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

16 Jun 2003

Volume 82, Issue 24, pp. 4215-4390

Issue Cover Spotlight Figure

Appl. Phys. Lett. 82, 4322 (2003); http://dx.doi.org/10.1063/1.1582366 (3 pages)

Hongwei Qu, Wei Yao, T. Garcia, Jiandi Zhang, A. V. Sorokin, S. Ducharme, P. A. Dowben, and V. M. Fridkin
Enlarge Image | Read More
Page 1 of 3 Pages Next Page | Jump to Page
back to top
RSS Feeds

Bistable chiral-splay nematic liquid crystal device using horizontal switching

Seo Hern Lee, Kyoung-Ho Park, Tae-Hoon Yoon, and Jae Chang Kim

Appl. Phys. Lett. 82, 4215 (2003); http://dx.doi.org/10.1063/1.1581368 (3 pages) | Cited 35 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The bistability in a chiral-splay nematic liquid crystal cell, which is obtained by adding a chiral additive to a splay cell, is proposed. In this letter, we describe a horizontal way of switching between the two states of the bistable chiral-splay cell, one state being characterized by a nontwisted director field with splay, the second state showing a director-field with 180° twist. The optimization of the various parameters of the device is described. © 2003 American Institute of Physics.
Show PACS
42.79.Kr Display devices, liquid-crystal devices
61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures

Nonvolatile two-color holographic recording in nondoped near-stoichiometric lithium tantalate crystals with continuous-wave lasers

Youwen Liu, Kenji Kitamura, Shunji Takekawa, Masaru Nakamura, Yasunori Furukawa, and Hideki Hatano

Appl. Phys. Lett. 82, 4218 (2003); http://dx.doi.org/10.1063/1.1583136 (3 pages) | Cited 10 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nonvolatile holograms have been recorded in nondoped near-stoichiometric LiTaO3 crystals by use of a near infrared (IR) laser for writing and a ultraviolet beam as a gating source. This material exhibits good overall two-color holographic recording characteristics including a high sensitivity of 0.086 cm/J with a gating intensity of 1 W/cm2 at 350 nm, a large refractive index change of as much as 1×10−4, a high resistance to IR erasure, and a long hologram lifetime of five years. The sensitivity can be further enhanced using writing and gating beams of a shorter wavelength without sacrificing readout nonvolatility. © 2003 American Institute of Physics.
Show PACS
42.40.Ht Hologram recording and readout methods
42.40.Eq Holographic optical elements; holographic gratings
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Quantum cascade lasers grown by metalorganic vapor phase epitaxy

J. S. Roberts, R. P. Green, L. R. Wilson, E. A. Zibik, D. G. Revin, J. W. Cockburn, and R. J. Airey

Appl. Phys. Lett. 82, 4221 (2003); http://dx.doi.org/10.1063/1.1583858 (3 pages) | Cited 13 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the growth of GaAs-based quantum cascade lasers using atmospheric pressure metalorganic vapor phase epitaxy. The necessary control of interface abruptness and layer thickness uniformity throughout the structure has been achieved using a horizontal reactor in combination with individually purged vent/run valves. A low-temperature threshold current density of 10 kA/cm2 and maximum operating temperature of 140 K have been measured. These performance levels are comparable with early GaAs-based devices grown using molecular-beam epitaxy. The measured emission wavelength (λ ∼ 11.8 μm) is approximately 3-μm longer than the calculated transition wavelength, which we explain using a model incorporating compositional grading of the active region barriers. © 2003 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.35.Ct Interface structure and roughness
81.05.Ea III-V semiconductors

White organic light-emitting devices using a phosphorescent sensitizer

Gang Cheng, Feng Li, Yu Duan, Jing Feng, Shiyong Liu, Song Qiu, Dong Lin, Yuguang Ma, and S. T. Lee

Appl. Phys. Lett. 82, 4224 (2003); http://dx.doi.org/10.1063/1.1584075 (3 pages) | Cited 72 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The efficiency of white organic light-emitting devices has been improved dramatically by the introduction of a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3] as a sensitizer. Ir(ppy)3 and 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) are codoped into 4,4′-N,N′-dicarbazole-biphenyl (CBP) host. The chromaticity of white emission can be tuned by adjusting the thickness of the codoped CBP layer or the concentration of Ir(ppy)3. The luminance efficiency of these devices is affected at the same time due to the severe difference in efficiency between the two primary emission peaks. © 2003 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices

Experimental synthesis of fiber Bragg gratings using optical low coherence reflectometry

Xavier Chapeleau, Dominique Leduc, Cyril Lupi, Roger Le Ny, Marc Douay, Pierre Niay, and Christian Boisrobert

Appl. Phys. Lett. 82, 4227 (2003); http://dx.doi.org/10.1063/1.1584090 (3 pages) | Cited 6 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We apply a combination of optical low coherence reflectometry and a layer-peeling method to the synthesis of a fiber grating. The index modulation amplitude we obtain is compared with a Krug measurement result and the dc refractive index is derived from the phase measurement. © 2003 American Institute of Physics.
Show PACS
42.79.Dj Gratings
42.81.Bm Fabrication, cladding, and splicing
42.81.Wg Other fiber-optical devices

Second-harmonic generation in two-dimensional periodically poled lithium niobate using second-order quasiphase matching

Peigen Ni, Boqin Ma, Xuehua Wang, Bingying Cheng, and Daozhong Zhang

Appl. Phys. Lett. 82, 4230 (2003); http://dx.doi.org/10.1063/1.1579856 (3 pages) | Cited 31 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Two-dimensional nonlinear photonic crystals of lithium niobate with square lattices were fabricated. In these crystals, efficient quasiphase-matched second-harmonic generation was demonstrated by using second-order quasiphase matching. As a mode-locked Nd:yttritium–aluminum–garnet laser at 1064 nm with 35 ps pulse was used, we obtained an average power of 0.86 mW at 532 nm with 2.73 mW input, which corresponds to 42% internal conversion efficiency. The variations of second-harmonic output with crystal temperature and incident angle were measured. In addition, the relation between the second-harmonic output and reversed duty cycle was studied. All the experimental results are well consistent with simulations. © 2003 American Institute of Physics.
Show PACS
42.70.Qs Photonic bandgap materials
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Submicron periodically poled flux-grown KTiOPO4

C. Canalias, V. Pasiskevicius, R. Clemens, and F. Laurell

Appl. Phys. Lett. 82, 4233 (2003); http://dx.doi.org/10.1063/1.1583144 (3 pages) | Cited 20 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A submicron domain grating has been created in a bulk ferroelectric. Electron-beam lithography and electric-field poling were used to fabricate the 800 nm period grating in a 0.5-mm-thick flux-grown KTiOPO4 sample. The domain structure was characterized with an atomic force microscope and was used to demonstrate electrically amplitude adjustable Bragg reflections. © 2003 American Institute of Physics.
Show PACS
77.80.Dj Domain structure; hysteresis
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.10.Dn Growth from solutions
77.22.Ej Polarization and depolarization
68.37.Ps Atomic force microscopy (AFM)

Gain switching of an external cavity grating-coupled surface emitting laser with wide tunability

Y. Hu, A. Gubenko, G. Venus, I. Gadjiev, N. Il’inskaja, S. Nesterov, E. Portnoi, M. Dubov, and I. Khrushchev

Appl. Phys. Lett. 82, 4236 (2003); http://dx.doi.org/10.1063/1.1584521 (2 pages) | Cited 3 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Gain-switched, single frequency operation of an external cavity grating-coupled surface emitting laser with a wavelength tuning range of 100 nm is presented. A short pulse duration of 41 ps and a high peak power of 0.88 W have been obtained. © 2003 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
back to top
RSS Feeds

Effect of thermal annealing on the lifetime of polymer light-emitting diodes

Jinook Kim, Jaeyoon Lee, C. W. Han, N. Y. Lee, and In-Jae Chung

Appl. Phys. Lett. 82, 4238 (2003); http://dx.doi.org/10.1063/1.1582359 (3 pages) | Cited 31 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermal annealing of a polymer light-emitting diode (PLED) is shown to result in a remarkable improvement in the long-term stability of the device. The annealing for such a PLED has to be layer-specific in that the annealing should be carried out for the layer with the lowest glass transition temperature (Tg) to harvest the benefits of annealing. Annealing of this key layer, which is usually the emitting layer, can enhance the thermal stability of the device. The best half-life is obtained at an annealing temperature above the Tg of emitting polymer. It is shown that the annealing of the emitting polymer layer results in a more than an order of magnitude increase in the half-life, in spite of a decrease in the efficiency of the device as the annealing temperature increases. © 2003 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
81.05.Lg Polymers and plastics; rubber; synthetic and natural fibers; organometallic and organic materials
81.40.Tv Optical and dielectric properties related to treatment conditions
61.72.Cc Kinetics of defect formation and annealing
81.40.Gh Other heat and thermomechanical treatments
68.60.Dv Thermal stability; thermal effects
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition

Enhanced absorbance of a strained nanoscale Si-layered system

Z. T. Kuznicki and M. Ley

Appl. Phys. Lett. 82, 4241 (2003); http://dx.doi.org/10.1063/1.1582365 (3 pages) | Cited 8 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Si modifications implemented at the nanoscale lead to optoelectronic and photovoltaic effects that can widen applications of conventional Si devices. The investigation exploits charge carrier and photon flux transformations at a so-called carrier collection limit. Comparison of the collection efficiencies of the same sample with and without a buried nanosystem allows a better understanding of the optical (absorbance) and electronic (carrier collection) behaviors. Experimental evidence for enhanced absorbance of a strained nanoscale Si-layered system has been found. © 2003 American Institute of Physics.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
72.40.+w Photoconduction and photovoltaic effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Formation of ring patterns surrounded by ripples by single-shot laser irradiation with ultrashort pulse width at the solid/liquid interface

Kenji Katayama, Hideaki Yonekubo, and Tsuguo Sawada

Appl. Phys. Lett. 82, 4244 (2003); http://dx.doi.org/10.1063/1.1582372 (3 pages) | Cited 12 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A single pulse (pulse width: 200 fs) was irradiated onto a water/silicon interface. The processed surface had many ring patterns surrounded by sinusoidal patterns within the irradiated spot. The diameter of their rings ranged from 500 nm to 10 μm. It was proposed that the oscillation of a bubble at the interface emitted an acoustic wave around itself and that the melted silicon surface, deformed due to acoustic pressure, solidified instantaneously in the course of the propagation of the acoustic wave on the silicon surface. © 2003 American Institute of Physics.
Show PACS
79.20.Ds Laser-beam impact phenomena
68.35.Iv Acoustical properties
68.35.Rh Phase transitions and critical phenomena
68.37.Ps Atomic force microscopy (AFM)

Sn-enhanced epitaxial thickness during low-temperature Ge(001) molecular-beam epitaxy

K. A. Bratland, Y. L. Foo, P. Desjardins, and J. E. Greene

Appl. Phys. Lett. 82, 4247 (2003); http://dx.doi.org/10.1063/1.1578712 (3 pages) | Cited 5 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF


See Also: Publisher's Note

Show Abstract
The incorporation of dilute Sn concentrations CSn during Ge(001) low-temperature molecular-beam epitaxy significantly increases the critical thickness h1(Ts) for the onset of epitaxial breakdown. With CSn = 6×1019 cm−3, h1 increases by an order of magnitude at Ts = 95 °C, while gains in h1(Ts) by factors ranging from 3.2 at 95 °C to 2.0 at 135 °C are obtained with CSn = 1×1018 cm−3 (20 parts per million!). Nevertheless, the ratio of the surface width at breakdown to the in-plane correlation length remains constant, independent of Ts and CSn, showing that epitaxial breakdown for both Ge(001) and Sn-doped Ge(001) is directly related to surface roughening. We attribute the dramatic Sn-induced increases in h1(Ts) to enhancements in both the Ge surface diffusivity and the probability of interlayer mass transport. This, in turn, results in more efficient filling of interisland trenches, and thus delays epitaxial breakdown during low-temperature growth. © 2003 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
68.55.A- Nucleation and growth
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.05.Cy Elemental semiconductors
68.47.Fg Semiconductor surfaces
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.35.Rh Phase transitions and critical phenomena
68.35.Fx Diffusion; interface formation

Lattice expansion in nanocrystalline niobium thin films

R. Banerjee, E. A. Sperling, G. B. Thompson, H. L. Fraser, S. Bose, and P. Ayyub

Appl. Phys. Lett. 82, 4250 (2003); http://dx.doi.org/10.1063/1.1582361 (3 pages) | Cited 42 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-purity nanocrystalline niobium (Nb) thin films have been deposited using high-pressure magnetron sputter deposition. Increasing the pressure of the sputtering gas during deposition has systematically led to reduced crystallite sizes in these films. Based on x-ray and electron diffraction results, it is observed that the nanocrystalline Nb films exhibit a significantly large lattice expansion with reduction in crystallite size. There is however, no change in the bcc crystal structure on reduction in crystallite size to below 5 nm. The lattice expansion in nanocrystalline Nb has been simulated by employing a recently proposed model based on linear elasticity and by appropriately modifying it to incorporate a crystallite-size-dependent width of the grain boundary. © 2003 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
61.72.Mm Grain and twin boundaries
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations

In situ x-ray diffraction study on AgI nanowire arrays

Yinhai Wang, Changhui Ye, Guozhong Wang, Lide Zhang, Yanmei Liu, and Zhongyan Zhao

Appl. Phys. Lett. 82, 4253 (2003); http://dx.doi.org/10.1063/1.1583856 (3 pages) | Cited 12 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The AgI nanowire arrays were prepared in the ordered porous alumina membrane by an electrochemical method. Transmission electron microscopy observation shows that the AgI nanowires are located in the channels of the alumina membrane. In situ x-ray diffractions show that the nanowire arrays possess hexagonal close-packed structure (β-AgI) at 293 K, orienting along the (002) plane, whereas at 473 K, the nanowire arrays possess a body-centered cubic structure (α-AgI), orienting along the (110) plane. The AgI nanowire arrays exhibit a negative thermal expansion property from 293 to 433 K, and a higher transition temperature from the β to α phase. We ascribe the negative thermal expansion behavior to the phase transition from the β to α phase, and the elevated transition temperature to the radial restriction by the channels of alumina membrane. © 2003 American Institute of Physics.
Show PACS
61.46.-w Structure of nanoscale materials
68.65.La Quantum wires (patterned in quantum wells)
81.07.Bc Nanocrystalline materials
81.07.Vb Quantum wires
65.80.-g Thermal properties of small particles, nanocrystals, nanotubes, and other related systems
61.05.cp X-ray diffraction
61.50.Ks Crystallographic aspects of phase transformations; pressure effects
64.70.K- Solid-solid transitions
61.66.Fn Inorganic compounds

SiGe-free strained Si on insulator by wafer bonding and layer transfer

T. A. Langdo, M. T. Currie, A. Lochtefeld, R. Hammond, J. A. Carlin, M. Erdtmann, G. Braithwaite, V. K. Yang, C. J. Vineis, H. Badawi, and M. T. Bulsara

Appl. Phys. Lett. 82, 4256 (2003); http://dx.doi.org/10.1063/1.1581371 (3 pages) | Cited 31 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
SiGe-free strained Si on insulator substrates were fabricated by wafer bonding and hydrogen-induced layer transfer of strained Si grown on bulk relaxed Si0.68Ge0.32 graded layers. Raman spectroscopy shows that the 49-nm thick strained Si on insulator structure maintains a 1.15% tensile strain even after SiGe layer removal. The strain in the structure is thermally stable during 1000 °C anneals for at least 3 min, while more extreme thermal treatments at 1100 °C cause slight film relaxation. The fabrication of epitaxially defined, thin strained Si layers directly on a buried insulator forms an ideal platform for future generations of Si-based microelectronics. © 2003 American Institute of Physics.
Show PACS
68.60.Bs Mechanical and acoustical properties
68.60.Dv Thermal stability; thermal effects
61.72.Cc Kinetics of defect formation and annealing
78.30.Hv Other nonmetallic inorganics
78.66.Db Elemental semiconductors and insulators

Selective modification of band gap in GaInNAs/GaAs structures by quantum-well intermixing

R. Macaluso, H. D. Sun, M. D. Dawson, F. Robert, A. C. Bryce, J. H. Marsh, and H. Riechert

Appl. Phys. Lett. 82, 4259 (2003); http://dx.doi.org/10.1063/1.1583865 (3 pages) | Cited 6 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report an investigation of selective quantum-well intermixing (QWI) in 1.3-μm GaInNAs/GaAs multi quantum wells by silica-cap-induced disordering processes. After thermal annealing under specific conditions, controlled shifts of band gap at room temperature of over 200 nm have been observed in sputtered SiO2-capped samples, while uncapped and SiO2-capped samples by plasma-enhanced chemical vapor deposition demonstrated negligible shift. This selective modification of the band gap in GaInNAs quantum wells has been confirmed by detailed photoluminescence and photoluminescence excitation spectroscopy, and by secondary ion mass spectrometry. The controlled tuning of the band gap of GaInNAs/GaAs by QWI is important for a wide range of photonic integrated circuits and advanced device applications. © 2003 American Institute of Physics.
Show PACS
78.67.De Quantum wells
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
68.65.Fg Quantum wells
78.55.Cr III-V semiconductors
68.35.Fx Diffusion; interface formation
61.72.Cc Kinetics of defect formation and annealing

Void-mediated formation of Sn quantum dots in a Si matrix

Y. Lei, P. Möck, T. Topuria, N. D. Browning, R. Ragan, K. S. Min, and H. A. Atwater

Appl. Phys. Lett. 82, 4262 (2003); http://dx.doi.org/10.1063/1.1584073 (3 pages) | Cited 9 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Atomic scale analysis of Sn quantum dots (QDs) formed during the molecular beam-epitaxy (MBE) growth of SnxSi1−x (0.05 ⩽ x ⩽ 0.1) multilayers in a Si matrix revealed a void-mediated formation mechanism. Voids below the Si surface are induced by the lattice mismatch strain between SnxSi1−x layers and Si, taking on their equilibrium tetrakaidecahedron shape. The diffusion of Sn atoms into these voids leads to an initial rapid coarsening of quantum dots during annealing. Since this formation process is not restricted to Sn, a method to grow QDs may be developed by controlling the formation of voids and the diffusion of materials into these voids during MBE growth. © 2003 American Institute of Physics.
Show PACS
81.07.Ta Quantum dots
68.65.Hb Quantum dots (patterned in quantum wells)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.72.Qq Microscopic defects (voids, inclusions, etc.)
68.49.Jk Electron scattering from surfaces
79.20.Uv Electron energy loss spectroscopy
61.72.Cc Kinetics of defect formation and annealing
68.37.Vj Field emission and field-ion microscopy
68.37.Lp Transmission electron microscopy (TEM)

Copper thin film of alternating textures

Hanchen Huang, H. L. Wei, C. H. Woo, and X. X. Zhang

Appl. Phys. Lett. 82, 4265 (2003); http://dx.doi.org/10.1063/1.1583866 (3 pages) | Cited 7 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is common for thin films to have a predominant texture, but not alternating textures. In this letter, we report a copper film of alternating textures through self-organization. Using dc magnetron sputtering technique, we deposit copper films on a SiO2/Si(111) substrate. A thin layer of copper of 〈111〉 texture is first developed, and another thin layer of 〈110〉 ensued. As deposition continues, a third layer of copper of 〈111〉 texture is formed on the top, leading to a sandwich copper thin film of alternating 〈111〉 and 〈110〉 textures. The film morphology is characterized with scanning electron microscopy and atomic force microscopy and the texture with x-ray diffraction. Based on anisotropic elastic analyses and molecular dynamics simulations, we propose a model of texture evolution during the formation of multilayers, attributing the texture evolution to the competition of surface and strain energies. © 2003 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Ps Atomic force microscopy (AFM)

Surface band-bending effects on the optical properties of indium gallium nitride multiple quantum wells

L.-H. Peng, C.-W. Shih, C.-M. Lai, C.-C. Chuo, and J.-I. Chyi

Appl. Phys. Lett. 82, 4268 (2003); http://dx.doi.org/10.1063/1.1583869 (3 pages) | Cited 6 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the use of selective wavelength excitation to examine the surface band-bending effects on the optical properties of 3.0-nm-thick indium gallium nitride (InGaN) multiple quantum wells (MQWs). Under a 355-nm excitation, the In0.18Ga0.82N well emission exhibits a linear dependence on the injected carrier density (Ninj) with a coefficient of (i) 8.5×10−18 meV cm3 for the spectral blueshift and (ii) 3×10−14 V cm2 for the change of internal field at a density up to Ninj ∼ 1019 cm−3 at 77 K. When excited by a shorter wavelength at 248 nm, the emission from the thin GaN cap layer quenches, but that from the InGaN wells prevails. These observations are attributed to the transportation of photogenerated carriers from the bent GaN surface and redistribution in the InGaN wells. By solving the rate and Poisson equations with a Fermi-level pinning in the band-structure analysis, the emission from the InGaN/GaN MQWs is shown dominant by the recombination between the high-lying subbands and the screening of internal field effects. © 2003 American Institute of Physics.
Show PACS
78.67.De Quantum wells
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
78.55.Cr III-V semiconductors
73.21.Cd Superlattices
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
73.20.At Surface states, band structure, electron density of states
73.21.Fg Quantum wells
81.07.St Quantum wells

Bioceramic hydroxyapatite at high pressures

Nenad Velisavljevic and Yogesh K. Vohra

Appl. Phys. Lett. 82, 4271 (2003); http://dx.doi.org/10.1063/1.1584076 (3 pages) | Cited 6 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A bioceramic hydroxyapatite, Ca10(PO4)6(OH)2 polycrystalline sample was studied under high pressures in a diamond anvil cell to investigate its structural, electrical, and mechanical properties under compression. Anisotropic compression effects were observed in x-ray diffraction studies below 8 GPa. Nanoindentation hardness measurements on pressure-treated hydroxyapatite samples show hardness value of 4.0±0.5 GPa which is comparable to the plasma-sprayed samples. Electrical studies show that the bioceramic sample retained its insulating properties to 65 GPa. The present studies demonstrate that a fully dense and translucent hydroxyapatite sample is attained above 10 GPa at 300 K. © 2003 American Institute of Physics.
Show PACS
62.50.-p High-pressure effects in solids and liquids
87.85.J- Biomaterials
61.66.Fn Inorganic compounds
62.20.Qp Friction, tribology, and hardness
72.80.Sk Insulators

Strain-induced ordering in InxGa1−xN alloys

L. K. Teles, L. G. Ferreira, J. R. Leite, L. M. R. Scolfaro, A. Kharchenko, O. Husberg, D. J. As, D. Schikora, and K. Lischka

Appl. Phys. Lett. 82, 4274 (2003); http://dx.doi.org/10.1063/1.1583854 (3 pages) | Cited 8 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The energetics and thermodynamic properties of cubic (c-)InxGa1−xN alloys are investigated by combining first-principles total energy calculations, a concentration-dependent cluster-based model, and Monte Carlo simulations. The search for the ground-state energies leads to the conclusion that biaxial strain suppresses phase separation, and acts as a driving force for chemical ordering in c-InxGa1−xN alloys. Ordered superlattice structures, with composition x ≅ 0.5 and stable up to T = 1000 K, arises as the relevant thermodynamic property of the strained alloy. We suggest that the In-rich phases recently observed by us in c-GaN/InxGa1−xN/GaN double heterostructures are ordered domains formed in the alloy layers due to biaxial strain. © 2003 American Institute of Physics.
Show PACS
68.65.Cd Superlattices
71.15.Nc Total energy and cohesive energy calculations

Emissions from single localized states observed in ZnCdS ternary alloy mesa structures

H. Kumano, Y. Hitaka, and I. Suemune

Appl. Phys. Lett. 82, 4277 (2003); http://dx.doi.org/10.1063/1.1583859 (3 pages) | Cited 2 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Sharp and discrete emission lines from single localized states in ZnCdS ternary alloys were clearly observed from selectively grown mesa structures. This is a demonstration that compound semiconductor alloy systems, which usually show broad emission spectra due to alloy fluctuations, are able to exhibit emissions from discrete energy levels with quasi-zero-dimensional density of states in limited mesa areas where limited number of deeper localized states will contribute. Introduction of ZnCdS/MgS short-period superlattices is found to play a significant role for the exciton migration enhancement from shallower to deeper localized states, which makes the observation of the emission lines from the single localized states possible in the ZnCdS alloy layers. © 2003 American Institute of Physics.
Show PACS
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
73.21.Cd Superlattices
73.20.Hb Impurity and defect levels; energy states of adsorbed species
71.35.Lk Collective effects (Bose effects, phase space filling, and excitonic phase transitions)
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.55.Et II-VI semiconductors

Preparation of clean reconstructed InAs(001) surfaces using HCl/isopropanol wet treatments

O. E. Tereshchenko, D. Paget, P. Chiaradia, J. E. Bonnet, F. Wiame, and A. Taleb-Ibrahimi

Appl. Phys. Lett. 82, 4280 (2003); http://dx.doi.org/10.1063/1.1583851 (3 pages) | Cited 16 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A simple treatment method using HCl/isopropanol solutions is given for preparation of high-quality InAs(001) surfaces. The surface structure and chemistry were characterized using low-energy electron diffraction and photoemission spectroscopy as a function of UHV temperature. The treatment removes the natural oxide and leaves on the surface a physisorbed overlayer containing arsenic and small amounts of InClx. Annealing at 330 °C induces desorption of this overlayer and reveals a clean arsenic-rich (2×4)/c(2×8) surface. The indium-rich (4×2)/c(8×2) reconstruction is obtained upon further annealing to 410 °C. © 2003 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
81.65.-b Surface treatments
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.43.Mn Adsorption kinetics
61.72.Cc Kinetics of defect formation and annealing
79.60.Bm Clean metal, semiconductor, and insulator surfaces

Formation of free-standing micropyramidal colloidal crystals grown on silicon substrate

Shigeki Matsuo, Takatomi Fujine, Koichi Fukuda, Saulius Juodkazis, and Hiroaki Misawa

Appl. Phys. Lett. 82, 4283 (2003); http://dx.doi.org/10.1063/1.1583138 (3 pages) | Cited 11 times

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The self-organization of microspheres is one of the simplest methods for fabricating three-dimensional (3D) photonic crystals (PhCs), but the 3D structure of such organized microspheres, colloidal crystals, is difficult to control. In this letter, we report a method for forming face-centered-cubic colloidal crystals into a pyramidal shape on an anisotropically etched silicon (100) and (110) substrate. The colloidal crystals were lifted from the substrate for observation after thermal bonding. Free-standing colloidal crystals with a well-defined “micropyramid” shape were obtained. This type of PhC formation is suitable for batch production as well as for handling a single pyramid. © 2003 American Institute of Physics.
Show PACS
42.70.Qs Photonic bandgap materials
82.70.Dd Colloids

Quantum design and synthesis of a boron–oxygen–yttrium phase

Denis Music, Valeriu Chirita, Ulrich Kreissig, Zsolt Czigány, Jochen M. Schneider, and Ulf Helmersson

Appl. Phys. Lett. 82, 4286 (2003); http://dx.doi.org/10.1063/1.1584522 (3 pages) | Cited 1 time

Online Publication Date: 10 June 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ab initio calculations are used to design a crystalline boron–oxygen–yttrium (BOY) phase. The essential constituent is yttrium substituting for oxygen in the boron suboxide structure (BO0.17) with Y/B and O/B ratios of 0.07. The calculations predict that the BOY phase is 0.36 eV/atom more stable than crystalline BO0.17 and experiments confirm the formation of crystalline thin films. The BOY phase was synthesized with reactive rf magnetron sputtering and identified with x-ray and selected area electron diffraction. Films with Y/B ratios ranging from 0.10 to 0.32, as determined via elastic recoil detection analysis, were grown over a wide range of temperatures (300–600 °C) and found to withstand 1000 °C. © 2003 American Institute of Physics.
Show PACS
81.15.Cd Deposition by sputtering
68.55.-a Thin film structure and morphology
62.20.D- Elasticity
68.60.Bs Mechanical and acoustical properties
81.40.Jj Elasticity and anelasticity, stress-strain relations
Page 1 of 3 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close