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

9 Jun 2008

Volume 92, Issue 23, Articles (23xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 92, 231901 (2008); http://dx.doi.org/10.1063/1.2938921 (3 pages)

N. A. Mara, D. Bhattacharyya, P. Dickerson, R. G. Hoagland, and A. Misra
Enlarge Image | Read More
Page 1 of 5 Pages Next Page | Jump to Page
back to top
RSS Feeds

Terahertz near-field imaging of metallic subwavelength holes and hole arrays

Andreas Bitzer and Markus Walther

Appl. Phys. Lett. 92, 231101 (2008); http://dx.doi.org/10.1063/1.2936303 (3 pages) | Cited 26 times

Online Publication Date: 9 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Metallic microstructures are investigated by time-resolved terahertz near-field imaging. By our approach, we can directly follow field diffraction from subwavelength structures as well as coupling to the surface. Near-field images of the spectral amplitude and phase of the electric field show the formation, propagation, and attenuation of surface waves and allow us to distinguish between propagating and stationary modes. Our results show that the field enhancement in an individual hole, together with the formation of standing waves on the metal surface between the holes, are key mechanisms for the extraordinary transmission phenomenon through periodic hole arrays.
Show PACS
78.70.Gq Microwave and radio-frequency interactions
78.47.D- Time resolved spectroscopy (>1 psec)

Efficient generation of cross-polarized femtosecond pulses in cubic crystals with holographic cut orientation

Lorenzo Canova, Stoyan Kourtev, Nikolay Minkovski, Aurélie Jullien, Rodrigo Lopez-Martens, Olivier Albert, and Solomon M. Saltiel

Appl. Phys. Lett. 92, 231102 (2008); http://dx.doi.org/10.1063/1.2939584 (3 pages) | Cited 14 times

Online Publication Date: 9 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report here an alternative and more efficient orientation of cubic crystals for generation of cross-polarized femtosecond laser pulses. We show both theoretically and experimentally that the cross polarized wave generation (XPWG) is more efficient when the fundamental beam propagates along the [011] direction (holographic cut) in the crystal than along the [001] direction previously reported. With the [011]-cut BaF2 crystal we measured the highest XPWG conversion efficiencies. We prove other very important advantages of the [011]-cut approach: weak induced phase mismatch and no need for its compensation.
Show PACS
42.65.-k Nonlinear optics
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Photonic bandgap of gradient quasidiamond lattice photonic crystal

Xian-Zi Dong, Qi Ya, Xin-Zhi Sheng, Zhi-Yuan Li, Zhen-Sheng Zhao, and Xuan-Ming Duan

Appl. Phys. Lett. 92, 231103 (2008); http://dx.doi.org/10.1063/1.2943278 (3 pages) | Cited 9 times

Online Publication Date: 10 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A three-dimensional (3D) photonic crystal (PhC) structure consisting of gradient quasidiamond lattices was fabricated using multiphoton photopolymerization nanofabrication technique. The photonic bandgap (PBG) of this 3D PhC was experimentally confirmed by reflection and transmission measurements and simulated with finite-difference time domain calculations. The results indicate that a 3D PhC with gradient lattices could effectively expand the width of the PBG and may be beneficial for developing complete-bandgap PhCs with low refractive index materials for applications in polymer based optoelectronic devices and integrated systems.
Show PACS
42.70.Qs Photonic bandgap materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
42.86.+b Optical workshop techniques

High frequency measurements on an AlN/GaN-based intersubband detector at 1550 and 780 nm

D. Hofstetter, E. Baumann, F. R. Giorgetta, J. Dawlaty, P. A. George, F. Rana, F. Guillot, and E. Monroy

Appl. Phys. Lett. 92, 231104 (2008); http://dx.doi.org/10.1063/1.2939433 (3 pages) | Cited 5 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on high frequency measurements on an AlN/GaN-based intersubband detector using mode-locked solid state lasers. Our experiments involving laser wavelengths of 1550 and 780 nm demonstrate not only the capability of such devices to work both at the fundamental and at a higher order intersubband transition, but they also allowed us to push the high frequency detection limit up to a value of 13.3 GHz. From the shape of the harmonic decay, we conclude that this limit is not due to intrinsic properties of the detector.
Show PACS
72.30.+q High-frequency effects; plasma effects
85.60.Gz Photodetectors (including infrared and CCD detectors)
68.65.Fg Quantum wells
42.55.Px Semiconductor lasers; laser diodes
42.60.Fc Modulation, tuning, and mode locking

Q-factor and density of optical modes in pyramidal and cone-shaped GaAs microcavities

M. Karl, T. Beck, S. Li, H. Kalt, and M. Hetterich

Appl. Phys. Lett. 92, 231105 (2008); http://dx.doi.org/10.1063/1.2946659 (3 pages) | Cited 4 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
GaAs pyramids on top of GaAs/AlAs distributed Bragg reflectors (DBRs) are studied as candidates for microcavities with low mode volume. Photoluminescence spectra of single pyramids with embedded quantum dots show cavity modes with quality (Q-) factors of up to 700. Furthermore, to assess the complex mode structure in pyramids a finite-difference time-domain simulation with rotational symmetry is used to evaluate cavity modes in a cone on top of a DBR. A cone angle around 46° was identified for highest Q-factors. Based on our calculations, approaches to improve the light confinement are suggested which should result in microcavities with high Q-factors.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
42.50.Pq Cavity quantum electrodynamics; micromasers

Fabrication and characterization of periodically poled lithium niobate waveguide using femtosecond laser pulses

Shuanggen Zhang, Jianghong Yao, Qing Shi, Yange Liu, Weiwei Liu, Zhangchao Huang, Fuyun Lu, and Enbang Li

Appl. Phys. Lett. 92, 231106 (2008); http://dx.doi.org/10.1063/1.2945275 (3 pages) | Cited 4 times

Online Publication Date: 13 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present in this letter the fabrication and characterization of thermally stable type II waveguides in Z-cut periodically poled lithium niobate crystals. The waveguides were fabricated by using a femtosecond laser and were utilized for second harmonic generation. Our experiments have shown that a quasiphase matching wavelength of 1548.2 nm, a tuning bandwidth of 2 nm, and a tuning temperature range of 150.4±1.6 °C can be achieved.
Show PACS
42.79.Gn Optical waveguides and couplers
42.60.Fc Modulation, tuning, and mode locking
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.86.+b Optical workshop techniques
back to top
RSS Feeds

Plasma actuated heat transfer

Subrata Roy and Chin-Cheng Wang

Appl. Phys. Lett. 92, 231501 (2008); http://dx.doi.org/10.1063/1.2938886 (3 pages)

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We introduce plasmas for film cooling enhancement in gas turbines and other engineering applications. We identify mechanisms to actuate essentially stagnant fluid just downstream of the cooling hole by employing three-dimensional body force for different hole geometries. Such methods actively alter flow structures in the vicinity of an actuator using an electrodynamic mechanism that induces attachment of cold jet to the work surface. Numerical results are compared with published experimental data and other numerical predictions for the latest film cooling technology. An effectiveness improvement of above 100% over the standard baseline design is predicted.
Show PACS
52.75.-d Plasma devices
47.85.L- Flow control
07.07.Tw Servo and control equipment; robots
02.60.Cb Numerical simulation; solution of equations

Effect of electron energy distribution function on the global model for high power microwave breakdown at high pressures

Sang Ki Nam and John P. Verboncoeur

Appl. Phys. Lett. 92, 231502 (2008); http://dx.doi.org/10.1063/1.2942382 (3 pages) | Cited 16 times

Online Publication Date: 13 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A global model (GM) was developed to investigate the effect of reaction kinetics and plasma parameters on high power microwave (HPM) breakdown time for multiple species. However, the GM requires specification of the electron energy distribution function (EEDF); the common assumption of a Maxwellian EEDF results in incorrect plasma parameters since the electrons are not in equilibrium. We examine the effect of the EEDF on the GM and develop a method to obtain a better EEDF to improve the fidelity of the prediction of HPM breakdown at high pressures.
Show PACS
52.80.Pi High-frequency and RF discharges
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
82.20.-w Chemical kinetics and dynamics

Angular emission and self-absorption studies of a tin laser produced plasma extreme ultraviolet source between 10 and 18 nm

O. Morris, F. O’Reilly, P. Dunne, and P. Hayden

Appl. Phys. Lett. 92, 231503 (2008); http://dx.doi.org/10.1063/1.2945645 (3 pages) | Cited 7 times

Online Publication Date: 13 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Extreme ultraviolet spectra from a tin laser produced plasma have been recorded over a range of angles between 20° and 90° from the target normal. Absolute intensity measurements are presented of both the 2% band centered on 13.5 nm and the total radiation emitted by the plasma between 10 and 18 nm. The in-band intensity is seen to be relatively constant out to an angle of 60° from the target normal, beyond which it drops off quite steeply. The spectra at wavelengths greater than 13.5 nm are strongly influenced by self-absorption by ions ranging from 6+ to 10+.
Show PACS
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
back to top
RSS Feeds

Deformability of ultrahigh strength 5 nm Cu/Nb nanolayered composites

N. A. Mara, D. Bhattacharyya, P. Dickerson, R. G. Hoagland, and A. Misra

Appl. Phys. Lett. 92, 231901 (2008); http://dx.doi.org/10.1063/1.2938921 (3 pages) | Cited 55 times

Online Publication Date: 9 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this work, micropillar compression testing has been used to obtain stress-strain curves for sputter-deposited Cu–Nb nanolaminate composites with nominal bilayer thickness of 10 nm. In addition to the extremely high flow strength of 2.4 GPa, the 5 nm Cu/5 nm Nb nanolaminate exhibits significant ductility, in excess of 25% true strain.
Show PACS
62.25.-g Mechanical properties of nanoscale systems
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity

Improved a-plane GaN quality grown with flow modulation epitaxy and epitaxial lateral overgrowth on r-plane sapphire substrate

Jeng-Jie Huang, Kun-Ching Shen, Wen-Yu Shiao, Yung-Sheng Chen, Tzu-Chi Liu, Tsung-Yi Tang, Chi-Feng Huang, and C. C. Yang

Appl. Phys. Lett. 92, 231902 (2008); http://dx.doi.org/10.1063/1.2942391 (3 pages) | Cited 9 times

Online Publication Date: 9 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors demonstrate superior crystal quality of a-plane GaN grown on r-plane sapphire substrate based on the flow modulation epitaxy (FME) technique, in which the Ga atom supply is alternatively switched on and off with continuous nitrogen supply. With the FME technique, a high growth rate of 2.3 μm/h can still be achieved. With or without epitaxial lateral overgrowth (ELOG), either c- or m-mosaic condition is significantly improved in the samples of using FME. With ELOG, the surface roughness can be reduced from 1.58 to 0.647 nm in an area of 10×10 μm2 microns by using the FME technique. Based on the results of photoluminescence measurement, one can also conclude the better optical property of the FME-grown a-plane GaN thin films. Besides, it is shown that tensile strain is more relaxed in the FME samples.
Show PACS
68.55.ag Semiconductors
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors

Advanced x-ray stress analysis method for a single crystal using different diffraction plane families

Muneyuki Imafuku, Hiroshi Suzuki, Kazuyuki Sueyoshi, Koichi Akita, and Shin-ichi Ohya

Appl. Phys. Lett. 92, 231903 (2008); http://dx.doi.org/10.1063/1.2912030 (3 pages)

Online Publication Date: 10 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Generalized formula of the x-ray stress analysis for a single crystal with unknown stress-free lattice parameter was proposed. This method enables us to evaluate the plane stress states with any combination of diffraction planes. We can choose and combine the appropriate x-ray sources and diffraction plane families, depending on the sample orientation and the apparatus, whenever diffraction condition is satisfied. The analysis of plane stress distributions in an iron single crystal was demonstrated combining with the diffraction data for Fe{211} and Fe{310} plane families.
Show PACS
07.85.-m X- and γ-ray instruments
61.05.-a Techniques for structure determination

Surface chemistry of plasma-assisted atomic layer deposition of Al2O3 studied by infrared spectroscopy

E. Langereis, J. Keijmel, M. C. M. van de Sanden, and W. M. M. Kessels

Appl. Phys. Lett. 92, 231904 (2008); http://dx.doi.org/10.1063/1.2940598 (3 pages) | Cited 21 times

Online Publication Date: 10 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The surface groups created during plasma-assisted atomic layer deposition (ALD) of Al2O3 were studied by infrared spectroscopy. For temperatures in the range of 25–150 °C, –CH3 and –OH were unveiled as dominant surface groups after the Al(CH3)3 precursor and O2 plasma half-cycles, respectively. At lower temperatures more –OH and C-related impurities were found to be incorporated in the Al2O3 film, but the impurity level could be reduced by prolonging the plasma exposure. The results demonstrate that –OH surface groups rule the surface chemistry of the Al2O3 process and likely that of plasma-assisted ALD of metal oxides from organometallic precursors in general.
Show PACS
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
52.77.Dq Plasma-based ion implantation and deposition
78.30.Hv Other nonmetallic inorganics

Thermal properties of calcium doped strontium barium niobate crystal

Ch. Y. Gao, H. R. Xia, J. Q. Xu, C. L. Zhou, H. J. Zhang, and J. Y. Wang

Appl. Phys. Lett. 92, 231905 (2008); http://dx.doi.org/10.1063/1.2943187 (2 pages) | Cited 4 times

Online Publication Date: 11 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Calcium doped strontium barium niobate is a tungsten-bronze ferroelectric crystal with a tetragonal unit cell. Thermophysical properties including specific heat, thermal expansion, and thermal diffusion were performed on a single crystal (Ca0.28Ba0.75)0.25(Sr0.60Ba0.40)0.75Nb2O6 (CSBN25) to determine thermal behaviors along the a and c axes. Negative thermal expansion was observed along the c axes below the Curie temperature. Isotropic thermal behavior (thermal diffusion and thermal conductivity) was observed around Curie temperature. The abnormal thermal behaviors are considered as arising due to the geometry of the dope-affected crystal.
Show PACS
65.40.Ba Heat capacity
65.40.De Thermal expansion; thermomechanical effects
66.70.Lm Other systems such as ionic crystals, molecular crystals, nanotubes, etc.
66.30.Xj Thermal diffusivity
77.80.-e Ferroelectricity and antiferroelectricity

Experimental verification and theoretical analysis of the relationships between hardness, elastic modulus, and the work of indentation

Rong Yang, Taihua Zhang, Peng Jiang, and Yilong Bai

Appl. Phys. Lett. 92, 231906 (2008); http://dx.doi.org/10.1063/1.2944138 (3 pages) | Cited 4 times

Online Publication Date: 11 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The relationship between hardness (H), reduced modulus (Er), unloading work (Wu), and total work (Wt) of indentation is examined in detail experimentally and theoretically. Experimental study verifies the approximate linear relationship. Theoretical analysis confirms it. Furthermore, the solutions to the conical indentation in elastic-perfectly plastic solid, including elastic work (We), H, Wt, and Wu are obtained using Johnson’s expanding cavity model and Lamé solution. Consequently, it is found that the We should be distinguished from Wu, rather than their equivalence as suggested in ISO14577, and (H/Er)/(Wu/Wt) depends mainly on the conical angle, which are also verified with numerical simulations.
Show PACS
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
81.40.Lm Deformation, plasticity, and creep
62.20.de Elastic moduli
62.20.F- Deformation and plasticity

Dislocation network at InN/GaN interface revealed by scanning tunneling microscopy

Y. Liu, Y. Cai, Lixin Zhang, M. H. Xie, N. Wang, S. B. Zhang, and H. S. Wu

Appl. Phys. Lett. 92, 231907 (2008); http://dx.doi.org/10.1063/1.2944145 (3 pages) | Cited 5 times

Online Publication Date: 11 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
For heteroepitaxy of InN on GaN(0001) by molecular-beam epitaxy, the lattice misfit strain is relieved by misfit dislocations (MDs) formed at the interface between InN and GaN. Imaging by scanning tunneling microscopy (STM) of the surfaces of thin InN epifilms reveals line feature parallel to 〈11math0〉. Their contrast becomes less apparent for thicker epifilms. From the interline spacing as well as a comparison with transmission electron microscopy studies, it is suggested that they correspond to the MDs beneath the surface. The STM contrast originates from both the surface distortion caused by the local strain at MDs and the electronic states of the defects.
Show PACS
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.20.At Surface states, band structure, electron density of states
68.35.Dv Composition, segregation; defects and impurities
68.55.ag Semiconductors

Elastic property of fcc metal nanowires via an atomic-scale analysis

Li Qiao and Xiaojing Zheng

Appl. Phys. Lett. 92, 231908 (2008); http://dx.doi.org/10.1063/1.2924310 (3 pages) | Cited 3 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A simple atomic-scale model based on the distortion of the unit cell generating the nanowire is proposed to predict the elastic characteristics of fcc metal nanowires. It allows for an analytical study on the mechanical behavior of nanomaterials from the perspective of atomic interactions. Bond-strength enhancing arising from the spontaneous bond relaxation has significant effects on the elastic properties of metal nanowires, which can be described by a scale function. Contribution from effects related to surface roughness and surface oxidation to the elastic modulus of nanostructures is also considered. There is good qualitative agreement between theoretical predictions and experimental observations.
Show PACS
62.23.Hj Nanowires
62.20.de Elastic moduli
81.40.Jj Elasticity and anelasticity, stress-strain relations
68.35.bd Metals and alloys
81.65.Mq Oxidation
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)

Nonradiative recombination at threading dislocations in n-type GaN: Studied by cathodoluminescence and defect selective etching

M. Albrecht, J. L. Weyher, B. Lucznik, I. Grzegory, and S. Porowski

Appl. Phys. Lett. 92, 231909 (2008); http://dx.doi.org/10.1063/1.2928226 (3 pages) | Cited 14 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dislocations in GaN single crystal were studied by means of spectral cathodoluminescence (CL) mapping and defect selective etching. We show that the c-type screw dislocations are not recombination active. The recombination strength of the a- and (a+c)-type dislocations is influenced by impurity gettering. While fresh dislocations exhibit a CL contrast of 0.01–0.05 in accordance with intrinsic dislocation states, grown in dislocations show a contrast of 0.25. From the analysis of spectral CL maps, we find that impurities such as oxygen and silicon are depleted in the surrounding of the dislocations. We explain the increased contrast by a reduced screening of the electrical field of the dislocation.
Show PACS
78.60.Hk Cathodoluminescence, ionoluminescence
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.65.Cf Surface cleaning, etching, patterning
61.72.Yx Interaction between different crystal defects; gettering effect
81.65.Tx Gettering
68.47.Fg Semiconductor surfaces

Superior hydrogen desorption kinetics of Mg(NH2)2 hollow nanospheres mixed with MgH2 nanoparticles

Lei Xie, Yaoqi Li, Rong Yang, Yang Liu, and Xingguo Li

Appl. Phys. Lett. 92, 231910 (2008); http://dx.doi.org/10.1063/1.2943284 (3 pages) | Cited 5 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Mg3N2 nanocubes were prepared by vaporized bulk magnesium in ammonia atmosphere associated with plasma metal reaction. Then the product transformed to Mg(NH2)2 hollow nanospheres after it was reacted with NH3 based on the Kirkendall effect. The electron microscopy results suggested that the obtained hollow nanospheres were around 100 nm and the shell thickness was about 10 nm. Because of its short distance for Mg2+ diffusion and large specific surface area for interaction between Mg(NH2)2 and MgH2, the structure dramatically enhanced the hydrogen desorption kinetics of Mg(NH2)2–2MgH2.
Show PACS
68.43.Nr Desorption kinetics
61.46.Df Structure of nanocrystals and nanoparticles ("colloidal" quantum dots but not gate-isolated embedded quantum dots)
52.77.-j Plasma applications
66.30.Ny Chemical interdiffusion; diffusion barriers
81.07.-b Nanoscale materials and structures: fabrication and characterization

Optical properties and morphology of InAs/InP (113)B surface quantum dots

A. Nakkar, H. Folliot, A. Le Corre, F. Doré, I. Alghoraibi, C. Labbé, G. Elias, S. Loualiche, M.-E. Pistol, P. Caroff, and C. Ellström

Appl. Phys. Lett. 92, 231911 (2008); http://dx.doi.org/10.1063/1.2943651 (3 pages)

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on long-wavelength photoluminescence (PL) emission at room temperature from self-organized InAs surface quantum dots grown by gas-source molecular beam epitaxy on a GaInAsP/InP (113)B substrate. The influence of arsenic pressure conditions during growth on the PL emission of surface quantum dots is detailed as well as oxide/contamination layer formation after growth. Experimental results are in good agreement with six-band k⋅p theory in the envelope function approximation.
Show PACS
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
68.65.Hb Quantum dots (patterned in quantum wells)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Tensile properties of carbon nanotubes grown on ultrahigh strength polyacrylonitrile-based and ultrahigh modulus pitch-based carbon fibers

Kimiyoshi Naito, Jenn-Ming Yang, Yoshihisa Tanaka, and Yutaka Kagawa

Appl. Phys. Lett. 92, 231912 (2008); http://dx.doi.org/10.1063/1.2944258 (3 pages) | Cited 6 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The tensile properties and fracture behavior of carbon nanotubes (CNTs) grown on ultrahigh tensile strength polyacrylonitrile (PAN)-based (T1000GB) and ultrahigh modulus pitch-based (K13D) carbon fibers have been investigated. The CNTs were grown on the carbon fiber surface using chemical vapor deposition. The statistical scattering of the tensile strength was also evaluated. The results clearly show that grafting of CNTs improves the mechanical properties and the Weibull modulus of ultrahigh tensile strength PAN-based and ultrahigh modulus pitch-based carbon fibers.
Show PACS
62.25.Mn Fracture/brittleness
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.46.Fg Nanotubes
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure

Photoluminescence in heavily doped ZnO:N:In films

Z. Z. Ye, L. L. Chen, B. H. Zhao, and H. P. He

Appl. Phys. Lett. 92, 231913 (2008); http://dx.doi.org/10.1063/1.2945630 (3 pages) | Cited 3 times

Online Publication Date: 12 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Temperature-dependent photoluminescence is used to investigate ZnO films codoped with In and N at different doping levels. Conversion from exciton recombination to band-to-band transition with increasing both doping level and temperature is observed. We suggest that ionization of the N acceptors and dissociation of excitons by impurity-induced local field are responsible for such conversion. For the film with N concentration of 4×1020 cm−3, the excitonic emission intensity shows anomalous temperature dependence due to localized carriers. The localization energy and the N acceptor level is determined to be about 5 and 164 meV, respectively.
Show PACS
78.66.Hf II-VI semiconductors
78.55.Et II-VI semiconductors
61.72.uj III-V and II-VI semiconductors
71.55.Gs II-VI semiconductors
71.35.-y Excitons and related phenomena

Effects of diffraction and dispersion on acoustic radiation-induced static pulses

John H. Cantrell

Appl. Phys. Lett. 92, 231914 (2008); http://dx.doi.org/10.1063/1.2937474 (3 pages) | Cited 4 times

Online Publication Date: 13 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is shown that the shapes of acoustic radiation-induced static strain and displacement pulses are defined locally by the energy density of the generating waveform and that diffraction and attenuation produce dramatic changes in the shape of static displacement pulses when using laser detection. The effects of dispersion on static pulses are obtained by including a dispersive term in the phase of the particle velocity solution to the nonlinear wave equation. The dispersion causes an evolutionary change in the shape of the energy density profile that leads to the generation of solitons experimentally observed in fused silica.
Show PACS
62.65.+k Acoustical properties of solids
43.25.Dc Nonlinear acoustics of solids
43.25.Rq Solitons, chaos

Linear and nonlinear optical properties of multifunctional PbVO3 thin films

Amit Kumar, Nikolas J. Podraza, Sava Denev, Jian Li, Lane W. Martin, Ying-Hao Chu, R. Ramesh, Robert W. Collins, and Venkatraman Gopalan

Appl. Phys. Lett. 92, 231915 (2008); http://dx.doi.org/10.1063/1.2943283 (3 pages) | Cited 4 times

Online Publication Date: 13 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Lead vanadate (PbVO3) is a multifunctional material which is both polar and magnetic. Its optical properties, important for linear and nonlinear optical spectroscopy of the material, are presented. Using spectroscopic ellipsometry, the refractive index and absorption versus wavelength of lead vanadate thin films at 295 K is reported. Using optical second harmonic generation, the nonlinear optical coefficients were determined to be d15/d31 = 0.20±0.02, d33/d31 = 316.0±4.4, and ∣d33∣ = 10.40±0.35 pm/V at a fundamental wavelength of 800 nm.
Show PACS
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.20.Ek Optical activity
77.55.-g Dielectric thin films
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials

Growth of highly strain-relaxed Ge1−xSnx/virtual Ge by a Sn precipitation controlled compositionally step-graded method

Shotaro Takeuchi, Yosuke Shimura, Osamu Nakatsuka, Shigeaki Zaima, Masaki Ogawa, and Akira Sakai

Appl. Phys. Lett. 92, 231916 (2008); http://dx.doi.org/10.1063/1.2945629 (3 pages) | Cited 24 times

Online Publication Date: 13 June 2008

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated Sn precipitation and strain relaxation behaviors in the growth of Ge1−xSnx layers on virtual Ge substrates (v-Ge) for strain engineering of Ge. By varying misfit strain at Ge1−xSnx/v-Ge and Ge1−ySny/Ge1−xSnx interfaces, we found that a critical misfit strain controls the onset of Sn precipitation at a given thickness of the Ge1−xSnx layer. A compositionally step-graded method, in which the critical misfit strain is taken into account, was applied to the growth of strain-relaxed Ge1−xSnx layers on v-Ge. Postdeposition annealing at each growth step led to lateral propagation of threading dislocations preexisting in the layer and originating from v-Ge, which resulted in high degree of strain relaxation. An epitaxial Ge layer was grown on the strain-relaxed Ge1−xSnx layer and an in-plane tensile strain of 0.68% was achieved.
Show PACS
68.55.ag Semiconductors
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
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
Page 1 of 5 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close