jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

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

15 Nov 2002

Volume 92, Issue 10, pp. 5621-6351

Page 1 of 5 Pages Next Page | Jump to Page
back to top
RSS Feeds

High-temperature performance in ∼4 μm type-II quantum well lasers with increased strain

Andrew P. Ongstad, Ron Kaspi, Joeseph R. Chavez, Gregory C. Dente, Michael L. Tilton, and Donald M. Gianardi

J. Appl. Phys. 92, 5621 (2002); http://dx.doi.org/10.1063/1.1513199 (6 pages) | Cited 11 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this article, we report on a systematic study of mid-IR, W-Integrated Absorber (W-IA), lasers that employ strained InAs/InxGa1−xSb/InAs active layers, in which the indium content of the hole bearing InxGa1−xSb has been varied from xIn=0 to xIn=0.45. The output characteristics of the lasers improve as the In percentage is increased; the threshold temperature sensitivity (T0) values are observed to increase from ≈35 to ≈50 K. Further, the differential quantum efficiencies as a function of temperature are significantly improved in the devices with xIn⩾0.25. For samples with nominally eight monolayers (8 ML) InAs/7 ML InxGa1−xSb/8 ML InAs, the lasing wavelength at 84 K is observed to shift from 3.33 μm for xIn=0 out to a maximum of 4.62 μm for xIn=0.35. This large shift is well predicted by an empirical psuedopotential model; the model also predicts that the position of the hole wave function is sensitively dependent on strain level and that for xIn<0.25, the holes are no longer confined in the W active region, but rather in the thick IA layers where they experience a bulklike density of states. This suggests that the improved thermal performance with increasing strain is due to the onset of hole quantum confinement in the W region, and improved or deeper hole confinement in that epitaxial layer. © 2002 American Institute of Physics.
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.)
78.67.De Quantum wells
81.05.Ea III-V semiconductors
81.07.St Quantum wells
71.15.Dx Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)

Photoacoustic study of KrF laser heating of Si: Implications for laser particle removal

Sergey I. Kudryashov and Susan D. Allen

J. Appl. Phys. 92, 5627 (2002); http://dx.doi.org/10.1063/1.1503859 (5 pages) | Cited 7 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A photoacoustic study of KrF laser heating of Si has revealed that the dominant mechanism of acoustic generation is thermoacoustic with a considerable contribution from the concentration–deformation mechanism at laser fluences below the Si melting threshold of 0.5 J/cm2. Upon Si melting the contraction of the molten material contributes significantly to acoustic generation. At fluences above 1.4 J/cm2 laser ablation of the molten layer enhances the amplitude of the compression pulse and diminishes that of the rarefaction pulse. The results of photoacoustic measurements allow optimization of experimental conditions for dry laser particle removal. © 2002 American Institute of Physics.
Show PACS
81.65.Cf Surface cleaning, etching, patterning
42.62.-b Laser applications
81.05.Cy Elemental semiconductors
62.65.+k Acoustical properties of solids
61.72.Cc Kinetics of defect formation and annealing
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
64.70.D- Solid-liquid transitions
68.35.Rh Phase transitions and critical phenomena
61.82.Fk Semiconductors

Terahertz optically pumped Si:Sb laser

S. G. Pavlov, H.-W. Hübers, H. Riemann, R. Kh. Zhukavin, E. E. Orlova, and V. N. Shastin

J. Appl. Phys. 92, 5632 (2002); http://dx.doi.org/10.1063/1.1515377 (3 pages) | Cited 23 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Far-infrared stimulated emission from optically pumped neutral Sb donors in silicon has been obtained. Lasing with a wavelength of 58.2 μm from the intracenter 2p0→1s(T2:Γ8) transition has been realized under CO2 laser pumping at liquid helium temperature. The population inversion mechanism is based on the relatively long-living excited state, 2p0, leading to an accumulation of the photoexcited electrons. © 2002 American Institute of Physics.
Show PACS
78.45.+h Stimulated emission
42.55.Px Semiconductor lasers; laser diodes
71.55.Cn Elemental semiconductors

Self-induced nonlinear Zernike filter realized with optically addressed liquid crystal spatial light modulator

K. Komorowska, A. Miniewicz, J. Parka, and F. Kajzar

J. Appl. Phys. 92, 5635 (2002); http://dx.doi.org/10.1063/1.1515949 (7 pages) | Cited 8 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Visualization of phase objects introducing small distortions to a plane wave front (such as turbulence of air) can be realized with the well-known Zernike filtering. In this work we discuss and present the use of an optically addressed liquid crystal spatial light modulator (OA LC SLM) performing self-induced nonlinear Zernike-type filtering. The OA LC SLM is made of a planar nematic liquid crystal layer sandwiched between a photoconductor (PVK:TNF 100-nm-thick polymer) and a polyimide orienting layer. The advantage of such a nonlinear Zernike filter over a conventional one is that no precise optical adjustment is necessary and the filtering is relatively easy to control by tuning the externally applied field to the modulator and the incoming light intensity. © 2002 American Institute of Physics.
Show PACS
42.79.Hp Optical processors, correlators, and modulators
42.79.Ci Filters, zone plates, and polarizers
47.80.-v Instrumentation and measurement methods in fluid dynamics
42.70.Df Liquid crystals
42.79.Kr Display devices, liquid-crystal devices
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order

Measurement of spectral lines produced by four-wave mixing in 30 km dispersion-shifted single-mode optical fiber

J. Jahanpanah

J. Appl. Phys. 92, 5642 (2002); http://dx.doi.org/10.1063/1.1516260 (5 pages)

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Interaction between two copropagating narrowband light waves in a monomode optical fiber can occur because of four-wave mixing phenomena. Light beams from two lasers, a tunable external cavity laser and a distributed feedback semiconductor laser with wavelength separation around 0.36 nm (45 GHz) at λ=1.545 μm, are first amplified by an erbium-doped amplifier and then launched into a 30 km dispersion-shifted fiber. The fiber acts as a nonlinear medium to mix two optical waves and generates one, two, three, and even four optical waves (sidebands) at other wavelengths. An optical spectrum analyzer with a resolution of 0.1 nm has been used to measure the power of the output sidebands. In good agreement with theory, by raising the power of input signals, the number of output sidebands and their powers is also increased. © 2002 American Institute of Physics.
Show PACS
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.81.-i Fiber optics
42.55.Wd Fiber lasers
42.60.By Design of specific laser systems

Propagation properties of a light wave in a film quasiwaveguide structure

Xi-Jing Zhang, Xi-Zhi Fan, Jun Liao, Hui-Tian Wang, N. B. Ming, Ling Qiu, and Yu-Quan Shen

J. Appl. Phys. 92, 5647 (2002); http://dx.doi.org/10.1063/1.1517731 (11 pages) | Cited 3 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We suggest a three-dimensional theoretical model to explain the origin of light wave propagation in a quasiwaveguide structure formed by a thin film of refractive index smaller than the substrate. The physical principles involved are illustrated by the use of a combination of multiple-wave interference and coherent multiple scattering. Not only the theoretical details and the important analytic formulas describing the properties of wave propagation in the quasiwaveguide were given, but also the positions and linewidths of the quasiwaveguide modes, the intensity distribution in the film, the intensity of the reflected spot, and the intensity distribution of the scattered light (m lines) are studied in detail. We divide the modes in the quasiwaveguide into three kinds: cavity modes, leaky modes, and degenerate modes. Some interesting problems are discussed. We investigate the properties of wave propagation in a quasiwaveguide made with a doped polymer film and discuss the origin of scattering. © 2002 American Institute of Physics.
Show PACS
42.79.Gn Optical waveguides and couplers
42.79.Wc Optical coatings
78.66.-w Optical properties of specific thin films

Tunable photonic band schemes of opals and inverse opals infiltrated with liquid crystals

Hiroyuki Takeda and Katsumi Yoshino

J. Appl. Phys. 92, 5658 (2002); http://dx.doi.org/10.1063/1.1516868 (5 pages) | Cited 12 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
When an optically birefringent nematic liquid crystal is infiltrated into the void regions of opals and inverse opals, degeneracies seen in photonic band schemes are found theoretically to disappear, resulting in the appearance of several new weak peaks in the reflection spectra. Tunabilities of the reflection peaks upon applied electric fields are discussed as a function of refractive indices and anisotropies of liquid crystals. Much larger tunabilities are demonstrated in inverse opals infiltrated with liquid crystals. © 2002 American Institute of Physics.
Show PACS
42.70.Qs Photonic bandgap materials
42.70.Df Liquid crystals
61.30.Pq Microconfined liquid crystals: droplets, cylinders, randomly confined liquid crystals, polymer dispersed liquid crystals, and porous systems
78.20.Jq Electro-optical effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
back to top
RSS Feeds

Influence of the focusing f number on the heating regime transition in laser absorption waves

Koichi Mori, Kimiya Komurasaki, and Yoshihiro Arakawa

J. Appl. Phys. 92, 5663 (2002); http://dx.doi.org/10.1063/1.1513869 (5 pages) | Cited 11 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Laser plasma was produced in air atmosphere using a transversely excited atmospheric CO2 pulse laser; the influence of the focusing f number (≡ focal length/laser beam diameter) on the threshold of a heating regime transition in laser absorption waves was then investigated. As a result, when the laser energy was 10 J/pulse, the transition threshold was 2.6±0.4 MW/cm2 with f=1.1 optics and 3.7±0.4 MW/cm2 with f=2.2. The difference was explained in terms of the front area and absorption layer thickness in the laser supported detonation regime. © 2002 American Institute of Physics.
Show PACS
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.35.Tc Shock waves and discontinuities

Pulse striations in glow discharge generated by a laser ablation plume

Y. Hoshi, H. Yoshida, and Y. Tsutsui

J. Appl. Phys. 92, 5668 (2002); http://dx.doi.org/10.1063/1.1513186 (5 pages) | Cited 8 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A unique form of striations, pulse striations, has been observed in a glow discharge by means of a laser-triggered pulse. Unlike conventional striations in a discharge tube, pulse striations are generated near an anode placed in free space. Pulse striations are stereoscopic in shape, appear static, and have a relatively short lifetime of around 1 ms. The wavelength of striations was found to be a function of ambient pressure only, while the relationship between wavelength and pressure in pulse striations was similar to that between specific volume and pressure in the polytropic process of neutral gases. Goldstein’s original equation is a function of pressure only and appears to describe more common striation phenomena than Goldstein’s law, which is additionally dependent on the radius of the discharge tube. An upper limit of current density, above which striations do not occur, exists. A lower limit of current density was also found in addition to the optimum current density for initiating striations. Laser-triggered pulse striations may enable the easy control of striation duration. © 2002 American Institute of Physics.
Show PACS
52.80.Hc Glow; corona

Parametric investigation of miniaturized cylindrical and annular Hall thrusters

A. Smirnov, Y. Raitses, and N. J. Fisch

J. Appl. Phys. 92, 5673 (2002); http://dx.doi.org/10.1063/1.1515106 (7 pages) | Cited 27 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Conventional annular Hall thrusters become inefficient when scaled to low power. An alternative approach, a 2.6 cm miniaturized cylindrical Hall thruster with a cusp-type magnetic field distribution, was developed and studied. Its performance was compared to that of a conventional annular thruster of the same dimensions. The cylindrical thruster exhibits discharge characteristics similar to those of the annular thruster, but it has a much higher propellant ionization efficiency. Significantly, a large fraction of multicharged xenon ions might be present in the outgoing ion flux generated by the cylindrical thruster. The operation of the cylindrical thruster is quieter than that of the annular thruster. The characteristic peak in the discharge current fluctuation spectrum at 50–60 kHz appears to be due to ionization instabilities. In the power range 50–300 W, the cylindrical and annular thrusters have comparable efficiencies (15%–32%) and thrusts (2.5–12 mN). For the annular configuration, a voltage less than 200 V was not sufficient to sustain the discharge at low propellant flow rates. The cylindrical thruster can operate at voltages lower than 200 V, which suggests that a cylindrical thruster can be designed to operate at even smaller power. © 2002 American Institute of Physics.
Show PACS
52.75.Di Ion and plasma propulsion
89.40.-a Transportation

Model of laser-aided heating and evaporation of particles

Pawan K. Tiwari and V. K. Tripathi

J. Appl. Phys. 92, 5680 (2002); http://dx.doi.org/10.1063/1.1513191 (4 pages) | Cited 1 time

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The efficacy of an intense laser for dissolving metallic particles in material processing plasmas has been examined. The laser penetrates in the skin layer of the particles and heats them. The temperature rise of the particle is, however, uniform due to the predominance of thermal conduction. As the particle temperature rises heating rate increases due to increase in electron-phonon collisional frequency. Once the transition to liquid phase occurs the conductivity falls drastically slowing the heating rate. However, in the vapor phase ionization begins and the plasma thus formed expands at the velocity of sound while simultaneously absorbing energy from the tail of the laser pulse. © 2002 American Institute of Physics.
Show PACS
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
64.70.D- Solid-liquid transitions
64.70.F- Liquid-vapor transitions
63.20.K- Phonon interactions

Measurements of atomic carbon density in processing plasmas by vacuum ultraviolet laser absorption spectroscopy

Norifusa Tanaka and Kunihide Tachibana

J. Appl. Phys. 92, 5684 (2002); http://dx.doi.org/10.1063/1.1513877 (7 pages) | Cited 4 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Measurements of the absolute C atom density in an inductively coupled plasma (ICP) source were carried out by using vacuum ultraviolet (VUV) laser absorption spectroscopy with the resonance lines of C atoms at wavelengths around 94.5 and 165.7 nm. A tunable VUV laser covering these wavelength ranges was generated by a two-photon resonance/four-wave mixing technique in Xe gas. No absorption at around 94.5 nm could be observed, but from the absorption spectra around 165.7 nm we successfully derived the absolute density of C atoms in the ICP source. The obtained values varied from 1×1010 to 1×1011 cm−3, depending on the source gas and operating conditions of the plasma source. The relatively small density values compared to other atomic species are attributed to the large loss rates, which mostly occur on the surface. © 2002 American Institute of Physics.
Show PACS
52.77.-j Plasma applications
52.25.-b Plasma properties
52.70.Kz Optical (ultraviolet, visible, infrared) measurements

Enhanced emission mode of a ferroelectric plasma cathode

K. Chirko, Ya. E. Krasik, J. Felsteiner, and A. Sternlieb

J. Appl. Phys. 92, 5691 (2002); http://dx.doi.org/10.1063/1.1516259 (7 pages) | Cited 13 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An enhanced electron emission mode of the ferroelectric plasma cathode operation is reported. The enhanced emission is achieved due to the generation of a dense plasma (1013–1014 cm−3) by the ionization of a thin neutral layer. The neutral layer is formed by a desorption process that accompanies the generation of a surface flashover plasma which has been induced by a driving current pulse applied to the ferroelectric sample. It was found that the application of a second driving current pulse with a several hundred μs delay with respect to the first driving current pulse causes an intense and uniform ionization of this neutral layer. Fast framing photographs of the light emission from this plasma and some parameters of the plasma and neutral flows are reported. Diode parameters were investigated under an accelerating voltage of 150–300 kV and pulse duration of 350 ns. Generation of an electron beam with current amplitude up to 2.5 kA is demonstrated. Also, it is shown that using the ferroelectric cathode in a reflex triode configuration allows the generation of high-power microwaves at a much smaller diode current amplitude as compared with explosive emission cathodes. © 2002 American Institute of Physics.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
52.59.Mv High-voltage diodes
52.75.Fk Magnetohydrodynamic generators and thermionic convertors; plasma diodes
77.80.-e Ferroelectricity and antiferroelectricity
82.45.-h Electrochemistry and electrophoresis
82.47.-a Applied electrochemistry
52.80.Wq Discharge in liquids and solids
back to top
RSS Feeds

Properties of hafnium oxide films grown by atomic layer deposition from hafnium tetraiodide and oxygen

Kaupo Kukli, Mikko Ritala, Jonas Sundqvist, Jaan Aarik, Jun Lu, Timo Sajavaara, Markku Leskelä, and Anders Hårsta

J. Appl. Phys. 92, 5698 (2002); http://dx.doi.org/10.1063/1.1515107 (6 pages) | Cited 30 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polycrystalline monoclinic HfO2 films were atomic layer deposited on Si(100) substrates by a nonhydrous carbon-free process of HfI4 and O2. The oxygen to hafnium ratio corresponded to the stoichiometric dioxide within the limits of accuracy of ion beam analysis. A 1.5–2.0 nm thick SiO2 interface layer formed between the HfO2 films and Si substrates. Hysteresis of the capacitance–voltage curves was observed in Al/HfO2/p-Si(100) structures with oxide grown in the substrate temperature range of 570–755 °C. The hysteresis ceased with an increase in O2 pressure. The effective permittivity of the dielectric layers varied between 12 and 16. The breakdown voltages were found to be lower in the case of higher oxygen doses and higher HfO2 deposition temperatures. © 2002 American Institute of Physics.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
77.55.-g Dielectric thin films
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
68.55.-a Thin film structure and morphology
77.22.Ch Permittivity (dielectric function)
77.22.Jp Dielectric breakdown and space-charge effects

Coverage dependence of hydrogen absorption into Pd(111)

K. Nobuhara, H. Kasai, H. Nakanishi, and A. Okiji

J. Appl. Phys. 92, 5704 (2002); http://dx.doi.org/10.1063/1.1512965 (3 pages) | Cited 13 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the absorption of H into Pd(111). In particular, we study the coverage dependence of the H-induced relaxation of the Pd lattice and the corresponding variation in the energy barrier for H absorption. We calculate, within density functional theory, the corresponding potential energy curves for the case where the H impinges on a frozen lattice surface, and on a lattice surface that is allowed to undergo H-induced relaxation. We consider the case where the final H coverage θ=1/9 and 1/4. From the results, it can be seen that, for both coverages, the energy barrier for H absorption takes a minimum value at a face-centered-cubic hollow site on the frozen lattice surface. Furthermore, the barrier is lowered by relaxation of the Pd lattice. The H-induced relaxation of the Pd lattice when θ=1/9 is more remarkable than when θ=1/4. © 2002 American Institute of Physics.
Show PACS
68.43.Mn Adsorption kinetics
73.20.Hb Impurity and defect levels; energy states of adsorbed species
68.47.De Metallic surfaces
68.35.Md Surface thermodynamics, surface energies
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
68.43.Fg Adsorbate structure (binding sites, geometry)

Photocrystallization of amorphous ZnO

Naoko Asakuma, Hiroshi Hirashima, Hiroaki Imai, Toshimi Fukui, Ayako Maruta, Motoyuki Toki, and Koichi Awazu

J. Appl. Phys. 92, 5707 (2002); http://dx.doi.org/10.1063/1.1513197 (4 pages) | Cited 10 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Structural changes stimulated by UV light irradiation for sol-gel-derived amorphous ZnO were investigated. Transformation of amorphous ZnO into the wurtzite phase was achieved by irradiation of 4.9 eV photons in air using a conventional low-pressure mercury lamp. On the other hand, the crystallization was not observed by UV irradiation in vacuum. Cleavage of the Zn–O network with electronic excitation and subsequent oxidation with activated oxygen species are deduced to be essential for the formation of the ordered structure from the amorphous phase.© 2002 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Fk Semiconductors
61.43.Dq Amorphous semiconductors, metals, and alloys

Atomic scale morphology of self-organized periodic elastic domains in epitaxial ferromagnetic MnAs films

M. Kästner, C. Herrmann, L. Däweritz, and K. H. Ploog

J. Appl. Phys. 92, 5711 (2002); http://dx.doi.org/10.1063/1.1512692 (3 pages) | Cited 40 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The surface of epitaxial MnAs layers grown on GaAs(001) substrates by molecular beam epitaxy is studied by atomic force microscopy and scanning tunneling microscopy (STM). A periodic array of alternating ridges and grooves is observed. The periodicity ranges from 200 to 900 nm and increases with increasing layer thickness. The terrace-step morphology and the surface reconstruction on the ridges and in the grooves are imaged by STM. It is found that both are independent from the ridge-groove structure, supporting the idea that the formation of the ridge-groove structure is due to elastic distortion of the film during cooling after growth.© 2002 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Dd Nonmetallic ferromagnetic materials
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.60.Bs Mechanical and acoustical properties
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
62.20.F- Deformation and plasticity

Impact of nucleation conditions on the structural and optical properties of M-plane GaN(1math00) grown on γ-LiAlO2

Yue Jun Sun, Oliver Brandt, Uwe Jahn, Tian Yu Liu, Achim Trampert, Sven Cronenberg, Subhabrata Dhar, and Klaus H. Ploog

J. Appl. Phys. 92, 5714 (2002); http://dx.doi.org/10.1063/1.1513874 (6 pages) | Cited 73 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the structural and optical properties of M-plane GaN(1math00) films grown on LiAlO2(100) with nucleation layers grown at high and low temperatures. Samples with a high temperature nucleation layer are found to exhibit a highly anisotropic surface morphology with pronounced corrugation, which basically replicates the surface morphology of the substrate. Photoluminescence spectra of these layers are dominated by a transition at 3.356 eV, which is absent for samples with a low-temperature nucleation layer. In conjunction with scanning electron microscopy, cathodoluminescence maps reveal that this transition predominantly stems from regions below the trenches of the surface corrugation. Transmission electron microscopy shows an abundance of stacking faults within these regions. Excitation-dependent and time-resolved photoluminescence demonstrates the intrinsic character of the 3.356 eV emission, which is thus attributed to excitons bound to stacking faults acting as ultrathin vertical quantum wells in these samples. Low-temperature nucleation is imperative to avoid thermal roughening of the substrate and thus the formation of a high density of stacking faults. © 2002 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
68.55.A- Nucleation and growth
68.35.B- Structure of clean surfaces (and surface reconstruction)
78.60.Hk Cathodoluminescence, ionoluminescence
61.72.Nn Stacking faults and other planar or extended defects
78.47.-p Spectroscopy of solid state dynamics
68.37.Lp Transmission electron microscopy (TEM)
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
71.35.Gg Exciton-mediated interactions

Correlations between embedded single gold nanoparticles in SiO2 thin film and nanoscale crater formation induced by pulsed-laser radiation

S. Papernov and A. W. Schmid

J. Appl. Phys. 92, 5720 (2002); http://dx.doi.org/10.1063/1.1512691 (9 pages) | Cited 30 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A model SiO2 thin-film system containing gold nanoparticles serving as nanoscale absorbing defects is investigated with the goal of unraveling the connection between the 351 nm pulsed-laser energy absorption process inside a single defect and the resulting film damage morphology. For this purpose, gold nanoparticles are lodged at a well-defined depth inside a SiO2 monolayer film. Particle sites, as well as nanoscale craters generated at these locations after 351 nm irradiation, are mapped by means of atomic force microscopy. The results of this mapping confirm a damage mechanism that involves initiation in the nanoscale defect followed by absorption spreading out to the surrounding matrix. At low laser fluences (below optically detected damage onset), the probability of crater formation and the amount of the material vaporized is, to within ±25% of the average value, almost independent of the particle size. Inhomogeneities in the particle environment are held responsible for variances in the laser-energy absorption process and, consequently, for the observed particle/crater correlation behavior. Investigation of the damage threshold as a function of particle size (2–19 nm range) showed that even few-nanometer-diameter particles can lead to a significant threshold reduction. The “nanoscale” damage threshold is introduced as a laser fluence causing localized melting without significant vaporization. © 2002 American Institute of Physics.
Show PACS
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.46.-w Structure of nanoscale materials
61.82.Rx Nanocrystalline materials
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.

Detection of trap activation by ionizing radiation in SiO2 by spatially localized cathodoluminescence spectroscopy

B. D. White, L. J. Brillson, M. Bataiev, L. J. Brillson, D. M. Fleetwood, R. D. Schrimpf, B. K. Choi, D. M. Fleetwood, and S. T. Pantelides

J. Appl. Phys. 92, 5729 (2002); http://dx.doi.org/10.1063/1.1512319 (6 pages) | Cited 4 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Microcathodoluminescence (CLS) spectroscopy is used to probe the effect of ionizing radiation on defects inside Al gate oxide structures. Micron-scale Al–SiO2–Si capacitors exposed to 10 keV x-ray irradiation exhibit spatially localized CLS emissions characteristic of multiple deep level traps, including positively charged oxygen-deficient centers and nonbridging oxygen hole centers (NBOHC). Irradiation produces both increases and decreases in their relative emission intensities, depending on spatial location within the oxide. These changes result in a gradient of E′ versus NBOHC defect densities across the oxide thickness between Al and Si interfaces. These results demonstrate that x-ray irradiation-induced deep level traps can be monitored spatially in metal-oxide-semiconductor gate structures, that x-ray irradiation produces separate increases or decreases in E′ versus NBOHC defect densities, and that these changes vary with position within the oxides. © 2002 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
78.60.Hk Cathodoluminescence, ionoluminescence
73.20.Hb Impurity and defect levels; energy states of adsorbed species
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
84.32.Tt Capacitors
71.55.-i Impurity and defect levels
61.80.Cb X-ray effects
61.82.Ms Insulators

Optical constants of methyl-pentaphenylsilole by spectroscopic ellipsometry

H. J. Peng, Z. T. Liu, H. Y Chen, Y. L. Ho, B. Z. Tang, M. Wong, H. C. Huang, and H. S. Kwok

J. Appl. Phys. 92, 5735 (2002); http://dx.doi.org/10.1063/1.1512312 (5 pages) | Cited 6 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The optical properties of 1-methyl-1,2,3,4,5-pentaphenylsilole thin films grown on silicon substrate were investigated using spectroscopic ellipsometry (SE). Accurate refractive index n and extinction coefficient k, in the wavelength range of 250 to 800 nm, were determined. Sellmeier equations, amorphous semiconductor model, and a three-oscillator classical Lorentz model were used to fit the data in different spectral ranges. A band gap of 2.78 eV and uv absorption peaks at 368 and 263 nm were derived from the SE spectrum. Additionally, the absorption spectra near the major band edges show optical properties similar to that of an amorphous semiconductor. © 2002 American Institute of Physics.
Show PACS
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Qn Polymers; organic compounds
78.40.Me Organic compounds and polymers
85.60.Jb Light-emitting devices
42.70.Jk Polymers and organics
71.20.Rv Polymers and organic compounds

Model for electrical isolation of GaN by light-ion bombardment

A. I. Titov and S. O. Kucheyev

J. Appl. Phys. 92, 5740 (2002); http://dx.doi.org/10.1063/1.1512690 (5 pages) | Cited 2 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a model for electrical isolation of GaN by light-ion bombardment. In our model, a decrease in the concentration of free carriers responsible for isolation is assumed to be due to the formation of complexes of ion-beam-generated point defects with shallow donor or acceptor dopants. These defect interaction processes are described in terms of quasichemical reactions. Results show that our model can adequately describe experimental data for electrical isolation in the case of MeV light-ion irradiation of n-GaN. © 2002 American Institute of Physics.
Show PACS
61.82.Fk Semiconductors
61.80.Jh Ion radiation effects
61.72.Yx Interaction between different crystal defects; gettering effect
71.55.Eq III-V semiconductors
61.72.J- Point defects and defect clusters
85.40.Ls Metallization, contacts, interconnects; device isolation
72.80.Ey III-V and II-VI semiconductors

Transmission electron microscopy of the induced damage by argon implantation in (111) HgCdTe at room temperature

Myriam H. Aguirre, Horacio R. Cánepa, and Noemí E. Walsöe de Reca

J. Appl. Phys. 92, 5745 (2002); http://dx.doi.org/10.1063/1.1512695 (4 pages) | Cited 3 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
HgCdTe (MCT) is an important semiconductor material used for infrared photovoltaic detectors. Although ion implantation is a widely used technique in the manufacture of devices based on MCT to obtain n/p junctions, a detailed understanding of the n-type behavior of the unannealed damage region has not yet been established. In this work, n/p junctions were formed by Ar++ implantation on MCT (111) grown by the isothermal vapor phase epitaxy method. Structural damage after implantation for different implantation doses (1013, 1014, and 1015 Ar++/cm2) was evaluated by transmission electron microscopy. At high doses, damage distribution exhibits a double region of defects. These were mainly vacancy dislocation loops and lines in the first region, whereas the second zone exhibited small dislocation loops. The observed n-type behavior after implantation was attributed to the generation and diffusion of Hg from the damaged region. © 2002 American Institute of Physics.
Show PACS
61.82.Fk Semiconductors
61.72.uj III-V and II-VI semiconductors
61.80.Jh Ion radiation effects
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.37.Lp Transmission electron microscopy (TEM)
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Transmission electron microscopy study of the InP/InGaAs and InGaAs/InP heterointerfaces grown by metalorganic vapor-phase epitaxy

Jean Decobert and Gilles Patriarche

J. Appl. Phys. 92, 5749 (2002); http://dx.doi.org/10.1063/1.1513891 (7 pages) | Cited 14 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
InP/InGaAs and InGaAs/InP interfaces in heterostructures grown by metalorganic vapor-phase epitaxy (MOVPE) have been studied by transmission electron microscopy (TEM). Cross-sectional TEM 002 dark field images of the direct (InP–InGaAs) and inverted (InGaAs–InP) interfaces revealed a great difference in abruptness. Whereas the direct interface is always well defined and flat, the inverted one is compositionally graded and shows surface undulations. InP–InGaAs heterostructures were studied for different layer thicknesses and phosphine flow rates. The results indicate that this effect originates more from the substitution of arsenic by phosphorus atoms in subsurface InGaAs monolayers rather than from As carryover to the InP layer. The strong As–P exchange observed over several InGaAs monolayers is related to the large difference in chemical bond strength between Ga–As and Ga–P. This is supported by comparison with InP/InAlAs/InP and InP/In1−xGaxAsyP1−y/InP (0.1<x<0.4) heterostructures. The inverted InAlAs/InP interface is much more abrupt than the InGaAs/InP one and does not show any surface undulations. Furthermore, the In1−xGaxAsyP1−y/InP interface surface undulations increase with x composition. These results, valid for our experimental configuration, indicate that MOVPE grown InGaAs/InP interfaces can be improved by using very low hydride flow during the switching sequence. © 2002 American Institute of Physics.
Show PACS
68.65.Cd Superlattices
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.35.Ct Interface structure and roughness
68.37.Lp Transmission electron microscopy (TEM)
68.35.Fx Diffusion; interface formation

Plasma mechanism of terahertz photomixing in high-electron mobility transistor under interband photoexcitation

V. Ryzhii, I. Khmyrova, A. Satou, P. O. Vaccaro, T. Aida, and M. Shur

J. Appl. Phys. 92, 5756 (2002); http://dx.doi.org/10.1063/1.1510596 (5 pages) | Cited 19 times

Online Publication Date: 31 October 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show that modulated near-infrared radiation can generate terahertz plasma oscillations in the channel of a high-electron mobility transistor. This effect is associated with a temporarily periodic injection of the electrons photoexcited by modulated near-infrared radiation into the transistor channel. The excitation of the plasma oscillations has the resonant character. It results in the pertinent excitation of the electric current in the external circuit that can be used for generation of terahertz electromagnetic radiation. © 2002 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
84.40.Dc Microwave circuits
73.50.Mx High-frequency effects; plasma effects
Page 1 of 5 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close