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

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

12 Nov 2007

Volume 91, Issue 20, Articles (20xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 91, 203501 (2007); http://dx.doi.org/10.1063/1.2806922 (3 pages)

Michael N. Feiginov and Dibakar Roy Chowdhury
Enlarge Image | Read More
Page 1 of 6 Pages Next Page | Jump to Page
back to top
RSS Feeds

Synthesis of efficient ZnO-based random lasing medium using laser-induced air breakdown processing

A. V. Kabashin, A. Trudeau, W. Marine, and M. Meunier

Appl. Phys. Lett. 91, 201101 (2007); http://dx.doi.org/10.1063/1.2809606 (3 pages) | Cited 3 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A simple local patterning laser-assisted method to transform bulk metallic Zn into a highly efficient ZnO-based random lasing medium is reported. The method uses the plasma of CO2 laser-induced air breakdown to treat the surface of a Zn target and thus transform it into a porous, nanostructured ZnO layer, which exhibits a strong exciton photoluminescence band in the UV (380 nm). We show that the synthesized ZnO-based material can work as an efficient random lasing medium, simultaneously strongly scattering and amplifying pumping light, leading to a mirrorless generation of few laser emission narrow (<0.5 nm) lines within the exciton band.
Show PACS
42.62.-b Laser applications
81.65.-b Surface treatments
78.55.Et II-VI semiconductors
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)

Random high-Q cavities in disordered photonic crystal waveguides

J. Topolancik, F. Vollmer, and B. Ilic

Appl. Phys. Lett. 91, 201102 (2007); http://dx.doi.org/10.1063/1.2809614 (3 pages) | Cited 14 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present direct observations of electromagnetic fields localized in disordered photonic crystal waveguides and report the modal volumes and quality factors of the confined modes. Geometrical perturbations distributed uniformly throughout the crystal lattice were introduced by changing orientations of the polygonal lattice elements. Cavities in the disordered waveguides were excited by resonant coupling through a chain of random open resonators. Localized optical resonances with sub-(λ/n)3 modal volumes and quality factors of up to ∼ 150 000 were observed.
Show PACS
61.72.Qq Microscopic defects (voids, inclusions, etc.)
61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling

Size dependence of nonlinear optical absorption and refraction of Mn-doped ZnSe nanocrystals

Chenli Gan, Min Xiao, David Battaglia, Narayan Pradhan, and Xiaogang Peng

Appl. Phys. Lett. 91, 201103 (2007); http://dx.doi.org/10.1063/1.2811713 (3 pages) | Cited 14 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nonlinear refractive index and nonlinear absorption coefficient of high-quality Mn:ZnSe nanocrystals are measured by z-scan technique at 800 nm wavelength. The synthesized nanocrystals with nucleation doping have tunable wavelength (between 565–610 nm), high quantum yield ( ∼ 50%), and high thermal as well as photochemical stabilities. The unique nanocrystal structure (with a MnSe core, Zn1−xMnxSe diffusion region, and an outer ZnSe layer) shows size-dependent nonlinear effects, which can be qualitatively explained by a simple model using crystal field. Studies of nonlinear optical properties are very important and necessary for high-power optical applications (such as light-emitting diodes and lasers) of such Mn-doped ZnSe nanocrystals.
Show PACS
78.67.Bf Nanocrystals, nanoparticles, and nanoclusters
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
81.07.Bc Nanocrystalline materials
81.05.Dz II-VI semiconductors
42.65.-k Nonlinear optics

Recombination dynamics and lasing in ZnO/ZnMgO single quantum well structures

T. V. Shubina, A. A. Toropov, O. G. Lublinskaya, P. S. Kop’ev, S. V. Ivanov, A. El-Shaer, M. Al-Suleiman, A. Bakin, A. Waag, A. Voinilovich, E. V. Lutsenko, G. P. Yablonskii, J. P. Bergman, G. Pozina, and B. Monemar

Appl. Phys. Lett. 91, 201104 (2007); http://dx.doi.org/10.1063/1.2812549 (3 pages) | Cited 6 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report a time-resolved study of the recombination dynamics in molecular beam epitaxy grown ZnO/ZnMgO single quantum wells (SQWs) of 1.0–4.5 nm width. The SQWs exhibit different emission properties, depending on both the well width and defect density. Stimulated emission has been achieved at room temperature in a separate confinement double heterostructure having a 3 nm wide SQW as an active region. It has been found that a critical parameter for the lasing is the inhomogeneous broadening of both QW and barrier emission bands.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.45.+h Stimulated emission
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Current-induced heating in quantum well and quantum wire intersubband emitter structures

Thomas Herrle, Stephan Haneder, Hans-Peter Tranitz, Matthias Reinwald, and Werner Wegscheider

Appl. Phys. Lett. 91, 201105 (2007); http://dx.doi.org/10.1063/1.2805813 (3 pages)

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We discuss the influence of current-induced heating on the current-voltage (I-V) characteristics and the spectral behavior in quantum well and quantum wire intersubband emitter structures. A conventional quantum cascade laser structure in the AlGaAs/GaAs material system with undoped cladding layers and an undoped active region is examined. This heterostructure serves as a first growth step for quantum wire intersubband emitters fabricated by the cleaved-edge overgrowth technique. We discuss the influence of electrons supplied by a remote δ-silicon doping. Duty-cycle dependent measurements on the quantum wire structures confirm the influence of current-induced heating on the I-V characteristics as well as on the emission spectra.
Show PACS
73.63.Hs Quantum wells
73.63.Kv Quantum dots
78.67.De Quantum wells
78.67.Hc Quantum dots
78.55.Cr III-V semiconductors

Zn0.76Mg0.24O homojunction photodiode for ultraviolet detection

K. W. Liu, D. Z. Shen, C. X. Shan, J. Y. Zhang, B. Yao, D. X. Zhao, Y. M. Lu, and X. W. Fan

Appl. Phys. Lett. 91, 201106 (2007); http://dx.doi.org/10.1063/1.2805816 (3 pages) | Cited 13 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Zn0.76Mg0.24O p-n photodiode was fabricated on (000l) Al2O3 substrate by plasma-assisted molecular beam epitaxy. Ni/Au and In metals deposited using vacuum evaporation were used as p-type and n-type contacts, respectively. Current-voltage measurements on the device showed weak rectifying behavior. The photodetectors exhibited a peak responsivity at around 325 nm. The ultraviolet-visible rejection ratio (R325 nm/R400 nm) of four orders of magnitude was obtained at 6 V bias. The photodetector showed fast photoresponse with a rise time of 10 ns and fall time of 150 ns. In addition, the thermally limited detectivity was calculated as 1.8×1010 cm Hz1/2/W at 325 nm, which corresponds to a noise equivalent power of 8.4×10−12 W/Hz1/2 at room temperature.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.60.Dw Photodiodes; phototransistors; photoresistors

Optical upconversion devices based on photosensitizer-doped organic light-emitting diodes

Jiashu Lu, Yuan Zheng, Zhijian Chen, Lixin Xiao, and Qihuang Gong

Appl. Phys. Lett. 91, 201107 (2007); http://dx.doi.org/10.1063/1.2813619 (3 pages) | Cited 2 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical upconversion of infrared light to visible light has been achieved in photosensitizer-doped organic light-emitting diodes, where poly(N-vinylcarbazole) doped with infrared photosensitizer of 2,4,7-trinitro-9-fluorenylidene)malonitrile was used as hole-transporting layer, and tris(8-hydroxyquinoline) aluminum acted as both emitting and electron-transporting layers. Both electroluminescent intensity and current were enhanced under infrared illumination. The enhancement ratio was obtained as 2.45 times for electroluminescent emission and 1.45 times for current. This work brought forth a prototype design for novel flexible organic optical upconversion device used in near infrared field.
Show PACS
85.60.Jb Light-emitting devices
85.60.Gz Photodetectors (including infrared and CCD detectors)

Entanglement generation using silicon wire waveguide

Hiroki Takesue, Yasuhiro Tokura, Hiroshi Fukuda, Tai Tsuchizawa, Toshifumi Watanabe, Koji Yamada, and Sei-ichi Itabashi

Appl. Phys. Lett. 91, 201108 (2007); http://dx.doi.org/10.1063/1.2814040 (3 pages) | Cited 22 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report an entanglement generation experiment that utilizes a silicon waveguide. Using spontaneous four-wave mixing in a 1.09-cm-long silicon wire waveguide, we generated 1.5 μm, high-purity time-bin entangled photons without temperature control and observed a two-photon interference fringe with >73% visibility.
Show PACS
42.65.Wi Nonlinear waveguides
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
03.67.Dd Quantum cryptography and communication security
42.50.Hz Strong-field excitation of optical transitions in quantum systems; multiphoton processes; dynamic Stark shift

Transmission of pillar-based photonic crystal waveguides in InP technology

Abigaël Kok, Erik Jan Geluk, Boudewijn Docter, Jos van der Tol, Richard Nötzel, Meint Smit, and Roel Baets

Appl. Phys. Lett. 91, 201109 (2007); http://dx.doi.org/10.1063/1.2814041 (3 pages) | Cited 7 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Waveguides based on line defects in pillar photonic crystals have been fabricated in InP/InGaAsP/InP technology. Transmission measurements of different line defects are reported. The results can be explained by comparison with two-dimensional band diagram simulations. The losses increase substantially at mode crossings and in the slow light regime. The agreement with the band diagrams implies a good control on the dimensions of the fabricated features, which is an important step in the actual application of these devices in photonic integrated circuits.
Show PACS
42.70.Qs Photonic bandgap materials
42.82.Et Waveguides, couplers, and arrays
78.66.Fd III-V semiconductors
42.82.Cr Fabrication techniques; lithography, pattern transfer

Optical limiting using Laguerre-Gaussian beams

Weiya Zhang and Mark G. Kuzyk

Appl. Phys. Lett. 91, 201110 (2007); http://dx.doi.org/10.1063/1.2814886 (3 pages) | Cited 2 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate optical limiting using the self-lensing effect of a higher-order Laguerre-Gaussian beam in a thin dye-doped polymer sample, which we find consistent with our model using Gaussian decomposition. The peak phase shift in the sample required for limiting is smaller than that for a fundamental Gaussian beam with the added flexibility that the nonlinear medium can be placed either in front of or behind the beam focus.
Show PACS
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.70.Jk Polymers and organics
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.79.Wc Optical coatings

Electrically probing photonic bandgap phenomena in contacted defect nanocavities

F. Hofbauer, S. Grimminger, J. Angele, G. Böhm, R. Meyer, M. C. Amann, and J. J. Finley

Appl. Phys. Lett. 91, 201111 (2007); http://dx.doi.org/10.1063/1.2812576 (3 pages) | Cited 12 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate an electrically tunable two dimensional photonic crystal nanocavity containing InAs self-assembled quantum dots (QDs). Photoluminescence and electroluminescence measurements are combined to probe the cavity mode structure and demonstrate a local electrical contact to the quantum dots. Measurements performed as a function of the electric field enable us to probe the capture, relaxation, and recombination dynamics of photogenerated carriers inside the quantum dots emitting into a modified photonic environment. Furthermore, the two dimensional photonic crystal is probed by spatially dependent photocurrent spectroscopy indicating a 3.5× enhancement of the local radiative lifetime of the QDs inside the photonic crystal environment.
Show PACS
73.40.-c Electronic transport in interface structures
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
42.70.Qs Photonic bandgap materials
78.55.-m Photoluminescence, properties and materials
78.60.Fi Electroluminescence
72.40.+w Photoconduction and photovoltaic effects

Fabrication and characterization of two-dimensional photonic crystal microcavities in nanocrystalline diamond

C. F. Wang, R. Hanson, D. D. Awschalom, E. L. Hu, T. Feygelson, J. Yang, and J. E. Butler

Appl. Phys. Lett. 91, 201112 (2007); http://dx.doi.org/10.1063/1.2813023 (3 pages) | Cited 72 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Diamond-based photonic devices offer exceptional opportunity to study cavity quantum electrodynamics at room temperature. Here we report fabrication and optical characterization of high quality photonic crystal microcavities based on nanocrystalline diamond. Fundamental modes near the emission wavelength of negatively charged nitrogen-vacancy centers (637 nm) with quality factors as high as 585 were observed. Three-dimensional finite-difference time-domain simulations were carried out, having excellent agreement with the experimental results in the values of the mode frequencies. Polarization of the modes was measured; their anomalous behavior provides important insights to scattering loss in these structures.
Show PACS
42.82.Cr Fabrication techniques; lithography, pattern transfer
42.86.+b Optical workshop techniques
42.70.Qs Photonic bandgap materials

Influence of electric field on spectral positions of dislocation-related luminescence peaks in silicon: Stark effect

T. Mchedlidze, T. Arguirov, M. Kittler, T. Hoang, J. Holleman, and J. Schmitz

Appl. Phys. Lett. 91, 201113 (2007); http://dx.doi.org/10.1063/1.2813024 (3 pages) | Cited 4 times

Online Publication Date: 14 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spectral positions of dislocation-related luminescence (DRL) peaks from dislocation loops located close to a p-n junction in silicon were shifted by carrier injection level. We suppose that the excitonic transition energies of DRL were reduced by an effective electric field at dislocation sites due to quadratic Stark effect (QSE). The field results from built-in junction field reduced by carrier injection. A constant of the shift, obtained from fitting of the data with QSE equation, was 0.0186 meV/(kV/cm)2. The effect can explain the diversity of DRL spectra in silicon and may allow tuning and modulation of DRL for future photonic applications.
Show PACS
71.55.Cn Elemental semiconductors
78.55.Ap Elemental semiconductors
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Free-running InGaAs/InP avalanche photodiode with active quenching for single photon counting at telecom wavelengths

R. T. Thew, D. Stucki, J.-D. Gautier, H. Zbinden, and A. Rochas

Appl. Phys. Lett. 91, 201114 (2007); http://dx.doi.org/10.1063/1.2815916 (3 pages) | Cited 21 times

Online Publication Date: 15 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present an InGaAs/InP avalanche photodiode with an active quenching circuit on an application specific integrated circuit (ASIC) that is capable of operating in both gated and free-running modes. The 1.6 mm2 ASIC chip is fabricated using complementary metal oxide semiconductor technology guaranteeing long-term stability, reliability, and compactness. In the free-running mode, we find a single photon detection efficiency of 10% with <2 kHz of noise.
Show PACS
78.66.Fd III-V semiconductors
85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)

Influence of nonlinear loss competition on pulse compression and nonlinear optics in silicon

En-Kuang Tien, Feng Qian, Nuh S. Yuksek, and Ozdal Boyraz

Appl. Phys. Lett. 91, 201115 (2007); http://dx.doi.org/10.1063/1.2807273 (3 pages) | Cited 8 times

Online Publication Date: 16 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Aggregate nonlinear response of silicon is determined by the competition between the free carrier absorption (FCA) and two-photon absorption (TPA). We show that the front end of optical pulses is always exposed to TPA dominated nonlinear regime, whereas the trailing edge can be seen at FCA dominated regime at high intensities. These two losses can be used for pulse compression if the center of the pulse is in FCA dominated nonlinear regime. To reach this operation regime, energy of 50 ps wide pulses has to be larger than 50 nJ (40 GW/cm2). Competition phenomenon is observed experimentally in a mode locked laser setup to generate 60 ps pulse of 60 nJ.
Show PACS
42.65.-k Nonlinear optics
42.60.Fc Modulation, tuning, and mode locking

One dimensional and two dimensional photonic crystal GaInSb/AlGaAsSb microlasers

M. Mueller, A. Bauer, T. Lehnhardt, K. Rössner, M. Hümmer, and A. Forchel

Appl. Phys. Lett. 91, 201116 (2007); http://dx.doi.org/10.1063/1.2805031 (3 pages) | Cited 1 time

Online Publication Date: 16 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The authors present microlasers on the GaInSb/AlGaAsSb material system. These microlasers are equipped with one dimensional or two dimensional photonic crystals (PhCs) acting as highly reflecting microscaled mirrors. Hence, microlasers with cavity lengths as short as 100 μm could be realized, exhibiting output powers per facet of up to 6 mW and side mode suppression ratios of 20 dB in continuous wave operation.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.55.Tv Photonic crystal lasers and coherent effects
42.55.Sa Microcavity and microdisk lasers
42.60.By Design of specific laser systems
42.70.Qs Photonic bandgap materials
42.79.Bh Lenses, prisms and mirrors

Spectrally narrowed emissions occurring near an interface between a single crystal thiophene/phenylene co-oligomer and a glass substrate

Takeshi Yamao, Kazunori Yamamoto, Yuki Taniguchi, and Shu Hotta

Appl. Phys. Lett. 91, 201117 (2007); http://dx.doi.org/10.1063/1.2815642 (3 pages) | Cited 12 times

Online Publication Date: 16 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polarized emission microspectroscopy has been investigated on a single crystal of a thiophene/phenylene co-oligomer. We measured polarized emissions occurring from the thin cloven facets of the crystal mounted on a glass substrate. The polarized UV light from a mercury lamp was used for the excitation. The spectrally narrowed emissions have been observed with an unusually low excitation intensity ( ∼ 90 mW/cm2) at the parts of the substrate very close to the interface between the crystal and the substrate.
Show PACS
78.55.Kz Solid organic materials
78.20.-e Optical properties of bulk materials and thin films
61.50.-f Structure of bulk crystals
61.66.Hq Organic compounds

Investigation of violet InGaN laser diodes with normal and reversed polarizations

Sheng-Horng Yen, Yen-Kuang Kuo, Meng-Lun Tsai, and Ta-Cheng Hsu

Appl. Phys. Lett. 91, 201118 (2007); http://dx.doi.org/10.1063/1.2815652 (3 pages) | Cited 2 times

Online Publication Date: 16 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The polarity is a special property for III-nitride materials with wurtzite structure along different orientations. The influence of normal and reversed polarizations on laser performance of the violet laser diodes with Ga-face and N-face configurations is studied numerically. Specifically, the laser performance, band diagram, carrier confinement, and emission wavelength are investigated. The results show that the threshold current is improved and emission wavelength is redshifted when the laser diode is with reversed polarization.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.70.Hj Laser materials
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
back to top
RSS Feeds

Subwavelength imaging by metallic slab lens with nanoslits

Ting Xu, Cunlei Du, Changtao Wang, and Xiangang Luo

Appl. Phys. Lett. 91, 201501 (2007); http://dx.doi.org/10.1063/1.2811711 (3 pages) | Cited 15 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A metallic slab lens featured with specially designed nano slits is presented to realize imaging for arbitrary object and image distances. Based on the particular propagation properties of surface plasmon polaritons in nanostructures, slits perforated in silver slab are designed with variant widths to produce desired optical phase retardations. Numerical simulation of an illustrative lens is performed through finite-difference time-domain method and shows that subwavelength imaging is realized at the designed position.
Show PACS
42.79.Bh Lenses, prisms and mirrors
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
71.36.+c Polaritons (including photon-phonon and photon-magnon interactions)

Electron temperature measurements in plasmas with surface wave absorption and wave cutoff frequency

Jung-Hyung Kim, S. J. You, Dae-Jin Seong, and Yong-Hyeon Shin

Appl. Phys. Lett. 91, 201502 (2007); http://dx.doi.org/10.1063/1.2812567 (3 pages) | Cited 2 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method for the measurements of electron temperature in the plasma using cutoff frequency and surface wave absorption frequency is described. The cutoff frequency, which gives directly the plasma density, is obtained from the transmission spectrum measured between two antennas exposed to the plasma. The surface wave absorption frequency, which has the information of the sheath determined by the electron density and the electron temperature, is obtained from the reflection spectrum measured at radiating antenna. The electron temperature is derived from the dispersion equation of the surface wave with the electron density measured from cutoff frequency.
Show PACS
52.35.Hr Electromagnetic waves (e.g., electron-cyclotron, Whistler, Bernstein, upper hybrid, lower hybrid)
52.25.-b Plasma properties
52.40.Kh Plasma sheaths

Gas-discharge plasma sources for nonlocal plasma technology

V. I. Demidov, C. A. DeJoseph, Jr., and V. Ya. Simonov

Appl. Phys. Lett. 91, 201503 (2007); http://dx.doi.org/10.1063/1.2815930 (3 pages) | Cited 3 times

Online Publication Date: 15 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nonlocal plasma technology is based on the effect of self-trapping of fast electrons in the plasma volume [ V. I. Demidov, C. A. DeJoseph, Jr., and A. A. Kudryavtsev, Phys. Rev. Lett. 95, 215002 (2006) ]. This effect can be achieved by changing the ratio of fast electron flux to ion flux incident on the plasma boundaries. This in turn leads to a significant change in plasma properties and therefore can be useful for technological applications. A gas-discharge device which demonstrates control of the plasma properties by this method is described.
Show PACS
52.50.Dg Plasma sources
52.80.-s Electric discharges

A high-brightness circular charged-particle beam system

T. Bemis, R. Bhatt, C. Chen, and J. Zhou

Appl. Phys. Lett. 91, 201504 (2007); http://dx.doi.org/10.1063/1.2815938 (3 pages)

Online Publication Date: 15 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method is presented for the design of a high-brightness nonrelativistic circular beam system including a charged-particle emitting diode, a diode aperture, a circular beam tunnel, and a focusing magnetic field that matches the beam from the emitter to the beam tunnel. The applied magnetic field is determined by balancing the forces throughout the gun and transport sections of the beam system. The method is validated by three-dimensional simulations.
Show PACS
29.27.-a Beams in particle accelerators
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)

The magnetic-field-induced transition from an expanding plasma to a double layer containing expanding plasma

C. Charles and R. W. Boswell

Appl. Phys. Lett. 91, 201505 (2007); http://dx.doi.org/10.1063/1.2814877 (3 pages) | Cited 33 times

Online Publication Date: 16 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic-field-induced transition from a simple expansion to a double layer is experimentally investigated in an argon low pressure radio frequency helicon source plasma. When the magnetic field is increased from 30 to 140 G in the plasma source, an abrupt increase in the plasma density and upstream potential is measured at 50 G. In the downstream plasma, the plasma density and potential show a small decrease with increasing magnetic field and no abrupt change. When the upstream jump is measured, simultaneous measurements in the downstream plasma show an ion beam characteristic of a double layer near the source exit.
Show PACS
52.50.Dg Plasma sources
52.25.Fi Transport properties
52.70.Ds Electric and magnetic measurements
back to top
RSS Feeds

Evolution of optical phonons in CdS nanowires, nanobelts, and nanosheets

Kyoung-Yeon Lee, Jung-Ran Lim, Heesuk Rho, Young-Jin Choi, Kyoung Jin Choi, and Jae-Gwan Park

Appl. Phys. Lett. 91, 201901 (2007); http://dx.doi.org/10.1063/1.2806937 (3 pages) | Cited 19 times

Online Publication Date: 12 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report Raman scattering from single and ensemble CdS nanowires, nanobelts, and nanosheets. The Raman spectra of nanobelts and nanosheets are notably different from those of nanowires, exhibiting a strong enhancement of the multiphonon response. Moreover, the first-order longitudinal optical (LO) phonon energy systematically increases with increasing lateral size from nanowires to nanobelts, and to nanosheets. These results suggest that the optical phonons in the CdS nanostructures are influenced by strain, crystallinity, and exciton-LO phonon coupling.
Show PACS
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
68.65.La Quantum wires (patterned in quantum wells)

Bulk silicon is susceptible to fatigue

Sanjit Bhowmick, Juan José Meléndez-Martínez, and Brian R. Lawn

Appl. Phys. Lett. 91, 201902 (2007); http://dx.doi.org/10.1063/1.2801390 (3 pages) | Cited 5 times

Online Publication Date: 13 November 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It has long been held that bulk silicon is immune from fatigue. We present contrary evidence demonstrating severe fatigue in macroscale cracks produced in cyclic loading of single-crystal silicon with a sphere indenter. The key ingredient is a component of shear stress acting on the cracks during contraction and expansion of the contact circle. This gives rise to frictional sliding at the crack walls, dislodging and ejecting slabs of material and debris onto the silicon surface. The damage expands with continued cycling, leading to progressive degradation of the surface. The results have implications concerning the function of silicon-based devices.
Show PACS
81.05.Cy Elemental semiconductors
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.M- Structural failure of materials
81.40.Pq Friction, lubrication, and wear
62.20.Qp Friction, tribology, and hardness
Page 1 of 6 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close