap of the dimer. Bonding and antibonding dipolar-quadrupolar plasmon couplings are closely related to the Fano resonances in this dimer system.
Show PACS
79.60.-i Photoemission and photoelectron spectra
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons

Demonstration of a self-mixing displacement sensor based on terahertz quantum cascade lasers

Yah Leng Lim, Paul Dean, Milan Nikolić, Russell Kliese, Suraj P. Khanna, Mohammad Lachab, Alex Valavanis, Dragan Indjin, Zoran Ikonić, Paul Harrison, Edmund H. Linfield, A. Giles Davies, Stephen J. Wilson, and Aleksandar D. Rakić

Appl. Phys. Lett. 99, 081108 (2011); http://dx.doi.org/10.1063/1.3629991 (3 pages) | Cited 5 times

Online Publication Date: 25 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
There has been growing interest in the use of terahertz (THz) quantum cascade lasers (QCLs) for sensing applications. However, the lack of compact and sensitive THz detectors has limited the potential for commercial exploitation of sensors based on these devices. We have developed a self-mixing sensing technique in which THz QCLs are used for both generation and interferometric sensing of THz radiation, eliminating the need for a separate detector. Using this technique, we have measured the displacement of a remote target, both with and without opaque (in the visible spectrum) materials in the beam path and demonstrated a stand-off distance of up to 7 m in air.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
07.60.Ly Interferometers
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

Enhanced photocurrent gain and spectrum range based on the composite consisting of SnO2 nanowires and CdSe quantum dots

M. L. Lu, C. H. Lin, and Y. F. Chen

Appl. Phys. Lett. 99, 081109 (2011); http://dx.doi.org/10.1063/1.3626588 (3 pages) | Cited 3 times

Online Publication Date: 26 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High sensitivity with additional spectral response based on the composite consisting of SnO2 nanowires (NWs) and CdSe quantum dots (QDs) has been demonstrated. The underlying mechanism is attributed to the spatial separation of photogenerated electrons and holes due to the charge transfer arising from type II band alignment between CdSe QD and SnO2 NW. This work shows that by selective decoration of suitable QDs, the photocurrent gain of NWs not only can be greatly enhanced, but also can be extended to a wider range photoresponse spectrum. Our result, therefore, provides a very useful guideline to create high efficiency photodetectors.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
79.60.Bm Clean metal, semiconductor, and insulator surfaces
72.80.Ey III-V and II-VI semiconductors
73.63.Kv Quantum dots
82.30.Fi Ion-molecule, ion-ion, and charge-transfer reactions
81.05.Dz II-VI semiconductors

Correlated photon-pair generation in a periodically poled MgO doped stoichiometric lithium tantalate reverse proton exchanged waveguide

M. Lobino, G. D. Marshall, C. Xiong, A. S. Clark, D. Bonneau, C. M. Natarajan, M. G. Tanner, R. H. Hadfield, S. N. Dorenbos, T. Zijlstra, V. Zwiller, M. Marangoni, R. Ramponi, M. G. Thompson, B. J. Eggleton, et al.

Appl. Phys. Lett. 99, 081110 (2011); http://dx.doi.org/10.1063/1.3628328 (3 pages) | Cited 6 times

Online Publication Date: 26 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate photon-pair generation in a reverse proton exchanged waveguide fabricated on a periodically poled magnesium doped stoichiometric lithium tantalate substrate. Detected pairs are generated via a cascaded second order nonlinear process where a pump laser at wavelength of 1.55 μm is first doubled in frequency by second harmonic generation and subsequently downconverted around the same spectral region. Pairs are detected at a rate of 42/s with a coincidence to accidental ratio of 0.7. This cascaded pair generation process is similar to four-wave-mixing where two pump photons annihilate and create a correlated photon pair.
Show PACS
42.79.Gn Optical waveguides and couplers
42.65.Wi Nonlinear waveguides
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
back to top
RSS Feeds

Portable nanosecond pulsed air plasma jet

J. L. Walsh and M. G. Kong

Appl. Phys. Lett. 99, 081501 (2011); http://dx.doi.org/10.1063/1.3623487 (3 pages) | Cited 4 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Low-temperature atmospheric pressure plasmas are of great importance in many emerging biomedical and materials processing applications. The redundancy of a vacuum system opens the gateway for highly portable plasma systems, for which air ideally becomes the plasma-forming gas and remote plasma processing is preferred to ensure electrical safety. Typically, the gas temperature observed in air plasma greatly exceeds that suitable for the processing of thermally liable materials; a large plasma-sample distance offers a potential solution but suffers from a diluted downstream plasma chemistry. This Letter reports a highly portable air plasma jet system which delivers enhanced downstream chemistry without compromising the low temperature nature of the discharge, thus forming the basis of a powerful tool for emerging mobile plasma applications.
Show PACS
52.75.-d Plasma devices
52.77.-j Plasma applications
52.80.Vp Discharge in vacuum
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
52.25.Fi Transport properties

Probing electron-phonon coupling in metals via observations of ablation plumes produced by two delayed short laser pulses

E. Axente, I. N. Mihailescu, J. Hermann, and T. E. Itina

Appl. Phys. Lett. 99, 081502 (2011); http://dx.doi.org/10.1063/1.3629774 (3 pages) | Cited 4 times

Online Publication Date: 25 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate electron-phonon coupling in metals by analyzing the composition of plumes produced by laser ablation with two delayed short laser pulses. Samples of Ti, Zr, and Hf are chosen since they have similar thermo-physical properties but significant different atomic masses. It is shown that the atomic emission intensity increases with the interpulse delay, whereas the nanoparticle emission intensity decreases. The characteristic time of plume changes is found to depend linearly on the metals’ atomic mass. Theoretical considerations suggest that the measured times equal to the characteristic times of electron-lattice relaxation.
Show PACS
63.20.kd Phonon-electron interactions
63.22.Kn Clusters and nanocrystals
78.47.J- Ultrafast spectroscopy (<1 psec)
79.20.Eb Laser ablation
back to top
RSS Feeds

Analysis of thermal band gap variations of PbS quantum dots by Fourier transform transmission and emission spectroscopy

B. Ullrich, J. S. Wang, and G. J. Brown

Appl. Phys. Lett. 99, 081901 (2011); http://dx.doi.org/10.1063/1.3623486 (3 pages) | Cited 9 times

Online Publication Date: 22 August 2011

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
Fourier transmission and emission spectroscopy was employed in the range from 5 to 300 K to measure the thermal band gap shift of 4.7 nm PbS quantum dots. The analytical comparison of fits carried out with the expressions of Varshni and Fan revealed limited accuracy of the Varshni fitting parameters. Evidence is presented that transmission spectroscopy in conjunction with the Fan model concurs with the microscopic material features, resulting in a tool to determine intrinsic properties of quantum dots.
Show PACS
78.67.Hc Quantum dots
81.07.Ta Quantum dots
71.20.Nr Semiconductor compounds
78.30.Hv Other nonmetallic inorganics
78.55.Hx Other solid inorganic materials

Two-photon-pumped stimulated emission from ZnO single crystal

T. C. He, R. Chen, W. W. Lin, F. Huang, and H. D. Sun

Appl. Phys. Lett. 99, 081902 (2011); http://dx.doi.org/10.1063/1.3628329 (3 pages) | Cited 6 times

Online Publication Date: 22 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on two-photon-pumped stimulated emission (SE) from ZnO single crystal at low temperature. Under nanosecond pulse excitation, two-photon absorption induced SE with a threshold of 2.8 MW/cm2 is observed, which is ascribed to the inelastic exciton-exciton scattering. The mechanism of the SE is further confirmed by temperature dependent photoluminescence spectra. However, it is interesting to find that under one photon pumping with the same power density, no SE is observed from the sample. Such unusual phenomenon is explained by the nonradiative surface recombination induced carriers depletion under single photon excitation.
Show PACS
78.55.Et II-VI semiconductors
78.47.J- Ultrafast spectroscopy (<1 psec)

THz dielectric anisotropy of metal slanted columnar thin films

T. Hofmann, D. Schmidt, A. Boosalis, P. Kühne, R. Skomski, C. M. Herzinger, J. A. Woollam, M. Schubert, and E. Schubert

Appl. Phys. Lett. 99, 081903 (2011); http://dx.doi.org/10.1063/1.3626846 (3 pages) | Cited 6 times

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The anisotropic optical dielectric functions of a metal (cobalt) slanted columnar thin film deposited by electron-beam glancing angle deposition are reported for the terahertz (THz) frequency domain using generalized spectroscopic ellipsometry. We employ a simple effective medium dielectric function homogenization approach to describe the observed optical response. The approach describes isolated, electrically conductive columns which render the thin film biaxial (orthorhombic). Our findings suggest controlled variability of dielectric polarizability and anisotropy in the THz spectral range by choice of geometry, material, and structure.
Show PACS
75.30.Gw Magnetic anisotropy
73.61.At Metal and metallic alloys
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons

Large area quasi-free standing monolayer graphene on 3C-SiC(111)

C. Coletti, K. V. Emtsev, A. A. Zakharov, T. Ouisse, D. Chaussende, and U. Starke

Appl. Phys. Lett. 99, 081904 (2011); http://dx.doi.org/10.1063/1.3618674 (3 pages) | Cited 12 times

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Large scale, homogeneous quasi-free standing monolayer graphene is obtained on cubic silicon carbide, i.e., the 3C-SiC(111) surface, which represents an appealing and cost effective platform for graphene growth. The quasi-free monolayer is produced by intercalation of hydrogen under the interfacial, (6math×6math)R30 °-reconstructed carbon layer. After intercalation, angle resolved photoemission spectroscopy reveals sharp linear π-bands. The decoupling of graphene from the substrate is identified by x-ray photoemission spectroscopy and low energy electron diffraction. Atomic force microscopy and low energy electron microscopy demonstrate that homogeneous monolayer domains extend over areas of hundreds of square-micrometers.
Show PACS
61.48.Gh Structure of graphene
79.60.Bm Clean metal, semiconductor, and insulator surfaces
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)

Periodic variation of stress in sputter deposited Si/WSi2 multilayers

Kimberly MacArthur, Bing Shi, Ray Conley, and Albert T. Macrander

Appl. Phys. Lett. 99, 081905 (2011); http://dx.doi.org/10.1063/1.3628242 (3 pages) | Cited 2 times

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A tension increment after sputter deposition of 1 nm of WSi2 onto sputtered Si was observed at low Ar gas pressures. Wafer curvature data on multilayers were found to have a periodic variation corresponding to the multilayer period, and this permitted statistical analyses to improve the sensitivity to small stresses. The observation of tension instead of compression in the initial stage of growth is reported, and a model invoking surface rearrangement is invoked. The data also bear on an unusual surface smoothing phenomena for sputtered Si surfaces caused by the sputter deposition of WSi2. We furthermore report that for low Ar pressures the Si layers are the predominant source of built-up stress.
Show PACS
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
68.65.Ac Multilayers
81.15.Cd Deposition by sputtering

A study of spin isomer conversion kinetics in supercritical fluid hydrogen for cryogenic fuel storage technologies

Manyalibo J. Matthews, Guillaume Petitpas, and Salvador M. Aceves

Appl. Phys. Lett. 99, 081906 (2011); http://dx.doi.org/10.1063/1.3628453 (3 pages) | Cited 1 time

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF


See Also: Publisher's Note

Show Abstract
A detailed kinetic study of para-ortho hydrogen conversion under supercritical conditions using rotational Raman scattering is presented. Isochoric measurements of initially low ortho concentrations over temperatures 32 < T < 280 K and densities 0.014 < ρ < 0.060 g/cm3 were used to derive kinetic rate constants k(ρ, T) by solving an autocatalytic kinetic rate equation. At low ortho concentrations and T < 100 K, k is found to be ∼2× higher than previous results based on thermal conductivity measurements, decreasing weakly with temperature, similar to Wigner’s original paramagnetic theory. Accurate modeling of k(ρ, T) is critical in predicting cryogenic hydrogen fuel tank dormancy performance for hydrogen-power vehicles.
Show PACS
88.30.R- Hydrogen storage
07.20.Mc Cryogenics; refrigerators, low-temperature detectors, and other low-temperature equipment

Controlled cation stoichiometry in pulsed laser deposition-grown BaTiO3 epitaxial thin films with laser fluence

Daisuke Kan and Yuichi Shimakawa

Appl. Phys. Lett. 99, 081907 (2011); http://dx.doi.org/10.1063/1.3628461 (3 pages) | Cited 5 times

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigated effects of the laser fluence on structural and ferroelectric properties in BaTiO3 epitaxial thin films grown by pulsed laser deposition. We find that the low laser fluence causes the cation non-stoichiometry in the films. X-ray diffraction and ferroelectric hysteresis loop measurements reveal the strong impacts of the fluence-dependent cation non-stoichiometry on the structural and ferroelectric properties of the films. The ferroelectricity is observed for the films grown with the fluence larger than 1.3 J/cm2, where the cation ratio is kept close to stoichiometric. These results demonstrate that the cation stoichiometry controlled with the laser fluence plays an important role in determining the structural and ferroelectric properties in the BaTiO3 films.
Show PACS
77.80.Dj Domain structure; hysteresis
61.66.Bi Elemental solids
61.66.Dk Alloys
81.15.Fg Pulsed laser ablation deposition
77.55.fe BaTiO3-based films
68.55.A- Nucleation and growth

Phase-change control of ferromagnetism in GeTe-based phase change magnetic thin-films by pulsed laser deposition

F. Tong, J. H. Hao, Z. P. Chen, G. Y. Gao, and X. S. Miao

Appl. Phys. Lett. 99, 081908 (2011); http://dx.doi.org/10.1063/1.3628660 (3 pages) | Cited 6 times

Online Publication Date: 23 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Phase change control of ferromagnetism in Ge0.98Fe0.02Te thin film prepared by pulsed laser deposition is investigated. The magnetic property of Fe doped phase change material GeTe is found to vary with phase change between amorphous and crystalline states corresponding to the variation of conductance during phase change. The results indicate that a fast control of ferromagnetism by phase change can be realized. The measurement of temperature dependent magnetization shows a long range ferromagnetic interaction in ordered crystalline phase and a short range ferromagnetic interaction in frustrated amorphous phase, which is consistent with phase change.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Et Exchange and superexchange interactions
75.50.Pp Magnetic semiconductors
81.05.Gc Amorphous semiconductors
81.15.Fg Pulsed laser ablation deposition
75.50.Dd Nonmetallic ferromagnetic materials

Enhancement of electric field and Raman scattering by Ag coated Ni nanotips

Dexian Ye, Stephen Mutisya, and Massimo Bertino

Appl. Phys. Lett. 99, 081909 (2011); http://dx.doi.org/10.1063/1.3627164 (3 pages) | Cited 4 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Localization and enhancement of electric field by Ag-coated vertical Ni nanotip arrays were studied by using finite-different time domain calculations. With the 30 nm thick Ag coating, the nanotips can localize and enhance the electric field to more than 103 times under the excitation of TE-polarized light with a 532 nm wavelength. Nanotip-enhanced Raman scattering of cytochrome-c protein was demonstrated in a confocal Raman microscope. Significant enhancement of Raman spectrum was achieved at 1 × 10−9 mol/l concentration of the proteins.
Show PACS
87.15.M- Spectra of biomolecules
02.70.Bf Finite-difference methods
78.30.Jw Organic compounds, polymers
87.14.E- Proteins

Void formation in melt-grown silicon studied by molecular dynamics simulations: From grown-in faulted dislocation loops to vacancy clusters

Johan Pohl and Karsten Albe

Appl. Phys. Lett. 99, 081910 (2011); http://dx.doi.org/10.1063/1.3630028 (3 pages)

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Molecular dynamics simulations of a dislocation based mechanism for void formation in silicon are presented. By studying a moving solid-liquid interface in Si, we observe the formation of dislocation loops on (111) facets consisting of coherency and anticoherency dislocations, which disband within nanoseconds into vacancy clusters of 10 or more vacancies. These vacancy clusters can act as nucleation seeds for the experimentally observed octahedral single and double voids.
Show PACS
61.72.Qq Microscopic defects (voids, inclusions, etc.)
61.72.jd Vacancies
61.72.Bb Theories and models of crystal defects

Anomalous complete opaqueness in a sparse array of gold nanoparticle chains

Benfeng Bai, Xiaowei Li, Ismo Vartiainen, Anni Lehmuskero, Guoguo Kang, Jari Turunen, Markku Kuittinen, and Pasi Vahimaa

Appl. Phys. Lett. 99, 081911 (2011); http://dx.doi.org/10.1063/1.3631671 (3 pages)

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on an anomalous polarization-switching extinction effect in a sparse array of gold nanoparticle chains: under normal incidence of light, the array is almost transparent for one polarization; whereas it is fully opaque (with nearly zero transmittance) for the orthogonal polarization within a narrow band, even though the nanoparticles cover only a tiny fraction (say, 3.5%) of the transparent substrate surface. We reveal that the strong polarization-dependent short-range dipolar coupling and long-range radiative coupling of gold nanoparticles in this highly asymmetric array is responsible for this extraordinary effect.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
81.05.Bx Metals, semimetals, and alloys
81.07.Wx Nanopowders
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Misfit dislocation formation via pre-existing threading dislocation glide in (11math2) semipolar heteroepitaxy

Po Shan Hsu, Erin C. Young, Alexey E. Romanov, Kenji Fujito, Steven P. DenBaars, Shuji Nakamura, and James S. Speck

Appl. Phys. Lett. 99, 081912 (2011); http://dx.doi.org/10.1063/1.3628459 (3 pages) | Cited 17 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cathodoluminescence (CL) was used to study the onset of mechanical stress relaxation in low indium composition semipolar (11math2) InxGa1−xN lattice-mismatched layers grown on bulk GaN substrates. Monochromatic CL of short interfacial misfit dislocation (MD) segments showed a single threading dislocation (TD) associated with each MD segment—demonstrating that the initial stage of MD formation in semipolar III-nitride heterostructures proceeded by the bending and glide of pre-existing TDs on the (0001) slip plane. The state of coherency as determined by panchromatic CL is also compared to that determined by x-ray diffraction analysis based on crystallographic epilayer tilt and Matthew-Blakeslee’s critical thickness calculations.
Show PACS
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
68.60.Bs Mechanical and acoustical properties
78.66.Fd III-V semiconductors
78.60.Hk Cathodoluminescence, ionoluminescence
81.40.Lm Deformation, plasticity, and creep
81.40.Jj Elasticity and anelasticity, stress-strain relations

Fabrication of thin, luminescent, single-crystal diamond membranes

Andrew P. Magyar, Jonathan C. Lee, Andi M. Limarga, Igor Aharonovich, Fabian Rol, David R. Clarke, Mengbing Huang, and Evelyn L. Hu

Appl. Phys. Lett. 99, 081913 (2011); http://dx.doi.org/10.1063/1.3628463 (3 pages) | Cited 7 times

Online Publication Date: 24 August 2011

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The formation of single-crystal diamond membranes is an important prerequisite for the fabrication of high-quality optical cavities in this material. Diamond membranes fabricated using lift-off processes involving the creation of a damaged layer through ion implantation often suffer from residual ion damage, which severely limits their usefulness for photonic structures. The current work demonstrates that strategic etch removal of the most highly defective material yields thin, single-crystal diamond membranes with strong photoluminescence and a Raman signature approaching that of single-crystal bulk diamond. These optically active membranes can form the starting point for fabrication of high-quality optical resonators.
Show PACS
81.05.ug Diamond
61.72.U- Doping and impurity implantation
81.65.Cf Surface cleaning, etching, patterning
78.30.Hv Other nonmetallic inorganics
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