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

3 Jun 2002

Volume 80, Issue 22, pp. 4085-4270

Page 1 of 3 Pages Next Page | Jump to Page
back to top
RSS Feeds

Comprehensive modeling of the electro-optical-thermal behavior of (AlGaIn)(AsSb)-based 2.0 μm diode lasers

M. Rattunde, C. Mermelstein, J. Schmitz, R. Kiefer, W. Pletschen, M. Walther, and J. Wagner

Appl. Phys. Lett. 80, 4085 (2002); http://dx.doi.org/10.1063/1.1481979 (3 pages) | Cited 15 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Strained triple-quantum-well, large-optical-cavity GaInSb/AlGaAsSb/GaSb diode lasers emitting at 1.98 μm at 300 K are investigated with regard to their high-power capability. As the heating of the active region is a limiting factor for these devices, a quantitative model is derived to simulate the performance of these lasers including thermal effects. The standard laser parameters, deduced from measurements on ridge waveguide lasers, and the measured thermal resistance of the mounted devices were then taken as input parameters. The output power and power efficiency of the lasers calculated using the presented model. Good agreement was found between calculated data and the measurements for different heatsink temperatures as well as for different laser geometries and mounting techniques. The maximum output power achieved for p-side down mounted 1000×150 μm2 broad-area laser was 1.7 W at 300 K in cw operation. © 2002 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation

Influence of the orientation of liquid crystalline poly(9,9-dioctylfluorene) on its lasing properties in a planar microcavity

T. Virgili, D. G. Lidzey, M. Grell, D. D. C. Bradley, S. Stagira, M. Zavelani-Rossi, and S. De Silvestri

Appl. Phys. Lett. 80, 4088 (2002); http://dx.doi.org/10.1063/1.1481977 (3 pages) | Cited 18 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a study of optically pumped laser emission from a microcavity containing an oriented layer of the liquid crystalline conjugated polymer poly(9,9-dioctylfluorene). The birefringence of the oriented polymer results in the definition of two cavity modes with electric vectors polarized perpendicular and parallel to the alignment direction. At high excitation density, the emission intensity from the cavity mode polarized parallel to the orientation direction increases rapidly compared to the orthogonal polarized mode and its linewidth narrows from 8 to 2 nm. We identify the parallel-polarized emission as laser action with a threshold excitation density of 7.8×1019 cm−3. © 2002 American Institute of Physics.
Show PACS
42.55.Sa Microcavity and microdisk lasers
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.70.Jk Polymers and organics
42.70.Df Liquid crystals
61.30.Vx Polymer liquid crystals
78.45.+h Stimulated emission
78.20.Fm Birefringence

High-power (λ ∼ 9 μm) quantum cascade lasers

S. Slivken, Z. Huang, A. Evans, and M. Razeghi

Appl. Phys. Lett. 80, 4091 (2002); http://dx.doi.org/10.1063/1.1482782 (3 pages) | Cited 20 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-power quantum cascade lasers emitting at λ>9 μm are demonstrated. Accurate control of layer thickness and interfaces is evidenced by x-ray diffraction. Excellent peak power for uncoated lasers, up to 3.5 W per facet for a 25 μm emitter width, is obtained at 300 K for 75 period structures. The threshold current density at 300 K is only 1.4 kA/cm2. From 300 to 425 K, the laser exhibits a characteristic temperature, T0, of 167 K. Over 150 mW of average power is measured per facet for a duty cycle of 6%. Simulation of the average power output reveals a thermal resistance of 12 K/W for epilayer-up mounted ridges. © 2002 American Institute of Physics.
Show PACS
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
68.65.Fg Quantum wells

Room-temperature operation of electrically pumped quantum-cascade microcylinder lasers

S. Anders, W. Schrenk, E. Gornik, and G. Strasser

Appl. Phys. Lett. 80, 4094 (2002); http://dx.doi.org/10.1063/1.1484246 (3 pages) | Cited 7 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present the lasing properties of microcylinder lasers that were processed into a quantum-cascade heterostructure. At room temperature, the GaAs/Al0.45Ga0.55As superlattice structure lases at 12.55 μm. Low mirror losses, an inherent advantage of microcylinder lasers, result in a low threshold current density of 2.2 kA/cm2 at 78 K. The microcylinder lasers compare favorably to both Fabry–Pérot and distributed feedback cavities that were processed from the same material. The maximum operating temperature of the microcylinders, 54 °C, exceeds the previously reported maximum operating temperature, −3 °C, for an InP-based microlaser. © 2002 American Institute of Physics.
Show PACS
42.55.Sa Microcavity and microdisk lasers
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
42.55.Px Semiconductor lasers; laser diodes
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures

Electro-optic characteristics of de Vries tilted smectic liquid crystals: Analog behavior in the smectic A∗ and smectic C∗ phases

N. A. Clark, T. Bellini, R.-F. Shao, D. Coleman, S. Bardon, D. R. Link, J. E. Maclennan, X.-H. Chen, M. D. Wand, D. M. Walba, P. Rudquist, and S. T. Lagerwall

Appl. Phys. Lett. 80, 4097 (2002); http://dx.doi.org/10.1063/1.1480472 (3 pages) | Cited 49 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Chiral smectic A liquid crystal materials of the de Vries type (with molecules tilted relative to the layer normal) exhibit analog field-induced (electroclinic) optic axis rotation accompanied by an increase in birefringence. We identify two such de Vries smectic A∗ materials and use them to develop and test models for these characteristic electro-optic effects. These materials also exhibit colossal analog field-induced optic axis rotation in the lower temperature smectic C∗ phase, a consequence of polarization charge stabilization, and of polarization screening of the applied field in the liquid crystal. © 2002 American Institute of Physics.
Show PACS
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order
78.20.Fm Birefringence
78.20.Jq Electro-optical effects

Comparing leakage currents and dark count rates in Geiger-mode avalanche photodiodes

J. C. Jackson, P. K. Hurley, B. Lane, A. Mathewson, and A. P. Morrison

Appl. Phys. Lett. 80, 4100 (2002); http://dx.doi.org/10.1063/1.1483119 (3 pages) | Cited 6 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter presents an experimental study of dark count rates and leakage current in Geiger-mode avalanche photodiodes (GM APD). Experimental results from circular diodes over a range of areas (20–500 μm diam), exhibit leakage current levels orders of magnitude higher than anticipated from dark count rates. Measurements of the area and peripheral components of the leakage current indicate that the majority of the current in reverse bias does not enter the high-field region of the diode, and therefore, does not contribute to the dark count rate. Extraction of the area leakage current term from large-area devices (500 μm) corresponds well with the measured dark count rates on smaller devices (20 μm). Finally, the work indicates how dark count measurements represent 10−18 A levels of leakage current detection in GM APDs. © 2002 American Institute of Physics.
Show PACS
85.60.Dw Photodiodes; phototransistors; photoresistors
85.60.Gz Photodetectors (including infrared and CCD detectors)
85.30.De Semiconductor-device characterization, design, and modeling
72.40.+w Photoconduction and photovoltaic effects

Mid-infrared (λ≈7.4 μm) quantum cascade laser amplifier for high power single-mode emission and improved beam quality

Mariano Troccoli, Claire Gmachl, Federico Capasso, Deborah L. Sivco, and Alfred Y. Cho

Appl. Phys. Lett. 80, 4103 (2002); http://dx.doi.org/10.1063/1.1479453 (3 pages) | Cited 22 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A quantum cascade laser amplifier has been developed. It was used to obtain high power single-mode emission at λ ≈ 7.4 μm from a quantum cascade distributed feedback laser, together with enhanced beam quality. Laser and amplifier are directly coupled in a master oscillator power amplifier configuration. Peak optical powers of 0.5 W at 80 K have been obtained. Ninety percent of the total power is thereby emitted within a divergence of 20° in the lateral direction. The device showed single mode operation with a side mode suppression ratio of 30 dB in the temperature range from 10 to 280 K. This allowed tuning of the emission wavelength in the range from 7.36 to 7.46 μm. The estimated peak amplifier gain is 6.4 and 4.9 dB at 80 and 300 K, respectively, and the cavity losses are 12.5 and 22 cm−1 at the corresponding temperatures. © 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.)
42.60.Fc Modulation, tuning, and mode locking
42.60.Da Resonators, cavities, amplifiers, arrays, and rings

Subwavelength patterns and high detection efficiency in fluorescence correlation spectroscopy using photonic structures

P.-F. Lenne, E. Etienne, and H. Rigneault

Appl. Phys. Lett. 80, 4106 (2002); http://dx.doi.org/10.1063/1.1483116 (3 pages) | Cited 8 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present theoretical and experimental evidence of subwavelength resolution and high detection efficiency in fluorescence correlation spectroscopy (FCS) using photonic structures. We show that multilayered dielectric mirrors or metallic mirrors may be used in a conventional FCS setup to improve fluorescence detection and fluctuation analysis. © 2002 American Institute of Physics.
Show PACS
07.60.-j Optical instruments and equipment
42.79.Wc Optical coatings
78.67.-n Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures
78.55.-m Photoluminescence, properties and materials
42.79.Bh Lenses, prisms and mirrors
back to top
RSS Feeds

Plasma chemistry fluctuations in a reactive arc plasma in the presence of magnetic fields

Johanna Rosén, André Anders, and Jochen M. Schneider

Appl. Phys. Lett. 80, 4109 (2002); http://dx.doi.org/10.1063/1.1483128 (3 pages) | Cited 4 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of a magnetic field on the plasma chemistry and pulse-to-pulse fluctuations of cathodic arc ion charge state distributions in a reactive environment were investigated. The plasma composition was measured by time-of-flight charge-to-mass spectrometry. The fluctuation of the concentrations of Al+, Al2+, and Al3+ was found to increase with an increasing magnetic field strength. We suggest that this is caused by magnetic field dependent fluctuations of the energy input into cathode spots as seen through fluctuations of the cathode potential. These results are qualitatively consistent with the model of partial local Saha equilibrium and are of fundamental importance for the evolution of the structure of films deposited by reactive cathodic arc deposition. © 2002 American Institute of Physics.
Show PACS
52.80.Mg Arcs; sparks; lightning; atmospheric electricity
52.25.Gj Fluctuation and chaos phenomena
52.27.Jt Nonneutral plasmas

Modification of laser energy deposition in a gas of deuterium clusters

D. R. Symes, A. J. Comley, J. W. G. Tisch, and R. A. Smith

Appl. Phys. Lett. 80, 4112 (2002); http://dx.doi.org/10.1063/1.1483129 (3 pages) | Cited 8 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The modification of energy deposition by a 70 fs laser pulse focused to an intensity of 1017 W cm−2 in a medium of deuterium clusters with mean atomic density of 1019 cm−3 has been investigated using short-pulse interferometry. A low-power (<1015 W cm−2) beam propagating transverse to the heating beam was used to destroy clusters in the low-density wings of the medium prior to the arrival of the main heating pulse. Images of the plasma channels produced by the heating beam show that the transverse beam can strongly modify the spatial deposition of laser energy. Using this effect, we have demonstrated a 15-fold enhancement of energy coupling to the densest regions of the cluster medium. © 2002 American Institute of Physics.
Show PACS
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
back to top
RSS Feeds

Stress as a governing parameter to control the crystallization of amorphous silicon films by thermal annealing

Sukti Hazra, Isao Sakata, Mitsuyuki Yamanaka, and Eiichi Suzuki

Appl. Phys. Lett. 80, 4115 (2002); http://dx.doi.org/10.1063/1.1482795 (3 pages) | Cited 3 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have fabricated nanocrystalline dots by thermal annealing (TA) of thermal chemical-vapor-deposited amorphous silicon (a-Si:H) films. In S. Hazra, I. Sakata, M. Yamanaka, and E. Suzuki, Appl. Phys. Lett. 80, 1159 (2002), we observed that ultrathin a-Si:H films (2–10 nm) are stressed because of the presence of deformed crystallites or paracrystallites. With the increase of thickness, volume fraction of paracrystallites decreased in the films and stress in the films gradually reduced. Therefore, by changing the thickness, we can control the stress in the a-Si:H films and thereby the dimensions (in the range of 5 to 10 nm) as well as volume fractions of nanocrystallites formed by TA. On the other hand, it has been found that relaxed a-Si:H networks form polycrystalline films by TA. © 2002 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
68.60.Bs Mechanical and acoustical properties
81.05.Cy Elemental semiconductors
61.43.Dq Amorphous semiconductors, metals, and alloys
81.05.Gc Amorphous semiconductors
81.40.Gh Other heat and thermomechanical treatments
61.46.-w Structure of nanoscale materials
81.07.Bc Nanocrystalline materials
68.65.Hb Quantum dots (patterned in quantum wells)
81.07.Ta Quantum dots

Interchain interaction and Davydov splitting in polythiophene crystals: An ab initio approach

Giovanni Bussi, Alice Ruini, Elisa Molinari, Marilia J. Caldas, Peter Puschnig, and Claudia Ambrosch-Draxl

Appl. Phys. Lett. 80, 4118 (2002); http://dx.doi.org/10.1063/1.1483905 (3 pages) | Cited 21 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The crystal-induced energy splitting of the lowest excitonic state in polymer crystals, the so-called Davydov splitting Δ, is calculated with a first-principles density-matrix scheme. We show that different crystalline arrangements lead to significant variations in Δ, from below to above the thermal energy kBT at room temperature, with relevant implications on the luminescence efficiency. This is one more piece of evidence supporting the fact that control of interchain interactions and solid-state packing is essential for the design of efficient optical devices. © 2002 American Institute of Physics.
Show PACS
71.70.Ch Crystal and ligand fields
71.35.Cc Intrinsic properties of excitons; optical absorption spectra
42.70.Jk Polymers and organics
61.41.+e Polymers, elastomers, and plastics
78.55.Kz Solid organic materials
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Stability of interfacial dislocations in (001) silicon surfacial grain boundaries

K. Rousseau, J. L. Rouvière, F. Fournel, and H. Moriceau

Appl. Phys. Lett. 80, 4121 (2002); http://dx.doi.org/10.1063/1.1481957 (3 pages) | Cited 15 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultrathin (001) silicon films bonded onto (001) silicon wafers, which form “surfacial grain boundaries” have been investigated by transmission electron microscopy. The samples were obtained by bonding one silicon-on-insulator (SOI) structure with one silicon wafer. After the removal of the SOI substrate, the remaining top thin film was further reduced by a thermal oxidation. Samples with a given film thickness selected in the 200 nm to 10 nm range were obtained. For very thin films, the thinning procedure can induce a mobility of the interfacial dislocations. To keep the interfaces stable, we have replaced the thermal oxidation thinning by a low-temperature chemical etching. © 2002 American Institute of Physics.
Show PACS
68.35.Dv Composition, segregation; defects and impurities
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.)
61.72.Mm Grain and twin boundaries
68.37.Lp Transmission electron microscopy (TEM)
81.65.Cf Surface cleaning, etching, patterning
81.65.Mq Oxidation

Characteristics of SrS:Cu thin-film electroluminescent device fabricated by pulsed-laser deposition

Jae Young Choe, S. M. Blomquist, and D. C. Morton

Appl. Phys. Lett. 80, 4124 (2002); http://dx.doi.org/10.1063/1.1483925 (3 pages) | Cited 2 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
SrS:Cu film was deposited by a pulsed-laser deposition method to fabricate the phosphor film for thin-film electroluminescent (EL) devices. The devices were annealed in dry nitrogen gas to give the characteristic blue emission with a chromaticity coordinate of (0.17, 0.24). The luminance at 100 Hz driving frequency reached 6 cd/cm2 with corresponding transferred charge of 4.1 μC/cm2. The excellent stoichiometry replication of the film from the target being sputtered, pulsed-laser deposition can serve as a convenient method for fabricating high-quality thin-film EL devices of different composition by changing target concentrations. © 2002 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
81.15.Fg Pulsed laser ablation deposition
78.66.Nk Insulators
42.79.Wc Optical coatings
81.40.Gh Other heat and thermomechanical treatments
81.40.Tv Optical and dielectric properties related to treatment conditions

Spatially-resolved valence-electron energy-loss spectroscopy of Zr-oxide and Zr-silicate films

Nobuyuki Ikarashi and Kenzo Manabe

Appl. Phys. Lett. 80, 4127 (2002); http://dx.doi.org/10.1063/1.1483130 (3 pages) | Cited 5 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We examined electronic structures in Zr-oxide (ZrO2) and Zr-silicate (ZrxSi1−xO2) films deposited on Si substrates by using valence-electron energy-loss spectroscopy combined with scanning transmission electron microscopy (the electron probe diameter was about 0.3 nm). Our analysis indicated that both valence-electron excitations in ZrO2 and in SiO2 occurred in the ZrxSi1−xO2 films. Therefore, the band gaps in the ZrxSi1−xO2 films should be dominated by an energy gap between O 2p and Zr 4d states. © 2002 American Institute of Physics.
Show PACS
71.20.Ps Other inorganic compounds
73.20.At Surface states, band structure, electron density of states
77.55.-g Dielectric thin films
79.20.Kz Other electron-impact emission phenomena
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.

Depth dependence of the tetragonal distortion of a GaN layer on Si(111) studied by Rutherford backscattering/channeling

M. F. Wu, ChangChun Chen, DeZhang Zhu, Shengqiang Zhou, A. Vantomme, G. Langouche, B. S. Zhang, and Hui Yang

Appl. Phys. Lett. 80, 4130 (2002); http://dx.doi.org/10.1063/1.1483389 (3 pages) | Cited 14 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Rutherford backscattering and channeling have been used to characterize the structure of a GaN layer grown on a Si(111) substrate. The results show that a 1.26 μm GaN epitaxial layer with a rather abrupt interface and a good crystalline quality (χmin = 3.4%) can be grown on a Si(111) substrate. Using the channeling angular scan around an off-normal 〈1math13〉 axis in the {10math0} plane of the GaN layer, the tetragonal distortion eT, which is caused by the elastic strain in the epilayer, can be determined. Moreover, the depth dependence of the eT can be obtained using this technique. A fully relaxed (eT = 0) GaN layer for a thickness <2.8 μm is expected. © 2002 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis

Three-dimensional self-assembly by ice crystallization

Sang Hyuk Im and O Ok Park

Appl. Phys. Lett. 80, 4133 (2002); http://dx.doi.org/10.1063/1.1483385 (3 pages) | Cited 2 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Three-dimensional self-assembly of colloidal particles by ice crystallization is observed in a water based-colloidal suspension. When water containing polystyrene beads freezes and is crystalized into ice, the polystyrene beads are extruded outward from the ice regions. Consequently, the concentration of polystyrene beads increases rapidly and they are assembled together into a regular structure. As ice crystallization proceeds, a color appears abruptly. This indicates that the polystyrene beads have been assembled three dimensionally. The generated three-dimensional structure is confirmed by scanning electron microscopy images and the existance of a photonic band gap measured by an ultraviolet-visible spectrophotometer. The sample fabricated by this method is compared with a sample made by conventional vertical deposition. © 2002 American Institute of Physics.
Show PACS
42.70.Qs Photonic bandgap materials
64.70.D- Solid-liquid transitions
82.70.Uv Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems, (hydrophilic and hydrophobic interactions)
07.60.Dq Photometers, radiometers, and colorimeters
07.60.Rd Visible and ultraviolet spectrometers

Comparison of nitrogen compositions in the as-grown GaNxAs1−x on GaAs measured by high-resolution x-ray diffraction and secondary-ion mass spectroscopy

W. J. Fan, S. F. Yoon, T. K. Ng, S. Z. Wang, W. K. Loke, R. Liu, and A. Wee

Appl. Phys. Lett. 80, 4136 (2002); http://dx.doi.org/10.1063/1.1483913 (3 pages) | Cited 44 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-resolution x-ray diffraction (HRXRD) and secondary-ion mass spectroscopy were used to measure the N compositions of a series of as-grown GaNAs samples grown by solid-source molecular-beam epitaxy. We found that N compositions measured by the two methods agree well at lower N compositions (x<3%), and deviate at larger N compositions (x>3%). The HRXRD measurement by using Vegard’s law to extract the lattice constant of GaNAs, underestimates N composition at larger N compositions. We found that the underestimation is up to 14.3% at the x = 4.2%. In order to explain the deviation, a model for analyzing the correlation between lattice parameters and point defects in the epilayer was carried out. © 2002 American Institute of Physics.
Show PACS
68.55.Nq Composition and phase identification
61.05.cp X-ray diffraction
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Suppression of phase segregation during molecular-beam epitaxial growth of GaMnN using nitrogen–hydrogen plasma

Y. Cui and L. Li

Appl. Phys. Lett. 80, 4139 (2002); http://dx.doi.org/10.1063/1.1483387 (3 pages) | Cited 23 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Epitaxial growth of GaMnN by electron-cyclotron-resonance plasma-assisted molecular-beam epitaxy using nitrogen–hydrogen plasma was studied by reflection high-energy electron diffraction, scanning electron microscopy, energy dispersive spectroscopy, and x-ray diffraction. The electron diffraction pattern changed from streaky to spotty when hydrogen was added to the nitrogen plasma, indicating that the effective group V/III ratio was increased. Films grown with nitrogen plasma are phase segregated into GaN and manganese nitrides. In contrast, when nitrogen–hydrogen plasma was used, the films are single phase Ga1−xMnxN, and x can be as high as 0.06. These results indicate that phase segregation can be suppressed by adding hydrogen to the nitrogen plasma during growth. © 2002 American Institute of Physics.
Show PACS
81.30.Mh Solid-phase precipitation
64.75.-g Phase equilibria
75.50.Pp Magnetic semiconductors
81.15.Jj Ion and electron beam-assisted deposition; ion plating
68.55.Nq Composition and phase identification
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
52.77.Dq Plasma-based ion implantation and deposition
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
61.66.Bi Elemental solids
61.66.Dk Alloys

Role of substrate in the pseudomorphic stabilization of rocksalt-type AlN phase in AlN/TiN superlattices

V. Pankov, M. Evstigneev, and R. H. Prince

Appl. Phys. Lett. 80, 4142 (2002); http://dx.doi.org/10.1063/1.1482798 (3 pages) | Cited 10 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The nonequilibrium B1 (rocksalt-type) AlN phase was successfully stabilized in stress-free AlN/TiN superlattices prepared by room-temperature pulsed laser deposition on thin film amorphous carbon substrates. The coatings displayed the same properties as reported for multilayers grown on thick crystalline substrates; namely, the existence of a critical thickness of AlN (about 1 nm for the present study) below which AlN crystallizes in the B1–AlN phase. Exceeding this value lead to AlN crystallization in its equilibrium hexagonal wurtzite-type structure, accompanied by considerable degradation of coating crystallinity due to the loss of coherent epitaxial growth of alternating TiN and AlN layers in the coating. It is concluded that neither an orientational effect of the substrate nor its stress-sustaining ability is required to provide a pseudomorphic stabilization of the nonequilibrium B1–AlN phase in AlN/TiN multilayered coatings. © 2002 American Institute of Physics.
Show PACS
68.65.Cd Superlattices
81.15.Fg Pulsed laser ablation deposition
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.05.Ea III-V semiconductors
68.35.Ct Interface structure and roughness
back to top
RSS Feeds

First-principles calculation of the piezoelectric tensor math of III–V nitrides

Fabio Bernardini and Vincenzo Fiorentini

Appl. Phys. Lett. 80, 4145 (2002); http://dx.doi.org/10.1063/1.1482796 (3 pages) | Cited 43 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report direct first-principles density-functional calculations of the piezoelectric tensor math relating polarization to applied stress for the binary compounds AlN, GaN, and InN. The values of math are rather sensitive to the choice of the exchange-correlation functional, and results are presented for both the local-density and gradient approximations. A comparison with experiment and with values predicted indirectly from the elastic math and piezoconstant math tensors is also presented. © 2002 American Institute of Physics.
Show PACS
77.65.Ly Strain-induced piezoelectric fields
81.05.Ea III-V semiconductors
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons

Mechanisms affecting the photoluminescence spectra of GaInNAs after post-growth annealing

E. Tournié, M.-A. Pinault, and A. Guzmán

Appl. Phys. Lett. 80, 4148 (2002); http://dx.doi.org/10.1063/1.1481978 (3 pages) | Cited 51 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated by photoluminescence spectroscopy and x-ray diffraction the influence of ex situ postgrowth annealing on the properties of a series of dedicated Ga(In)(N)As ternary and quaternary quantum wells (QWs) confined by various barrier layers. We show that the low growth temperature and not N per se, is largely responsible for the low radiative efficiency of Ga(In)NAs QWs. Furthermore, postgrowth annealing induces a blueshift of the photoluminescence line in the case of quaternary GaInNAs QWs only, while x-ray diffraction reveals the absence of compositional change. We conclude with the occurrence of a local reorganization of the N-bonding configuration within the GaInNAs quaternary material during annealing. © 2002 American Institute of Physics.
Show PACS
78.67.De Quantum wells
78.55.Cr III-V semiconductors
68.65.Fg Quantum wells
61.72.Cc Kinetics of defect formation and annealing
81.07.St Quantum wells

Electron lifetime of heavily Be-doped In0.53Ga0.47As as a function of growth temperature and doping density

D. Vignaud, J. F. Lampin, E. Lefebvre, M. Zaknoune, and F. Mollot

Appl. Phys. Lett. 80, 4151 (2002); http://dx.doi.org/10.1063/1.1483126 (3 pages) | Cited 7 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electron lifetime has been studied by a pump–probe optical transmission technique in heavily Be-doped InGaAs lattice matched to InP as a function of the growth temperature (350 ⩽ Tg ⩽ 500 °C) and doping (2×1019 ⩽ [Be] ⩽ 2.6×1020 cm−3). Reduction of the growth temperature to 350–400 °C induces the creation of electron recombining centers, efficient at the lowest doping studied here. But, for higher dopings, these defects have negligible effects compared to intrinsic Auger processes: the high diffusion of Be can thus be limited by growing heterostructures at reduced temperatures without compromising the electron lifetime. Subpicosecond electron lifetimes have been measured at the highest doping. © 2002 American Institute of Physics.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
71.55.Eq III-V semiconductors
72.80.Ey III-V and II-VI semiconductors
81.05.Ea III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics
66.30.J- Diffusion of impurities

Electron field emission from excimer laser crystallized amorphous silicon

Y. F. Tang, S. R. P. Silva, B. O. Boskovic, J. M. Shannon, and M. J. Rose

Appl. Phys. Lett. 80, 4154 (2002); http://dx.doi.org/10.1063/1.1482141 (3 pages) | Cited 9 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show field emission from excimer laser crystallized (ELC) hydrogenated amorphous silicon (a-Si:H) at current densities and threshold fields suitable for display applications. The laser crystallized a-Si:H gives rise to a densely packed and relative sharp surface morphology that gives emission currents of the order of 10−5 A (current densities ≈ 0.04 A/cm2) at threshold fields less than 15 V/μm in a diode configuration, without the need for a forming process. With the progress in utilizing ELC in flat panel driver electronics, a fully integrated field emission display on a single glass substrate can now be envisaged. © 2002 American Institute of Physics.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
81.05.Cy Elemental semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
07.07.Hj Display and recording equipment, oscilloscopes, TV cameras, etc.

Crossover from in-plane to perpendicular anisotropy in Pt/CoFe/AlOx sandwiches as a function of Al oxidation: A very accurate control of the oxidation of tunnel barriers

S. Monso, B. Rodmacq, S. Auffret, G. Casali, F. Fettar, B. Gilles, B. Dieny, and P. Boyer

Appl. Phys. Lett. 80, 4157 (2002); http://dx.doi.org/10.1063/1.1483122 (3 pages) | Cited 23 times

Online Publication Date: 23 May 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
By measuring the extraordinary Hall effect on a series of naturally oxidized Pt3 nm/Co90Fe10 0.6 nm/Al tAl samples with 0<tAl<1.2 nm, a first crossover from in-plane to perpendicular magnetic anisotropy is observed when tAl is varied from 0 to 0.2 nm. The CoFe magnetization remains out of plane for 0.2<tAl<0.5 nm. When the Al thickness is further increased, a second crossover back to in plane takes place. In a series of samples in which the Al thickness is kept constant, the same behavior is observed as the time of exposure to an oxygen plasma is varied. The results clearly indicate that the degree of oxidation of Al at the CoFe/AlOx interface has a dramatic effect on the magnetic anisotropy of the transition-metal layer. These sharp crossovers of anisotropy provide a very accurate and convenient way to monitor the oxidation of the tunnel barrier in magnetic tunnel junctions. This technique is also applied to characterize the oxidation kinetics of various ultrathin metallic layers as well as the aging effect in alumina barriers. © 2002 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.50.Bb Fe and its alloys
75.30.Gw Magnetic anisotropy
81.65.Mq Oxidation
75.45.+j Macroscopic quantum phenomena in magnetic systems
72.15.Gd Galvanomagnetic and other magnetotransport effects
Page 1 of 3 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close