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

22 Mar 1999

Volume 74, Issue 12, pp. 1645-1775

Page 1 of 2 Pages Next Page | Jump to Page
back to top
RSS Feeds

Enhancement of hard x-ray emission from a copper target by multiple shots of femtosecond laser pulses

Yoichiro Hironaka, Yasushi Fujimoto, Kazutaka G. Nakamura, Ken-ichi Kondo, and Masatake Yoshida

Appl. Phys. Lett. 74, 1645 (1999); http://dx.doi.org/10.1063/1.123641 (3 pages) | Cited 10 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The x-ray generation from a copper disk target by irradiation of femtosecond laser pulses (42 fs, 4T W in maximum) has been investigated. The intensity of the x rays is enhanced about 100 times by the multiple laser shots on the target. A temporal profile of the x rays consists of two components: a short pulse with a time duration of 6 ps and a pulse with exponential decay. The enhancement of the x rays corresponds to the increase of the short-pulse component. A relationship between the intensity enhancement and morphology of the irradiated target is discussed. © 1999 American Institute of Physics.
Show PACS
07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
68.35.B- Structure of clean surfaces (and surface reconstruction)

Laser action in polydialkylfluorene films: Influence of low-temperature thermal treatment

M. N. Shkunov, R. Österbacka, A. Fujii, K. Yoshino, and Z. V. Vardeny

Appl. Phys. Lett. 74, 1648 (1999); http://dx.doi.org/10.1063/1.123642 (3 pages) | Cited 28 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have used a variety of optical probes to investigate the changes occurring upon low-temperature thermal treatment to the emissive properties of dialkyl substituted polyfluorene thin films. We found that the low-temperature-driven morphological changes involving aggregates formation, which are observed in the absorption and photoluminescence spectra at low excitation intensities, give rise at high excitation intensities to laser action in the blue spectral range. In some cases, switching between two stimulated emission bands was also observed. © 1999 American Institute of Physics.
Show PACS
78.45.+h Stimulated emission
42.70.Hj Laser materials
78.66.Qn Polymers; organic compounds
61.41.+e Polymers, elastomers, and plastics
68.55.-a Thin film structure and morphology
42.70.Jk Polymers and organics
42.55.Rz Doped-insulator lasers and other solid state lasers
78.55.Kz Solid organic materials
78.40.Me Organic compounds and polymers
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency

All-optical inverter operating at 1.53 μm laser in erbium yttrium aluminum garnets

Yoshinobu Maeda

Appl. Phys. Lett. 74, 1651 (1999); http://dx.doi.org/10.1063/1.123643 (3 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An all-optical inverter derived from the negative nonlinear absorption effect was demonstrated in erbium–yttrium aluminum garnet crystals using 1.53 μm laser diode. The effect was obtained at wavelengths of 1532 to 1534 nm in absorption spectra corresponding to the transition from the 4I15/2 to the 4I13/2 levels in Er3+ for sample lengths greater than 1.0 mm. The reversed-phase transmitted wave forms were observed at modulation frequencies from 1 kHz to 1 GHz. The negative nonlinear absorption effect can be explained by considering an enhanced absorption model for a four-level system of the Er3+ ion. © 1999 American Institute of Physics.
Show PACS
42.79.Ta Optical computers, logic elements, interconnects, switches; neural networks
42.65.Pc Optical bistability, multistability, and switching, including local field effects
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency

Bistability and self-pulsation in quantum-dot lasers with intracavity quantum-dot saturable absorbers

O. Qasaimeh, W.-D. Zhou, J. Phillips, S. Krishna, P. Bhattacharya, and M. Dutta

Appl. Phys. Lett. 74, 1654 (1999); http://dx.doi.org/10.1063/1.123644 (3 pages) | Cited 20 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Self-organized In0.4Ga0.6As/GaAs quantum-dot single-mode ridge waveguide lasers with intracavity absorber were grown by molecular beam epitaxy. Bistability in the light–current characteristics of 3 μm single-mode edge-emitting laser was obtained by controlling the intracavity absorber voltage. Self-pulsation was also observed with a center frequency of 1.6 GHz and linewidth <10 MHz. © 1999 American Institute of Physics.
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
42.65.Pc Optical bistability, multistability, and switching, including local field effects
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
78.66.Fd III-V semiconductors

Remanent photoinduced birefringence in thin photochromic sol–gel films

J. Peretti, J. Biteau, J.-P. Boilot, F. Chaput, V. I. Safarov, J.-M. Lehn, and A. Fernández-Acebes

Appl. Phys. Lett. 74, 1657 (1999); http://dx.doi.org/10.1063/1.123645 (3 pages) | Cited 13 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High remanent optical anisotropy in photochromic sol–gel films is shown to be photoinduced by discoloration with linearly polarized visible light. This anisotropy results in a linear dichroism in the visible absorption band and in an important birefringence in the near-infrared transparency region. The kinetics of the whole process are quantitatively well described by a simple analytical model. Intrinsic characteristics of the individual molecule, such as the photochemical quantum yield and the anisotropy of their optical properties, are determined. The potential application of this effect to optical data storage is discussed. © 1999 American Institute of Physics.
Show PACS
42.70.Gi Light-sensitive materials
42.70.Jk Polymers and organics
78.20.Fm Birefringence
78.66.Qn Polymers; organic compounds
42.70.Ln Holographic recording materials; optical storage media

Modeling and experimental observation of parametric processes in segmented KTiOPO4 channel waveguides

Michael Sundheimer, Pierre Aschieri, Pascal Baldi, and John Bierlein

Appl. Phys. Lett. 74, 1660 (1999); http://dx.doi.org/10.1063/1.123646 (3 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter presents a modeling technique for quasiphase-matched parametric processes in segmented channel waveguides and the results of measurements of infrared parametric fluorescence in segmented KTiOPO4 channel waveguides. We demonstrate both theoretically and experimentally a strong dependence of optical parametric oscillator tuning curves and parametric conversion efficiency (parametric gain) on the segmentation duty cycle. We show that the optimum conversion efficiency for parametric interactions in segmented waveguides is obtained for duty cycles greater than 50%. Our results validate the use of an effective continuous waveguide model for segmented channel waveguide calculations over a wide range of wavelengths and duty cycles. © 1999 American Institute of Physics.
Show PACS
42.65.Yj Optical parametric oscillators and amplifiers
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.65.Wi Nonlinear waveguides
42.82.Et Waveguides, couplers, and arrays
78.55.Hx Other solid inorganic materials

Integration of wavelength signal divider and infrared photodetectors based on the plasma dispersion effect in SiGe/Si

Baojun Li, Zuimin Jiang, Chengwen Pei, Jie Qin, Xun Wang, Guozheng Li, Jianjun Wan, and Enke Liu

Appl. Phys. Lett. 74, 1663 (1999); http://dx.doi.org/10.1063/1.123647 (3 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Based on the plasma dispersion effect, a single-mode SiGe wavelength signal divider (WSD) integrated with infrared photodetectors for optical communication at the wavelengths of 1.3 and 1.55 μm is proposed and fabricated by molecular beam epitaxy. The device performances are measured. The crosstalks of the WSD at a forward modulation bias of 1.2 V are −25 and −18 dB at 1.3 and 1.55 μm, respectively. The insertion losses are 2.01 and 2.64 dB for 1.3 and 1.55 μm, respectively. At −5 V reverse bias, the dark currents of the detectors at the 1.3 and 1.55 μm output branches are 45 and 64 nA, respectively. Photocurrent responsivities of 0.08 and 0.07 A/W for the two detectors at the 1.3 and 1.55 μm output branches have been achieved. The quantum efficiencies of the whole WSD and detector integration system are estimated to be about 19% and 18.2% for the 1.3 and 1.55 μm output branches, respectively. © 1999 American Institute of Physics.
Show PACS
42.79.Sz Optical communication systems, multiplexers, and demultiplexers
85.60.Gz Photodetectors (including infrared and CCD detectors)
42.82.Et Waveguides, couplers, and arrays
73.50.Mx High-frequency effects; plasma effects
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
back to top
RSS Feeds

Laser-induced fluorescence and Langmuir probe determination of Cl2+ and Cl+ absolute densities in transformer-coupled chlorine plasmas

M. V. Malyshev, N. C. M. Fuller, K. H. A. Bogart, V. M. Donnelly, and Irving P. Herman

Appl. Phys. Lett. 74, 1666 (1999); http://dx.doi.org/10.1063/1.123648 (3 pages) | Cited 28 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Laser induced fluorescence detection of Cl2+ has been used to track their relative concentration in a high-density inductively (transformer) coupled (TCP) 10 mTorr chlorine plasma as a function of the 13.56 MHz radio frequency (rf) power. This relative Cl2+ number density was compared to the total absolute positive ion density (ni+ = nCl++nCl2+) obtained with a Langmuir probe. Both nCl2+ and ni+ doubled with increasing rf power from 8 to ∼55 W in the capacitively coupled (dim) mode. Above the transition from a capacitively to inductively coupled (bright-mode) plasma at ∼85±35 W, nCl2+ decayed with rf power while ni+ continued to increase. Consequently, Cl2+ is the dominant ion in dim-mode operation and Cl+ is the dominant ion in bright-mode operation, at ni+ ≥ 6×1010 cm−3. With the plasma operating in the reaction ion etch (RIE) mode (the stage powered at 14.56 MHz, and no TCP power) nCl2+ tracked ni+ over the entire range of powers (2–150 W). Thus, Cl2+ is the dominant ion during capacitively coupled RIE operation. © 1999 American Institute of Physics.
Show PACS
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.70.Ds Electric and magnetic measurements
52.27.Jt Nonneutral plasmas
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Generation of tunable far-infrared radiation by the interaction of a superluminous ionizing front with an electrically biased photoconductor

D. Hashimshony, A. Zigler, and K. Papadopoulos

Appl. Phys. Lett. 74, 1669 (1999); http://dx.doi.org/10.1063/1.123649 (3 pages) | Cited 11 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Tunable radiation in the 0.1 THz to a few THz range by the interaction of a superluminous photoconducting front with an electrostatic “frozen-wave” configuration in a semiconductor is reported. The interaction converts the energy contained in the “frozen wave” into far-infrared radiation, whose frequency depends on the energy in the laser pulse creating the superluminous front and the wavelength of the static wave. © 1999 American Institute of Physics.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
78.30.Fs III-V and II-VI semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.55.Et II-VI semiconductors
back to top
RSS Feeds

Kinetic shape formation during Gd thin film and Si(100) solid phase reaction

G. L. Molnár, G. Petö, Z. Vértesy, and E. Zsoldos

Appl. Phys. Lett. 74, 1672 (1999); http://dx.doi.org/10.1063/1.123650 (3 pages) | Cited 4 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The initial stage of the solid phase reaction between gadolinium thin film and Si(100) substrate was investigated by x-ray diffraction and scanning electron microscopy. The interdiffusion was retarded by deliberate contamination of the Gd/Si interface to slow down the extremely rapid reaction. The surface of the reacted film showed pattern formation in separate spots. The fractal-like development of this rare-earth silicide indicates a kinetic-type process—modified by the structure of the Gd film and by the emerging stresses—rather than a previously proposed nucleation-controlled growth. © 1999 American Institute of Physics.
Show PACS
68.35.Fx Diffusion; interface formation
66.30.Ny Chemical interdiffusion; diffusion barriers
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
05.45.Df Fractals

Observation of change in shape of oxygen precipitates in high-temperature annealed silicon by transmission electron microscopy

K. Sakai, T. Yamagami, and K. Ojima

Appl. Phys. Lett. 74, 1675 (1999); http://dx.doi.org/10.1063/1.123651 (2 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Changes in size and shape of oxygen precipitates in Czochralski silicon after high-temperature annealing in an Ar atmosphere were observed using a transmission electron microscopy. The oxide precipitates introduced by 750 °C after 4 h annealing in an Ar atmosphere had their corners rounded off by thermal annealing at 1200 °C, and disappeared by 1300 °C although we observed no change in shape at 1050 °C. © 1999 American Institute of Physics.
Show PACS
61.72.Cc Kinetics of defect formation and annealing
81.05.Cy Elemental semiconductors
81.30.Mh Solid-phase precipitation
64.75.-g Phase equilibria
61.72.J- Point defects and defect clusters

Synthesis and properties of Sr2CeO4 blue emission powder phosphor for field emission displays

Yong Dong Jiang, Fuli Zhang, Christopher J. Summers, and Zhong Lin Wang

Appl. Phys. Lett. 74, 1677 (1999); http://dx.doi.org/10.1063/1.123652 (3 pages) | Cited 65 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A blue emission powder phosphor Sr2CeO4 for field emission displays was prepared using a chemical coprecipitation technique, which is most suitable for large-scale production. The powders were fired at different temperatures to optimize the properties. Firing the powder at 1200 °C for 2 h gave the highest luminescence efficiency of 5.4 lm/W at 4 kV and 29.0 lm/W at 10 kV. The emission peak of this phosphor is at ∼470 nm and Commission International de l’Eclairage coordinates are x = 0.19, y = 0.26. © 1999 American Institute of Physics.
Show PACS
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
85.45.Fd Field emission displays (FEDs)
78.60.Hk Cathodoluminescence, ionoluminescence
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
82.60.Nh Thermodynamics of nucleation

Formation of low-index facets in Ga0.2In0.8As and InAs islands on a InP(113)B substrate

D. Lacombe, A. Ponchet, S. Fréchengues, V. Drouot, N. Bertru, B. Lambert, and A. Le Corre

Appl. Phys. Lett. 74, 1680 (1999); http://dx.doi.org/10.1063/1.123653 (3 pages) | Cited 14 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Strained Ga0.2In0.8As and InAs islands were grown on a InP(113)B substrate by gas source molecular beam epitaxy and examined by transmission electron microscopy and atomic force microscopy. The islands are mainly bounded by the low-index facets {001}, {111}B, and {110} [inclination with respect to the (113)B surface of 25°, 29°, and 31°, respectively]. Some of the consequences of the substrate orientation on the island shape and formation are discussed. © 1999 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties

Scaling laws in annealed LiCoOx films

M. U. Kleinke, J. Davalos, C. Polo da Fonseca, and A. Gorenstein

Appl. Phys. Lett. 74, 1683 (1999); http://dx.doi.org/10.1063/1.123654 (3 pages) | Cited 8 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The surface morphology evolution due to the annealing process of LiCoOx thin films deposited by rf sputtering is studied by means of an atomic force microscope. Linear relationships were observed in log–log plots of interface width versus window length, as predicted by scaling laws. For as-grown films, only one growth exponent α is evidenced. For annealed films two different slopes α1 and α2 were observed, indicating distinct growth dynamics in the system. The roughness exponent for the as-grown film and the internal morphology of the crystalline grains for the annealed films can be described by a diffusional process. The macrostructure shows characteristics of a Kardar–Parisi–Zhang system [M. Kardar, G. Parisi, Y. C. Zhang, Phys. Rev. Lett. 56, 889 (1986); J. Krim and G. Palasantzas, Int. J. Mod. Phys. B 9, 599 (1995)]. An activation energy Ed = (0.11±0.01) eV is determined for the diffusion process. © 1999 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
68.35.B- Structure of clean surfaces (and surface reconstruction)

Self-mediated growth of single-crystal and entirely (111)-oriented C60 films on alkali halide substrates

Z. Dai, H. Naramoto, K. Narumi, S. Yamamoto, and A. Miyashita

Appl. Phys. Lett. 74, 1686 (1999); http://dx.doi.org/10.1063/1.123655 (3 pages) | Cited 3 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied C60 film growth on alkali halide substrates, KCl (200), KBr (200), and NaCl (200), by using two or three C60 monolayers, which grow at a very low deposition rate, as a self-mediating layer. Continuously and entirely (111)-oriented epitaxial C60 films have been grown in a quite wide temperature range, 40–120 °C, and at very different deposition rates, from 1.5 to 35 Å/min. More over, single-crystal and entirely (111)-oriented C60 films with a grain size of 1–3 μm could be also grown at relative high temperature and low deposition rate, approximately 120 °C and 1.5 Å/min, respectively. © 1999 American Institute of Physics.
Show PACS
81.05.ub Fullerenes and related materials
61.48.-c Structure of fullerenes and related hollow and planar molecular structures
68.55.-a Thin film structure and morphology

The critical thickness of an epilayer deposited on a semiconductor-on-insulator compliant substrate

Tong-Yi Zhang and Yan-Jing Su

Appl. Phys. Lett. 74, 1689 (1999); http://dx.doi.org/10.1063/1.123656 (3 pages) | Cited 14 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The critical thickness of an epilayer grown on a compliant substrate with the semiconductor-on-insulator configuration is investigated on the assumption that sliding boundary conditions hold along the interface between the thin crystal substrate and the amorphous underneath layer. An exact solution determining the critical thickness is formulated using both superposition and Fourier transformation. The results show that the critical thickness increases with the decreases in the thickness of the thin crystal substrate and the elastic constant of the insulator. © 1999 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
68.35.Ct Interface structure and roughness
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
68.35.Gy Mechanical properties; surface strains

Fractal aggregation and optical absorption of copper nanoparticles prepared by in situ chemical reduction within a Cu2+-polymer complex

C. Huang and C. Z. Yang

Appl. Phys. Lett. 74, 1692 (1999); http://dx.doi.org/10.1063/1.123657 (3 pages) | Cited 12 times

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
A polymer-matrix nanocomposite containing copper particles has been prepared by in situ chemical reduction within a Cu2+-poly(itaconic acid-co-acrylic acid) complex solid film. The copper particle size in the order of 10 nm is controlled by the initial content of the metal ions in the complex. Their fractal pattern and the value of the fractal dimension indicate that there exists a cluster-cluster aggregation process in the present system. Optical absorption spectra of copper-polymer nanocomposites show distinct plasma absorption bands and quantum size effect in the samples. The calculated blueshift of the resonance peak based on a quantum-sphere model gives remarkable agreement with the experimental data as the size of copper particles embedded in the polymer becomes smaller. © 1999 American Institute of Physics.
Show PACS
81.05.Qk Reinforced polymers and polymer-based composites
78.40.-q Absorption and reflection spectra: visible and ultraviolet
82.30.Fi Ion-molecule, ion-ion, and charge-transfer reactions
78.30.-j Infrared and Raman spectra
05.45.Df Fractals
81.07.-b Nanoscale materials and structures: fabrication and characterization
back to top
RSS Feeds

The adsorption of oxygen at GaN surfaces

Tosja K. Zywietz, Jörg Neugebauer, and Matthias Scheffler

Appl. Phys. Lett. 74, 1695 (1999); http://dx.doi.org/10.1063/1.123658 (3 pages) | Cited 73 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A critical point in device fabrication based on GaN is the controlled doping and the incorporation of impurities like, e.g., oxygen. We have explored the adsorption of oxygen at the wurtzite (0001) and (000math) GaN surfaces employing density-functional theory. Our results show that both surface orientations are very active towards oxygen adsorption, explaining the high oxygen concentrations typically observed in GaN. However, the (0001) and (000math) surfaces behave differently and oxygen incorporation is expected to be higher at the (000math) surface. The different reactivity is explained in terms of the specific structural configurations. © 1999 American Institute of Physics.
Show PACS
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
68.35.Dv Composition, segregation; defects and impurities
81.05.Ea III-V semiconductors
81.65.Mq Oxidation

Charge transfer in photovoltaics consisting of interpenetrating networks of conjugated polymer and TiO2 nanoparticles

A. C. Arango, S. A. Carter, and P. J. Brock

Appl. Phys. Lett. 74, 1698 (1999); http://dx.doi.org/10.1063/1.123659 (3 pages) | Cited 94 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study the effect of blended and layered titanium dioxide (TiO2) nanoparticles on charge transfer processes in conjugated polymer photovoltaics. A two order of magnitude increase in photoconductivity and sharp saturation is observed for layered versus blended structures, independent of the cathode work function. Using electrodes with similar work functions, we observe low dark currents and open circuit voltages of 0.7 V when a TiO2 nanoparticle layer is self-assembled onto the indium–tin–oxide electrode. Our results for the layered morphologies are consistent with charge collection by exciton diffusion and dissociation at the TiO2 interface. © 1999 American Institute of Physics.
Show PACS
73.50.Pz Photoconduction and photovoltaic effects
73.30.+y Surface double layers, Schottky barriers, and work functions
71.35.-y Excitons and related phenomena
71.20.Rv Polymers and organic compounds
72.15.Nj Collective modes (e.g., in one-dimensional conductors)
73.61.Ph Polymers; organic compounds

Optical properties of InAs quantum dots in a Si matrix

R. Heitz, N. N. Ledentsov, D. Bimberg, A. Yu. Egorov, M. V. Maximov, V. M. Ustinov, A. E. Zhukov, Zh. I. Alferov, G. E. Cirlin, I. P. Soshnikov, N. D. Zakharov, P. Werner, and U. Gösele

Appl. Phys. Lett. 74, 1701 (1999); http://dx.doi.org/10.1063/1.123660 (3 pages) | Cited 32 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the optical properties of nanoscale InAs quantum dots (QDs) in a Si matrix. At a growth temperature of 400 °C, the deposition of 7 ML InAs leads to the formation of coherent islands with dimensions in the 2–4 nm range. A luminescence band in the 1.3 μm region found exclusively for samples with such InAs QDs exhibits a pronounced excitation density dependence of the peak position and a decay time of 440 ns. The optical properties suggest an indirect type II transition for InAs/Si QDs. The electronic structure of InAs/Si QDs is discussed in view of available band offset information. © 1999 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Effects of surface reconstruction on III–V semiconductor interface formation: The role of III/V composition

B. Z. Nosho, W. H. Weinberg, W. Barvosa-Carter, B. R. Bennett, B. V. Shanabrook, and L. J. Whitman

Appl. Phys. Lett. 74, 1704 (1999); http://dx.doi.org/10.1063/1.123661 (3 pages) | Cited 24 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using molecular-beam epitaxy and in situ scanning tunneling microscopy, we demonstrate how different reconstructions associated with different III–V growth surfaces can create interfacial roughness, and that an understanding of this phenomenon can be used to control the roughness on the atomic scale. Specifically, the different compositions of a clean InAs(001)-(2×4) surface (V/III=0.5 ML/0.75 ML) and an Sb-terminated one (∼1.7 ML/1 ML) cause the InSb-like interfacial surface to have a bilevel morphology. This surface roughness can be eliminated by depositing additional In to exactly compensate for the difference. It is likely that similar types of roughness occur in all heterostructures where the growth surface reconstruction changes at the interfaces, and that a similar procedure will be equally effective at reducing that roughness. © 1999 American Institute of Physics.
Show PACS
68.35.Ct Interface structure and roughness
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.55.-a Thin film structure and morphology

Effects of embedded crystallites in amorphous silicon on light-induced defect creation

Toshihiro Kamei, Paul Stradins, and Akihisa Matsuda

Appl. Phys. Lett. 74, 1707 (1999); http://dx.doi.org/10.1063/1.123662 (3 pages) | Cited 39 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate effects of embedded crystallites in hydrogenated amorphous silicon on light-induced metastable dangling-bond defect creation in a systematic manner. Inclusion of a small volume fraction of crystallites into the amorphous matrix significantly suppresses defect creation against moderate light illumination. Excess carriers generated in the amorphous matrix tend to recombine in the embedded crystallites, which suppresses nonradiative recombination within the amorphous matrix and the subsequent defect creation. The presence of a small volume fraction of crystallites, however, is no longer effective to improve the stability against strong light exposure such as pulsed laser irradiation. In this case, the higher carrier concentration favors bimolecular direct carrier recombination within the amorphous matrix. © 1999 American Institute of Physics.
Show PACS
61.43.Dq Amorphous semiconductors, metals, and alloys
71.23.Cq Amorphous semiconductors, metallic glasses, glasses
72.40.+w Photoconduction and photovoltaic effects
71.55.Jv Disordered structures; amorphous and glassy solids
72.80.Cw Elemental semiconductors
72.80.Ng Disordered solids

Trapping of minority carriers in multicrystalline silicon

D. Macdonald and A. Cuevas

Appl. Phys. Lett. 74, 1710 (1999); http://dx.doi.org/10.1063/1.123663 (3 pages) | Cited 87 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Abnormally high effective carrier lifetimes have been observed in multicrystalline silicon wafers using both transient and steady-state photoconductance techniques. A simple model based on the presence of trapping centers explains this phenomenon both qualitatively and quantitatively. By fitting this model to experimental data acquired with a quasi-steady-state photoconductance technique, it is possible to determine the trap density, trap energy, and the ratio between the mean-trapping time and mean-escape time. A correlation between trap density and dislocation density in the material has been found. © 1999 American Institute of Physics.
Show PACS
72.80.Cw Elemental semiconductors
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.40.+w Photoconduction and photovoltaic effects

Structural characterization of amorphized InP: Evidence for chemical disorder

C. J. Glover, M. C. Ridgway, K. M. Yu, G. J. Foran, T. W. Lee, Y. Moon, and E. Yoon

Appl. Phys. Lett. 74, 1713 (1999); http://dx.doi.org/10.1063/1.123664 (3 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Extended x-ray absorption fine-structure measurements at the In K edge of amorphous InP are presented. The presence of chemical disorder in the form of like-atom bonding has been unambiguously demonstrated in stoichiometric InP amorphized by ion implantation. In–In bonding comprised 14%±4% of the In–atom constituent bonds. Also, relative to the crystalline value of four P atoms, an increase in the total In coordination number to 4.16±0.32 atoms was observed for the amorphous phase, as composed of 3.56±0.19 P and 0.60±0.13 In atoms. Experimental results were consistent with recent ab initio structural calculations and, furthermore, demonstrated that amorphous InP is best described by a Polk-like continuous random network, containing both even- and odd-membered rings. © 1999 American Institute of Physics.
Show PACS
61.43.Dq Amorphous semiconductors, metals, and alloys
78.70.Dm X-ray absorption spectra

Spatially resolved observation of Coulomb blockade and negative differential conductance on a Ag cluster on the clean GaAs(110) surface

C.-S. Jiang, T. Nakayama, and M. Aono

Appl. Phys. Lett. 74, 1716 (1999); http://dx.doi.org/10.1063/1.123665 (3 pages) | Cited 10 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
By performing current-image tunneling spectroscopy at room temperature, we have observed the staircase current–voltage (I–V) characteristic and negative differential conductance on a single Ag cluster on a clean GaAs(110) surface. The I–V characteristics have changed spatially with the position of the tip on the cluster. The characteristics are understood in terms of Coulomb blockade and resonance of electron standing-wave states in the cluster with the states of the underlying substrate. © 1999 American Institute of Physics.
Show PACS
73.23.Hk Coulomb blockade; single-electron tunneling
73.40.Ns Metal-nonmetal contacts
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
Page 1 of 2 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close