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28 Jun 2004

Volume 84, Issue 26, pp. 5299-5475

Issue Cover Spotlight Figure

Appl. Phys. Lett. 84, 5398 (2004); http://dx.doi.org/10.1063/1.1767591 (3 pages)

E. Menard, K. J. Lee, D.-Y. Khang, R. G. Nuzzo, and J. A. Rogers
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Atomic-scale characterization of perovskite superlattice using chemical lattice imaging and spatially resolved electron energy-loss spectroscopy

K. Kimoto, Y. Matsui, H. Yamada, M. Kawasaki, X. Yu, Y. Kaneko, and Y. Tokura

Appl. Phys. Lett. 84, 5374 (2004); http://dx.doi.org/10.1063/1.1767279 (3 pages) | Cited 1 time

Online Publication Date: 17 June 2004

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The layered structure of a perovskite tricolor superlattice {SrTiO3(STO)/LaAlO3(LAO)/La0.6Sr0.4MnO3(LSMO)}n on an STO substrate is investigated using transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS). Conventional TEM imaging is not effective for thickness evaluation, in which both LAO and LSMO layers show the same image contrast because of the similarity in their mean atomic numbers. We observe 001 lattice fringes, which are chemically sensitive in the case of the perovskite structure ABO3, since the 001 structure factor is proportional to the difference between A- and B-site atomic scattering factors. The thickness of each layer is evaluated with an accuracy of one unit cell. We also apply spatially resolved EELS to analyze the depth profile of Ti, Mn, and La contents.
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68.65.Cd Superlattices
79.20.Uv Electron energy loss spectroscopy
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Mechanisms of injection enhancement in organic light-emitting diodes through insulating buffer

J. M. Zhao, Y. Q. Zhan, S. T. Zhang, X. J. Wang, Y. C. Zhou, Y. Wu, Z. J. Wang, X. M. Ding, and X. Y. Hou

Appl. Phys. Lett. 84, 5377 (2004); http://dx.doi.org/10.1063/1.1764943 (3 pages) | Cited 16 times

Online Publication Date: 17 June 2004

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Three types of organic light-emitting diodes are fabricated. Tris-8-hydroxyquinoline aluminum (Alq3) is used as an electron-transporting layer (ETL) and sodium stearate (NaSt) as an electron-injecting buffer. The optimal thickness of NaSt for electron injection is different for cathodes of different metals, such as Mg, Al, and Ag. This is attributed to the different work functions of cathodes, which result in different initial barrier heights for electron injection from cathodes into ETL, and explained based on tunneling theory.
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85.60.Jb Light-emitting devices
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Ballistic transport in InSb/InAlSb antidot lattices

Hong Chen, J. J. Heremans, J. A. Peters, N. Goel, S. J. Chung, and M. B. Santos

Appl. Phys. Lett. 84, 5380 (2004); http://dx.doi.org/10.1063/1.1764945 (3 pages) | Cited 5 times

Online Publication Date: 17 June 2004

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We investigate magnetotransport properties of antidot lattices fabricated on high-mobility InSb/InAlSb heterostructures. The temperature dependencies of the ballistic magnetoresistance peaks due to the antidot lattice are studied, and compared with mobility and density data over the same temperature range. A scattering time particular to antidot lattices is deduced, with a linear dependence on temperature between 0.4 and 50 K, attributed to acoustic phonon scattering. The mobility does not vary substantially over this temperature range, whereas above ∼ 60 K a quadratic dependence of inverse mobility on temperature is noticed, attributed to optical phonon scattering. The very weak temperature dependence of the width of the ballistic magnetoresistance peaks indicates negligible thermal smearing for electrons in the InSb quantum well, a result of the small electron effective mass.
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72.20.My Galvanomagnetic and other magnetotransport effects
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
73.63.Kv Quantum dots
75.47.-m Magnetotransport phenomena; materials for magnetotransport
72.20.Ht High-field and nonlinear effects

Mobility studies of field-effect transistor structures based on anthracene single crystals

A. N. Aleshin, J. Y. Lee, S. W. Chu, J. S. Kim, and Y. W. Park

Appl. Phys. Lett. 84, 5383 (2004); http://dx.doi.org/10.1063/1.1767282 (3 pages) | Cited 18 times

Online Publication Date: 17 June 2004

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The charge carrier transport in anthracene single crystals has been studied by means of field-effect transistor (FET) structure. The FET mobility (μFET) revealed the nonmonotonous, reliant on gate-voltage (Vg), temperature dependence with the maximum μFET ∼ 0.02 cm2/V s at T ∼ 170–180 K and Vg ∼ −30 V. At temperatures below 180 K the mobility decreases and becomes thermally activated with the Vg-dependent activation energy Ea ∼ 40–70 meV governed by shallow traps. The space-charge-limited current is the dominant transport mechanism in FET structures based on anthracene single crystals.
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85.30.Tv Field effect devices
72.20.Ht High-field and nonlinear effects
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Nonlinear self-modulation and subharmonic acoustic spectroscopy for damage detection and location

I. Solodov, J. Wackerl, K. Pfleiderer, and G. Busse

Appl. Phys. Lett. 84, 5386 (2004); http://dx.doi.org/10.1063/1.1767283 (3 pages) | Cited 16 times

Online Publication Date: 17 June 2004

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A self-modulation mode of nonlinear acoustic vibrations of cracked defects has been analyzed and observed experimentally. Spectral patterns of the self-modulation are attributed to the sum-frequency type resonance in a multi-degree-of-freedom system and include a subharmonic spectrum as a particular case. Both the subharmonic and self-modulation modes demonstrate a high localization around the defect and provide opportunities for early detection and recognition of damaged areas.
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81.70.Cv Nondestructive testing: ultrasonic testing, photoacoustic testing
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.M- Structural failure of materials
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Size-dependent oxygen-related electronic states in silicon nanocrystals

J. S. Biteen, N. S. Lewis, H. A. Atwater, and A. Polman

Appl. Phys. Lett. 84, 5389 (2004); http://dx.doi.org/10.1063/1.1765200 (3 pages) | Cited 36 times

Online Publication Date: 17 June 2004

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Silicon nanocrystals embedded in SiO2 were isolated with a selective etching procedure, and the isolated nanocrystals’ excitonic emission energy was studied during controlled oxidation. Nanocrystals having initial diameters, d0, of ∼ 2.9–3.4 nm showed a photoluminescence (PL) blueshift upon oxidatively induced size reduction, as expected from models of quantum confinement. Oxidation of smaller Si nanocrystals (d0 ∼ 2.5–2.8 nm) also initially resulted in a PL blueshift, but a redshift in the PL was then observed after growth of ∼ 0.3 monolayers of native oxide. This decrease in excitonic emission energy during oxidation is consistent with the theoretically predicted formation of an oxygen-related excitonic recombination state.
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78.55.Hx Other solid inorganic materials
78.66.Sq Composite materials
81.65.Cf Surface cleaning, etching, patterning
81.65.Mq Oxidation
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Percolation network of growing V2O5 nanowires

Yu Jin Chang, Byung Hyun Kang, Gyu Tae Kim, Sung Joon Park, and Jeong Sook Ha

Appl. Phys. Lett. 84, 5392 (2004); http://dx.doi.org/10.1063/1.1767284 (3 pages) | Cited 5 times

Online Publication Date: 17 June 2004

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Percolation network of the growing V2O5 nanowires was demonstrated by devising a simple but practical method to investigate the percolation phenomena. As the reaction proceeded in the ammonium(meta)vanadate solution at room temperature, the lengths of V2O5 nanowires increased at a speed of 0.13 μm/day at an early stage of the growth and 0.03 μm/day on the average up to 3 months. Percolation network was made by abruptly freezing the homogeneously dispersed aqueous solutions of V2O5 nanowires in liquid nitrogen. After 7 h of aging time, an abrupt increase of the conductance was observed, revealing the satisfaction of the percolation threshold (pc ∼ 0.17) at the average wire length of 40 nm.
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61.46.-w Structure of nanoscale materials
81.40.Cd Solid solution hardening, precipitation hardening, and dispersion hardening; aging
73.61.Ng Insulators
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Characterization of line-defect-waveguide lasers in two-dimensional photonic-crystal slabs

Atsushi Sugitatsu, Takashi Asano, and Susumu Noda

Appl. Phys. Lett. 84, 5395 (2004); http://dx.doi.org/10.1063/1.1767285 (3 pages) | Cited 16 times

Online Publication Date: 17 June 2004

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Here we investigate a line-defect-waveguide laser in a two-dimensional photonic-crystal slab. The change δλ in lasing wavelength for a change δW in waveguide width is found to be extremely large: δλ/δW = 2. It is two orders of magnitude greater than that for a conventional distributed-feedback laser. An investigation of the electromagnetic-field distribution at the waveguide-mode edge is made, giving an indication of the cavity-mode structure for lasing oscillation. Fourier transform analysis reveals that the extremely large tunability originates from the “zigzag” mode behavior of the line-defect waveguide in the photonic crystal, due to two-dimensional distributed feedback and reflection.
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42.55.Tv Photonic crystal lasers and coherent effects
42.70.Qs Photonic bandgap materials
42.55.Px Semiconductor lasers; laser diodes
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A printable form of silicon for high performance thin film transistors on plastic substrates

E. Menard, K. J. Lee, D.-Y. Khang, R. G. Nuzzo, and J. A. Rogers

Appl. Phys. Lett. 84, 5398 (2004); http://dx.doi.org/10.1063/1.1767591 (3 pages) | Cited 32 times

Online Publication Date: 17 June 2004

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Free-standing micro- and nanoscale objects of single crystal silicon can be fabricated from silicon-on-insulator wafers by lithographic patterning of resist, etching of the exposed top silicon, and removing the underlying SiO2 to lift-off the remaining silicon. A large collection of such objects constitutes a type of material that can be deposited and patterned, by dry transfer printing or solution casting, onto plastic substrates to yield mechanically flexible thin film transistors that have excellent electrical properties. Effective mobilities of devices built with this material, which we refer to as microstructured silicon (μs-Si), are demonstrated to be as high as 180 cm2/V s on plastic substrates. This form of “top down” microtechnology might represent an attractive route to high performance flexible electronic systems.
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85.30.Tv Field effect devices
85.40.Hp Lithography, masks and pattern transfer
81.65.Cf Surface cleaning, etching, patterning
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Chemistry-mediated two-dimensional to three-dimensional transition of In thin films

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

Appl. Phys. Lett. 84, 5401 (2004); http://dx.doi.org/10.1063/1.1767595 (3 pages) | Cited 1 time

Online Publication Date: 17 June 2004

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This letter reports a mechanism of chemistry-mediated two-dimensional to three-dimensional (2D–3D) transition during In thin film deposition, and the corresponding evolution of nanoscale islands. Using magnetron sputtering technique, we deposit In on Au substrate. Despite the fact that In wets on Au, In islands prevail over the uniform film soon after the deposition starts. The 2D–3D transition is found to be a result of the formation of Au3In on the Au substrate. The alloy formation leads to nonwetting of In, thereby the high mobility of In atoms and In clusters, and eventually well-separated In islands. The structures of In and Au are characterized by scanning electron microscopy, transmission electron microscopy, and electron diffraction.
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64.70.K- Solid-solid transitions
81.15.Cd Deposition by sputtering
82.30.Nr Association, addition, insertion, cluster formation
81.05.Bx Metals, semimetals, and alloys
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
82.33.Hk Reactions on clusters
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
61.46.-w Structure of nanoscale materials
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Eu2+-doped Ca-α-SiAlON: A yellow phosphor for white light-emitting diodes

Rong-Jun Xie, Naoto Hirosaki, Ken Sakuma, Yoshinobu Yamamoto, and Mamoru Mitomo

Appl. Phys. Lett. 84, 5404 (2004); http://dx.doi.org/10.1063/1.1767596 (3 pages) | Cited 186 times

Online Publication Date: 17 June 2004

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In this letter, a yellow oxynitride phosphor α-SiAlON with compositions of Ca0.625EuxSi0.75−3xAl1.25+3xOxN16−x (Ca-α-SiAlON:Eu, x = 0–25) was prepared by gas pressure sintering. The diffuse reflection spectrum, photoluminescence spectrum, and chromaticity of the powder phosphors were presented. It absorbs light efficiently in the UV–visible spectral region, and shows a single intense broadband emission at 583–603 nm. This phosphor may become a good candidate for creating white light, typically warm white light, when coupled to a blue light-emitting diode (λem = 450 nm).
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78.55.Hx Other solid inorganic materials
78.40.Ha Other nonmetallic inorganics
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Formation of Ge nanocrystals in HfAlO high-k dielectric and application in memory device

Ying Qian Wang, Jing Hao Chen, Won Jong Yoo, Yee-Chia Yeo, Sun Jung Kim, Rohit Gupta, Zerlinda Y. L. Tan, Dim-Lee Kwong, An Yan Du, and N. Balasubramanian

Appl. Phys. Lett. 84, 5407 (2004); http://dx.doi.org/10.1063/1.1767597 (3 pages) | Cited 29 times

Online Publication Date: 17 June 2004

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Formation of Ge nanocrystals embedded in HfAlO high-k dielectric by co-sputtering of HfO2, Al2O3, and Ge, followed by rapid thermal annealing was demonstrated. Analysis by transmission electron microscopy and x-ray photoelectron spectroscopy confirmed the formation of nonoxidized Ge nanocrystals with a minimum size of about 5 nm embedded in HfAlO dielectric. We also demonstrated the application of such nanocrystals in nonvolatile memory devices, achieving a 2.2 V memory window as obtained from the C–V characterization of the memory device.
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61.46.-w Structure of nanoscale materials
77.84.-s Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials
79.60.Bm Clean metal, semiconductor, and insulator surfaces
84.30.Sk Pulse and digital circuits
61.72.Cc Kinetics of defect formation and annealing
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Optimization of mid-infrared InAs/GaSb type-II superlattices

H. J. Haugan, F. Szmulowicz, G. J. Brown, and K. Mahalingam

Appl. Phys. Lett. 84, 5410 (2004); http://dx.doi.org/10.1063/1.1767598 (3 pages) | Cited 11 times

Online Publication Date: 17 June 2004

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The effect of small changes in GaSb layer width on the photoresponse spectrum of 20.5 Å InAs/InSb-interfaces/X Å GaSb type-II superlattice (SL) suitable for mid-infrared detection was investigated. By decreasing the GaSb width X from 27 to 18 Å, the cut-off wavelength was increased from 4.03 to 4.55 μm. This decrease of the SL band gap and other effects of the design changes on photoresponse spectrum with narrower GaSb layers are explained by a nonperturbative, modified envelope function approximation calculation that includes the interface coupling of heavy, light, and spin–orbit holes resulting from the in-plane asymmetry at InAs/GaSb interfaces.
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73.21.Cd Superlattices
71.20.Nr Semiconductor compounds
85.25.Pb Superconducting infrared, submillimeter and millimeter wave detectors
85.60.Gz Photodetectors (including infrared and CCD detectors)
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Work-function difference between Al and n-GaN from Al-gated n-GaN/nitrided-thin-Ga2O3/SiO2 metal oxide semiconductor structures

Choelhwyi Bae, Cristiano Krug, Gerald Lucovsky, Arpan Chakraborty, and Umesh Mishra

Appl. Phys. Lett. 84, 5413 (2004); http://dx.doi.org/10.1063/1.1767599 (3 pages) | Cited 5 times

Online Publication Date: 17 June 2004

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In most previous reports on Al-gated n-GaN/SiO2 metal–oxide–semiconductor (MOS) structures, the work–function difference between Al and n-GaN (ϕms) has been chosen as 0 V by assuming that the work function of the Al gate and n‐GaN are both 4.1 eV. In this letter, ϕms is determined as ∼ 0.1 V using Al-gated n-GaN/nitrided-thin-Ga2O3/SiO2 MOS capacitors by measuring flatband voltage as a function of oxide thickness. Formation of an ultrathin ( ∼ 0.6-nm-thick) Ga2O3 layer on n-GaN prior to the deposition of SiO2 is important to prevent uncontrolled parasitic oxidation of then-GaN surface and possibly reduces the interface dipole between n-GaN and SiO2.
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73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
84.32.Tt Capacitors
73.30.+y Surface double layers, Schottky barriers, and work functions
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In situ ultraviolet treatment in an Ar ambient upon p-type hydrogenated amorphous silicon–carbide windows of hydrogenated amorphous silicon based solar cells

Seung Yeop Myong, Sang Soo Kim, and Koeng Su Lim

Appl. Phys. Lett. 84, 5416 (2004); http://dx.doi.org/10.1063/1.1767601 (3 pages) | Cited 16 times

Online Publication Date: 17 June 2004

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We proposed an in situ postdeposition ultraviolet treatment in an Ar ambient (UTA) to improve the p/i interface of amorphous silicon based solar cell. We have increased the conversion efficiency by ∼ 16% by improving the built-in potential and reducing recombination at the p/i interface. Through spectroscopic ellipsometry and Fourier-transform infrared measurements, it is concluded that the UTA process induces structural modification of the p-type hydrogenated amorphous silicon–carbide (p-a-SiC:H) window layer. An ultrathin p-a-SiC:H contamination layer formed during the UTA process acts as a buffer layer at the interface.
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84.60.Jt Photoelectric conversion
81.05.Gc Amorphous semiconductors
81.05.Cy Elemental semiconductors
78.30.Hv Other nonmetallic inorganics
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
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Metalorganic vapor phase epitaxy InSb p+nn+ photodiodes with low dark current

Y. Paltiel, A. Sher, A. Raizman, S. Shusterman, M. Katz, A. Zemel, Z. Calahorra, and M. Yassen

Appl. Phys. Lett. 84, 5419 (2004); http://dx.doi.org/10.1063/1.1767602 (3 pages) | Cited 1 time

Online Publication Date: 17 June 2004

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Photodiodes of InSb were fabricated on epilayers grown by metalorganic vapor phase epitaxy (MOVPE). Dark reverse current density as low as 1×10−7 A/cm2 at −0.1 V bias, and zero-bias-resistance area products as high as 1×106 Ω cm2 were measured. These values are comparable to the best values reported for InSb diodes grown by molecular-beam epitaxy. The very good uniformity of the diode dark current implies that MOVPE is a promising growth technique for the fabrication of state-of-the-art focal plane InSb detector arrays.
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85.60.Dw Photodiodes; phototransistors; photoresistors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.05.Ea III-V semiconductors
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Improvements of InGaN/GaN quantum-well interfaces and radiative efficiency with InN interfacial layers

Yung-Chen Cheng, Cheng-Ming Wu, Meng-Kuo Chen, C. C. Yang, Zhe-Chuan Feng, Gang Alan Li, Jer-Ren Yang, Andreas Rosenauer, and Kung-Je Ma

Appl. Phys. Lett. 84, 5422 (2004); http://dx.doi.org/10.1063/1.1767603 (3 pages) | Cited 9 times

Online Publication Date: 17 June 2004

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The optical properties and nanostructures of two InGaN/GaN quantum-well (QW) samples of slightly different structures are compared. In one of the samples, InN interfacial layers of a few monolayers are added to the structure between wells and barriers for improving the QW interface quality. Compared with the standard barrier-doped QW sample, the addition of the InN interfacial layers does improve the QW interface quality and hence the photon emission efficiency. The strain state analysis images show the high contrast between the clear QW interface in the sample with InN layers and the diffusive QW boundaries in the reference sample. The detection-energy-dependent photoluminescence excitation data reveal the consistent results.
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78.67.De Quantum wells
78.55.Cr III-V semiconductors
78.60.Fi Electroluminescence
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Three-dimensional particle-in-cell simulations of rapid start-up in strapped oven magnetrons due to variation in the insulating magnetic field

J. W. Luginsland, Y. Y. Lau, V. B. Neculaes, R. M. Gilgenbach, M. C. Jones, M. H. Frese, and J. J. Watrous

Appl. Phys. Lett. 84, 5425 (2004); http://dx.doi.org/10.1063/1.1765732 (3 pages) | Cited 16 times

Online Publication Date: 17 June 2004

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A three-dimensional parallel particle-in-cell code, ICEPIC, is used to simulate the geometry and the magnetic field profiles of the recent low-noise, fast startup magnetron experiments at the University of Michigan. The fast startup, the power levels, and the starting currents that have been observed in these experiments are quantitatively reproduced in the simulations. The tendency for low noise operation has also been reproduced with the use of an azimuthally varying magnetic field.
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84.40.Fe Microwave tubes (e.g., klystrons, magnetrons, traveling-wave, backward-wave tubes, etc.)
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Coulomb blockade in suspended Si3N4-coated single-walled carbon nanotubes

H. B. Peng and J. A. Golovchenko

Appl. Phys. Lett. 84, 5428 (2004); http://dx.doi.org/10.1063/1.1765733 (3 pages) | Cited 9 times

Online Publication Date: 17 June 2004

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Uniform coaxial coating of suspended single-walled carbon nanotubes with high-quality dielectric silicon nitride has been obtained by low-pressure chemical vapor deposition. A three-terminal device has been demonstrated by coating a suspended metallic nanotube grown directly on contacting metal electrodes with subsequent patterning of a top gate electrode. Large charging energies have been observed in the suspended nanotubes and the conversion factor from gate voltage to the electrostatic potential in the nanotube approaches unity, which can be attributed to the device geometry.
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73.23.Hk Coulomb blockade; single-electron tunneling
81.07.De Nanotubes
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Temperature stability of permittivity and dielectric relaxation in multilayered thin films of (Ba0.80Sr0.20)(Ti1−xZrx)O3 with a compositionally graded layer

B. L. Cheng, Can Wang, S. Y. Wang, T. W. Button, H. B. Lu, Y. L. Zhou, Z. H. Chen, and G. Z. Yang

Appl. Phys. Lett. 84, 5431 (2004); http://dx.doi.org/10.1063/1.1767605 (3 pages) | Cited 14 times

Online Publication Date: 17 June 2004

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Mutilayered thin (Ba0.80Sr0.20)(Ti1−xZrx)O3 (BSTZ) films with various compositional graded layers (CGL) have been successfully fabricated on Nb doped SrTiO3 substrates by pulsed-laser deposition technique with four BSTZ ceramic targets (x = 0.36,0.18,0.08,0). The gradients of compositions are artificially tailored in multilayered thin films by varying the CGL, and x-ray diffraction indicates that the internal stress is modulated in the multilayered films. Influence of the composition gradient on the dielectric properties has been investigated at the temperature range from 120 to 440 K. Temperature stability of permittivity of the multilayered films is found to be improved with the increase of the gradients of compositions. Moreover, a dielectric relaxation process with activation energy of 1.02 eV is observed, which is also related to the composition gradient, and can be described to motion of oxygen vacancies. The results show that the temperature stability of permittivity can be tailed by the design of multilayered film with CGL, and the internal stress induced by the gradients of composition could influence the relaxation process.
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77.55.-g Dielectric thin films
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
68.55.-a Thin film structure and morphology
77.22.Gm Dielectric loss and relaxation
77.22.Ch Permittivity (dielectric function)
81.15.Fg Pulsed laser ablation deposition
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Photonic crystals through holographic lithography: Simple cubic, diamond-like, and gyroid-like structures

Chaitanya K. Ullal, Martin Maldovan, Edwin L. Thomas, Gang Chen, Yong-Jin Han, and Shu Yang

Appl. Phys. Lett. 84, 5434 (2004); http://dx.doi.org/10.1063/1.1765734 (3 pages) | Cited 71 times

Online Publication Date: 17 June 2004

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See Also: Erratum

Show Abstract
We show how to fabricate three basic photonic crystal structures with simple cubic, fcc, and bcc translational symmetry by interference lithography. The structures are fabricable by the interference of beams launched from the same half space. The simple cubic structure is size scalable while the structure with fcc translational symmetry possesses two band gaps. Both these structures are experimentally realized.
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42.70.Qs Photonic bandgap materials
42.82.Cr Fabrication techniques; lithography, pattern transfer

Nonlinear transmission properties of a deep-etched microstructured waveguide

S. Linden, J. P. Mondia, H. M. Van Driel, T. C. Kleckner, C. R. Stanley, D. Modotto, A. Locatelli, C. De Angelis, R. Morandotti, and J. S. Aitchison

Appl. Phys. Lett. 84, 5437 (2004); http://dx.doi.org/10.1063/1.1765738 (3 pages) | Cited 1 time

Online Publication Date: 17 June 2004

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In this letter, we investigate the nonlinear transmission properties of a one-dimensional micro-structured AlGaAs waveguide with a defect in the middle of a deep-etched Bragg grating. The transmitted spectrum depends on the spectral position of the incident pulse spectrum with respect to the defect mode as well as the pulse intensity. These findings are very important for all optical switching applications and can be explained by the interplay between self-phase modulation of the incident 250 fs pulses in the waveguide and the filtering properties of the defect mode.
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42.65.Wi Nonlinear waveguides
81.65.Cf Surface cleaning, etching, patterning
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.79.Dj Gratings
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Rotation of two-dimensional arrays of microparticles trapped by circularly polarized light

Kenji Miyakawa, Hiroto Adachi, and Yoshinori Inoue

Appl. Phys. Lett. 84, 5440 (2004); http://dx.doi.org/10.1063/1.1767953 (3 pages) | Cited 3 times

Online Publication Date: 17 June 2004

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We investigate the creation and the rotation of the array of microparticles trapped by circularly polarized light. We find that a smooth rotation requires two-dimensional structure having a rotational symmetry along the light beam axis. We show that it is possible to control smoothly both the rate and the sense of rotation not only by varying the handedness and the power of the incident beam but also by varying the position of the beam focus.
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37.10.Vz Mechanical effects of light on atoms, molecules, and ions
37.10.De Atom cooling methods
37.10.Gh Atom traps and guides
37.10.Mn Slowing and cooling of molecules
37.10.Pq Trapping of molecules
42.25.Ja Polarization
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Carbon nanotube electron source based ionization vacuum gauge

Changkun Dong and Ganapati R. Myneni

Appl. Phys. Lett. 84, 5443 (2004); http://dx.doi.org/10.1063/1.1767956 (3 pages) | Cited 7 times

Online Publication Date: 17 June 2004

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The results of fabrication and performance of an ionization vacuum gauge using a carbon nanotube electron source are presented. The electron source was constructed with multiwall nanotubes, which were grown using thermal chemical vapor deposition. The electron emission of the source was stable in vacuum pressure up to 10−7 Torr, which is better than the metal field emitters. The measurement linearity of the gauge was better than ±10% from 10−6 to 10−10 Torr. The gauge sensitivity of 4 Torr−1 was achieved under 50 μA electron emission in nitrogen. The gauge is expected to find applications in vacuum measurements from 10−7 Torr to below 10−11 Torr.
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85.35.Kt Nanotube devices
07.30.Dz Vacuum gauges
07.77.Ka Charged-particle beam sources and detectors
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Single-mode operation of terahertz quantum cascade lasers with distributed feedback resonators

Lukas Mahler, Rüdeger Köhler, Alessandro Tredicucci, Fabio Beltram, Harvey E. Beere, Edmund H. Linfield, David A. Ritchie, and A. Giles Davies

Appl. Phys. Lett. 84, 5446 (2004); http://dx.doi.org/10.1063/1.1767957 (3 pages) | Cited 15 times

Online Publication Date: 17 June 2004

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Distributed feedback terahertz quantum-cascade lasers emitting at 4.34 and 4.43 THz are presented. Mode selection is based on a complex-coupling scheme implemented into the top-contact layer by a combination of wet chemical etching and ohmic-contact deposition. Single-mode emission stable at all injection currents and operating temperatures is shown, with a side-mode suppression ratio exceeding 20 dB. Peak output powers of up to 1.8 mW are obtained at low temperatures.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
81.65.Cf Surface cleaning, etching, patterning
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