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

Flickr Twitter UniPHY Group iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Next Issue

2 Jan 2006

Volume 88, Issue 1, Articles (01xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 88, 011112 (2006); http://dx.doi.org/10.1063/1.2161387 (3 pages)

Yoshinori Tanaka, Takashi Asano, Ranko Hatsuta, and Susumu Noda
Enlarge Image | Read More
Page 1 of 4 Pages Next Page | Jump to Page
back to top
RSS Feeds

Coherent detection of pulsed narrowband terahertz radiation

Hua Cao and Ajay Nahata

Appl. Phys. Lett. 88, 011101 (2006); http://dx.doi.org/10.1063/1.2159104 (3 pages) | Cited 4 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the generation and coherent detection of narrowband terahertz radiation using a Q-switched laser pumped optical parametric oscillator as the optical source. Narrowband terahertz radiation is produced using conventional difference frequency mixing and coherently detected via a frequency domain technique that relies on coherent upconversion of the terahertz field combined with optical homodyning to suppress background noise. GaSe crystals are used for both generation and coherent detection processes. Although we provide a proof-of-principle demonstration at 2 THz, the infrared radiation may be tuned from the far-infrared through the midinfrared by simply tuning the idler wavelength of the optical parametric oscillator and the orientation of the two crystals.
Show PACS
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
85.60.Gz Photodetectors (including infrared and CCD detectors)
42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
42.65.Yj Optical parametric oscillators and amplifiers
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Strongly frequency dependent focusing efficiency of a concave lens based on two-dimensional photonic crystals

E. Foca, H. Föll, J. Carstensen, V. V. Sergentu, I. M. Tiginyanu, F. Daschner, and R. Knöchel

Appl. Phys. Lett. 88, 011102 (2006); http://dx.doi.org/10.1063/1.2159105 (3 pages) | Cited 6 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Results of an experimental study of a concave lens based on a two-dimensional microwave photonic crystal with neff<1 are shown. We demonstrate that the lens focuses electromagnetic radiation for transverse electric (TE) and transverse magnetic (TM) polarizations. Intensity gains as high as 5.4 for TE polarization and 6.3 for TM polarization were achieved for definite frequencies lying in the explored interval from 6 to 15 GHz, the smallest area of the focal spot being equal to 0.24λ2 and 1.02λ2 for TE and TM polarizations respectively. The proposed lens serves as a model system that can be scaled to THz and optical frequencies.
Show PACS
42.79.Bh Lenses, prisms and mirrors
42.70.Qs Photonic bandgap materials
85.60.-q Optoelectronic devices
42.15.Eq Optical system design

Electron-beam-induced domain poling in LiNbO3 for two-dimensional nonlinear frequency conversion

Yinnon Glickman, Emil Winebrand, Ady Arie, and Gil Rosenman

Appl. Phys. Lett. 88, 011103 (2006); http://dx.doi.org/10.1063/1.2159089 (3 pages) | Cited 15 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A bulk of LiNbO3 was periodically poled in two dimensions to achieve noncollinear second-harmonic generation. The sample was fabricated using an electron-beam indirect exposure. This method used a dielectric buffer layer deposited on LiNbO3 Z−-polar face to trap the incident electrons. These localized electrons formed a charge droplet which generated a strong electric field and triggered the domain inversion process in the LiNbO3. Tailored two-dimensional domain configurations enabled quasi-phase-matched frequency doubling of a Nd:YLF laser at 15 different input angles. The measured angular dependence was in agreement with calculations based on the nonlinear reciprocal lattice vectors of the poled structure.
Show PACS
61.80.Fe Electron and positron radiation effects
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Qs Photonic bandgap materials
77.80.Dj Domain structure; hysteresis
77.22.Ej Polarization and depolarization
81.20.-n Methods of materials synthesis and materials processing

Observation of micromechanically controlled tuning of photonic crystal line-defect waveguide

Satoshi Iwamoto, Satomi Ishida, Yasuhiko Arakawa, Masatoshi Tokushima, Akiko Gomyo, Hirohito Yamada, Akio Higo, Hiroshi Toshiyoshi, and Hiroyuki Fujita

Appl. Phys. Lett. 88, 011104 (2006); http://dx.doi.org/10.1063/1.2159570 (3 pages) | Cited 10 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We fabricated a photonic crystal (PC) line-defect waveguide integrated with a microelectromechanical actuator and demonstrated the optical switching operation. The device consisted of a PC line-defect waveguide fabricated in a silicon-on-insulator substrate and a polycrystalline-Si dielectric plate located above the PC waveguide. An applied voltage moved the dielectric plate towards the PC surface due to the electrostatic force. This motion increased out-of-plane scattering of the guided light through the evanescent interaction with the dielectric plate, and modulated the transmittance of the PC waveguide. With only a 5 μm interaction length, an extinction ratio of ∼ 10 dB was obtained at a wavelength of 1568 nm under an applied voltage of 60 V. The response time of the switching operation was approximately 1 ms.
Show PACS
42.82.Et Waveguides, couplers, and arrays
42.70.Qs Photonic bandgap materials
42.79.Gn Optical waveguides and couplers
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
42.65.Pc Optical bistability, multistability, and switching, including local field effects

Real-time phase-shift measurement during formation of a volume holographic grating in nanoparticle-dispersed photopolymers

Naoaki Suzuki and Yasuo Tomita

Appl. Phys. Lett. 88, 011105 (2006); http://dx.doi.org/10.1063/1.2159580 (3 pages) | Cited 8 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe the real-time measurement of the phase shift between the light interference pattern and a volume holographic grating recorded in dry photopolymers. The time evolution of the refractive index modulation including its magnitude and phase shift is measured for one-component and nanoparticle-dispersed photopolymers. It is confirmed that phase shifts in nanoparticle-dispersed photopolymers depend on the magnitude of the refractive index of nanoparticles relative to that of polymerized monomers.
Show PACS
42.40.Ht Hologram recording and readout methods
42.40.Lx Diffraction efficiency, resolution, and other hologram characteristics
42.40.Pa Volume holograms
42.70.Jk Polymers and organics
42.70.Ln Holographic recording materials; optical storage media

2×3 Thermo-optical switch utilizing total internal reflection

Hui Yu, Xiaoqing Jiang, Jianyi Yang, Yi Tang, and Minghua Wang

Appl. Phys. Lett. 88, 011106 (2006); http://dx.doi.org/10.1063/1.2161396 (3 pages) | Cited 3 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A photonic switch of 2×3 structure was designed and fabricated using the thermo-optical effect of polymer materials. By setting sectional electrode and exerting voltage to proper section, we can control the reflection region length and ray propagation trace. Input light can be switched freely among three output ports. The experiment results show that, for the “half-reflection” state, the extinction ratio is 16.6 dB for the half-reflection port; and for the “bar” state, the extinction ratio for the reflection port is 26.8 dB. The power consumption is on the scale of 100 mW and varies with different function mode.
Show PACS
42.65.Pc Optical bistability, multistability, and switching, including local field effects
42.15.Eq Optical system design

Spatially tunable laser emission in dye-doped photonic liquid crystals

Yuhua Huang, Ying Zhou, and Shin-Tson Wu

Appl. Phys. Lett. 88, 011107 (2006); http://dx.doi.org/10.1063/1.2161167 (3 pages) | Cited 36 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A spatially tunable laser emission of the dye-doped cholesteric liquid crystal (CLC) cell using a one-dimensional temperature gradient is demonstrated. The photoexcitation of dye-doped CLC device using a frequency-doubled pulsed Nd: yttrium–aluminium–garnet laser gives rise to laser emission in the yellow-red spectral range. The lasing wavelength is widely tunable from 577 to 670 nm by shifting the position of the dye-doped CLC cell with respect to the pumping beam. The lowest excitation energy and maximum lasing efficiency occur at λ ∼ 605 nm which corresponds to the peak fluorescence emission of the dye.
Show PACS
42.55.Tv Photonic crystal lasers and coherent effects
42.60.Fc Modulation, tuning, and mode locking
42.70.Qs Photonic bandgap materials
42.70.Hj Laser materials

Effects of temperature fluctuation on highly dispersive photonic crystal fibers

Yongqiang Jiang, Xiaonan Chen, Brie Howley, Maggie Y. Chen, and Ray T. Chen

Appl. Phys. Lett. 88, 011108 (2006); http://dx.doi.org/10.1063/1.2162684 (3 pages) | Cited 3 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Chromatic dispersion of highly dispersive photonic crystal fibers (PCFs) is theoretically simulated and experimentally measured as a function of temperature. We have theoretically confirmed that PCFs designed at highly dispersive region show stronger temperature dependence than conventional telecommunication fibers and dispersion compensation fibers due to phase matching wavelength shift and large dispersion slope. For a fabricated highly dispersive PCF, the variation of the dispersion is measured to be around +0.28%/°C from 21 to 80 °C, and around +0.21%/°C from 21 to 50 °C at an optical wavelength around 1550 nm.
Show PACS
42.81.Dp Propagation, scattering, and losses; solitons
42.70.Qs Photonic bandgap materials
42.65.-k Nonlinear optics

Elimination of mode grouping in InGaAsP/InP ridge waveguide laser using quantum-well intermixing

J. H. Teng, J. R. Dong, S. J. Chua, R. Yin, B. C. Foo, B. Z. Wang, and Y. J. Wang

Appl. Phys. Lett. 88, 011109 (2006); http://dx.doi.org/10.1063/1.2138362 (3 pages) | Cited 1 time

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, we report the observation of the longitudinal mode grouping effect in the InGaAsP/InP multiquantum-well ridge waveguide laser. Two mode groups were observed and showed different behaviors with the changing of the injection current. The higher order lateral modes and the current spreading in the ridge waveguide structure is proposed to be responsible for this mode grouping phenomena. A one-step quantum-well intermixing process using the SiO2 electrical isolation layer itself was introduced and proved to be effective in improving the lateral electrical and optical confinement in a ridge waveguide laser structure as well as eliminating the mode grouping.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Vertical coupling of long-range surface plasmon polaritons

Hyong Sik Won, Ki Cheol Kim, Seok Ho Song, Cha-Hwan Oh, Pill Soo Kim, Suntak Park, and Sang In Kim

Appl. Phys. Lett. 88, 011110 (2006); http://dx.doi.org/10.1063/1.2159558 (3 pages) | Cited 36 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We evaluated and demonstrated strong vertical-coupling characteristics of vertical directional couplers based on long-range surface plasmon polaritons (LRSPPs) at 1.55 μm wavelength. Fundamental even and odd modes supported by LRSPP metal-stripe waveguides compete more strongly on vertical coupling structures than on lateral coupling structures, possibly leading to less power consumption for switching and to compactness in device length and width. LRSPP-based vertically coupled routing of signals can also be a powerful means of developing three-dimensional photonic integrated circuits and optical printed circuit boards.
Show PACS
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
42.82.Et Waveguides, couplers, and arrays
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Site specific Eu3+ stimulated emission in GaN host

J. H. Park and A. J. Steckl

Appl. Phys. Lett. 88, 011111 (2006); http://dx.doi.org/10.1063/1.2161159 (3 pages) | Cited 15 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the observation of site-specific Eu3+ stimulated emission in GaN:Eu laser structures. Two main Eu sites have been identified from emission peaks associated with the math→math transition during above band gap optical pumping with a pulsed N2 laser (337 nm): (a) Eux emitting at ∼ 620 nm—present in short cavities ( ∼ 100 μm), exhibiting stimulated (side) emission threshold and a fast decay time constant (30–35 μs); (b) Euy emitting at ∼ 621 nm—present in long cavities ( ∼ 7 mm) and in surface emission, exhibiting no stimulated emission threshold and a slow decay time constant (150–250 μs).
Show PACS
42.55.Px Semiconductor lasers; laser diodes
78.45.+h Stimulated emission
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Investigation of point-defect cavity formed in two-dimensional photonic crystal slab with one-sided dielectric cladding

Yoshinori Tanaka, Takashi Asano, Ranko Hatsuta, and Susumu Noda

Appl. Phys. Lett. 88, 011112 (2006); http://dx.doi.org/10.1063/1.2161387 (3 pages) | Cited 19 times

Online Publication Date: 5 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Three-missing-hole point-defect cavities formed in a two-dimensional photonic crystal slab with a silicon-on-insulator structure are investigated. It is theoretically revealed that radiation loss to the SiO2-cladding side is four times higher than that to the air-cladding side due to the smaller refractive index contrast. In addition, in-plane radiation due to transverse electric-transverse magnetic (TE-TM) coupling occurs due to the vertical structural asymmetry. The amount of TE-TM coupling loss is comparable with that of radiation loss to the SiO2 cladding. Experimental results agreed well with theoretical predictions. This treatment can be applied to point-defect cavities in one-sided dielectric cladding structures and in three-dimensional configurations.
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)

Observation of two-photon absorption enhancement at double defect modes in one-dimensional photonic crystals

Jie Shen, Zhuangjian Zhang, Zhongyi Hua, Guohong Ma, and Sing Hai Tang

Appl. Phys. Lett. 88, 011113 (2006); http://dx.doi.org/10.1063/1.2162698 (3 pages) | Cited 2 times

Online Publication Date: 6 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
One-dimensional photonic crystals (1D PC) with two CdS defect layers in a SiO2/TiO2 dielectric thin film stack were fabricated. Two-photon absorption (TPA) coefficients of the CdS defect layers in the 1D PC were investigated using femtosecond pump-probe method. Significant enhancement of the TPA coefficient in the CdS defect layers was observed to occur at the two defect modes. Experimental results show that the enhanced TPA coefficient at the defect mode of 800 nm is larger than that at the defect mode of 762 nm. A numerical simulation by matrix transfer method is performed and agrees with the experimental results very well.
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)
78.47.-p Spectroscopy of solid state dynamics

Planar optical waveguide in potassium titanyl arsenate formed by oxygen ion implantation at low doses

Yi Jiang, Ke-Ming Wang, Xue-Lin Wang, Chuan-Lei Jia, Lei Wang, Yang Jiao, Qing-Ming Lu, Hong-Ji Ma, Rui Nie, and Ding-Yu Shen

Appl. Phys. Lett. 88, 011114 (2006); http://dx.doi.org/10.1063/1.2162665 (3 pages) | Cited 1 time

Online Publication Date: 6 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Monomode, nonleaky planar optical waveguides have been fabricated in x-cut biaxial crystal potassium titanyl arsenate (KTiOAsO4 or KTA) by 3.0 MeV O+ ion implantation at doses from 5×1012 to 1×1014 ions/cm2 at room temperature. The waveguide properties were characterized by the method of prism coupling at 633 nm. Positive changes of both nx and ny refractive indices (corresponding TE and TM polarized light separately) occur in the waveguide region. The propagation loss of the waveguide formed at a dose of 5×1013 ions/cm2 was reduced to 0.66 dB/cm after annealing at 230 °C for 30 minutes. Continuous and homogeneous magnified field pattern of the propagation light in the annealed waveguide was collected and studied by end-coupling method.
Show PACS
42.79.Gn Optical waveguides and couplers
42.82.Et Waveguides, couplers, and arrays
42.82.Cr Fabrication techniques; lithography, pattern transfer
42.70.-a Optical materials
81.40.Gh Other heat and thermomechanical treatments
back to top
RSS Feeds

Co–Fe–B–Si–Nb bulk glassy alloys with superhigh strength and extremely low magnetostriction

Chuntao Chang, Baolong Shen, and Akihisa Inoue

Appl. Phys. Lett. 88, 011901 (2006); http://dx.doi.org/10.1063/1.2159107 (3 pages) | Cited 25 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Co-based bulk glassy alloys with diameters up to 4 mm were formed in a [(Co1−xFex)0.75B0.2Si0.05]96Nb4 system. The bulk glassy alloys exhibit a superhigh fracture strength of 3980–4170 MPa and Young’s modulus of 190–210 GPa. The bulk glassy alloys also exhibit excellent soft-magnetic properties, i.e., high saturation magnetization of 0.71–0.97 T, low coercive force of 0.7–1.8 A/m, high permeability of 1.48–3.25×104, and extremely low saturation magnetostriction of 0.55–5.76×10−6. The first successful synthesis of the Co–Fe–B–Si-based bulk glassy alloys exhibiting superhigh fracture strength and excellent soft-magnetic properties with extremely low magnetostriction is encouraging for future development of Co-based bulk glassy alloys as new engineering and functional materials.
Show PACS
81.05.Kf Glasses (including metallic glasses)
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.M- Structural failure of materials
75.80.+q Magnetomechanical effects, magnetostriction
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

High-quality m-plane GaN thin films deposited on γ-LiAlO2 by ion-beam-assisted molecular-beam epitaxy

J. W. Gerlach, A. Hofmann, T. Höche, F. Frost, B. Rauschenbach, and G. Benndorf

Appl. Phys. Lett. 88, 011902 (2006); http://dx.doi.org/10.1063/1.2159100 (3 pages) | Cited 13 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
GaN(1math00) thin films are deposited on γ-LiAlO2(100) by low-energy-ion-beam-assisted molecular-beam epitaxy. Structural properties of the epitaxial GaN films are investigated by x-ray diffraction, transmission electron microscopy, and atomic force microscopy. X-ray diffraction measurements give evidence for a high crystalline quality far better than previously reported in literature. Cross-section transmission electron microscopy and atomic force microscopy show an anisotropy in defect structure and surface topography parallel and perpendicular to the GaN c axis. Optical properties are examined by photoluminescence spectroscopy at various temperatures. The spectra exhibit a strong and sharp near-band-gap transition, as well as a donor-acceptor pair transition.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.15.Jj Ion and electron beam-assisted deposition; ion plating
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
68.37.Lp Transmission electron microscopy (TEM)
68.37.Ps Atomic force microscopy (AFM)

Influence of structural nonuniformity and nonradiative processes on the luminescence efficiency of InGaAsN quantum wells

L. Geelhaar, M. Galluppi, G. Jaschke, R. Averbeck, H. Riechert, T. Remmele, M. Albrecht, M. Dworzak, R. Hildebrant, and A. Hoffmann

Appl. Phys. Lett. 88, 011903 (2006); http://dx.doi.org/10.1063/1.2159566 (3 pages) | Cited 11 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We compare the luminescence efficiency (i.e., room-temperature photoluminescence intensity), fluctuations in composition and thickness, degree of localization, and luminescence decay times of In0.37Ga0.63As0.983N0.017 quantum wells grown by molecular-beam epitaxy at different temperatures and annealed under a comprehensive variety of conditions. Luminescence efficiency is not directly coupled to structural nonuniformity or localization, and even three-dimensional growth is not detrimental by itself. In contrast, there is always a correlation between luminescence efficiency and nonradiative decay time. Therefore, the luminescence efficiency of InGaAsN quantum wells depends almost exclusively on the density of nonradiative recombination centers, while the influence of structural nonuniformity is negligible.
Show PACS
78.67.De Quantum wells
78.55.Cr III-V semiconductors
61.72.Cc Kinetics of defect formation and annealing

Investigation of silicon diffusion into yttrium using x-ray photoelectron spectroscopy

S. Y. Chiam, W. K. Chim, A. C. H. Huan, J. S. Pan, and J. Zhang

Appl. Phys. Lett. 88, 011904 (2006); http://dx.doi.org/10.1063/1.2159567 (3 pages) | Cited 3 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The reactions of yttrium (Y) metal on silicon (Si) are investigated by x-ray photoelectron spectroscopy (XPS). Low-temperature annealing studies are performed to investigate the diffusion of Si. It is found that Si diffusion occurs even under low annealing temperatures of <300 °C in an ultrahigh vacuum environment. This is attributed to the weakening of the Si–Si covalent bonds by metallic Y. XPS depth profiling of room-temperature-oxidized films revealed a possible oxygen-mediated pathway which allowed significant Si diffusion at room temperature for silicate formation.
Show PACS
66.30.J- Diffusion of impurities
79.60.Bm Clean metal, semiconductor, and insulator surfaces
61.72.S- Impurities in crystals
61.72.Cc Kinetics of defect formation and annealing

Thermomechanical criteria for overlay alignment in flexible thin-film electronic circuits

Helena Gleskova, I-Chun Cheng, Sigurd Wagner, and Zhigang Suo

Appl. Phys. Lett. 88, 011905 (2006); http://dx.doi.org/10.1063/1.2161391 (3 pages) | Cited 7 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A simple mechanical model for a deposited film∕substrate couple is presented to describe how film deposition at an elevated temperature induces change in the substrate’s in-plane dimensions at room temperature. The model provides a quantitative guideline for reducing, or completely eliminating, this elongation, by tailoring the tensile built-in stress in the deposited film. The dimensional stability so achieved is necessary for accurate overlay alignment of photomasks during the fabrication of thin-film electronic circuits.
Show PACS
85.40.Sz Deposition technology

Fluorescence upconversion in Sm-doped Gd2O3

D. Dosev, I. M. Kennedy, M. Godlewski, I. Gryczynski, K. Tomsia, and E. M. Goldys

Appl. Phys. Lett. 88, 011906 (2006); http://dx.doi.org/10.1063/1.2161400 (3 pages) | Cited 21 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the observation of efficient fluorescence upconversion in Sm-doped Gd2O3 nanopowders prepared by the spray pyrolysis method. The blue upconversion emission was observed with low-power continuous-wave excitation at 514, 561, 594, and 633 nm and with a pulsed femtosecond at 710 nm, in a laser scanning confocal microscope. This result indicates that Sm-doped Gd2O3 has the potential as a fluorescent label that may be excited in red, yellow, and green with blue emission.
Show PACS
81.07.Wx Nanopowders
78.55.Hx Other solid inorganic materials
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.47.-p Spectroscopy of solid state dynamics
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
81.16.Be Chemical synthesis methods

Experimental demonstration of the relationship between the OH− content and photoluminescence in Tb-doped YPO4∙2H2O

Weihua Di, Xiaojun Wang, Baojiu Chen, Shaozhe Lu, and Xinguang Ren

Appl. Phys. Lett. 88, 011907 (2006); http://dx.doi.org/10.1063/1.2158703 (3 pages) | Cited 9 times

Online Publication Date: 3 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Tb-doped YPO4∙2H2O was synthesized via a simple wet-chemical route. Both the crystallinity of samples and the concentration of OH− adsorbed at the surface were experimentally controlled by adjusting the reaction time. An abnormal phenomenon that photoluminescence efficiency decreases with the increase of crystallinity demonstrates enormously adverse effect of OH− on photoluminescence, especially, as the OH− content reaches a critical value, the luminescent efficiency decreases more drastically. This strong dependence of photoluminescence on the OH− content indicates that to control the OH− content in a limited range or to reduce the OH− effect as much as possible is an efficient way to improve photoluminescence efficiency.
Show PACS
78.55.Hx Other solid inorganic materials
68.43.Mn Adsorption kinetics

Epitaxy of nonpolar AlN on 4H-SiC (1-100) substrates

R. Armitage, J. Suda, and T. Kimoto

Appl. Phys. Lett. 88, 011908 (2006); http://dx.doi.org/10.1063/1.2161809 (3 pages) | Cited 19 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
AlN has been grown on 4H-SiC (1-100) substrates by rf-plasma molecular beam epitaxy. The epilayers assume a metastable 4H structure to match the in-plane stacking arrangement of the substrate. Initial two-dimensional nucleation of 4H-AlN is revealed by reflection high-energy electron diffraction. The epitaxial quality is evidenced by narrow x-ray diffraction ω-scan linewidths less than 70 arcsec for both symmetric and asymmetric reflections. The AlN growth surface exhibits a smooth and anisotropic morphology similar to that of GaN (1-100). Large residual stress is present in the epilayers, consistent with incomplete relaxation of misfit strain during growth.
Show PACS
81.05.Ea III-V semiconductors
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.47.Fg Semiconductor surfaces
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.60.Bs Mechanical and acoustical properties

Change in cation nonstoichiometry at interfaces during crystal growth in polycrystalline BaTiO3

Si-Young Choi, Suk-Joong L. Kang, Sung-Yoon Chung, Takahisa Yamamoto, and Yuichi Ikuhara

Appl. Phys. Lett. 88, 011909 (2006); http://dx.doi.org/10.1063/1.2162680 (3 pages) | Cited 5 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using an embedded single crystal in a polycrystalline matrix and quantitative electron energy loss spectroscopy, we have demonstrated that Ti-excess grain boundary nonstoichiometry can vary with the extent of boundary migration. While a slight excess in Ti was detected at the boundaries between small matrix grains, a large increase in Ti/Ba ratio, to as much as ∼ 1.50 compared to the stoichiometric value, was present at the interface between a growing single crystal and the matrix grains when the embedded crystal grew up to a few hundred micrometers. This change in nonstoichiometry was attributed to a continuous accumulation of excessive Ti at the moving boundary during crystal growth. The present result indicates that growth kinetics can critically affect the interface chemistry in polycrystals.
Show PACS
61.66.Bi Elemental solids
61.66.Dk Alloys
79.20.Uv Electron energy loss spectroscopy
61.72.Mm Grain and twin boundaries
66.30.Lw Diffusion of other defects
66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.Fx Diffusion; interface formation

High conductivity of Ga-doped rock-salt ZnO under pressure: Hint on deep-ultraviolet-transparent conducting oxides

A. Segura, J. A. Sans, D. Errandonea, D. Martinez-García, and V. Fages

Appl. Phys. Lett. 88, 011910 (2006); http://dx.doi.org/10.1063/1.2161392 (3 pages) | Cited 17 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter reports on transport and optical experiments under pressure in thin films of Ga-doped ZnO in both the wurtzite and rock-salt phases. The conductivity of heavily Ga-doped ZnO thin films is shown to decrease by only a factor of 2 in the wurtzite-to-rock-salt phase transition, occurring at about 11.5 GPa, while the optical gap increases from 4 to more than 5 eV. Ga-doped rock-salt ZnO is shown to behave as a deep-ultraviolet-transparent conducting oxide, with resistivity values as low as 10−3 Ω cm. The analysis of Burstein–Moss shift and free carrier absorption in rock-salt ZnO yield an estimation of the electron-hole reduced effective mass and electronic dielectric constant. Given the similarity between the electronic structures of rock-salt ZnO under pressure and rock-salt MgxZn1−xO at ambient pressure, this alloy could be a good deep-ultraviolet-transparent conducting oxide.
Show PACS
81.05.Dz II-VI semiconductors
73.61.Ga II-VI semiconductors
78.66.Hf II-VI semiconductors
62.50.-p High-pressure effects in solids and liquids
68.55.A- Nucleation and growth
61.72.uj III-V and II-VI semiconductors

Reduced electronegativity difference as a factor leading to the formation of Al-based glassy alloys with a large supercooled liquid region of 50 K

Dmitri V. Louzguine-Luzgin, Akihisa Inoue, and Walter José Botta

Appl. Phys. Lett. 88, 011911 (2006); http://dx.doi.org/10.1063/1.2159420 (3 pages) | Cited 15 times

Online Publication Date: 4 January 2006

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the electronegativity difference among the constituent elements on the stability of the supercooled liquid in two Al-based glassy alloys is studied. A record-large value of the supercooled liquid region of about 50 K is obtained based on the electronegativity difference concept within a certain composition range.
Show PACS
81.05.Kf Glasses (including metallic glasses)
61.43.Fs Glasses
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
Page 1 of 4 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Your Recent History Recent History Help

Recently Viewed

  1. Enhanced optical transmission through metal films with rotation-symmetrical hole arrays
  2. Subwavelength imaging with opaque nonlinear left-handed lenses
  3. Carrier transport in PbS nanocrystal conducting polymer composites
  4. Single-electron tunneling at room temperature in TixSi1−xO2 nanocomposite thin films
  5. Single electrospun regioregular poly(3-hexylthiophene) nanofiber field-effect transistor
Go to AIP Home
Copyright © American Institute of Physics
close