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

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

27 Jun 2005

Volume 86, Issue 26, Articles (26xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 86, 263107 (2005); http://dx.doi.org/10.1063/1.1952585 (3 pages)

B. Yang, M. S. Marcus, D. G. Keppel, P. P. Zhang, Z. W. Li, B. J. Larson, D. E. Savage, J. M. Simmons, O. M. Castellini, M. A. Eriksson, and M. G. Lagally
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Magnetoelasticity of chain-structured ferromagnetic composites

H. M. Yin and L. Z. Sun

Appl. Phys. Lett. 86, 261901 (2005); http://dx.doi.org/10.1063/1.1954895 (3 pages) | Cited 4 times

Online Publication Date: 20 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A micromechanics-based model with particle interaction has been developed to study the effective elastic properties of chain-structured ferromagnetic composites subject to both magnetic and mechanical loading. Magnetomechanical coupled behavior is numerically simulated and magnetic-field-dependent elasticity is calculated using the Green’s function technique in a manner such that microstructure evolution is considered. Due to the magnetic angular momentum, the effective shear modulus of the composites increases much faster than the effective Young’s modulus as the magnetic field increases. Two mechanisms resulting in magnetic-field-dependent elasticity are demonstrated.
Show PACS
75.80.+q Magnetomechanical effects, magnetostriction
75.40.Mg Numerical simulation studies
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity

Unintentionally doped n-type Al0.67Ga0.33N epilayers

M. L. Nakarmi, N. Nepal, J. Y. Lin, and H. X. Jiang

Appl. Phys. Lett. 86, 261902 (2005); http://dx.doi.org/10.1063/1.1954875 (3 pages) | Cited 14 times

Online Publication Date: 20 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Unintentionally doped Al0.67Ga0.33N epilayers were grown on AlN∕sapphire templates by metalorganic chemical vapor deposition. Optimized undoped Al0.67Ga0.33N epilayers exhibited an n-type conductivity as confirmed by Hall-effect measurement with a room-temperature resistivity of about 85 Ω cm. Variable temperature Hall-effect measurement revealed the existence of a shallow donor level with activation energy of about 90 meV. The photoluminescence (PL) spectra exhibited an emission peak at 4.13 eV (4.06 eV) related to an impurity transition at 10 K (300 K). Temperature dependent PL measurement also confirmed the existence of a shallow donor with comparable activation energy as that obtained by Hall-effect measurement. Isolated oxygen impurities are believed to be a strong candidate of the donor that remains as a shallow state in AlxGa1−xN up to x ∼ 0.7. Compensating defects and the nature of the O donor in Al0.67Ga0.33N epilayers are also discussed.
Show PACS
81.05.Ea III-V semiconductors
68.55.A- Nucleation and growth
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
71.55.Eq III-V semiconductors
61.72.uj III-V and II-VI semiconductors

Fine-structure N-polarity InN/InGaN multiple quantum wells grown on GaN underlayer by molecular-beam epitaxy

Song-Bek Che, Wataru Terashima, Yoshihiro Ishitani, Akihiko Yoshikawa, Takeyoshi Matsuda, Hirotatsu Ishii, and Seikoh Yoshida

Appl. Phys. Lett. 86, 261903 (2005); http://dx.doi.org/10.1063/1.1954877 (3 pages) | Cited 15 times

Online Publication Date: 20 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have succeeded in the growth of very-fine-structure InN/InGaN (3–16 nm/9 nm) multi-quantum wells (MQWs) on GaN underlayer and characterized them by transmission electron microscopy (TEM), high-resolution x-ray diffraction (XRD), and photoluminescence (PL) at 13 K. Clear satellite diffraction peaks and sharp heterointerfaces were observed by XRD and TEM, respectively. A single PL-emission peak at 1.75 μm was observed in the ten-periods InN(16.1 nm)/In0.67Ga0.33N(9.2 nm) MQWs. The use of the InGaN as a barrier layer instead of GaN resulted in remarkable reduction of lattice mismatch between the well and barrier, which was essential for the fabrication of MQWs with superior interface quality. This successful growth of fine-structure InN/InGaN MQWs would be an important step for the application of InN in optical communication devices.
Show PACS
81.07.St Quantum wells
81.05.Ea III-V semiconductors
68.65.Fg Quantum wells
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.67.De Quantum wells
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
68.37.Lp Transmission electron microscopy (TEM)

Band alignment in GaInNP/GaAs heterostructures grown by gas-source molecular-beam epitaxy

M. Izadifard, T. Mtchedlidze, I. Vorona, W. M. Chen, I. A. Buyanova, Y. G. Hong, and C. W. Tu

Appl. Phys. Lett. 86, 261904 (2005); http://dx.doi.org/10.1063/1.1952586 (3 pages) | Cited 6 times

Online Publication Date: 20 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Low-temperature photoluminescence (PL), PL excitation, and optically detected cyclotron resonance measurements are employed to determine band alignment in GaInNP/GaAs heterostructures grown by gas-source molecular-beam epitaxy. The type II band alignment at the Ga0.46In0.54NxP1−x/GaAs interface is concluded for the alloys with x ≥ 0.5% based on (i) highly efficient PL upconversion observed in the N containing samples and (ii) appearance of a near-infrared PL emission attributed to the spatially indirect type II transitions. Compositional dependence of the conduction band offset at the Ga1−yInyNxP1−x/GaAs interface is also estimated.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.05.Ea III-V semiconductors
68.55.A- Nucleation and growth
71.20.Nr Semiconductor compounds
76.40.+b Diamagnetic and cyclotron resonances

Spectrally enhanced light emission from aperiodic photonic structures

L. Dal Negro, J. H. Yi, V. Nguyen, Y. Yi, J. Michel, and L. C. Kimerling

Appl. Phys. Lett. 86, 261905 (2005); http://dx.doi.org/10.1063/1.1954897 (3 pages) | Cited 36 times

Online Publication Date: 21 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Light-emitting silicon-rich, SiNx/SiO2 Thue-Morse (T-M) multilayer structures have been fabricated in order to investigate the generation and transmission of light in strongly aperiodic deterministic dielectrics. Photoluminescence and optical transmission data experimentally demonstrate the presence of emission enhancement effects occurring at wavelengths corresponding to multiple T-M resonance states. Emission enhancement effects by a factor of almost 6 with respect to homogeneous SiNx dielectrics have been experimentally measured, in good agreement with transfer matrix simulations. The unprecedented degree of structural flexibility of T-M systems can provide alternative routes towards the fabrication of optically active multiwavelength photonic devices.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
68.65.Ac Multilayers
78.55.Hx Other solid inorganic materials

Radiation-induced electron traps in Al0.14Ga0.86N by 1 MeV electron radiation

Michael R. Hogsed, Yung Kee Yeo, Mo Ahoujja, Mee-Yi Ryu, James C. Petrosky, and Robert L. Hengehold

Appl. Phys. Lett. 86, 261906 (2005); http://dx.doi.org/10.1063/1.1977185 (3 pages) | Cited 4 times

Online Publication Date: 21 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electrical properties of defects induced in n-type molecular-beam-epitaxial-grown Al0.14Ga0.86N are studied using deep-level transient spectroscopy (DLTS) to explore the radiation tolerance of AlGaN-based electronic and optoelectronic devices. It has been found that four electron traps labeled R1 (0.15±0.02 eV), R2 (0.21±0.02 eV), R3 (0.26±0.02 eV), and R4 (0.33±0.03 eV) are created in the electron irradiated Al0.14Ga0.86N. The electron trap R4 is the most prominent radiation-induced defect in the DLTS spectrum and appears to be unique to AlGaN. Although the other radiation-induced traps anneal significantly at or below 400 K, this R4 trap is thermally stable up to 450 K, and could significantly affect the performance of AlGaN-based devices.
Show PACS
71.55.Eq III-V semiconductors
61.82.Fk Semiconductors
61.80.Fe Electron and positron radiation effects
73.61.Ey III-V semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
61.72.Cc Kinetics of defect formation and annealing

In situ observation of coalescence-related tensile stresses during metalorganic chemical vapor deposition of GaN on sapphire

Srinivasan Raghavan, Jeremy Acord, and Joan M. Redwing

Appl. Phys. Lett. 86, 261907 (2005); http://dx.doi.org/10.1063/1.1968436 (3 pages) | Cited 4 times

Online Publication Date: 22 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Surface roughness and stress evolution were monitored in situ during the growth of GaN on sapphire substrates using low-temperature AlN buffer layers of varying thickness. A reduction in buffer layer thickness decreases the concentration of GaN nucleation sites which in turn increases the time to nuclei coalescence, thus varying the temporal evolution of surface roughness. By monitoring the accompanying changes in stress evolution, it is shown that island coalescence consisting of initial contact followed by subsequent surface roughness reduction is a source of tensile stress during growth of GaN films on sapphire. Such delayed coalescence also leads to an improvement in the structural properties of the material.
Show PACS
81.05.Ea III-V semiconductors
68.60.Bs Mechanical and acoustical properties
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
68.47.Fg Semiconductor surfaces
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Crystallization of amorphous In2O3–10 wt % ZnO thin films annealed in air

Burag Yaglioglu, Hyo-Young Yeom, and David C. Paine

Appl. Phys. Lett. 86, 261908 (2005); http://dx.doi.org/10.1063/1.1977209 (3 pages) | Cited 27 times

Online Publication Date: 23 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the crystallization of amorphous indium zinc oxide (a-IZO) with stoichiometry of In2Zn0.38O3.38 (In2O3–10 wt % ZnO) thin films deposited by dc magnetron sputtering. Transmission electron microscopy and glancing incidence x-ray diffraction were used to show that, when annealed in air at 500 °C, the product of a-IZO thin film crystallization is a compositionally modulated crystal of high-pressure corundum In2O3 phase. The composition, microstructure, resistivity, carrier density, and mobility of this new IZO phase are reported and are compared to the bixbyite ITO (In2O3–9.8 wt % SnO2) deposited and annealed under identical conditions.
Show PACS
81.05.Gc Amorphous semiconductors
64.70.K- Solid-solid transitions
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
61.72.Cc Kinetics of defect formation and annealing
73.61.Le Other inorganic semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
68.37.Lp Transmission electron microscopy (TEM)

Electrochemical lithium doping of a pentacene molecule semiconductor

Baizeng Fang, Haoshen Zhou, and Itaru Honma

Appl. Phys. Lett. 86, 261909 (2005); http://dx.doi.org/10.1063/1.1954873 (3 pages) | Cited 10 times

Online Publication Date: 23 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Li-doped pentacene has been developed by using an electrochemical approach; that is, constant-potential electrolysis. Li-doped pentacene was characterized by Raman spectrometry and x-ray diffraction measurements. Lithium doping introduces a modification of the C–H vibrational modes located at the end of pentacene molecules. A low doping level has been observed for electrochemical synthesis of Li-doped pentacene, and lithium species are supposed to be intercalated between the two-dimensional pentacene layers. The lithium-doped pentacene exhibits a conductivity of ∼ 6×10−3 S cm−1.
Show PACS
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.05.Hd Other semiconductors
61.72.up Other materials
82.45.Aa Electrochemical synthesis
82.45.Hk Electrolysis
78.66.Qn Polymers; organic compounds
78.30.Jw Organic compounds, polymers
73.61.Ph Polymers; organic compounds
68.55.A- Nucleation and growth
61.72.S- Impurities in crystals

Efficiency of multiple atom doping in wide band gap semiconductors

Takehide Miyazaki and Satoshi Yamasaki

Appl. Phys. Lett. 86, 261910 (2005); http://dx.doi.org/10.1063/1.1977207 (3 pages) | Cited 10 times

Online Publication Date: 24 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a thermodynamic model calculation for the efficiency of an impurity-atom-complex formation suggested for doping of wide band gap semiconductors, where the complexes with various sizes coexist at local equilibrium as suggested by Van de Walle and Neugebauer [J. Appl. Phys. 95, 3851 (2004)] . When the size of a target complex becomes large, the effect of configurational entropy of smaller complexes shows up in the energetics and may even hamper stabilization of the target. Thus one should design a target complex with the size being as small as possible and the binding energy as large as possible, in order to make the concept of multiple atom doping a real technology.
Show PACS
61.72.up Other materials
65.40.G- Other thermodynamical quantities

Selective excitation of tryptophan fluorescence decay in proteins using a subnanosecond 295 nm light-emitting diode and time-correlated single-photon counting

Colin D. McGuinness, Kulwinder Sagoo, David McLoskey, and David J. S. Birch

Appl. Phys. Lett. 86, 261911 (2005); http://dx.doi.org/10.1063/1.1984088 (3 pages) | Cited 21 times

Online Publication Date: 24 June 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate an AlGaN light-emitting diode (LED) giving pulses of ∼ 600 ps full width half maximum, 0.35 μW average power, 0.6 mW peak power, and ∼ 12 nm bandwidth at 295 nm. This source is ideal for protein intrinsic tryptophan fluorescence decay research without the unwanted excitation of tyrosine and paves the way to lab-on-a-chip protein assays using fluorescence decay times. Fluorescence decay and anisotropy decay measurements of human serum albumin are reported and the usefulness of the 295 nm LED demonstrated in comparisons with a nanosecond flashlamp and LEDs with nominal wavelength emission of 280 nm.
Show PACS
33.50.Dq Fluorescence and phosphorescence spectra
36.20.Kd Electronic structure and spectra
87.14.E- Proteins
87.15.M- Spectra of biomolecules
87.64.-t Spectroscopic and microscopic techniques in biophysics and medical physics
87.80.-y Biophysical techniques (research methods)
85.60.Jb Light-emitting devices
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close