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15 Sep 2008

Volume 93, Issue 11, Articles (11xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 93, 111901 (2008); doi:10.1063/1.2980583 (3 pages)

W.-J. Lee, E.-A. Choi, J. Bang, B. Ryu, and K. J. Chang
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Wavelength tuning and emission width widening of ultrabroad quantum dash interband laser

C. L. Tan, H. S. Djie, Y. Wang, C. E. Dimas, V. Hongpinyo, Y. H. Ding, and B. S. Ooi

Appl. Phys. Lett. 93, 111101 (2008); doi:10.1063/1.2981578 (3 pages) | Cited 7 times

Online Publication Date: 15 September 2008

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The authors report the demonstration of the bandgap-tuned InAs quantum dash broadband laser with widened laser emission linewidth at room temperature using postgrowth intermixing technique. The 100 nm wavelength blueshifted, as-cleaved laser exhibits ultrabroad lasing spectral coverage of ∼ 85 nm at a center wavelength of 1.54 μm with a total emission power of ∼ 1 W per device. Compared to the as-grown laser, this laser shows broader lasing bandwidth ( ∼ 41 nm) with improved spectral ripple (<1 dB).
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Polarization-dependent coupling to plasmon modes on submicron gold wire in photonic crystal fiber

H. W. Lee, M. A. Schmidt, H. K. Tyagi, L. Prill Sempere, and P. St. J. Russell

Appl. Phys. Lett. 93, 111102 (2008); doi:10.1063/1.2982083 (3 pages) | Cited 22 times

Online Publication Date: 15 September 2008

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We present experimental results on coupling to surface plasmon modes on gold nanowires selectively introduced into polarization-maintaining photonic crystal fibers. Highly polarization- and wavelength-dependent transmission is observed. In one sample 24.5 mm long, the transmission on and off resonance differs by as much as 45 dB. Near-field optical images of the light emerging from such a gold-filled fiber show light guided on the wire at surface plasmon resonances. Finite element simulations are in good agreement with the experimental results. These gold-filled fibers can be potentially used as in-fiber wavelength-dependent filters and polarizers and as near-field tips for sub-wavelength-scale imaging.
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73.22.Lp Collective excitations
42.70.Qs Photonic bandgap materials
73.21.Hb Quantum wires

Acceleration and suppression of photoemission of GaAs quantum dots embedded in photonic crystal microcavities

Takashi Kuroda, Naoki Ikeda, Takaaki Mano, Yoshimasa Sugimoto, Tetsuyuki Ochiai, Keiji Kuroda, Shunsuke Ohkouchi, Nobuyuki Koguchi, Kazuaki Sakoda, and Kiyoshi Asakawa

Appl. Phys. Lett. 93, 111103 (2008); doi:10.1063/1.2978401 (3 pages) | Cited 7 times

Online Publication Date: 15 September 2008

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We fabricated optical microcavities in a photonic crystal slab embedded with GaAs quantum dots by electron beam lithography and droplet epitaxy. The Purcell effect of exciton emission of GaAs quantum dots was confirmed for the first time by microphotoluminescence and lifetime measurements.
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78.67.Hc Quantum dots
42.70.Qs Photonic bandgap materials
78.55.-m Photoluminescence, properties and materials

Mapping local defects of extended media using localized structures

F. Pedaci, G. Tissoni, S. Barland, M. Giudici, and J. Tredicce

Appl. Phys. Lett. 93, 111104 (2008); doi:10.1063/1.2977603 (3 pages) | Cited 12 times

Online Publication Date: 15 September 2008

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The stable positions of localized structures depend on spatial gradients in the system parameters and on the local defects of the hosting medium. We propose a general method to disclose and visualize the local defects of the medium structure, otherwise not detected. The method is based on the observation of the spatiotemporal behavior of localized structures in the presence of controlled gradients in the experimental parameters. We experimentally show an application of this method in a broad-area semiconductor vertical cavity surface emitting laser with optical injection. The comparison of the experimental results with numerical simulations shows a very good agreement.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Effects of laser pulse duration on extreme ultraviolet spectra from double optical gating

Steve Gilbertson, Hiroki Mashiko, Chengquan Li, Eric Moon, and Zenghu Chang

Appl. Phys. Lett. 93, 111105 (2008); doi:10.1063/1.2982589 (3 pages) | Cited 8 times

Online Publication Date: 15 September 2008

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Previously a two-color field was combined with a polarization gating to allow for the generation of single isolated attosecond pulses from multicycle lasers. Here, the scaling of energy for the extreme ultraviolet pulses corresponding to single attosecond pulses as a function of input laser pulse duration was investigated for argon, neon, and helium gas. Laser pulses as long as 12 fs were able to generate extreme ultraviolet supercontinua with high photon flux. The spectra profile depended strongly on the carrier envelope phase of the pump laser.
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42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
32.30.Jc Visible and ultraviolet spectra

Waveguiding and nonlinear optical properties of three-dimensional waveguides in LiTaO3 written by high-repetition rate ultrafast laser

Ben McMillen, Kevin P. Chen, Honglin An, Simon Fleming, Vincent Hartwell, and David Snoke

Appl. Phys. Lett. 93, 111106 (2008); doi:10.1063/1.2980437 (3 pages) | Cited 8 times

Online Publication Date: 15 September 2008

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We report the fabrication of waveguides in lithium tantalate using a 250 kHz high-repetition rate ultrafast laser at 771 nm and the characterization of the resulting laser induced structure with second harmonic microscopy. Waveguides operating at the 1.5 μm telecommunication wavelength were formed above and below the focal volume using pulse energies ranging from 100 to 1.6 J and translation speeds from 100 μm/s to 5 mm/s. The second harmonic microscopy reveals no degradation of the electro-optic coefficient in the guiding region above the focal volume.
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42.62.Cf Industrial applications
42.70.Mp Nonlinear optical crystals
42.65.Wi Nonlinear waveguides
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.87.-d Optical testing techniques

Electron dominated impact ionization and avalanche gain characteristics in InAs photodiodes

A. R. J. Marshall, C. H. Tan, M. J. Steer, and J. P. R. David

Appl. Phys. Lett. 93, 111107 (2008); doi:10.1063/1.2980451 (3 pages) | Cited 6 times

Online Publication Date: 15 September 2008

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An experimental investigation into impact ionization in InAs photodiodes is presented. Photomultiplication measurements on p-i-n and n-i-p diodes show that while high avalanche gains can be obtained for electron initiated multiplication, there is virtually no gain with hole initiated multiplication. This indicates that the electron ionization coefficient is significantly greater than the hole ionization coefficient raising the possibility of extremely low noise InAs avalanche photodiodes when gain is initiated by electrons. The onset of electron initiated impact ionization was detectable at electric fields below 10 kV cm−1 with useful gain observed at biases below 10 V.
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85.60.Dw Photodiodes; phototransistors; photoresistors
85.30.Kk Junction diodes

Continuous terahertz-wave generation using a monolithically integrated horn antenna

E. Peytavit, A. Beck, T. Akalin, J-F. Lampin, F. Hindle, C. Yang, and G. Mouret

Appl. Phys. Lett. 93, 111108 (2008); doi:10.1063/1.2983741 (3 pages) | Cited 4 times

Online Publication Date: 16 September 2008

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A transverse electromagnetic horn antenna is monolithically integrated with a standard ultrafast interdigitated electrode photodetector on low-temperature-grown GaAs. Continuous-wave terahertz radiation is generated at frequencies up to 2 THz with a maximum power of approximately 1 μW at 780 GHz. Experimental variations in the terahertz power as function of the frequency are explained by means of electromagnetic simulations of the antenna and the photomixer vicinity.
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84.40.Ba Antennas: theory, components and accessories
84.40.-x Radiowave and microwave (including millimeter wave) technology
85.60.Gz Photodetectors (including infrared and CCD detectors)

Room temperature continuous-wave operation of InAs/InP(100) quantum dot lasers grown by gas-source molecular-beam epitaxy

S. G. Li, Q. Gong, Y. F. Lao, K. He, J. Li, Y. G. Zhang, S. L. Feng, and H. L. Wang

Appl. Phys. Lett. 93, 111109 (2008); doi:10.1063/1.2985900 (3 pages) | Cited 15 times

Online Publication Date: 18 September 2008

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We report on the InAs quantum dots (QDs) laser in the 1.55 μm wavelength region grown by gas source molecular-beam epitaxy. The active region of the laser structure consists of fivefold-stacked InAs QD layers embedded in the InGaAsP layer. Ridge waveguide lasers were processed and continuous-wave mode operation was achieved between 20 and 70 °C, with characteristic temperature of 69 K. High internal quantum efficiency (56%) and low infinite length threshold current density (128 A/cm2 per QD layer) was obtained for the as-cleaved devices at room temperature. The lasing wavelength range between 1.556 and 1.605 μm can be covered by varying the laser cavity length.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Enhancement of two-photon excited fluorescence in two-dimensional nonlinear optical polymer photonic crystal waveguides

Shin-ichiro Inoue and Shiyoshi Yokoyama

Appl. Phys. Lett. 93, 111110 (2008); doi:10.1063/1.2985902 (3 pages) | Cited 3 times

Online Publication Date: 18 September 2008

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We examined two-photon excited fluorescence (TPEF) in two-dimensional highly nonlinear optical polymer photonic crystal waveguides with metallic cladding. A large TPEF enhancement of approximately two orders of magnitude was observed, originating from resonance between the external pump laser field and a photonic band mode. The results for TPEF enhancement are in good agreement with experimental photonic band resonances obtained by angle-resolved reflectivity measurements and the theoretical photonic band structure generated by three-dimensional finite-difference time-domain calculations, indicating that it is possible to use band dispersion control to design artificial nonlinear two-photon excitation processes.
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42.50.Hz Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift
42.70.Qs Photonic bandgap materials
42.70.Jk Polymers and organics
78.55.Kz Solid organic materials

Characteristics of GaN-based photonic crystal surface emitting lasers

Tien-chang Lu, Shih-Wei Chen, Tsung-Ting Kao, and Tzu-Wei Liu

Appl. Phys. Lett. 93, 111111 (2008); doi:10.1063/1.2986527 (3 pages) | Cited 6 times

Online Publication Date: 18 September 2008

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Characteristics of GaN-based photonic crystal surface emitting lasers (PCSELs) were investigated and analyzed. The GaN-based PCSEL emits a blue wavelength at 401.8 nm with a linewidth of 1.6 Å and shows a threshold energy density about 2.7 mJ/cm2 under the optical pumping at room temperature. The lasing wavelength emitted from PCSELs with different lattice constants occurs at the calculated band edges showing different polarization angles due to the light diffracted in specific directions, corresponding exactly to Γ, K, and M directions in the K-space. Furthermore, the PCSEL also shows a spontaneous emission coupling efficiency β of about 5×10−3 and a characteristic temperature of 148 K.
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42.55.Px Semiconductor lasers; laser diodes
42.55.Tv Photonic crystal lasers and coherent effects
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Ultrahigh-Q two-dimensional photonic crystal slab nanocavities in very thin barriers

Eiichi Kuramochi, Hideaki Taniyama, Takasumi Tanabe, Akihiko Shinya, and Masaya Notomi

Appl. Phys. Lett. 93, 111112 (2008); doi:10.1063/1.2987459 (3 pages) | Cited 16 times

Online Publication Date: 18 September 2008

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We demonstrate that width-modulated line-defect nanocavities in photonic crystals with long air slots on either side can maintain an ultrahigh Q even with very thin in-plane photonic crystal (only several rows of air holes). Although it is commonly believed that high-Q photonic crystal nanocavities require relatively thick in-plane barriers, surprisingly these nanocavities fabricated in silicon photonic crystals exhibit an ultrahigh Q (>106) even with very thin barriers. This design may be useful for various nanocavity applications.
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42.70.Qs Photonic bandgap materials

Plastic distributed feedback laser biosensor

M. Lu, S. S. Choi, U. Irfan, and B. T. Cunningham

Appl. Phys. Lett. 93, 111113 (2008); doi:10.1063/1.2987484 (3 pages) | Cited 12 times

Online Publication Date: 18 September 2008

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A replica-molded plastic-based vertically emitting distributed feedback (DFB) laser has been demonstrated for label-free chemical and biomolecular detection in which the emission wavelength is modulated by changes in bulk and surface-adsorbed material permittivity. A one-dimensional surface grating formed in UV-curable polymer on a flexible plastic substrate is coated with a thin polymer film incorporating organic laser dye. When optically pumped with a ∼ 10 ns pulse at λ = 532 nm, the DFB laser exhibits stimulated emission in the λ = 585–620 nm wavelength range with a linewidth as narrow as δλ = 0.09 nm. While exposed to chemical solutions with different refractive indices and adsorbed charged polymer monolayers, the laser sensor demonstrates single mode emission over a tuning range of ∼ 14 nm and the ability to perform kinetic monitoring of surface-adsorbed mass. A protein-protein interaction experiment is used to demonstrate the capability to characterize antibody-antigen affinity binding constants.
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87.80.-y Biophysical techniques (research methods)
42.55.Mv Dye lasers
87.14.E- Proteins
87.15.R- Reactions and kinetics
77.22.Ch Permittivity (dielectric function)

Three-dimensional optical antennas: Nanocones in an apertureless scanning near-field microscope

M. Fleischer, C. Stanciu, F. Stade, J. Stadler, K. Braun, A. Heeren, M. Häffner, D. P. Kern, and A. J. Meixner

Appl. Phys. Lett. 93, 111114 (2008); doi:10.1063/1.2987485 (3 pages) | Cited 10 times

Online Publication Date: 18 September 2008

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A sharp-tipped gold nanocone and the vertically aligned metallic tip of a near-field optical microscope together form a three-dimensional optical antenna with a highly controllable gap. Confocal measurements with different laser modes show the efficient axial excitation of the cones with a longitudinally polarized field. In the antenna configuration, extremely strong field enhancement up to a factor of 100 is obtained by tuning the gap between the two sharp tips down to few nanometers.
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84.40.Ba Antennas: theory, components and accessories
07.79.Fc Near-field scanning optical microscopes

Near-infrared absorption of germanium thin films on silicon

V. Sorianello, A. Perna, L. Colace, G. Assanto, H. C. Luan, and L. C. Kimerling

Appl. Phys. Lett. 93, 111115 (2008); doi:10.1063/1.2987999 (3 pages) | Cited 5 times

Online Publication Date: 18 September 2008

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Using differential optical absorption spectroscopy of germanium thin films epitaxially grown on silicon, we accurately evaluate the near-infrared absorption versus wavelength and temperature. The results allow for optimized design and realization of Ge-on-Si photodetectors.
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78.66.Db Elemental semiconductors and insulators
78.30.Am Elemental semiconductors and insulators

Projecting deep-subwavelength patterns from diffraction-limited masks using metal-dielectric multilayers

Yi Xiong, Zhaowei Liu, and Xiang Zhang

Appl. Phys. Lett. 93, 111116 (2008); doi:10.1063/1.2985898 (3 pages) | Cited 16 times

Online Publication Date: 19 September 2008

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We utilize a metal-dielectric multilayer structure to generate deep-subwavelength one-dimensional and two-dimensional periodic patterns with diffraction-limited masks. The working wavelength and the pattern are set by the flexible design of the multilayer structure. This scheme is suitable to be applied to deep-subwavelength photolithography. As an example, we numerically demonstrate pattern periods down to 50 nm under 405 nm light illumination.
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81.16.Rf Micro- and nanoscale pattern formation
81.16.Nd Micro- and nanolithography

High density patterned quantum dot arrays fabricated by electron beam lithography and wet chemical etching

V. B. Verma and J. J. Coleman

Appl. Phys. Lett. 93, 111117 (2008); doi:10.1063/1.2981207 (3 pages) | Cited 10 times

Online Publication Date: 19 September 2008

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We present a quantum dot (QD) fabrication method which allows for the definition of the explicit location and size of an individual QD. We have obtained high optical quality, high density QD arrays utilizing hydrogen silsesquioxane, a negative tone electron beam resist, as a wet etch mask for an underlying quantum well. Linewidths as small as 24 meV from a large ensemble of QDs have been demonstrated in photoluminescence measurements at 77 K. The magnitude of the experimentally obtained blueshift due to quantum confinement effects is found to be consistent with that predicted by theory.
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81.16.Nd Micro- and nanolithography
81.65.Cf Surface cleaning, etching, patterning
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors
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Contrasting characteristics of linear-field and cross-field atmospheric plasma jets

J. L. Walsh and M. G. Kong

Appl. Phys. Lett. 93, 111501 (2008); doi:10.1063/1.2982497 (3 pages) | Cited 53 times

Online Publication Date: 15 September 2008

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This letter reports an experimental study of two types of atmospheric pressure plasma jets in terms of their fundamental properties and their efficiency in etching polymeric materials. The first plasma jet has a cross-field configuration with its electric field perpendicular to its gas flow field, whereas the second is a linear-field device having parallel electric and flow fields. The linear-field jet is shown to drive electron transportation to the downstream application region, thus facilitating more active plasma chemistry there. This is responsible for its etching rate of polyamide films being 13-fold that of its cross-field counterpart.
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52.77.Bn Etching and cleaning
81.65.Cf Surface cleaning, etching, patterning
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
52.25.Fi Transport properties
52.75.-d Plasma devices
52.30.-q Plasma dynamics and flow

Measurement of electron density by Stark broadening in an ablative pulsed plasma thruster

Feng Liu, Zongfu Nie, Xu Xu, Qianhong Zhou, Linsen Li, and Rongqing Liang

Appl. Phys. Lett. 93, 111502 (2008); doi:10.1063/1.2983747 (3 pages)

Online Publication Date: 16 September 2008

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Electron density was measured by Stark broadening in an ablative pulsed plasma thruster. The asymmetrical deconvolution is used to obtain Stark broadening. The result shows that the electron density in the discharge channel is 2.534×1022 m−3 when the discharge energy is 5 J and the measured electron temperature is 18 000 K, and it is in excellent agreement with other experimental and theoretical data. The electron density in the discharge channel increases very minimally with increasing discharge energy.
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52.25.-b Plasma properties
52.75.-d Plasma devices
52.80.-s Electric discharges

Exciting circular TEmn modes at low terahertz region

T. H. Chang, C. H. Li, C. N. Wu, and C. F. Yu

Appl. Phys. Lett. 93, 111503 (2008); doi:10.1063/1.2987486 (3 pages) | Cited 4 times

Online Publication Date: 18 September 2008

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This work proposes an approach to generate circular TEmn modes at low terahertz region through sidewall couplings. With proper arrangement of the couplings on the circumference of the waveguide, they then jointly excite the desired mode. A model is developed to calculate the coupling strength and to analyze the mode purity. Accordingly, three mode converters TE21, TE01, and TE41, were designed, built, and tested at W-band. Back-to-back transmission measurements exhibit excellent agreement with the results of simulations. The measured optimal transmissions are 91%, 95%, and 89% with 3 dB bandwidths of 18.3, 24.0, and 20.2 GHz, respectively.
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41.20.Jb Electromagnetic wave propagation; radiowave propagation
42.79.Gn Optical waveguides and couplers
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Structural and electronic properties of crystalline InGaO3(ZnO)m

W.-J. Lee, E.-A. Choi, J. Bang, B. Ryu, and K. J. Chang

Appl. Phys. Lett. 93, 111901 (2008); doi:10.1063/1.2980583 (3 pages) | Cited 6 times

Online Publication Date: 15 September 2008

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Based on theoretical calculations, we find that the crystal structure of InGaO3(ZnO)m consists of an alternating stack of a wurtzite (Ga/Zn)–O block and an In–O octahedral layer. In the (Ga/Zn)–O block, the Ga atoms favor a modulated boundary structure against a flat boundary structure. The band spectrum shows that hole carriers are spatially confined whereas electrons move more freely through the whole crystal. The characteristics of a superlattice structure appears especially in the flat boundary structure. The band gap decreases with m due to the reduction in the quantum confinement effect.
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61.66.Fn Inorganic compounds
71.20.Ps Other inorganic compounds
72.80.Sk Insulators
72.20.Fr Low-field transport and mobility; piezoresistance
71.15.-m Methods of electronic structure calculations

Evidence of complete band gap and resonances in a plate with periodic stubbed surface

Tsung-Tsong Wu, Zi-Gui Huang, Tzu-Chin Tsai, and Tzung-Chen Wu

Appl. Phys. Lett. 93, 111902 (2008); doi:10.1063/1.2970992 (3 pages) | Cited 21 times

Online Publication Date: 16 September 2008

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In this paper, we numerically and experimentally demonstrate the existence of complete band gaps and resonances in a plate with a periodic stubbed surface. Numerical results show that a complete band gap forms as the stub height reaches about three times the plate thickness. In the experiment, we used a pulsed laser to generate broadband elastic waves and used optical devices as well as point piezoelectric transducers to detect wave signals. The results show that the numerical predictions are in very good agreement with those measured experimentally. Remarkable resonances on the top surface of the stubs are found and discussed.
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42.70.Qs Photonic bandgap materials
62.30.+d Mechanical and elastic waves; vibrations

Nature of quasi-LO phonon in ZnO

Y. Y. Tay, T. T. Tan, M. H. Liang, F. Boey, and S. Li

Appl. Phys. Lett. 93, 111903 (2008); doi:10.1063/1.2983656 (3 pages) | Cited 5 times

Online Publication Date: 16 September 2008

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The quasi-LO phonon mode is related to the specific defects that strongly affect the photonic properties of materials such as zinc oxide (ZnO). The line shapes of the quasi-LO phonon of ZnO annealed in different environments have been investigated. The experimental results show that this mode has the greatest Raman shift to lower wavenumber for the ZnO annealed in ambient atmosphere, suggesting that it has the largest concentration of defects that may be related to its green emission.
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63.20.D- Phonon states and bands, normal modes, and phonon dispersion
61.72.Cc Kinetics of defect formation and annealing
78.20.-e Optical properties of bulk materials and thin films
78.30.Fs III-V and II-VI semiconductors

Reduction of stacking fault density in m-plane GaN grown on SiC

Y. S. Cho, Q. Sun, I.-H. Lee, T.-S. Ko, C. D. Yerino, J. Han, B. H. Kong, H. K. Cho, and S. Wang

Appl. Phys. Lett. 93, 111904 (2008); doi:10.1063/1.2985816 (3 pages) | Cited 19 times

Online Publication Date: 16 September 2008

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We report the reduction in basal-plane stacking faults (BSFs) in m-plane GaN grown on m-plane SiC. The origin of BSFs is linked to heteronucleation of m-plane GaN and the presence of N-face basal-plane sidewalls of three-dimensional islands. Graded AlGaN layers help to alleviate mismatched nucleation and the generation of BSFs. Transmission electron microscopy shows that the density of BSFs is decreased to the low 105 cm−1. Anisotropy in on-axis x-ray rocking curves, a salient feature in m-plane GaN heteroepitaxial layers, is greatly reduced. A possible mechanism of BSF generation, and the demonstration of improved InGaN/GaN quantum well emission are presented.
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68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Dd Experimental determination of defects by diffraction and scattering
78.67.De Quantum wells
78.55.Cr III-V semiconductors
61.72.Nn Stacking faults and other planar or extended defects
68.37.Og High-resolution transmission electron microscopy (HRTEM)
68.55.ag Semiconductors

Microstructural properties of phosphorus-doped p-type ZnO grown by radio-frequency magnetron sputtering

Min-Suk Oh, Dae-Kue Hwang, Yong-Seok Choi, Jang-Won Kang, Seong-Ju Park, Chi-Sun Hwang, and Kyoung Ik Cho

Appl. Phys. Lett. 93, 111905 (2008); doi:10.1063/1.2936962 (3 pages) | Cited 16 times

Online Publication Date: 18 September 2008

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Phosphorus (P)-doped ZnO thin films were grown by radio-frequency magnetron sputtering to study the microstructural properties of p-type ZnO. As-grown P-doped ZnO, a semi-insulator, was converted to p-type ZnO after being annealed at 800 °C in an N2 ambient. X-ray diffraction, secondary-ion-mass spectrometry, and Hall effect measurements indicated that P2O5 phases in as-grown P-doped ZnO disappeared after thermal annealing to form a substitutional P at an O lattice site, which acts as an acceptor in P-doped ZnO. Transmission electron microscopy showed that the formation of stacking faults was facilitated to release the strain in P-doped ZnO during post-thermal annealing.
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81.15.Cd Deposition by sputtering
61.72.Cc Kinetics of defect formation and annealing
68.55.ag Semiconductors
73.61.Ga II-VI semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
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