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

8 Nov 2010

Volume 97, Issue 19, Articles (19xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 97, 193101 (2010); http://dx.doi.org/10.1063/1.3504664 (3 pages)

Qingzhen Hao, Yong Zeng, Xiande Wang, Yanhui Zhao, Bei Wang, I-Kao Chiang, Douglas H. Werner, Vincent Crespi, and Tony Jun Huang
Enlarge Image | Read More
Page 1 of 4 Pages Next Page | Jump to Page
back to top
RSS Feeds

Terahertz intersubband absorption in GaN/AlGaN step quantum wells

H. Machhadani, Y. Kotsar, S. Sakr, M. Tchernycheva, R. Colombelli, J. Mangeney, E. Bellet-Amalric, E. Sarigiannidou, E. Monroy, and F. H. Julien

Appl. Phys. Lett. 97, 191101 (2010); http://dx.doi.org/10.1063/1.3515423 (3 pages) | Cited 10 times

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate terahertz intersubband absorptions at frequencies of 2.1 THz (λ ≈ 143 μm) and 4.2 THz (λ ≈ 70 μm) in nitride-based semiconductor quantum wells. The structures consist of a 3 nm thick GaN well, an Al0.05Ga0.95N step barrier, and a 3 nm thick Al0.1Ga0.9N barrier. The absorption is detected at 4.7 K. The structure design has been optimized to approach a flat-band potential in the wells to allow for an intersubband absorption in the terahertz frequency range and to maximize the optical dipole moments.
Show PACS
73.21.Fg Quantum wells
78.70.Gq Microwave and radio-frequency interactions
78.67.De Quantum wells

Enhancement of spontaneous emission rate and reduction in amplified spontaneous emission threshold in electrodeposited three-dimensional ZnO photonic crystal

Yongchun Zhong, Zhounan Yue, George K. L. Wong, Yan Yan Xi, Yuk Fan Hsu, Aleksandra B. Djurišić, Jian-Wen Dong, Wen-Jie Chen, and Kam Sing Wong

Appl. Phys. Lett. 97, 191102 (2010); http://dx.doi.org/10.1063/1.3499274 (3 pages)

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
ZnO photonic crystal (PC) with face-center-cube type structure is fabricated by electrodeposition using holographic lithographically made organic (SU-8) template. Photonic band gap effect (reflection peak and transmission dip in infrared spectral region) is clearly seen. Observation of strong enhancement and blueshift of the emission peak (from 383.8 to 378.8 nm), shortening of the exciton photoluminescence lifetime (from 88 to 34 ps), and reduction in amplified spontaneous emission threshold of ZnO PC compared to that of the reference nonstructured electrodeposited ZnO showed clear evidence of PC structure affecting the ZnO exciton emission.
Show PACS
81.05.Dz II-VI semiconductors
81.15.Pq Electrodeposition, electroplating
78.67.Pt Multilayers; superlattices; photonic structures; metamaterials
78.55.Et II-VI semiconductors
78.45.+h Stimulated emission
42.70.Qs Photonic bandgap materials

AlGaN solar-blind avalanche photodiodes with high multiplication gain

Lu Sun, Jilin Chen, Jianfei Li, and Hao Jiang

Appl. Phys. Lett. 97, 191103 (2010); http://dx.doi.org/10.1063/1.3515903 (3 pages) | Cited 3 times

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the fabrication and characterization of the solar-blind AlGaN avalanche photodiodes grown by metal-organic chemical vapor deposition on c-plane sapphire substrate. The fabricated devices with 100 μm diameter active area exhibit a peak responsivity of 79.8 mA/W at 270 nm and zero bias, corresponding to an external quantum efficiency of 37%. Multiplication gains as high as more than 2500 were obtained in these devices.
Show PACS
85.30.Kk Junction diodes
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Enhancement of random lasing through fluorescence resonance energy transfer and light scattering mediated by nanoparticles

C. S. Wang, Y. L. Chen, H. Y. Lin, Y. T. Chen, and Y. F. Chen

Appl. Phys. Lett. 97, 191104 (2010); http://dx.doi.org/10.1063/1.3515913 (3 pages) | Cited 3 times

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A simple approach for the enhancement of random lasing based on fluorescence resonance energy transfer and light scattering mediated by nanoparticles is reported. To illustrate our working principle, ZnO nanorods decorated with TiO2 nanoparticles were chosen as an example. It is shown that the random laser action of ZnO nanorods can be significantly improved by the assistance of TiO2 nanoparticles. Moreover, due to the inherent nature of higher refractive index of TiO2 than ZnO, the TiO2 nanoparticles can serve efficiently as better nanoscatterers, which can promote the formation of closed-loop paths. Our strategy provided here is very useful for the future development of high efficiency optoelectronic devices.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Electroluminescence from AlN nanowires grown on p-SiC substrate

H. Y. Yang, S. F. Yu, Y. Y. Hui, and S. P. Lau

Appl. Phys. Lett. 97, 191105 (2010); http://dx.doi.org/10.1063/1.3513308 (3 pages) | Cited 1 time

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Aluminum nitride (AlN) nanowires were prepared by the carbothermal reduction method. A heterojunction light-emitting diode (LED) was fabricated by depositing randomly aligned AlN nanowires onto p-type 4H–SiC substrate. When a forward bias voltage greater than 8 V was applied to the LED, a broad band emission peaked at 417 nm could be observed. The peak deconvolution revealed four emission peaks at ∼ 400, 420, 468, and 525 nm. These emission peaks may be attributed to the radiative recombination between electrons from trap-level states and holes from the valence band of the AlN nanowires.
Show PACS
85.60.Jb Light-emitting devices
81.07.Gf Nanowires
78.67.Lt Quantum wires
81.05.Ea III-V semiconductors
78.60.Fi Electroluminescence
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping

Crystal defect topography of Stranski–Krastanow quantum dots by atomic force microscopy

K. Gradkowski, T. C. Sadler, L. O. Mereni, V. Dimastrodonato, P. J. Parbrook, G. Huyet, and E. Pelucchi

Appl. Phys. Lett. 97, 191106 (2010); http://dx.doi.org/10.1063/1.3514237 (3 pages) | Cited 1 time

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a technique to monitor the defect density in capped quantum dot (QD) structures by performing an atomic force microscopy (AFM) of the final surface. Using this method we are able to correlate their density with the optical properties of the dot structures grown at different temperatures. Parallel transmission electron microscopy analysis shows that the AFM features are directly correlated with the density of stacking faults that originate from abnormally large dots. The technique is rapid and noninvasive making it an ideal diagnostic tool for optimizing the parameters of practical QD-based devices.
Show PACS
68.37.Ps Atomic force microscopy (AFM)
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
73.61.Ey III-V semiconductors
61.72.Nn Stacking faults and other planar or extended defects
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Strong light-matter coupling at terahertz frequencies at room temperature in electronic LC resonators

Markus Geiser, Christoph Walther, Giacomo Scalari, Mattias Beck, Milan Fischer, Laurent Nevou, and Jérôme Faist

Appl. Phys. Lett. 97, 191107 (2010); http://dx.doi.org/10.1063/1.3511446 (3 pages) | Cited 3 times

Online Publication Date: 9 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Strong light-matter coupling at room temperature in the terahertz (THz) range is demonstrated. The studied system consists of electronic intersubband transitions in AlxGa1−xAs parabolic quantum wells coupled to an electronic LC microcavity resonator allowing strong subwavelength confinement of the cavity mode. The measured Rabi frequency is 0.48 THz, corresponding to 14% of the center frequency, independent of the temperature of the system in the range 10–300 K.
Show PACS
78.67.De Quantum wells
81.05.Ea III-V semiconductors
73.21.Fg Quantum wells

Zero-cell photonic crystal nanocavity laser with quantum dot gain

Masahiro Nomura, Yasutomo Ota, Naoto Kumagai, Satoshi Iwamoto, and Yasuhiko Arakawa

Appl. Phys. Lett. 97, 191108 (2010); http://dx.doi.org/10.1063/1.3514556 (3 pages) | Cited 3 times

Online Publication Date: 9 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate laser oscillation in a hexagonal-lattice photonic crystal nanocavity using an InGaAs quantum dot gain material by optical pumping at 5 K. The cavity comprises a defect created by shifting several air holes in a two-dimensional photonic crystal slab structure without removing any air holes to achieve both small mode volume and a high cavity quality factor. The measured cavity quality factors and estimated mode volume for the nanocavity are ∼ 33 000 and 0.004 μm3 [0.23(λ0/n)3]. The laser threshold is compared between the zero-cell and L3-type nanocavity lasers, and the zero-cell nanolasers are found to have lower thresholds of about one-third of the L3-type nanolasers. This result suggests that a higher Purcell factor of the zero-cell nanolaser is reflected as a lower laser threshold.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.70.Qs Photonic bandgap materials
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Lambda shifted photonic crystal cavity laser

Martin Schubert, Troels Suhr, Sara Ek, Elizaveta S. Semenova, Jørn M. Hvam, and Kresten Yvind

Appl. Phys. Lett. 97, 191109 (2010); http://dx.doi.org/10.1063/1.3501968 (3 pages) | Cited 1 time

Online Publication Date: 10 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose and demonstrate an alternative type of photonic crystal laser design that shifts all the holes in the lattice by a fixed fraction of the targeted emission wavelength. The structures are realized in InGaAsP (λ = 1.15) with InGaAsP quantum wells (λ = 1.52) as gain material. Cavities with shifts of 1/4 and 3/4 of the emission wavelength were fabricated and characterized. Measurements show threshold behavior for several modes at room temperature. Both structures are simulated using a finite difference time domain method to identify the resonances in the spectra and calculate the mode volume of the dominant mode.
Show PACS
42.55.Tv Photonic crystal lasers and coherent effects
42.70.Qs Photonic bandgap materials
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems
42.70.Hj Laser materials
42.55.Px Semiconductor lasers; laser diodes
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Influence of the spatial pump distribution on the performance of high power vertical-external-cavity surface-emitting lasers

A. Chernikov, J. Herrmann, M. Scheller, M. Koch, B. Kunert, W. Stolz, S. Chatterjee, S. W. Koch, T. L. Wang, Y. Kaneda, J. M. Yarborough, J. Hader, and J. V. Moloney

Appl. Phys. Lett. 97, 191110 (2010); http://dx.doi.org/10.1063/1.3515911 (3 pages) | Cited 1 time

Online Publication Date: 10 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The performance of a 1040 nm vertical-external-cavity surface-emitting laser is studied as function of the size and shape of the pumped area. The input-output characteristics of the device are monitored while simultaneously tracking the temperature in the active region. It is shown that the pump spot shape plays a crucial role in optimizing the laser output. Improvements up to a factor of 5 are found for a super-Gaussian in comparison to the standard Gaussian shape. For the large pump-spot sizes needed for high output powers, it turns out that the power-scalability breaks down due to the suppressed lateral heat flow.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.By Design of specific laser systems

The antiguiding parameter in mid-infrared optically pumped semiconductor lasers

A. P. Ongstad, G. C. Dente, M. L. Tilton, R. Kaspi, and J. R. Chavez

Appl. Phys. Lett. 97, 191111 (2010); http://dx.doi.org/10.1063/1.3509798 (3 pages)

Online Publication Date: 10 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We describe measurements of the antiguiding parameter, α, for several optically pumped semiconductor lasers. Three laser structures were investigated; two of the lasers utilize W-quantum wells (QWs) in which 14 InAs/In0.4 GaSb/InAs QWs are imbedded in lattice-matched In0.25 GaAsSb layers. The emission wavelengths of the W lasers were ∼ 3.5 and 4.5 μm, respectively. The other laser, a double heterostructure (DH) design, contained a ∼ 1.5 μm InAsSb active region embedded in ∼ 2.5 μm thick AlAsSb clad regions. The emission wavelength of the DH was λ ∼ 3.8 μm. We employed the Hakki–Paoli method [ B. W. Hakki and T. L. Paoli, J. Appl. Phys., 44, 4113, (1973)] in conjunction with a Fourier transform infrared spectrometer to measure subthreshold gain and index variations as a function of pump intensity. To reduce errors associated with incoherent background emission a full spectral curve fit was used to determine the differential gain and index. The results reveal the antiguiding factor in the W lasers to be low with α ∼ 1.0. The antiguiding factor for the DH was markedly larger with α = 9.4±1.3. We attribute the low α for the W lasers to the higher QW gain as well as to inhomogeneous broadening induced by the 14 QWs. The differing well widths and the independent optical pumping of the wells, leads to a net gain spectrum that is symmetrical about the gain peak. This symmetry, in turn, leads to small differential index shifts at the gain peak; the result of the small differential index and large differential gain is low antiguiding
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Electrostatically tunable optomechanical “zipper” cavity laser

R. Perahia, J. D. Cohen, S. Meenehan, T. P. Mayer Alegre, and O. Painter

Appl. Phys. Lett. 97, 191112 (2010); http://dx.doi.org/10.1063/1.3515296 (3 pages) | Cited 5 times

Online Publication Date: 12 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A tunable nanoscale “zipper” laser cavity, formed from two doubly clamped photonic crystal nanobeams, is demonstrated. Pulsed, room temperature, optically pumped lasing action at λ = 1.3 μm is observed for cavities formed in a thin membrane containing InAsP/GaInAsP quantum-wells. Metal electrodes are deposited on the ends of the nanobeams to allow for microelectromechanical actuation. Electrostatic tuning over a range of Δλ = 20 nm for an applied voltage amplitude of 9 V and modulation at a frequency as high as νm = 6.7 MHz of the laser wavelength is demonstrated.
Show PACS
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.60.Fc Modulation, tuning, and mode locking
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)

Continuous control of spatial mode rotation using second harmonic generation

Jun-Hee Park, Woo-Kyung Kim, Woo-Jin Jeong, Myung-Gun Song, Hun-Hwa Kim, Kyung-Hwan Koo, Yeung-Lak Lee, Yena Kim, Ju-Han Lee, Woo-Seok Yang, and Han-Young Lee

Appl. Phys. Lett. 97, 191113 (2010); http://dx.doi.org/10.1063/1.3507267 (3 pages)

Online Publication Date: 12 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This paper reports a continuously rotating spatial mode contributed from the interference between two second harmonic (SH) high-order modes, TM10 and TM01, which were generated in z-cut MgO:LN ridge waveguides with a periodically poled structure. The TM10 and TM01 SH modes were generated from the mixed first harmonic (FH) modes, the phase-matching conditions of the two modes were controlled to be close and to overlap so that the two modes can interference each other. The experiment results showed the interference of the two modes created an odd mode distribution with a specific angle and the distribution was continuously rotating according to the operation temperature.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.Wi Nonlinear waveguides
42.79.Nv Optical frequency converters

Birefringence controlled room-temperature picosecond spin dynamics close to the threshold of vertical-cavity surface-emitting laser devices

M. Y. Li, H. Jähme, H. Soldat, N. C. Gerhardt, M. R. Hofmann, and T. Ackemann

Appl. Phys. Lett. 97, 191114 (2010); http://dx.doi.org/10.1063/1.3515855 (3 pages) | Cited 4 times

Online Publication Date: 12 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We analyze the spin-induced circular polarization dynamics at the threshold of vertical-cavity surface-emitting lasers at room-temperature using a hybrid excitation combining electrically pumping without spin preference and spin-polarized optical injection. After a short pulse of spin-polarized excitation, fast oscillations of the circular polarization degree (CPD) are observed within the relaxation oscillations. A theoretical investigation of this behavior on the basis of a rate equation model shows that these fast oscillations of CPD could be suppressed by means of a reduction of the birefringence of the laser cavity.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Ultrasharp edge filtering in nanotethered photonic wires

A. Talneau, I. Sagnes, R. Gabet, Y. Jaouen, and H. Benisty

Appl. Phys. Lett. 97, 191115 (2010); http://dx.doi.org/10.1063/1.3513279 (3 pages) | Cited 1 time

Online Publication Date: 12 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Within a suspended photonic wire, the periodically-spaced nanotethers sustaining the wire can behave as damped transverse resonators that interact with the partially reflecting effect of the wire-tether intersection, and thus modify the Bragg reflection mechanism. This specific resonant mechanism is explored using a transfer matrix model, and is shown to result in an ultrasharp filter edge. This sharp behavior is evidenced experimentally on 300–400-nm-wide InP suspended wires through transmission data and further consolidated by optical low coherence reflectometry time-frequency analysis.
Show PACS
42.79.Ci Filters, zone plates, and polarizers
81.07.Gf Nanowires
42.79.Gn Optical waveguides and couplers
42.82.Et Waveguides, couplers, and arrays
back to top
RSS Feeds

Measurements of colliding shock wave and supersonic gas flow

D. Kaganovich, M. H. Helle, D. F. Gordon, and A. Ting

Appl. Phys. Lett. 97, 191501 (2010); http://dx.doi.org/10.1063/1.3511329 (3 pages) | Cited 1 time

Online Publication Date: 11 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The collision between a laser generated shock wave and a supersonic flow from a gas jet was studied using pump-probe Schlieren shadowgraphy. The velocity of a gas escaping into vacuum from a high pressure gas jet nozzle was measured and verified in simulation. Time resolved tracking of the shock wave provided critical information about the gas jet vertical velocity and horizontal gas density profile. The measured velocity of the diatomic gas jet was found to be close to the theoretical maximum escape velocity of the gas released into vacuum. Modification of the hemispherical shock wave structure by the supersonic flow was minimal. However, the propagation of the shock wave was observed to be substantially effected by the gas flow.
Show PACS
47.40.Nm Shock wave interactions and shock effects
47.60.Kz Flows and jets through nozzles
47.40.Ki Supersonic and hypersonic flows
back to top
RSS Feeds

Dangling bond charge transition levels in AlAs, GaAs, and InAs

Hannu-Pekka Komsa and Alfredo Pasquarello

Appl. Phys. Lett. 97, 191901 (2010); http://dx.doi.org/10.1063/1.3515422 (3 pages) | Cited 1 time

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Charge transition levels of dangling bonds in III–V semiconductors (AlAs, GaAs, and InAs) are determined via hybrid density-functional calculations. In GaAs, the Ga and As levels are found at 0.28 eV below the conduction band and at 0.16 eV above the valence band, respectively, in good correspondence with measured levels. These defect levels line up across the present semiconductor series for a band alignment based on experimental offsets. For In0.53Ga0.47As, both the In and Ga levels are inferred to resonate with the conduction band while the As level remains in the gap at 0.1 eV from the valence band.
Show PACS
71.55.Eq III-V semiconductors
71.20.Nr Semiconductor compounds
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Control of surface adatom kinetics for the growth of high-indium content InGaN throughout the miscibility gap

Michael Moseley, Jonathan Lowder, Daniel Billingsley, and W. Alan Doolittle

Appl. Phys. Lett. 97, 191902 (2010); http://dx.doi.org/10.1063/1.3509416 (3 pages) | Cited 4 times

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The surface kinetics of InGaN alloys grown via metal-modulated epitaxy (MME) are explored in combination with transient reflection high-energy electron diffraction intensities. A method for monitoring and controlling indium segregation in situ is demonstrated. It is found that indium segregation is more accurately associated with the quantity of excess adsorbed metal, rather than the metal-rich growth regime in general. A modified form of MME is developed in which the excess metal dose is managed via shuttered growth, and high-quality InGaN films throughout the miscibility gap are grown.
Show PACS
68.55.ag Semiconductors
68.43.Mn Adsorption kinetics
68.35.Dv Composition, segregation; defects and impurities
64.75.Bc Solubility
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Coherent controlling plasmon transport properties in metal nanowire coupled to quantum dot

Mu-Tian Cheng, Ya-Qin Luo, Pei-Zhen Wang, and Guang-Xing Zhao

Appl. Phys. Lett. 97, 191903 (2010); http://dx.doi.org/10.1063/1.3514245 (3 pages) | Cited 1 time

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate theoretically the transport properties of surface plasmon in a metal nanowire with linear and nonlinear dispersion relations coupled to a quantum dot with three levels in cascaded configuration by full quantum-mechanical approach. The transmission and reflection amplitudes are obtained. The reflection spectrum shows two peaks for the surface plasmon with linear dispersion relation while it can exhibit four peaks when the plasmon has quadratic dispersion relation. The calculations reveal that one can control the plasmon transport properties by adjusting Rabi frequency and circular frequency of a classic optical field.
Show PACS
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
61.46.Km Structure of nanowires and nanorods (long, free or loosely attached, quantum wires and quantum rods, but not gate-isolated embedded quantum wires)
78.67.Uh Nanowires
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

In situ synchrotron x-ray characterization of ZnO atomic layer deposition

D. D. Fong, J. A. Eastman, S. K. Kim, T. T. Fister, M. J. Highland, P. M. Baldo, and P. H. Fuoss

Appl. Phys. Lett. 97, 191904 (2010); http://dx.doi.org/10.1063/1.3514254 (3 pages) | Cited 4 times

Online Publication Date: 8 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The utility of in situ synchrotron x-ray scattering and fluorescence in gaining insight into the early stages of the atomic layer deposition process is demonstrated in this study of ZnO growth on Si. ZnO films are found to initially grow as islands, with the onset of coalescence occurring during the fourth growth cycle. The start of coalescence is accompanied by a small increase in surface roughness. After ten cycles of growth, the growth rate decreases from 4.2 to 3.0 Å per cycle, with the growth following expected self-limiting behavior. The overall growth process is consistent with the model of Puurunen and Vandervorts for substrate-inhibited growth [ R. L. Puurunen and W. Vandervorst, J. Appl. Phys. 96, 7686 (2004)] .
Show PACS
68.55.ag Semiconductors
68.49.Uv X-ray standing waves
78.70.Ck X-ray scattering
81.05.Dz II-VI semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)

Experimental demonstration of multiwire endoscopes capable of manipulating near-fields with subwavelength resolution

Pavel A. Belov, George K. Palikaras, Yan Zhao, Atiqur Rahman, Constantin R. Simovski, Yang Hao, and Clive Parini

Appl. Phys. Lett. 97, 191905 (2010); http://dx.doi.org/10.1063/1.3516161 (3 pages)

Online Publication Date: 9 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Endoscopes formed by arrays of metallic wires can transmit, magnify, and demagnify near-field distributions with subwavelength resolution. Our experiments demonstrate that despite their small apertures, the parallel multiwire endoscopes can be used to transmit near-field distributions with a resolution of five thousandths of a wavelength to a distance of a half-wavelength in the microwave frequency range, and tapered multiwire endoscopes with flat input and output interfaces provide threefold image magnification and demagnification.
Show PACS
85.60.Gz Photodetectors (including infrared and CCD detectors)
42.79.Pw Imaging detectors and sensors
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
42.30.Va Image forming and processing
87.85.Pq Biomedical imaging

Controlling metamaterial resonances via dielectric and aspect ratio effects

Sher-Yi Chiam, Ranjan Singh, Weili Zhang, and Andrew A. Bettiol

Appl. Phys. Lett. 97, 191906 (2010); http://dx.doi.org/10.1063/1.3514248 (3 pages) | Cited 3 times

Online Publication Date: 9 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study ways to enhance the sensitivity and dynamic tuning range of the fundamental inductor-capacitor (LC) resonance in split ring resonators (SRRs) by controlling the aspect ratio of the SRRs and their substrate thickness. We conclude that both factors can significantly affect the LC resonance. We show that metafilms consisting of low height SRRs on a thin substrate are most sensitive to changes in their dielectric environment and thus show excellent potential for sensing applications.
Show PACS
42.82.Gw Other integrated-optical elements and systems
42.70.-a Optical materials
42.79.Wc Optical coatings

Parametric analysis of the strain-dependent behavior of a metamaterial electric resonator

B. Arritt, B. Adomanis, T. Khraishi, and D. Smith

Appl. Phys. Lett. 97, 191907 (2010); http://dx.doi.org/10.1063/1.3507892 (3 pages) | Cited 2 times

Online Publication Date: 10 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper, we describe the strain-dependent behavior of an electric-LC (ELC) resonator unit cell, commonly used in metamaterial designs. We leverage analytic expression to understand the way strain manifests itself in a change in electromagnetic (EM) response. We verify the simplified physical models using full-wave simulations and generalize the trends to accommodate the strain profile for any arbitrary plane-stress loading scenario.
Show PACS
84.40.Az Waveguides, transmission lines, striplines
41.20.Jb Electromagnetic wave propagation; radiowave propagation

Structural fingerprints of electronic change in the phase-change-material: Ge2Sb2Te5

B. Cai, D. A. Drabold, and S. R. Elliott

Appl. Phys. Lett. 97, 191908 (2010); http://dx.doi.org/10.1063/1.3516039 (3 pages) | Cited 1 time

Online Publication Date: 10 November 2010

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this paper, we generate a-Ge2Sb2Te5 models via ab initio molecular dynamic simulations, track the dynamic changes of network at 500 K, and correlate the structural changes in the course of the simulation with changes in electronic structure. Considerable fluctuations of the electronic gap are observed even for a model in equilibrium. We compare our study to experiments and other simulations.
Show PACS
71.20.Lp Intermetallic compounds
05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion
71.15.-m Methods of electronic structure calculations

Transient phenomena in the dielectric breakdown of HfO2 optical films probed by ultrafast laser pulse pairs

Duy N. Nguyen, Luke A. Emmert, Dinesh Patel, Carmen S. Menoni, and Wolfgang Rudolph

Appl. Phys. Lett. 97, 191909 (2010); http://dx.doi.org/10.1063/1.3511286 (3 pages) | Cited 2 times

Online Publication Date: 10 November 2010

Full Text: Read Online (HTML) | Download PDF


See Also: Publisher's Note

Show Abstract
The laser induced breakdown threshold of HfO2 films is studied with single pairs of pulses of variable delay and 50 fs and 1 ps pulse duration. Two distinct transient regimes are observed that can be related to the relaxation of the electron density from the conduction band via an intermediate state to the valence band. The experimental results are in good agreement with a theoretical model that assumes occupation of mid gap states after the first pulse on a time scale of several tens of picoseconds and subsequent decay of this population via recombination with holes in the valence band on a time scale of several tens of milliseconds.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.-g Dielectric thin films
73.61.Ng Insulators
77.22.Jp Dielectric breakdown and space-charge effects
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
71.20.Ps Other inorganic compounds
Page 1 of 4 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close