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 Jan 2007

Volume 90, Issue 4, Articles (04xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 90, 043507 (2007); http://dx.doi.org/10.1063/1.2435508 (3 pages)

D. Y. Kim and A. J. Steckl
Enlarge Image | Read More
Page 1 of 6 Pages Next Page | Jump to Page
back to top
RSS Feeds

Manipulating exciton fine structure in quantum dots with a lateral electric field

B. D. Gerardot, S. Seidl, P. A. Dalgarno, R. J. Warburton, D. Granados, J. M. Garcia, K. Kowalik, O. Krebs, K. Karrai, A. Badolato, and P. M. Petroff

Appl. Phys. Lett. 90, 041101 (2007); http://dx.doi.org/10.1063/1.2431758 (3 pages) | Cited 58 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The fine structure of the neutral exciton in a single self-assembled InGaAs quantum dot is investigated under the effect of a lateral electric field. Stark shifts up to 1.5 meV, an increase in linewidth, and a decrease in photoluminescence intensity were observed due to the electric field. The authors show that the lateral electric field strongly affects the exciton fine-structure splitting due to active manipulation of the single particle wave functions. Remarkably, the splitting can be tuned over large values and through zero.
Show PACS
73.21.La Quantum dots
71.35.-y Excitons and related phenomena
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
78.20.Jq Electro-optical effects

Terahertz imaging diagnostics of cancer tissues with a chemometrics technique

Sachiko Nakajima, Hiromichi Hoshina, Masatsugu Yamashita, Chiko Otani, and Norio Miyoshi

Appl. Phys. Lett. 90, 041102 (2007); http://dx.doi.org/10.1063/1.2433035 (3 pages) | Cited 30 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Terahertz spectroscopic images of paraffin-embedded cancer tissues have been measured by a terahertz time domain spectrometer. For the systematic identification of cancer tumors, the principal component analysis and the clustering analysis were applied. In three of the four samples, the cancer tissue was recognized as an aggregate of the data points in the principal component plots. By the agglomerative hierarchical clustering, the data points were well categorized into cancer and the other tissues. This method can be also applied to various kinds of automatic discrimination of plural components by terahertz spectroscopic imaging.
Show PACS
87.63.-d Non-ionizing radiation equipment and techniques
87.57.N- Image analysis
87.19.X- Diseases
02.50.-r Probability theory, stochastic processes, and statistics

Low transparency current density and high temperature operation from ten-layer p-doped 1.3 μm InAs/InGaAs/GaAs quantum dot lasers

C. Y. Liu, S. F. Yoon, Q. Cao, C. Z. Tong, and H. F. Li

Appl. Phys. Lett. 90, 041103 (2007); http://dx.doi.org/10.1063/1.2434156 (3 pages) | Cited 12 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High temperature photoluminescence up to 100 °C was demonstrated from the p-doped ten-layer InAs/InGaAs quantum dot (QD) laser structure. 1.3 μm InAs QD lasers were fabricated using pulsed anodic oxidation from this structure. High output power of 882 mW and low transparency current density of 5.9 A/cm2/QD layer were obtained. Ground state (GS) lasing could be maintained from a QD laser with short cavity length of 611 μm, corresponding to the maximum modal gain of 23.1 cm−1 from this laser system. GS continuous wave operation up to 100 °C was also demonstrated from an InAs QD laser (50×2500 μm2).
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Direct full compensation of the aberrations in quantitative phase microscopy of thin objects by a single digital hologram

L. Miccio, D. Alfieri, S. Grilli, P. Ferraro, A. Finizio, L. De Petrocellis, and S. D. Nicola

Appl. Phys. Lett. 90, 041104 (2007); http://dx.doi.org/10.1063/1.2432287 (3 pages) | Cited 28 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Aberrations and the distortions due to the imaging optics can be compensated in quantitative phase microscopy of thin phase objects by digital holography using a single hologram. The reconstructed quantitative phase microscopy phase distribution map can be directly corrected in the reconstructed image plane by a numerical method. To remove this unwanted aberration, in the special case of thin objects, the authors perform a two-dimensional fit with the Zernike polynomials of the reconstructed unwrapped phase. Subtraction of the fitted polynomial from the original phase map gives quantitative phase microscopy phase map free of aberrations.
Show PACS
42.40.Kw Holographic interferometry; other holographic techniques
07.60.Pb Conventional optical microscopes
42.30.Wb Image reconstruction; tomography

Phase retrieval in x-ray coherent Fresnel projection-geometry diffraction

Liberato De Caro, Cinzia Giannini, Alessia Cedola, Daniele Pelliccia, Stefano Lagomarsino, and Werner Jark

Appl. Phys. Lett. 90, 041105 (2007); http://dx.doi.org/10.1063/1.2431457 (3 pages) | Cited 4 times

Online Publication Date: 23 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Coherent x-ray diffraction experiments were performed in Fresnel regime, within a line-projection geometry. A planar x-ray waveguide was used to focus coherent cylindrical waves onto a 7.2 μm Kevlar fiber, which acts as a phase object for hard x rays. The phase was retrieved, by using a Fourier-based iterative phasing algorithm, consistent with measured diffraction data and known constraints in real space, with a submicrometer spatial resolution.
Show PACS
61.05.cp X-ray diffraction
07.85.-m X- and γ-ray instruments

Chaos-assisted nonresonant optical pumping of quadrupole-deformed microlasers

Sang-Bum Lee, Juhee Yang, Songky Moon, Jai-Hyung Lee, Kyungwon An, Jeong-Bo Shim, Hai-Woong Lee, and Sang Wook Kim

Appl. Phys. Lett. 90, 041106 (2007); http://dx.doi.org/10.1063/1.2432298 (3 pages) | Cited 9 times

Online Publication Date: 23 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Efficient nonresonant optical pumping of a high-Q scar mode in a two-dimensional quadrupole-deformed microlaser has been demonstrated based on ray and wave chaos. Threefold enhancement in the lasing power was achieved at a properly chosen pumping angle. The experimental result is consistent with ray tracing and wave overlap integral calculations.
Show PACS
42.55.Sa Microcavity and microdisk lasers
42.65.Sf Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics
42.15.Dp Wave fronts and ray tracing

Low dislocation densities and long carrier lifetimes in GaN thin films grown on a SiNx nanonetwork

J. Xie, Ü. Özgür, Y. Fu, X. Ni, H. Morkoç, C. K. Inoki, T. S. Kuan, J. V. Foreman, and H. O. Everitt

Appl. Phys. Lett. 90, 041107 (2007); http://dx.doi.org/10.1063/1.2433754 (3 pages) | Cited 20 times

Online Publication Date: 24 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Significant improvement of structural and optical qualities of GaN thin films on sapphire substrates was achieved by metal organic chemical vapor deposition with in situ SiNx nanonetwork. Transmission electron microscope (TEM) studies revealed that screw- and edge-type dislocations were reduced to 4.4×107 and 1.7×107 cm−2, respectively, for a ∼ 5.5-μm-thick layer. Furthermore, room temperature carrier lifetimes of 2.22 and 2.49 ns were measured by time-resolved photoluminescence (TRPL) for samples containing single and double SiNx network layers, respectively, representing a significant improvement over the previous studies. The consistent trends among the TEM, x-ray diffraction, and TRPL measurements suggest that in situ SiNx network reduces line defects effectively as well as the point-defect-related nonradiative centers.
Show PACS
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
73.61.Ey III-V semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics

Optical filter based on two-dimensional photonic crystal surface-mode cavity in amorphous silicon-on-silica structure

Ziyang Zhang, Matteo Dainese, Lech Wosinski, Sanshui Xiao, Min Qiu, Marcin Swillo, and Ulf Andersson

Appl. Phys. Lett. 90, 041108 (2007); http://dx.doi.org/10.1063/1.2432228 (3 pages) | Cited 10 times

Online Publication Date: 24 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An optical filter based on side coupling between silicon wire waveguide and two-dimensional photonic crystal surface-mode cavity is presented. The design is optimized numerically by parallel three-dimensional finite-different time-domain simulations. The device is then fabricated on amorphous silicon-on-silica structure. The drop wavelength is observed around 1580 nm. The extinction ratio of the filter is larger than 10 dB and the intrinsic quality factor of the surface-mode cavity is approximately 2000.
Show PACS
42.79.Ci Filters, zone plates, and polarizers
42.70.Qs Photonic bandgap materials
42.79.Gn Optical waveguides and couplers
42.15.Eq Optical system design

Cavity resonances in finite plasmonic chains

P. Ghenuche, I. G. Cormack, G. Badenes, P. Loza-Alvarez, and R. Quidant

Appl. Phys. Lett. 90, 041109 (2007); http://dx.doi.org/10.1063/1.2435513 (3 pages) | Cited 10 times

Online Publication Date: 24 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on the observation of cavity resonances along finite gold nanoparticle chains which, unlike continuous gold nanowires, lead to a high field concentration at their extremity. The mode signature has been assessed by probing the local field bound to the metal with two-photon luminescence spectroscopy. Simulations based on the Green dyadic method corroborate a good agreement with the measurements and bring further insight to the physics involved.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.68.+m Optical properties of surfaces
78.55.Hx Other solid inorganic materials
73.22.Lp Collective excitations

Effect of temporal pulse shape on optical damage

C. W. Carr, J. B. Trenholme, and M. L. Spaeth

Appl. Phys. Lett. 90, 041110 (2007); http://dx.doi.org/10.1063/1.2431705 (3 pages) | Cited 18 times

Online Publication Date: 25 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The conditions under which optical materials are susceptible to laser-induced damage is a topic which has been the subject of considerable study. Laser parameters such as wavelength and temporal pulse duration have been studied extensively. Until this work the effect of temporal pulse shape has not been considered. The authors present here data from a simple single-parameter model and a supporting experiment which predicts that a flat-in-time pulse will produce damage at approximately 80% of the fluence of a Gaussian pulse of the same duration.
Show PACS
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
42.60.Fc Modulation, tuning, and mode locking
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Generation of continuous-wave broadband entangled beams using periodically poled lithium niobate waveguides

Ken-ichiro Yoshino, Takao Aoki, and Akira Furusawa

Appl. Phys. Lett. 90, 041111 (2007); http://dx.doi.org/10.1063/1.2437057 (3 pages) | Cited 11 times

Online Publication Date: 25 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Continuous-wave light beams with broadband quantum entanglement are created with two independent squeezed light beams generated by two periodically poled lithium niobate waveguides and a symmentric beam splitter. The quantum entanglement is confirmed with a sufficient criterion ΔA,B2 = 〈[Δ(mathA−mathB)]2〉+〈[Δ(mathA+mathB)]2〉<1 and the observed ΔA,B2 is 0.75 over the bandwidth of 30 MHz. Although the bandwidth is limited by that of the detector so far, it would be broadened up to 10 THz which would be only limited by the bandwidth of phase matching for the second-order nonlinear process.
Show PACS
03.67.Mn Entanglement measures, witnesses, and other characterizations
42.50.Dv Quantum state engineering and measurements
42.65.Lm Parametric down conversion and production of entangled photons

Terahertz quantum-cascade lasers based on a three-well active module

H. Luo, S. R. Laframboise, Z. R. Wasilewski, G. C. Aers, H. C. Liu, and J. C. Cao

Appl. Phys. Lett. 90, 041112 (2007); http://dx.doi.org/10.1063/1.2437071 (3 pages) | Cited 57 times

Online Publication Date: 25 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on a design of terahertz quantum-cascade lasers based on three-well active modules. Each module consists of two tunnel-coupled wells for the two lasing states and another well for both resonant-phonon depopulation and carrier injection. This design is the simplest so far among the various published working devices. The test device has a lasing frequency of 3.4 THz and maximum operating temperature of 142 K.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Wave front evolution of negatively refracted waves in a photonic crystal

Ethan Schonbrun, Qi Wu, Wounjhang Park, Tsuyoshi Yamashita, Christopher J. Summers, Maxim Abashin, and Yeshaiahu Fainman

Appl. Phys. Lett. 90, 041113 (2007); http://dx.doi.org/10.1063/1.2435344 (3 pages) | Cited 14 times

Online Publication Date: 25 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using a heterodyne near-field scanning microscope, the authors analyze the phase and amplitude of the electric field of an optical wave across the boundary of positive to negative refraction media. The photonic crystal acts as an extremely anisotropic material with a negative curvature of its dispersion surface whose shape is resolved experimentally. This extreme anisotropy results in the beam having a peculiar phase evolution through propagation that does not occur in isotropic media. A focusing wave is produced by negative refraction, which has diverging wave fronts before the internal focus and converging wave fronts after the focus.
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)

Tomographic reconstruction of picosecond acoustic strain propagation

Motonobu Tomoda, Osamu Matsuda, Oliver B. Wright, and Roberto Li Voti

Appl. Phys. Lett. 90, 041114 (2007); http://dx.doi.org/10.1063/1.2432238 (3 pages) | Cited 8 times

Online Publication Date: 26 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
By means of an ultrafast optical technique, picosecond acoustic strain pulses in a transparent medium are tomographically visualized. The authors reconstruct strain pulses in Au-coated glass from time-domain reflectivity changes as a function of the optical angle of incidence, with ∼ 1 ps temporal and ∼ 100 nm spatial resolutions.
Show PACS
42.30.Wb Image reconstruction; tomography
78.47.-p Spectroscopy of solid state dynamics
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
62.65.+k Acoustical properties of solids

Use of anisotropic laser etching to the top n-GaN layer to alleviate current-crowding effect in vertical-structured GaN-based light-emitting diodes

Tron-Min Chen, Shui-Jinn Wang, Kai-Ming Uang, Shiue-Lung Chen, Wei-Chih Tsai, Wei-Chi Lee, and Ching-Chung Tsai

Appl. Phys. Lett. 90, 041115 (2007); http://dx.doi.org/10.1063/1.2432254 (3 pages) | Cited 4 times

Online Publication Date: 26 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To equalize the resistance of all possible current paths in regular vertical-conducting metal-substrate GaN-based light-emitting diodes (VM-LEDs), an anisotropic laser etching to the surface layer (n-GaN) of 40 mil VM-LEDs for improving light emission uniformity and light output power is proposed and demonstrated. The feasibility of the proposed scheme was verified by current and light emission distribution as well as light extraction rate simulations. In conjunction with a nonuniform excimer laser beam irradiation through a mask and rotation of the epitaxy wafer, VM-LEDs with a concave-surface n-GaN layer were also fabricated. Typical improvement in light output power by 38%–26% at an injection current of 350 mA as compared to the one without anisotropic etching has been obtained.
Show PACS
85.60.Jb Light-emitting devices
back to top
RSS Feeds

Efficient coupling of high intensity short laser pulses into snow clusters

T. Palchan, S. Pecker, Z. Henis, S. Eisenmann, and A. Zigler

Appl. Phys. Lett. 90, 041501 (2007); http://dx.doi.org/10.1063/1.2435348 (3 pages) | Cited 10 times

Online Publication Date: 24 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Measurements of energy absorption of high intensity laser pulses in snow clusters are reported. Targets consisting of sapphire coated with snow nanoparticles were found to absorb more than 95% of the incident light compared to 50% absorption in flat sapphire targets.
Show PACS
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression

Electron trapping in radio-frequency atmospheric-pressure glow discharges

D. W. Liu, J. J. Shi, and M. G. Kong

Appl. Phys. Lett. 90, 041502 (2007); http://dx.doi.org/10.1063/1.2425045 (3 pages) | Cited 20 times

Online Publication Date: 25 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, the authors present experimental evidence of electron trapping in radio-frequency (rf) atmospheric-pressure glow discharges. By linking electron density to nanosecond plasma images and optical emission spectroscopy, they show that electron trapping occurs under most discharge conditions. The level of electron trapping increases with increasing discharge current or/and increasing excitation frequency, and manifests itself in the change of the differential conductivity at the point of the gas breakdown. Finally, they demonstrate that electron trapping is largely related to whether the half rf period is shorter than the electron transition time across the electrode gap.
Show PACS
52.80.Hc Glow; corona
52.80.Pi High-frequency and RF discharges
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.70.Ds Electric and magnetic measurements
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Fi Transport properties
back to top
RSS Feeds

Integrated cantilever sensors with a torsional resonance mode for ultraresoluble on-the-spot bio/chemical detection

Dazhong Jin, Xinxin Li, Hanhan Bao, Zhixiang Zhang, Yuelin Wang, Haitao Yu, and Guomin Zuo

Appl. Phys. Lett. 90, 041901 (2007); http://dx.doi.org/10.1063/1.2433753 (3 pages) | Cited 11 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Torsion-mode resonance is built in an integrated cantilever sensor for ultraresoluble detection of specifically bio/chemical mass adsorption. The superior mass resolution of the torsion-mode cantilever to a conventional bending-mode one is verified by energy-dissipation analysis and Q-factor simulation. With integrated transverse piezoresistance for frequency-shift signal readout and Lorentz force for resonance excitation, the torsion-mode sensor is optimally designed for high sensitivity. The microfabricated torsion-mode sensor is measured with a high close-loop Q factor in air. By Allan-variance analysis for the measured frequency stability, 23 fg resolution is obtained for the torsion-mode sensor, which is much improved compared to the 313 fg for the conventional flexure-mode sensor. The torsional sensor is used to recognize biotin-avidin specific combination, resulting in 443 Hz frequency shift for 50 μM streptavidin solution.
Show PACS
87.80.-y Biophysical techniques (research methods)
87.14.E- Proteins
87.15.N- Properties of solutions of macromolecules
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
82.80.-d Chemical analysis and related physical methods of analysis
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Anharmonic decay of subterahertz coherent acoustic phonons in GaN

Tzu-Ming Liu, Shih-Ze Sun, Chieh-Feng Chang, Chang-Chi Pan, Guan-Ting Chen, Jen-Inn Chyi, Vitalyi Gusev, and Chi-Kuang Sun

Appl. Phys. Lett. 90, 041902 (2007); http://dx.doi.org/10.1063/1.2433755 (3 pages) | Cited 5 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter examines the anharmonic decay in GaN of subthermal (ℏω⪡kBT) coherent longitudinal acoustic (LA) phonons with a frequency in the subterahertz range. In a collisionless regime (ωτ>1), the anharmonic decay rate of subterahertz coherent LA phonons in GaN shows square dependence on the phonon frequency and cubic dependence on the crystal temperature. As confirmed by the authors experiments, this behavior agrees with a model based on Herring scattering, indicating its importance for the estimation of acoustic attenuation in the subterahertz range.
Show PACS
63.20.Ry Anharmonic lattice modes
63.20.D- Phonon states and bands, normal modes, and phonon dispersion

Magnetic resonances in metallic double split rings: Lower frequency limit and bianisotropy

Lei Zhou and S. T. Chui

Appl. Phys. Lett. 90, 041903 (2007); http://dx.doi.org/10.1063/1.2431776 (3 pages) | Cited 7 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors employ a rigorous theory to study the electromagnetic resonances in double split rings of circular cross sections. The inter-ring interactions split each single-ring mode to two modes with different symmetries, and the bianisotropy of each mode is suppressed as two rings approach. They obtain analytical expressions to estimate the frequency of the fundamental (magnetic) mode, which facilitate the design of structures with the lowest possible resonance frequencies. Numerical calculations based on the present theory are supported by finite-difference-time-domain simulations on realistic structures and experimental data published previously.
Show PACS
75.30.Gw Magnetic anisotropy

Fluorescent polymer-porous silicon microcavity devices for explosive detection

I. A. Levitsky, W. B. Euler, N. Tokranova, and A. Rose

Appl. Phys. Lett. 90, 041904 (2007); http://dx.doi.org/10.1063/1.2432247 (3 pages) | Cited 17 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Conjugated polymers entrapped in porous silicon microcavity have been studied as optical sensors for low volatility explosives such as trinitrotoluene. The fluorescence spectra of entrapped polymers were modulated by the microcavity via a spectral “hole” that matches the resonance peak of the microcavity reflectance. Exposure of the porous silicon microcavity containing entrapped polymer to explosives vapor results in a red shift of the resonance peak and the spectral hole, accompanied by the quenching of the fluorescence. This multiplexed response provides multiple monitoring parameters, enabling the development of an optical sensor array for the detection of target explosive vapor.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
42.70.Jk Polymers and organics

Nonlinear electrical conducting behavior of carbon nanotube networks in silicone elastomer

C. H. Liu and S. S. Fan

Appl. Phys. Lett. 90, 041905 (2007); http://dx.doi.org/10.1063/1.2432283 (3 pages) | Cited 14 times

Online Publication Date: 22 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this work the authors investigated the electrical conducting properties of multiwalled carbon nanotube (MWNT) networks in the flexible polydimethylsiloxane rubber as a function of applied voltages. The results indicated that the I-V curves showed nonlinear relationships, which can be fitted to quadratic functions. The electrical resistance of the samples varies with the voltages more sharply in lower range. The nonlinear mechanism was related to the materials system including both the MWNTs and the matrix material. Furthermore, the I-V characteristic of the MWNT network/ZnO nanocomposite layer junction has shown a well rectified behavior at low voltages.
Show PACS
73.63.Rt Nanoscale contacts
73.40.Ei Rectification

Yellow-emitting Sr3SiO5:Ce3+,Li+ phosphor for white-light-emitting diodes and yellow-light-emitting diodes

Ho Seong Jang and Duk Young Jeon

Appl. Phys. Lett. 90, 041906 (2007); http://dx.doi.org/10.1063/1.2432947 (3 pages) | Cited 64 times

Online Publication Date: 23 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, a yellow-emitting Sr3SiO5:Ce3+,Li+ phosphor is reported. Through transitions of 5d→4f (2F7/2 and 2F5/2) in Ce3+, the phosphor showed a very broad and strong yellow emission under near ultraviolet (UV) or blue light excitation. The energy levels of Ce3+ in Sr3SiO5 were suggested from its absorption and excitation spectra. White light could be obtained by combining this phosphor with 460 or 405 nm light-emitting diodes (LEDs) [(x,y) = (0.3086,0.3167) or (0.3173, 0.3103)]. Additionally, a yellow LED was fabricated using a near-UV LED (380 nm chip) with Sr3SiO5:Ce3+,Li+.
Show PACS
78.40.Ha Other nonmetallic inorganics
78.55.Hx Other solid inorganic materials
85.60.Jb Light-emitting devices

Raman scattering spectra of coupled LO-phonon-plasmon modes in N-In codoped p-type ZnO thin films

J. F. Kong, H. Chen, H. B. Ye, W. Z. Shen, J. L. Zhao, and X. M. Li

Appl. Phys. Lett. 90, 041907 (2007); http://dx.doi.org/10.1063/1.2432955 (3 pages) | Cited 6 times

Online Publication Date: 23 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors report on a detailed Raman study of N–In codoped p-type ZnO thin films with the hole density ranging from 7.30×1016 to 2.30×1018 cm−3. In addition to the identification of E2(high) modes of ZnO and InN at ∼ 434 and ∼ 488 cm−1, respectively, clear coupled longitudinal-optical phonon-hole-plasmon modes have been observed. A theoretical analysis combining the deformation potential and electro-optic mechanisms can well reproduce the line shapes of the coupled modes, where the yielded hole densities and mobilities are found to be in good agreement with the data from Hall measurements.
Show PACS
78.30.Fs III-V and II-VI semiconductors
78.66.Hf II-VI semiconductors
78.20.Jq Electro-optical effects
73.50.Dn Low-field transport and mobility; piezoresistance
63.20.kk Phonon interactions with other quasiparticles

Room temperature epitaxial growth of m-plane GaN on lattice-matched ZnO substrates

Atsushi Kobayashi, Satoshi Kawano, Yuji Kawaguchi, Jitsuo Ohta, and Hiroshi Fujioka

Appl. Phys. Lett. 90, 041908 (2007); http://dx.doi.org/10.1063/1.2433758 (3 pages) | Cited 37 times

Online Publication Date: 23 January 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors have grown high-quality m-plane GaN (1math00) films on ZnO (1math00) substrates using pulsed laser deposition. They have found that annealing in a box made of ceramic ZnO improves the surface morphology of m-plane ZnO substrates and have succeeded in the layer-by-layer growth of m-plane GaN on the annealed ZnO substrates even at room temperature (RT). X-ray diffraction reveals that high crystalline quality m-plane GaN grows on the RT buffer layer at 700 °C. The 300-nm-thick m-plane GaN film grown on the ZnO substrate contains the residual strains because the lattice mismatches between them are quite small. The relationship of in-plane and out-of-plane strains is consistent with the calculation using the elastic constants.
Show PACS
81.05.Ea III-V semiconductors
81.15.Fg Pulsed laser ablation deposition
68.55.A- Nucleation and growth
61.72.Cc Kinetics of defect formation and annealing
68.35.B- Structure of clean surfaces (and surface reconstruction)
Page 1 of 6 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close