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

1 Sep 2000

Volume 88, Issue 5, pp. 2187-3105

Page 1 of 7 Pages Next Page | Jump to Page
back to top
RSS Feeds

Large improvement in quantum fluorescence yield of Er3+-doped fluorozirconate and fluoroindate glasses by Ce3+ codoping

Zhicong Meng, Tomoshi Yoshimura, Kei Fukue, Mitsuhiro Higashihata, Yoshiki Nakata, and Tatsuo Okada

J. Appl. Phys. 88, 2187 (2000); http://dx.doi.org/10.1063/1.1287229 (4 pages) | Cited 23 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The fluorescence characteristics of different Ce3+:Er3+-codoped fluoride host glasses, such as fluorozirconate and fluoroindate glass, are reported. It is shown that Ce3+ codoping into Er3+ doped fluoride glasses resulted in a quenching of Er3+ ions from the 4I11/2 to the 4I13/2 state, and the branching ratio for the Er3+ 4I11/2→4I13/2 transition increased from 0.20 to over 0.80 by codoping 2.0 mol % Ce3+. Further, the fluorescence quantum yield at 1.55 μm was also significantly improved. A Ce3+:Er3+-codoped fluorozirconate fiber laser operating at 1.55 μm band with 980 nm excitation has been realized for the first time, which clearly indicates the effectiveness of Ce3+ codoping. © 2000 American Institute of Physics.
Show PACS
42.70.Ce Glasses, quartz
78.55.Hx Other solid inorganic materials
78.47.-p Spectroscopy of solid state dynamics
42.55.Wd Fiber lasers

Infrared quantum counter studies in europium doped lanthanum trifluoride

Wenyan Tian, Ranjit S. Pandher, and B. Rami Reddy

J. Appl. Phys. 88, 2191 (2000); http://dx.doi.org/10.1063/1.1287237 (3 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Violet upconversion signals in the wavelength region 340–420 nm were observed from LaF3:Eu3+ under 583 nm dye laser excitation. The intensities of some upconversion signals enhanced ∼8× under double resonance excitation by a 583 nm dye laser and a 790.6 nm Ti: sapphire laser. © 2000 American Institute of Physics.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Polarization self-modulation of speckle patterns in a bundle of photorefractive crystals

Nadezhda Nazhestkina, Ervin Nippolainen, Alexei A. Kamshilin, Victor V. Prokofiev, and Timo Jaaskelainen

J. Appl. Phys. 88, 2194 (2000); http://dx.doi.org/10.1063/1.1287524 (6 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The experimental and theoretical studies of a polarization self-modulation effect in photorefractive Bi12TiO20 crystals are presented. We developed an approximate theory that allows optimizing the performance of the adaptive sensor based on the polarization self-modulation effect. To diminish external voltage simultaneously keeping the aperture of the sensor large enough, we constructed a sensor consisted of several Bi12TiO20 crystals of different orientations. High sensitivity and adaptability to slow environment changes of the proposed sensor make it useful for various applications, particularly for laser ultrasound detection. © 2000 American Institute of Physics.
Show PACS
42.30.Ms Speckle and moiré patterns
42.70.Gi Light-sensitive materials
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.25.Ja Polarization
07.60.Ly Interferometers
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing

Optical second-order nonlinearity of poled borosilicate glass containing CuCl

Jun Sasai, Katsuhisa Tanaka, and Kazuyuki Hirao

J. Appl. Phys. 88, 2200 (2000); http://dx.doi.org/10.1063/1.1288011 (5 pages) | Cited 1 time

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of surface etching on second-harmonic (SH) intensity and Maker fringe pattern have been examined for poled borosilicate glasses containing CuCl. A drastic decrease in the SH intensity was observed with anode-side surface etching, while such a decrease did not appear when the cathode-side surface etching was carried out. However, after 20 μm etching of the anode-side surface, a decrease in SH intensity with the cathode-side etching was observed. For some samples, the theoretical Maker fringe pattern derived on the assumption that the SH wave is generated from a thin layer near the anode-side surface is in good agreement with the experimental one. On the other hand, other samples show oscillation in the fringe, which originates from the interference of SH waves generated from both surfaces. These results suggest that the nonlinear layer is present at both surfaces, although it is much weaker near the cathode. It is thought that the origin of the nonlinearity is attributable to migration of Cu+ and Cl−. © 2000 American Institute of Physics.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
81.65.Cf Surface cleaning, etching, patterning
81.05.Kf Glasses (including metallic glasses)

Laser rapid prototyping in nonlinear medium

K. Daneshvar, M. Raissi, and S. M. Bobbio

J. Appl. Phys. 88, 2205 (2000); http://dx.doi.org/10.1063/1.1288503 (6 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have measured the second harmonic generation (SHG) using a 1.06 μm Q-switched pump beam in powdered nonlinear crystals suspended in a photopolymeric solution. The powdered crystals used include lithium niobate, LiNbO3, and potassium titanyl phosphate. Measurements were made as a function of the grain size and the number of grains per unit volume. The photopolymeric solution is transparent at the pump beam frequency while it is highly absorbing at the SH and it is the SH which transforms the photopolymer from liquid to solid. The results show that relatively intense SH incoherent light is produced in powder after the pump intensity exceeds a certain threshold. SHG does not depend on the grain size up to a critical grain size beyond which SHG falls off rapidly. Furthermore, the emission increases linearly as a function of the number of grains per unit volume and eventually levels off and stays constant. A practical focus of these studies has been in the areas of laser induced rapid prototyping and three dimensional real time image formation. This study clearly demonstrates the application of a nonlinear optical medium in high resolution rapid prototyping. Furthermore, because efficient SHG occurs for very small powder grain size this technique may provide a way of realizing high resolution three dimensional imaging in which the feature size is only a few microns. © 2000 American Institute of Physics.
Show PACS
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.62.Cf Industrial applications
42.70.Jk Polymers and organics

Effect of heterobarrier leakage on the performance of high-power 1.5 μm InGaAsP multiple-quantum-well lasers

L. Shterengas, R. Menna, W. Trussell, D. Donetsky, G. Belenky, J. Connolly, and D. Garbuzov

J. Appl. Phys. 88, 2211 (2000); http://dx.doi.org/10.1063/1.1289054 (4 pages) | Cited 13 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Broad stripe 1.5 μm InGaAsP/InP multiple-quantum-well graded-index separate-confinement heterostructure lasers with different waveguide widths and doping profiles were designed, fabricated, and characterized. A record value of more than 16 W of pulsed optical power was obtained from lasers with a broadened waveguide design. Studies of the characteristics of lasers with different p-doping profiles as well as modeling data show that the heterobarrier electron leakage is responsible for the effect of the device optical power saturation with current. © 2000 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.)
42.79.Ry Gradient-index (GRIN) devices
61.72.S- Impurities in crystals
42.86.+b Optical workshop techniques

Holographic gratings in the optically isotropic state of polymer azobenzene liquid-crystal films

Takahiro Yamamoto, Satoshi Yoneyama, Osamu Tsutsumi, Akihiko Kanazawa, Takeshi Shiono, and Tomiki Ikeda

J. Appl. Phys. 88, 2215 (2000); http://dx.doi.org/10.1063/1.1287761 (6 pages) | Cited 18 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We attempted formation of holographic gratings in an optically isotropic state of polymer azobenzene liquid-crystal films. On irradiation of writing beams at 488 nm, first-order diffraction beams of a probe beam at 633 nm were immediately observed even though the films exhibited the optically isotropic state. The diffraction beams quickly disappeared by turning off the writing beams. The first-order diffraction efficiency was affected by polarization of the writing beams. When unpolarized light was employed as the writing beams, diffraction beams were hardly observed. On the other hand, the highest diffraction efficiency was obtained with the linearly polarized writing beams. It is speculated that photoinduced alignment of azobenzene moieties in bright fringes of the interference pattern would be responsible for the grating formation. Furthermore, it was found that rubbing treatment slightly enhanced the diffraction efficiency. By turning on and off the writing beams, dynamic control of the diffraction beams could be achieved. © 2000 American Institute of Physics.
Show PACS
42.40.Eq Holographic optical elements; holographic gratings
61.30.-v Liquid crystals
back to top
RSS Feeds

Efficacy of high-frequency, low-voltage plasma immersion ion implantation of a bar-shaped target

Xiubo Tian, Zhaoming Zeng, Xuchu Zeng, Baoyin Tang, and Paul K. Chu

J. Appl. Phys. 88, 2221 (2000); http://dx.doi.org/10.1063/1.1287221 (5 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Elevated-temperature plasma immersion ion implantation (PIII) increases the surface hardness and thickness of the modified layer and is traditionally performed at a high energy (typically above 5 keV) and low current density. In this article, we report the benefits of a different approach by high-frequency, low-voltage plasma immersion ion implantation (HLPIII). Experiments and a two-dimensional theoretical simulation are conducted to demonstrate the advantages of the process on a bar-shaped sample in terms of ion dose, dose uniformity, and modified layer thickness. Simulation of the sheath dynamics illustrates that the thinner plasma sheath in HLPIII is geometrically more conformal to the target surface, and the incident ion flux is more uniform along the exposed surface when compared to the traditional high-voltage PIII process. The higher ion dose and thicker modified layer can be attributed to the higher ion current density. HLPIII is thus the preferred technique to enhance the surface properties of large and complex-shaped specimens such as a metal track. © 2000 American Institute of Physics.
Show PACS
61.80.Jh Ion radiation effects
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
52.40.Hf Plasma-material interactions; boundary layer effects
61.82.Bg Metals and alloys

Heavy-particle hybrid modeling of transients in a direct-current argon discharge

Z. Donkó

J. Appl. Phys. 88, 2226 (2000); http://dx.doi.org/10.1063/1.1288008 (8 pages) | Cited 21 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A hybrid model incorporating heavy-particle processes was developed to describe the transient behavior of a low-pressure, cold-cathode, direct-current-excited argon discharge, recently studied experimentally by Jelenković and Phelps [J. Appl. Phys. 85, 7089 (1999)]. The transients were initiated by applying a high-voltage pulse to the discharge, which induced a transition from the Townsend state to the abnormal glow mode. The model made it possible to calculate the transient electrical characteristics, as well as the spatiotemporal changes of the light intensity distribution of the discharge. While in the initial state of the discharge most of the light emission occurs near the anode, with the development of the cathode sheath (taking place on the μs time scale), intensity peaks corresponding to the negative glow (created by electron-impact excitation) and the cathode glow (created by heavy-particle excitation) could be identified. The results of the simulations are in good agreement with the experimental observations, both in terms of electrical signals and light intensity distributions. It was also found that hybrid models not taking into account heavy-particle processes (and assuming that the secondary electron emission coefficient depends on the reduced electric field at the cathode surface) do not give satisfactory agreement with the experimental data. © 2000 American Institute of Physics.
Show PACS
52.80.Dy Low-field and Townsend discharges
52.80.Hc Glow; corona
52.20.Hv Atomic, molecular, ion, and heavy-particle collisions
52.65.-y Plasma simulation

Calculated gas temperature profiles in argon glow discharges

I. Revel, L. C. Pitchford, and J. P. Boeuf

J. Appl. Phys. 88, 2234 (2000); http://dx.doi.org/10.1063/1.1288171 (6 pages) | Cited 45 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We use a previously developed model for the electrical properties of glow discharges, coupled to a Monte Carlo simulation of the heavy particles (ions and fast neutrals) in the cathode sheath region, to calculate the gas heating source term in glow discharges in argon with planar electrodes. The gas temperature profile is calculated from the one-dimensional heat transport equation, and we report results for discharge current densities up to 4 mA/cm2 for a value of pd (product of the gas pressure and gap spacing) of 1.5 Torr cm. The gas temperature peaks at a position slightly inside the cathode sheath, and at the highest current density reported here the gas temperature reaches 354 K. A large fraction of the energy gained by the ions in the sheath is transported directly to the cathode (mostly through fast neutrals), and the fractional ion energy converted to thermal motion of the gas decreases with increasing current density. We report some results to show the dependence of the gas temperature on the thermal accommodation coefficient. For a constant current, the calculated discharge voltage is somewhat higher when gas heating is taken into account. © 2000 American Institute of Physics.
Show PACS
52.80.Hc Glow; corona
52.65.Pp Monte Carlo methods
52.25.-b Plasma properties

Energy distribution of ions and fast neutrals in microdischarges for display technology

G. J. M. Hagelaar, G. M. W. Kroesen, and M. H. Klein

J. Appl. Phys. 88, 2240 (2000); http://dx.doi.org/10.1063/1.1287758 (6 pages) | Cited 20 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this work we present simple theoretical predictions as well as full Monte Carlo calculations of the energy distribution of the ion and fast neutral fluxes impinging on the materials that surround the microdischarges in plasma display panels and plasma addressed liquid crystal displays. We consider various rare gas ion species in different microdischarge designs. Often simple theoretical distribution functions are in good agreement with the results of Monte Carlo calculations. Under the influence of symmetric charge transfer collisions the ion energy distribution is essentially different from a Maxwellian distribution, and the ion motion is strongly orientated along the electric field. The flux of the fast neutrals formed by symmetric charge transfer is usually even larger than the ion flux itself. © 2000 American Institute of Physics.
Show PACS
42.79.Kr Display devices, liquid-crystal devices
85.60.Pg Display systems
52.75.-d Plasma devices
52.65.Pp Monte Carlo methods
52.80.-s Electric discharges
52.25.-b Plasma properties

Diagnostics of inductively coupled chlorine plasmas: Measurement of Cl2+ and Cl+ densities

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

J. Appl. Phys. 88, 2246 (2000); http://dx.doi.org/10.1063/1.1288156 (6 pages) | Cited 30 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The absolute densities of positive ions (Cl2+ and Cl+) are obtained over a 2–20 mTorr pressure range and 5–1000 W input radio-frequency rf power range in a transformer-coupled Cl2 plasma. The relative number density of Cl2+ is measured by laser-induced fluorescence. These laser-induced fluorescence data are calibrated by Langmuir-probe measurements of total positive-ion density at low powers to yield absolute values for nCl2+ and are corrected for changes in rotational temperature with rf power. In turn, the nCl2+ data are used to determine the effective-mass correction for refined Langmuir-probe measurements of the total positive-ion density. The density of Cl+ is then the difference between the total positive-ion and Cl2+ densities. For all the pressures, Cl2+ is found to be the dominant ion in the capacitively coupled regime (input powers below 100 W), while Cl+ is the dominant ion at higher powers (>300 W) of the inductively coupled regime. Experimental results are compared to those from a simple global model. This work is a continuation of a study that provides a complete set of experimentally measured plasma parameters over a broad range of conditions in a chlorine plasma, produced with a commercial, inductively coupled rf source. © 2000 American Institute of Physics.
Show PACS
52.70.Ds Electric and magnetic measurements
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Modeling of the microdischarges in plasma addressed liquid crystal displays

G. J. M. Hagelaar, G. M. W. Kroesen, U. van Slooten, and H. Schreuders

J. Appl. Phys. 88, 2252 (2000); http://dx.doi.org/10.1063/1.1287529 (11 pages) | Cited 30 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Plasma addressed liquid crystal (PALC) is a promising technology for large size flat display devices, which uses gas discharges as electrical switches for the addressing of a liquid crystal (LC) layer. This work presents a comprehensive two-dimensional fluid model, that we developed for the simulation of the microdischarges occurring in PALC displays. The model comprises continuity equations and drift-diffusion equations for plasma particle species, a balance equation for the electron energy, and Poisson’s equation for the electric field. Using this model, we succeeded in simulating the full PALC operation, reproducing a series of discharge pulses and afterglows in three consecutive PALC discharge channels. Results are presented for helium and helium–hydrogen mixtures. The results include: calculated particle densities, current–voltage curves, plasma decay times, surface charges, and LC transmission profiles. The influence of electrical crosstalk between adjacent channels is demonstrated.© 2000 American Institute of Physics.
Show PACS
42.79.Kr Display devices, liquid-crystal devices
52.65.-y Plasma simulation
52.80.Hc Glow; corona
85.60.Pg Display systems
52.75.-d Plasma devices
52.25.Fi Transport properties

Probe diagnostics of supermagnetron plasma with applications of continuous and pulse-modulated rf electric fields

Haruhisa Kinoshita, Fumihiko Fukushima, Masashi Kando, Yukito Nakagawa, and Tsutomu Tsukada

J. Appl. Phys. 88, 2263 (2000); http://dx.doi.org/10.1063/1.1288700 (5 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Parameters of supermagnetron plasma produced by rf (radio frequency) pulse, with 49.6 ms on and 0.4 ms off, were investigated by probe characteristics measured at 10–100 μs after the rf pulse in order to avoid disturbance in the measurement. The plasma parameters obtained by a continuous rf electric field and the phase differences of the rf electric field to both parallel electrodes were compared with those of rf pulse plasma. A double probe was mainly used in Ar as a standard gas, and a single probe was used in He gas for rf electric field free measurements using pulse-modulated rf plasma. He gas was used for extended time measurements because of a low probe contamination as a result of sputtering from two electrodes. A high electron density of an order of 1011 cm−3 was observed at low gas pressure (20 mTorr) for Ar plasma, and a low electron temperature of 1.1–1.2 eV was observed for He rf plasma. As for an rf phase difference dependence between two rf powers supplied to two parallel electrodes, maximum and minimum electron densities were observed at phase differences of 180° and 0°, respectively. © 2000 American Institute of Physics.
Show PACS
52.70.Ds Electric and magnetic measurements
52.50.Gj Plasma heating by particle beams
52.25.-b Plasma properties

Power transfer and mode transitions in low-frequency inductively coupled plasmas

K. N. Ostrikov, S. Xu, and M. Y. Yu

J. Appl. Phys. 88, 2268 (2000); http://dx.doi.org/10.1063/1.1289055 (4 pages) | Cited 54 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Operation and mode jumps in low-frequency (500 kHz) radio-frequency inductively coupled plasmas are investigated. The discharge is driven by a flat inductive coil which can excite the electrostatic (E) and electromagnetic (H) discharge modes. The power transfer efficiency and mode transition behavior are studied. It is found that the power reflection coefficient as a function of the input power is minimal in the vicinity of the mode transitions and exhibits hysteresis, which is also observed when the operating gas pressure is varied. © 2000 American Institute of Physics.
Show PACS
52.80.Dy Low-field and Townsend discharges
back to top
RSS Feeds

Determination of the size, shape, and composition of indium-flushed self-assembled quantum dots by transmission electron microscopy

J. P. McCaffrey, M. D. Robertson, S. Fafard, Z. R. Wasilewski, E. M. Griswold, and L. D. Madsen

J. Appl. Phys. 88, 2272 (2000); http://dx.doi.org/10.1063/1.1287226 (6 pages) | Cited 29 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Single and multiple layers of self-assembled InAs quantum dots (QDs) produced by the indium-flush technique have been studied by transmission electron microscopy (TEM) in an effort to develop techniques to reproducibly grow QDs of uniform size and shape. To monitor the changes in QD dimensions, plan-view samples of capped single layers were studied as well as cross-sectional samples of QDs in multiple layers and stacks. The changes in the observed round- and square-shaped QD images under various plan-view TEM imaging conditions, as well as the contrast reversal in the center of QD images viewed in cross-section are modeled using the many-beam Bloch-wave approach, including strain. The sizes and shapes of the QDs are determined through the interpretation of the observed (primarily strain) contrast in plan-view and the observed (primarily atomic number) contrast in cross-sectional TEM. © 2000 American Institute of Physics.
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)

Atomistic simulation of diffuse x-ray scattering from defects in solids

K. Nordlund, P. Partyka, R. S. Averback, I. K. Robinson, and P. Ehrhart

J. Appl. Phys. 88, 2278 (2000); http://dx.doi.org/10.1063/1.1287525 (11 pages) | Cited 18 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Diffuse x-ray scattering is a powerful means to study the structure of defects in crystalline solids. The traditional analysis of diffuse x-ray scattering experiments relies on analytical and numerical methods which are not well suited for studying complicated defect configurations. We present here an atomistic simulation method by which the diffuse x-ray scattering can be calculated for an arbitrary finite-sized defect in any material where reliable interatomic force models exist. We present results of the method for point defects, defect clusters and dislocations in semiconductors and metals, and show that surface effects on diffuse scattering, which might be important for the investigation of shallow implantation damage, will be negligible in most practical cases. We also compare the results with x-ray experiments on defects in semiconductors to demonstrate how the method can be used to understand complex damage configurations. © 2000 American Institute of Physics.
Show PACS
61.05.cf X-ray scattering (including small-angle scattering)
61.72.J- Point defects and defect clusters
61.72.Lk Linear defects: dislocations, disclinations
78.70.Ck X-ray scattering

Time-dependent measurement of the trapped charge in electron irradiated insulators: Application to Al2O3–sapphire

M. Belhaj, S. Odof, K. Msellak, and O. Jbara

J. Appl. Phys. 88, 2289 (2000); http://dx.doi.org/10.1063/1.1287131 (6 pages) | Cited 20 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A method is described which uses a scanning electron microscope for the investigation of charge trapping in insulators under electron bombardment. The technique commonly used to deduce the amount of trapped charge and its spatial extent is based on the mirror effect, while in the present approach the electron-beam deflections are measured during the primary irradiation. We have performed measurements of the trapped charge during time in an Al2O3–sapphire sample under electron irradiation. Furthermore, the effects of the electron-beam energy and current on charging are also examined and the errors concerning the method are discussed in detail. © 2000 American Institute of Physics.
Show PACS
72.20.Ee Mobility edges; hopping transport
72.20.Fr Low-field transport and mobility; piezoresistance
61.82.Ms Insulators
72.80.Sk Insulators
61.80.Fe Electron and positron radiation effects

Effects of doping impurity and growth orientation on dislocation generation in GaAs crystals grown from the melt: A qualitative finite-element study

X. A. Zhu and C. T. Tsai

J. Appl. Phys. 88, 2295 (2000); http://dx.doi.org/10.1063/1.1287600 (7 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dislocations in gallium arsenide (GaAs) crystals are generated by excessive thermal stresses induced during the crystal growth process. The presence of dislocations has adverse effects on the performance and reliability of the GaAs-based devices. It is well known that dislocation density can be significantly reduced by doping impurity atoms into a GaAs crystal during its growth process. A viscoplastic constitutive equation that couples the microscopic dislocation density with the macroscopic plastic deformation is employed in a crystallographic finite element model for calculating the dislocation density generated in the GaAs crystal during its growth process. The dislocation density is considered as an internal state variable and the drag stress caused by doping impurity is included in this constitutive equation. A GaAs crystal grown by the vertical Bridgman process is adopted as an example to study the influences of doping impurity and growth orientation on dislocation generation. The calculated results show that doping impurity can significantly reduce the dislocation density generated in the crystal. The level of reduction is also influenced by the growth orientation during the crystal growth process. © 2000 American Institute of Physics.
Show PACS
61.72.Bb Theories and models of crystal defects
81.05.Ea III-V semiconductors
81.10.Fq Growth from melts; zone melting and refining
61.72.Lk Linear defects: dislocations, disclinations
61.72.Yx Interaction between different crystal defects; gettering effect
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep
02.70.Dh Finite-element and Galerkin methods
61.72.uj III-V and II-VI semiconductors

Multidimensional alignment structure for the liquid crystal director field

Charles D. Hoke and Philip J. Bos

J. Appl. Phys. 88, 2302 (2000); http://dx.doi.org/10.1063/1.1287772 (3 pages) | Cited 21 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An alignment technique for liquid crystal devices is presented that consists of polymer walls made from monomers that are oriented by an electric field while cured with a spatially patterned UV light source. The technique provides defined boundary conditions of the liquid crystal director field in three dimensions. © 2000 American Institute of Physics.
Show PACS
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
61.30.Eb Experimental determinations of smectic, nematic, cholesteric, and other structures
61.41.+e Polymers, elastomers, and plastics
82.35.-x Polymers: properties; reactions; polymerization
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
82.50.-m Photochemistry

Observation of sp3 bonding in tetrahedral amorphous carbon using visible Raman spectroscopy

Z. Y. Chen, J. P. Zhao, T. Yano, T. Ooie, M. Yoneda, and J. Sakakibara

J. Appl. Phys. 88, 2305 (2000); http://dx.doi.org/10.1063/1.1288160 (4 pages) | Cited 14 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Visible Raman spectroscopy excited at 532 nm was used to characterize the carbon bonding in tetrahedral amorphous carbon (ta-C) films. The vibrational modes of the sp3 bonding in ta-C films were revealed directly. An additional Raman band occurring below 1350 cm−1 was observed. It consisted of two features centered on ∼1270 and ∼1170 cm−1, which were associated with sp3 bond stretching. The observed sp3 related Raman spectrum approached the vibrational density of states of amorphous diamond. © 2000 American Institute of Physics.
Show PACS
61.43.Er Other amorphous solids
78.35.+c Brillouin and Rayleigh scattering; other light scattering
63.50.-x Vibrational states in disordered systems
78.40.Pg Disordered solids
68.55.-a Thin film structure and morphology

Photoluminescence, deep level transient spectroscopy and transmission electron microscopy measurements on MeV self-ion implanted and annealed n-type silicon

D. C. Schmidt, B. G. Svensson, M. Seibt, C. Jagadish, and G. Davies

J. Appl. Phys. 88, 2309 (2000); http://dx.doi.org/10.1063/1.1288020 (9 pages) | Cited 24 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Deep-level transient spectroscopy (DLTS), photoluminescence (PL), and transmission electron microscopy (TEM) measurements have been made on n-type silicon after implanting with 5.6 MeV Si3+ ions using doses of 109–1014 cm−2 and anneals at 525 and 750 °C. In all the samples, there is only a small dependence of the widths and energies of the PL zero-phonon lines on implantation dose, allowing the high resolution of PL to be exploited. In samples annealed at 525 °C, the PL intensity can provide a measure of the concentration of defects over the implantation range, 109–1012 cm−2. Carbon-hydrogen complexes are identified as transient species with increasing dose, and the “T” center is related to a DLTS trap 0.20 eV below the conduction band energy Ec. At the highest doses in these samples, TEM imaging shows the presence of nanometer-sized clusters, and the PL spectra show that many previously unreported defects exist in the implanted zone, in addition to two broad bands centered on ∼885 and ∼930 MeV. The multiplicity of defects supports recent suggestions that a range of interstitial complexes is present in the annealed samples. Annealing at 750 °C produces complete recovery in both the DLTS and PL spectra for doses of less than 1013 cm−2. At higher doses, {113} self-interstitial aggregates are observed in TEM, along with the “903” PL signal associated with the {113} defects, and the Ec−0.33 eV “KA” DLTS trap. These data support the recent identification of that trap with the {113} defects. The well-resolved PL spectra show that many previously reported defects also exist in samples implanted with a dose of 1014 cm−2 and annealed at 750 °C, again implying the presence of a range of interstitial complexes. © 2000 American Institute of Physics.
Show PACS
78.55.Ap Elemental semiconductors
61.72.uf Ge and Si
61.82.Fk Semiconductors
71.55.Cn Elemental semiconductors
61.80.Jh Ion radiation effects
61.72.Cc Kinetics of defect formation and annealing

Polarization and spectroscopy analysis of the scattering by nanoscopic objects in the near-field optics

Nicolas Richard

J. Appl. Phys. 88, 2318 (2000); http://dx.doi.org/10.1063/1.1287531 (8 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show, in this article, the polarization effects around nanoscopic objects in the near-field optics. This analysis accounts of the variation of the total electric field intensity scattered by the objects with the incident wavelength. These are illuminated through a transparent glass substrate under the condition of total internal reflection. The use of different materials is discussed in the optical images according to the incident wavelength at constant height. Using numerical simulations based on the Green’s dyadic technique, we compute the total transmitted intensity of the scattered light in the attenuated total reflection configuration at constant height by varying the incident wavelength. The role of localized plasmon resonance is brought to the fore in the optical images for nanoscopic and metallic objects. © 2000 American Institute of Physics.
Show PACS
07.79.Fc Near-field scanning optical microscopes
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
42.25.Ja Polarization
42.25.Fx Diffraction and scattering

Particle irradiation of doping superlattices: An optical investigation

D. J. Brink, H. W. Kunert, and R. Sieberhagen

J. Appl. Phys. 88, 2326 (2000); http://dx.doi.org/10.1063/1.1286926 (5 pages) | Cited 2 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical properties of α- and β-particle irradiated doped superlattices (npnp) were studied by photoluminescence, ellipsometry, and Raman spectroscopy. Irradiation causes a substantial shift of the main emission band. Single-wavelength ellipsometry shows a small drop in extinction coefficient, but no measurable change in real index of refraction or in depletion width between n and p layers. Thermal annealing at 450 K results in the formation of a new emission band at 1.51 eV. High temperature annealing reverses all radiation induced changes. © 2000 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
78.30.Fs III-V and II-VI semiconductors
61.80.Fe Electron and positron radiation effects
61.80.Jh Ion radiation effects
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.72.Cc Kinetics of defect formation and annealing

Covering of substrate holes through particle deposition

Shih-Yuan Lu

J. Appl. Phys. 88, 2331 (2000); http://dx.doi.org/10.1063/1.1286330 (5 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A methodology is proposed to determine the minimum coating thickness for covering substrate holes through particle deposition. The particle deposition process is carried out with a combined, two-dimensional, on-lattice model, in which both deterministic and nondeterministic driving forces are taken into account. The normalized covering thickness (hc/Dw) is investigated subject to variation in the Peclet number (Pe) and the size of the depositing particle, normalized hole size (Dw/L), and degree of postcontact restructuring allowed. It is found that ballistic particle movement gives a slightly better covering structure for smaller holes while diffusive particle movement much more efficiently covers larger holes. The normalized covering thickness increases with increasing normalized hole size and with decreasing normalized depositing particle size. Postcontact restructuring first improves the covering capability of the depositing particle, but then impairs it if further restructuring is allowed. It is further found that the normalized covering thickness scales with the normalized hole size as hc/Dw∼(Dw/L)E with E=0.67, 0.56, and 0.36 for Pe of infinity, 0.5, and 0.1, respectively. © 2000 American Institute of Physics.
Show PACS
81.15.Aa Theory and models of film growth
05.50.+q Lattice theory and statistics (Ising, Potts, etc.)
Page 1 of 7 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close