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

18 Apr 2005

Volume 86, Issue 16, Articles (16xxxx)

Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Role of light scattering in excimer laser annealing of Si

Antonino La Magna, Paola Alippi, Vittorio Privitera, and Guglielmo Fortunato

Appl. Phys. Lett. 86, 161905 (2005); http://dx.doi.org/10.1063/1.1906318 (3 pages) | Cited 7 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied, by means of simulations and experiments, the interaction between the electromagnetic field, generated by excimer laser, and Si device. This study strictly refers to laser annealing process, recently attracting a broad interest as an alternative thermal treatment. Our numerical methodology is based on coupling the simulation of the electromagnetic field, for the calculation of the heat source distribution, and the simulations of the thermal, phase, and impurity fields. Simulations of laser irradiation in metal-oxide-semiconductor transistor structures are discussed and compared to the corresponding experimental analysis. Our results are useful to understand problematics and perspectives of the laser annealing application in the fabrication of scaled devices.
Show PACS
85.30.Tv Field effect devices
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.72.Cc Kinetics of defect formation and annealing
61.82.Fk Semiconductors

The influence of surface steps on the formation of Ag-induced reconstructions on Si(111)

K. Vanormelingen, K. Paredis, and A. Vantomme

Appl. Phys. Lett. 86, 161906 (2005); http://dx.doi.org/10.1063/1.1906310 (3 pages) | Cited 1 time

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using scanning tunneling microscopy, the influence of Si(111) surface steps on the formation of Ag-induced reconstructions was investigated. For low Ag coverage, both the 3×1 and the math×math structures form at the upper step edge while for increasing coverage, the math×math areas grow at the expense of the 3×1 and 7×7 regions. This growth critically depends on the height of the adjacent step. For a monoatomic step, the math×math patch grows uniformly (at the same level) over the upper and lower terrace resulting in a wandering of the step, while higher steps are splitted into two levels due to the formation of high and low Ag-covered areas. Furthermore, a quantitative description of the growth of the math×math patches is given, based on the shape evolution of the math×math regions and from the analysis of antiphase boundaries.
Show PACS
68.47.Fg Semiconductor surfaces
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.35.B- Structure of clean surfaces (and surface reconstruction)

Refractive index and density in F- and Cl-doped silica glasses

Hiroshi Kakiuchida, Noriaki Shimodaira, Edson H. Sekiya, Kazuya Saito, and Akira J. Ikushima

Appl. Phys. Lett. 86, 161907 (2005); http://dx.doi.org/10.1063/1.1897062 (3 pages) | Cited 3 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The refractive index and density of fluorine- and chlorine-doped silica glasses were measured as functions of fictive temperature. The halogen concentrations were observed to have a refractive index or density that is independent of the fictive temperature were found. This implies that these properties are not affected by any heat-treatment conditions.
Show PACS
81.05.Kf Glasses (including metallic glasses)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.72.S- Impurities in crystals
81.40.Tv Optical and dielectric properties related to treatment conditions
81.40.Gh Other heat and thermomechanical treatments

Momentum matrix element and conduction band nonparabolicity in wurtzite GaN

S. Shokhovets, G. Gobsch, and O. Ambacher

Appl. Phys. Lett. 86, 161908 (2005); http://dx.doi.org/10.1063/1.1906313 (3 pages) | Cited 15 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Comparing the imaginary part of the dielectric function of wurtzite GaN measured by spectroscopic ellipsometry at room temperature with calculations, we found the values of Ep = (19.8±0.5) eV, m0* = (0.201±0.005)m0, and F = −0.89±0.05 for the momentum matrix element, electron effective mass at the conduction band edge, and parameter F describing the influence of remote bands, respectively. We also observed a remarkable nonparabolicity of the conduction band. The data obtained are consistent with A sets of valence band parameters reported earlier providing a parameterization of band structure of wurtzite GaN in the vicinity of the Γ point.
Show PACS
71.20.Nr Semiconductor compounds
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
77.22.Ch Permittivity (dielectric function)

Room temperature aging of the χ(2) susceptibility induced in silica glasses by thermal poling

Alexandre Kudlinski, Yves Quiquempois, and Gilbert Martinelli

Appl. Phys. Lett. 86, 161909 (2005); http://dx.doi.org/10.1063/1.1914959 (3 pages) | Cited 4 times

Online Publication Date: 14 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The stability of the χ(2) susceptibility induced in poled Infrasil™ silica glass samples is studied at room temperature. To this end, the second-order nonlinearity spatial distribution is determined as a function of the aging duration ranging from 0 (immediately after poling) to 14 months. An important decrease of the nonlinear layer width is observed although the χ(2) magnitude remains unaffected. The experimental results reported in this Letter suggest a movement of charges within the nonlinear region without recombination.
Show PACS
81.05.Kf Glasses (including metallic glasses)
42.70.Ce Glasses, quartz
77.22.Ej Polarization and depolarization
81.40.Cd Solid solution hardening, precipitation hardening, and dispersion hardening; aging
81.40.Gh Other heat and thermomechanical treatments

Bonding properties and their relation to residual stress and refractive index of amorphous Ta(N,O) films investigated by x-ray absorption spectroscopy

J. C. Jan, P. D. Babu, H. M. Tsai, C. W. Pao, J. W. Chiou, S. C. Ray, K. P. Krishna Kumar, W. F. Pong, M.-H. Tsai, C. A. Jong, and T. S. Chin

Appl. Phys. Lett. 86, 161910 (2005); http://dx.doi.org/10.1063/1.1905784 (3 pages) | Cited 3 times

Online Publication Date: 15 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This work presents N, O K-edge x-ray absorption near-edge structure (XANES) and Ta L3-edge extended x-ray absorption fine structure (EXAFS) studies of amorphous Ta(N,O) films prepared with various flow rate ratios of N2/O2. The N and O K-edge XANES and Ta L3-edge EXAFS spectra demonstrate the presence of N2 molecules. These spectra also show that Ta(N,O) films have similar local atomic structure as that of Ta2O5. No evidence of the formation of Ta–N bond was obtained. The intensities of the π* feature in the N K-edge spectra and the features of O 2p–Ta 5d hybridized states were found to correlate with the residual stress and the refractive index, respectively.
Show PACS
78.66.Nk Insulators
68.60.Bs Mechanical and acoustical properties
68.55.-a Thin film structure and morphology
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.70.Dm X-ray absorption spectra

Nanobump arrays fabricated by laser irradiation of polystyrene particle layers on silicon

S. M. Huang, Z. Sun, B. S. Luk’yanchuk, M. H. Hong, and L. P. Shi

Appl. Phys. Lett. 86, 161911 (2005); http://dx.doi.org/10.1063/1.1886896 (3 pages) | Cited 19 times

Online Publication Date: 15 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Two-dimensional (2D) nanobump arrays were fabricated by laser irradiation of a regular lattice of absorptive polystyrene (PS) microspheres on an undoped (100) Si wafer. The experiments were performed with single-pulse 248 nm KrF laser radiation. The structure of the arrays fabricated by this method was characterized by field emission scanning electron microscope and atomic force microscope. The near-field effects under the absorptive particle are studied. The ablation and thermal processes induced by the optical near-field around the particles are investigated. The formation mechanism of nanobumps is discussed.
Show PACS
81.07.Bc Nanocrystalline materials
81.05.Cy Elemental semiconductors
81.16.Dn Self-assembly
81.16.Mk Laser-assisted deposition
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Rx Nanocrystalline materials
61.82.Fk Semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.37.Vj Field emission and field-ion microscopy
68.37.Ps Atomic force microscopy (AFM)
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)

Reduced subpicosecond electron relaxation in GaNxAs1−x

S. Sinning, T. Dekorsy, M. Helm, G. Mussler, L. Däweritz, and K. H. Ploog

Appl. Phys. Lett. 86, 161912 (2005); http://dx.doi.org/10.1063/1.1904709 (3 pages)

Online Publication Date: 15 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on time resolved femtosecond carrier dynamics in molecular beam epitaxy grown GaNxAs1−x with a nitrogen fraction of 1.3%. The intraband carrier relaxation time in GaNxAs1−x is found to be significantly larger than in GaAs. We compare the experimental results with carrier-polar optical phonon scattering rates calculated within the band anticrossing model. From the results we conclude that the slowing down of the carrier relaxation is a result of the strongly modified band structure in GaNxAs1−x.
Show PACS
73.61.Ey III-V semiconductors
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
78.47.-p Spectroscopy of solid state dynamics
73.20.At Surface states, band structure, electron density of states
63.20.K- Phonon interactions
back to top
RSS Feeds

On the band structure lineup of ZnO heterostructures

Winfried Mönch

Appl. Phys. Lett. 86, 162101 (2005); http://dx.doi.org/10.1063/1.1897436 (2 pages) | Cited 14 times

Online Publication Date: 11 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The interface-induced gap states (IFIGS) are the fundamental mechanism which determines the band structure lineup at semiconductor interfaces. The valence-band offsets of semiconductor heterostructures are given by the difference of the respective IFIGS branch-point energies and electric-dipole terms which may be omitted for elemental group-IV semiconductors, SiC, as well as the III–V, II–VI, and I–III–VI2 compounds and alloys. The branch-point energy of ZnO is determined as 3.04±0.21 eV from an analysis of experimental valence-band offsets reported for various ZnO heterostructures.
Show PACS
73.20.At Surface states, band structure, electron density of states
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Inhomogeneous distribution of dislocations in a SiGe graded layer and its influence on surface morphology and misfit dislocations at the interface of strained Si/Si0.8Ge0.2

X. L. Yuan, T. Sekiguchi, J. Niitsuma, Y. Sakuma, S. Ito, and S. G. Ri

Appl. Phys. Lett. 86, 162102 (2005); http://dx.doi.org/10.1063/1.1905802 (3 pages) | Cited 5 times

Online Publication Date: 12 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To improve the quality of a strained Si layer on a SiGe virtual substrate, the distribution of dislocations in a graded SiGe layer is characterized using electron beam induced current (EBIC). A crosshatch pattern of dark and bright bands running along the two 〈110〉 directions is observed in an EBIC image taken with a 25-keV-electron beam at 80 K. These dark and bright EBIC bands are attributed, respectively, to high- and low-density dislocation regions in the graded SiGe layer, as is confirmed by transmission electron microscopy. The effects of such an inhomogeneous dislocation distribution on the surface morphology and the generation of misfit dislocations (MDs) at the interface of strained Si/SiGe are investigated. Comparison between the EBIC image and an atomic force microscope image shows that the high-density dislocation regions are correlated with ridges on the surface topography. A chemical etching image shows that most of the MDs lie along the edges of surface ridges. Possible mechanisms of MD generation at the interface of the strained Si/SiGe are proposed.
Show PACS
81.05.Cy Elemental semiconductors
81.05.Hd Other semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.65.Cf Surface cleaning, etching, patterning
68.35.Ct Interface structure and roughness
68.55.-a Thin film structure and morphology
68.37.Lp Transmission electron microscopy (TEM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)

Spectral and temporal resolution of recombination from multiple excitation states in modulation-doped AlGaN/GaN multiple quantum well heterostructures

M. Furis, A. N. Cartwright, E. L. Waldron, and E. F. Schubert

Appl. Phys. Lett. 86, 162103 (2005); http://dx.doi.org/10.1063/1.1905785 (3 pages)

Online Publication Date: 12 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Time-resolved photoluminescence measurements of carrier lifetimes in modulation-doped (100 Å) AlxGa1−xN/(100 Å) GaN multiple quantum well heterostructures are reported. The photoluminescence (PL) spectrum exhibits several lines associated with recombination of carriers from multiple excited electron states to the hole ground state. The PL decay times associated with ground state recombination, e0h0, are found to be much longer than the inverse repetition rate of our system (20 μs) and estimated to be 9 ms. The experimental lifetimes associated with carrier recombination from excited states vary between 4 μs for the first excited state, e1h0, and 4.5 ns for the fourth excited state, e4h0. These lifetimes are in very good agreement with a self-consistent calculation of radiative recombination lifetimes which takes into account piezoelectric and spontaneous polarization. The significant differences in recombination lifetimes are the result of the large built-in electric field in the wells (0.5 MV/cm).
Show PACS
78.67.De Quantum wells
73.63.Hs Quantum wells
78.55.Cr III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths

Spin control in heteromagnetic nanostructures

A. V. Scherbakov, A. V. Akimov, D. R. Yakovlev, W. Ossau, L. Hansen, A. Waag, and L. W. Molenkamp

Appl. Phys. Lett. 86, 162104 (2005); http://dx.doi.org/10.1063/1.1906322 (3 pages) | Cited 8 times

Online Publication Date: 12 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We suggest and verify experimentally a concept of heteromagnetic semiconductor structures. It is based on spin diffusion between layers of the nanostructure with different magnetic properties and allows to control the spin-switching rate for magnetic ions. A ten times increase of spin-lattice relaxation rate of magnetic Mn ions is achieved in Zn1−xMnxSe/Be1−yMnyTe heteromagnetic structures with an inhomogeneous distribution of Mn ions.
Show PACS
75.50.Pp Magnetic semiconductors
75.40.Gb Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.)
75.50.Tt Fine-particle systems; nanocrystalline materials
76.60.Es Relaxation effects
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions

Direct observation of copper depletion and potential changes at copper indium gallium diselenide grain boundaries

M. J. Hetzer, Y. M. Strzhemechny, M. Gao, M. A. Contreras, A. Zunger, and L. J. Brillson

Appl. Phys. Lett. 86, 162105 (2005); http://dx.doi.org/10.1063/1.1906331 (3 pages) | Cited 36 times

Online Publication Date: 12 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have used micro-Auger electron spectroscopy, cathodoluminescence spectroscopy, and work function measurements in copper indium gallium diselenide polycrystalline solar cell films cleaved in ultrahigh vacuum. We establish that, relative to the grain interior, the grain boundary shows (1) a Cu composition decrease, as large as a factor of two, (2) a work function decrease of up to 480 meV, and (3) no additional radiative recombination centers despite a high concentration of grain boundary (GB) defects. These results confirm theoretical predictions that (i) polar GB interfaces are stabilized by massive ( ∼ 50%) removal of Cu atoms, leading to (ii) a valence band offset between GB and grain interiors that (iii) repels holes from the GB, thus likely reducing GB electron-hole recombination and improving photovoltaic (and other photonic) device operation.
Show PACS
81.05.Hd Other semiconductors
79.20.Fv Electron impact: Auger emission
78.66.Li Other semiconductors
78.60.Hk Cathodoluminescence, ionoluminescence
61.72.Mm Grain and twin boundaries
73.30.+y Surface double layers, Schottky barriers, and work functions
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
73.61.Le Other inorganic semiconductors

High mobility two-dimensional hole system in GaAs/AlGaAs quantum wells grown on (100) GaAs substrates

M. J. Manfra, L. N. Pfeiffer, K. W. West, R. de Picciotto, and K. W. Baldwin

Appl. Phys. Lett. 86, 162106 (2005); http://dx.doi.org/10.1063/1.1900949 (3 pages) | Cited 21 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the transport properties of a high mobility two-dimensional hole system (2DHS) confined in GaAs/AlGaAs quantum wells grown by molecular-beam epitaxy on the (100) surface of GaAs. The quantum wells are modulation doped with carbon utilizing a resistive filament source. At T = 0.3 K and carrier density p = 1×1011 cm−2, a mobility of 106 cm2/Vs is achieved. At fixed carrier density p = 1011 cm−2, the mobility is found to be a nonmonotonic function of the quantum well width. The mobility peaks at 106 cm2/Vs for a 15-nm well and is reduced for both smaller and larger well widths for these (100) samples. The mobility anisotropy is found to be small. Mobility along [0math1] is approximately 20% higher than along the [011] direction. In addition, the low-temperature carrier density is found to have low sensitivity to light. The hole density increases by only ∼ 10% after exposure to red light at T = 4.2 K. In structures designed for a lower carrier density of 3.6×1010 cm−2, a mobility of 800 000 cm2/Vs is achieved at T = 15 mK.
Show PACS
81.07.St Quantum wells
81.05.Ea III-V semiconductors
73.63.Hs Quantum wells
73.50.Fq High-field and nonlinear effects
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.43.Qt Magnetoresistance

Electron spin interferometry using a semiconductor ring structure

Y. K. Kato, R. C. Myers, A. C. Gossard, and D. D. Awschalom

Appl. Phys. Lett. 86, 162107 (2005); http://dx.doi.org/10.1063/1.1906301 (3 pages) | Cited 17 times

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A ring structure fabricated from GaAs is used to achieve interference of the net spin polarization of conduction band electrons. Optically polarized spins are split into two packets by passing through two arms of the ring in the diffusive transport regime. Optical pumping with circularly polarized light on one arm establishes dynamic nuclear polarization which acts as a local effective magnetic field on electron spins due to the hyperfine interaction. This local field causes one spin packet to precess faster than the other, thereby controlling the spin interference when the two packets are combined.
Show PACS
85.75.−d
78.47.-p Spectroscopy of solid state dynamics

Sulfur-induced exciton localization in Te-rich ZnSTe alloy

X. D. Yang, Z. Y. Xu, Z. Sun, Y. Ji, B. Q. Sun, I. K. Sou, and W. K. Ge

Appl. Phys. Lett. 86, 162108 (2005); http://dx.doi.org/10.1063/1.1906303 (3 pages) | Cited 1 time

Online Publication Date: 13 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Exciton localization in Te-rich ZnSTe epilayers has been studied by photoluminescence (PL) and time-resolved PL. The sulfur-related exciton emission is found to dominate the radiative recombination at low temperature and is shifted to the low energy with the increase of S concentration. By measuring the PL dependence on temperature and by analyzing the PL decay process, we have clarified the localization nature of the sulfur-related exciton emission. Furthermore, the difference of the localization effect in Te- and S-rich ZnSTe is also compared and discussed.
Show PACS
71.35.-y Excitons and related phenomena
78.66.Hf II-VI semiconductors
78.55.Et II-VI semiconductors
78.47.-p Spectroscopy of solid state dynamics

Electronic transitions at defect states in Cz p-type silicon

A. Castaldini, D. Cavalcoli, A. Cavallini, S. Binetti, and S. Pizzini

Appl. Phys. Lett. 86, 162109 (2005); http://dx.doi.org/10.1063/1.1881788 (3 pages) | Cited 8 times

Online Publication Date: 14 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Point and extended defects introduced in p-type Cz Si by oxygen precipitation and plastic deformation have been investigated with electrical and optical methods. Different materials (oxygen precipitated and/or deformed Cz Si and Fz Si) were examined in order to separate the role of oxygen precipitation, plastic deformation, and metallic contamination on the radiative and nonradiative electronic transitions at defect centers. A deep hole trap, named T1, has been associated with dislocation-related impurity centers; additional deep traps have been related to contamination by grown-in transition metals and to clusters involving oxygen atoms.
Show PACS
81.05.Cy Elemental semiconductors
71.55.Cn Elemental semiconductors
61.72.Nn Stacking faults and other planar or extended defects
61.72.J- Point defects and defect clusters
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.55.Ap Elemental semiconductors
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
81.10.Dn Growth from solutions
81.10.Fq Growth from melts; zone melting and refining
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)

Depletion characteristics of two-dimensional lateral p‐n-junctions

D. Reuter, C. Werner, A. D. Wieck, and S. Petrosyan

Appl. Phys. Lett. 86, 162110 (2005); http://dx.doi.org/10.1063/1.1897829 (3 pages) | Cited 9 times

Online Publication Date: 14 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have fabricated two-dimensional in-plane p‐n junctions from a p-doped pseudomorphic GaAs/In0.1Ga0.9As/Al0.35Ga0.65As heterostructure employing Si compensation doping by focused ion beam implantation. The current–voltage characteristics at room temperature showed good rectifying behavior, and the current in the reverse direction was below 1 nA for voltages up to 10 V. The depletion width was measured by optical beam-induced current, and a linear dependence on the reverse bias was found which is in contrast to the square root dependence observed in three-dimensional junctions. The results agree well with theoretical predictions.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.72.uj III-V and II-VI semiconductors
73.40.Ei Rectification
72.40.+w Photoconduction and photovoltaic effects

Charging efficiency and lifetime of image-bound electrons on a dielectric surface

M. Biasini, R. D. Gann, J. A. Yarmoff, A. P. Mills, L. N. Pfeiffer, K. W. West, X. P. A. Gao, and B. C. D. Williams

Appl. Phys. Lett. 86, 162111 (2005); http://dx.doi.org/10.1063/1.1906314 (3 pages) | Cited 3 times

Online Publication Date: 14 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The surface charge generated on an Al0.24Ga0.76As/GaAs quantum well sample by electron bombardment was monitored by measuring the change in the conductivity of the channel. Upon turning off the electron bombardment the surface charge on adsorbed layers of xenon and water at 8 K decays in room temperature darkness with a lifetime τ = 0.30±0.02 s. The average charging efficiency, μ0, defined as the ratio of the charge collected by the surface to the beam current times the charging time, is μ0 ≃ 0.001. Surface charging proves to be an effective method for contactless gating of field effect devices.
Show PACS
73.63.Hs Quantum wells
73.21.Fg Quantum wells
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
73.40.-c Electronic transport in interface structures

Free and bound excitons in GaN/AlGaN homoepitaxial quantum wells grown on bulk GaN substrate along the nonpolar (11math0) direction

H. Teisseyre, C. Skierbiszewski, B. Łucznik, G. Kamler, A. Feduniewicz, M. Siekacz, T. Suski, P. Perlin, I. Grzegory, and S. Porowski

Appl. Phys. Lett. 86, 162112 (2005); http://dx.doi.org/10.1063/1.1899258 (3 pages) | Cited 15 times

Online Publication Date: 15 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nonpolar multiple quantum wells (MQWs) have been grown by plasma assisted molecular beam epitaxy on bulk GaN crystals oriented along the (11math0) direction. The photoluminescence intensity of the nonpolar MQWs was significantly higher than that found for the polar samples, both at low (10 K) and room temperature. This is a consequence of the lack of built-in electric field in samples grown along the (11math0) direction. Clearly resolved spectra of the excitons have been observed in the studied MQWs. Studies of these excitonic structures, by means of polarization and temperature measurements enabled us to assign the observed lines to free and bound excitons in GaN quantum wells.
Show PACS
81.07.St Quantum wells
81.05.Ea III-V semiconductors
78.67.De Quantum wells
73.21.Fg Quantum wells
78.55.Cr III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.65.Fg Quantum wells
back to top
RSS Feeds

Soft magnetic ternary iron-boron-based bulk metallic glasses

Chih-Yuan Lin, Hung-Yu Tien, and Tsung-Shune Chin

Appl. Phys. Lett. 86, 162501 (2005); http://dx.doi.org/10.1063/1.1901808 (3 pages) | Cited 44 times

Online Publication Date: 11 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ternary iron-boron-based bulk metallic glasses (BMGs) were explored exhibiting capability of thick amorphous casting at least 1 mm in rod diameter or 0.5 mm in plate thickness, excellent soft magnetic properties with saturation magnetization 1.56 T and coercivity smaller than 40 A/m, and electrical resistivity larger than 200 μΩ cm. The BMG alloys represented by the formulas MaFebBc are based on two simple selection rules: (1) M is an element with an atomic radius at least 130% that of Fe; (2) M possesses eutectic points with both Fe and B, and the M-Fe eutectic is at the Fe-rich end. Among more than 30 candidate M elements, Sc, Y, Dy, Ho, and Er fulfill BMG capability at the composition range, in at %, 3<a<10, 18<c<27, whereas a+b+c = 100. It is very remarkable that with a tiny addition of M, such as 4 at %, the critical cooling rate to form an amorphous state is abruptly lowered by more than four orders of magnitude as compared with Fe-B binary alloys, and a bulk amorphous state is achievable with only three elements (conventional ones 4–7 elements). These alloys are promising as core materials for transformers.
Show PACS
75.50.Bb Fe and its alloys
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
72.15.Cz Electrical and thermal conduction in amorphous and liquid metals and alloys

Magnetic anisotropy and domain patterning of amorphous films by He-ion irradiation

Jeffrey McCord, Thomas Gemming, Ludwig Schultz, Jürgen Fassbender, Maciej Oskar Liedke, Michael Frommberger, and Eckhard Quandt

Appl. Phys. Lett. 86, 162502 (2005); http://dx.doi.org/10.1063/1.1906321 (3 pages) | Cited 24 times

Online Publication Date: 12 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic anisotropy in amorphous soft magnetic FeCoSiB films was modified by He-ion irradiation. A rotation of uniaxial anisotropy depending on the applied field direction in the irradiated areas is observed by magnetometry and complementary domain observation by Kerr microscopy. No significant degradation in magnetic properties relative to the as-deposited state is found from the magnetization loops on nonpatterned films. Using irradiation together with photolithography, the films were treated locally, resulting in “anisotropy patterned” structures. Complicated periodic domain patterns form due to the locally varying anisotropy distribution. Overall magnetic properties and domain patterns are adjusted.
Show PACS
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.30.Gw Magnetic anisotropy
75.60.Ch Domain walls and domain structure
75.50.Bb Fe and its alloys
78.20.Ls Magneto-optical effects
61.80.Jh Ion radiation effects
75.70.Ak Magnetic properties of monolayers and thin films

Intergranular strain correlation with magnetic behavior in steel

Roxana Hutanu, Lynann Clapham, and R. B. Rogge

Appl. Phys. Lett. 86, 162503 (2005); http://dx.doi.org/10.1063/1.1904710 (3 pages) | Cited 3 times

Online Publication Date: 12 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The correlation between the magnetic behavior and intergranular residual strain was investigated on several mild steel samples which were plastically deformed in the range 0.5%–20% engineering strain followed by unloading. At low deformation levels (0.5%– ∼ 2%) the samples exhibited Luders banding, but after 2% strain the samples appeared uniformly deformed. Magnetic Barkhausen noise (MBN) measurements were used to characterize magnetic behavior and neutron diffraction measurements were used to determine the inter-granular strain. MBN results indicated a high MBN value in the direction transverse to the applied stress. This corresponded to a high strain in the (100) crystallographic direction (the easy magnetization direction), as observed using neutron diffraction. Little correlation was obtained between the MBN result and the (112) strain, which is generally assumed to reflect the macroscopic residual stress. Angular MBN and neutron diffraction results further confirmed the strong correlation between the (100) strain and the MBN result.
Show PACS
75.50.Bb Fe and its alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity

Effects of cation disorder and size on metamagnetism in A-site substituted Pr0.5Ca0.5MnO3 system

K. R. Mavani and P. L. Paulose

Appl. Phys. Lett. 86, 162504 (2005); http://dx.doi.org/10.1063/1.1905786 (3 pages) | Cited 10 times

Online Publication Date: 14 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of A-site cation disorder and size on metamagnetism of ABO3 type charge and orbital ordered Pr0.5Ca0.5MnO3 system have been studied by substituting Ba+2 for Ca+2 or La+3 for Pr+3. Substitution of 5% Ba+2 or 5% La+3 drastically reduces the critical magnetic field (Hc) for metamagnetism and induces successive steplike metamagnetic transitions at low temperatures. Interestingly, with further increase in substitution, Hc rises. We find that there is a sharp decrease in electrical resistivity corresponding to the metamagnetic transitions, which is indicative of strongly correlated magnetic and electronic transitions in these manganites.
Show PACS
75.47.Lx Magnetic oxides
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

Magnetostriction in ⟨110⟩ and ⟨112⟩ oriented crystals Tb0.36Dy0.64(Fe0.85Co0.15)2

Tianyu Ma, Chengbao Jiang, and Huibin Xu

Appl. Phys. Lett. 86, 162505 (2005); http://dx.doi.org/10.1063/1.1896430 (3 pages) | Cited 16 times

Online Publication Date: 15 April 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Magnetostriction of ⟨110⟩ and ⟨112⟩ oriented crystals Tb0.36Dy0.64(Fe0.85Co0.15)2 under various conditions of compressive prestress and applied fields was investigated at room temperature (30 °C), elevated temperature (100 °C) and cryogenic temperature (−80 °C). Obvious magnetostriction jump effect was observed in both ⟨110⟩ and ⟨112⟩ oriented crystals at room temperature and elevated temperature, but less obvious at cryogenic temperature. When the compressive prestress is not higher than 10 MPa, the ⟨112⟩ oriented crystal exhibits larger magnetostriction than that of ⟨110⟩ oriented crystal in low applied field at room temperature and cryogenic temperature, but smaller magnetostriction at elevated temperature.
Show PACS
75.50.Bb Fe and its alloys
75.80.+q Magnetomechanical effects, magnetostriction
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close