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

10 Oct 2005

Volume 87, Issue 15, Articles (15xxxx)

Issue Cover Spotlight Figure

Appl. Phys. Lett. 87, 151103 (2005); http://dx.doi.org/10.1063/1.2089157 (3 pages)

Andrew B. Greytak, Carl J. Barrelet, Yat Li, and Charles M. Lieber
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Use of AlInN layers in optical monitoring of growth of GaN-based structures on free-standing GaN substrates

I. M. Watson, C. Liu, E. Gu, M. D. Dawson, P. R. Edwards, and R. W. Martin

Appl. Phys. Lett. 87, 151901 (2005); http://dx.doi.org/10.1063/1.2089175 (3 pages) | Cited 16 times

Online Publication Date: 3 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
When lattice matched to GaN, the AlInN ternary alloy has a refractive index ∼ 7% lower than that of GaN. This characteristic can be exploited to perform in situ reflectometry during epitaxial growth of GaN-based multilayer structures on free-standing GaN substrates, by insertion of a suitable Al0.82In0.18N layer. The real-time information on growth rates and cumulative layer thicknesses thus obtainable is particularly valuable in the growth of optical resonant cavity structures. We illustrate this capability with reference to the growth of InGaN/GaN multiple quantum-well structures, including a doubly periodic structure with relatively thick GaN spacer layers between groups of wells. Al0.82In0.18N insertion layers can also assist in the fabrication of resonant cavity structures in postgrowth processing, for example, acting as sacrificial layers in a lift-off process exploiting etch selectivity between Al0.82In0.18N and GaN.
Show PACS
81.05.Ea III-V semiconductors
68.65.Fg Quantum wells
81.07.St Quantum wells

Effect of B content on nanostructure evolution and twinning deformation of nanocrystallite in nc-Ti(N,B)/a-(TiB2,BN) nanocomposite thin films

Y. H. Lu, Z. K. Xu, Haydn Chen, Y. G. Shen, and K. Y. Li

Appl. Phys. Lett. 87, 151902 (2005); http://dx.doi.org/10.1063/1.2093926 (3 pages) | Cited 6 times

Online Publication Date: 4 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanostructure evolution and deformation of nanocrystallites in nanocrystalline (nc-) Ti(N,B)/amorphous (a-) (TiB2,BN) thin films were investigated by high resolution transmission electron microscopy. The results indicated that the incorporation of B into TiN led to the formation of the nanocomposite that consists of nc-Ti(N,B) grains embedded in an amorphous matrix. Increasing B content accelerated not only the formation of more [200]-oriented grains but also the twining deformation in nanocrystallites. The deformation was enhanced with increasing B content, which was attributed to the decrease of grain size with increasing B content and the formation of nc-Ti(N,B) solid solution by dissolving B into the TiN lattice.
Show PACS
61.46.-w Structure of nanoscale materials
68.55.-a Thin film structure and morphology
61.72.Mm Grain and twin boundaries
61.43.Er Other amorphous solids
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep

1.55 μm emission from InAs quantum dots grown on GaAs

Tung-Po Hsieh, Pei-Chin Chiu, Jen-Inn Chyi, Nien-Tze Yeh, Wen-Jeng Ho, Wen-Hao Chang, and Tzu-Min Hsu

Appl. Phys. Lett. 87, 151903 (2005); http://dx.doi.org/10.1063/1.2099536 (3 pages) | Cited 15 times

Online Publication Date: 4 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report a comparative study on the growth of InAs quantum dots (QDs) on GaAs by metalorganic chemical vapor deposition using triethylgallium (TEGa) and trimethylgallium (TMGa) for the GaAs cap layer. QDs exhibit 1.3 μm photoluminescence (PL) at room temperature, as the GaAs cap layer is directly grown on the QDs. The PL emission can be extended to 1.49 μm when an In0.25Ga0.75As overgrown layer is inserted between the cap layer and the InAs QDs. The use of TMGa or TEGa for the growth of the GaAs cap layer is essential for a further increase in the emission wavelength of the InAs QDs. Strong PL emission at 1.55 μm with a linewidth of 28 meV can be obtained as the GaAs cap layer is grown by TEGa, while the optical properties degrade severely when using TMGa.
Show PACS
78.55.Cr III-V semiconductors
78.67.Hc Quantum dots

Effect of Cu deficiency on the optical bowing of chalcopyrite CuIn1−xGaxSe2

Sung-Ho Han, Falah S. Hasoon, Joel W. Pankow, Allen M. Hermann, and Dean H. Levi

Appl. Phys. Lett. 87, 151904 (2005); http://dx.doi.org/10.1063/1.2089154 (3 pages) | Cited 7 times

Online Publication Date: 4 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical bowing coefficients are used to describe the band gap variation of a composite semiconductor alloy. It is known to be related to the electronic structure and the lattice deformation in the semiconductor alloys. Spectroscopic ellipsometry study shows that the optical bowing coefficient of slightly Cu-poor polycrystalline Cu0.9In1−xGaxSe2 is larger than that of stoichiometric polycrystalline CuIn1−xGaxSe2 and band gaps are larger when Cu becomes poor. This can be explained by an increase in valence band offset due to reduced p-d coupling and an increase of perturbation potential ΔV due to lattice deformation.
Show PACS
71.20.Nr Semiconductor compounds
78.66.Li Other semiconductors

Efficient pure blue electroluminescence from ter(9,9, 9″,9″-bihexyl-9′,9′-diphenyl)-fluorenes

Gang Cheng, Yingfang Zhang, Yi Zhao, Shiyong Liu, Shi Tang, and Yuguang Ma

Appl. Phys. Lett. 87, 151905 (2005); http://dx.doi.org/10.1063/1.2099539 (3 pages) | Cited 7 times

Online Publication Date: 4 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An oligomer of polyfluorene, ter(9,9, 9″,9″-bihexyl-9′,9′-diphenyl)fluorenes (THPF), is used as a blue-emitting material to achieve efficient pure blue electroluminescence. Based on a 4,4′,4″-tri(N-carbazolyl)-triphenylamine hole-transporting layer, a 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline hole-blocking layer, an (8-hydroxyquinoline) aluminum electron-transporting layer, and a LiF/Al cathode, the device has two emission peaks at 404 and 424 nm, chromaticity coordinates at (0.18, 0.09), and a maximum efficiency of 1.27 cd/A. By using a submonolayer of 5,6,11,12-tetraphenylnaphthacene as a carrier detector, we demonstrate that THPF functions well as an electron-transporting layer, similar to Alq.
Show PACS
78.60.Fi Electroluminescence

Air-bridged lateral growth of an Al0.98Ga0.02N layer by introduction of porosity in an AlN buffer

T. Wang, J. Bai, P. J. Parbrook, and A. G. Cullis

Appl. Phys. Lett. 87, 151906 (2005); http://dx.doi.org/10.1063/1.2089182 (3 pages) | Cited 21 times

Online Publication Date: 5 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrated air-bridged lateral growth of an Al0.98Ga0.02N layer with significant dislocation reduction by introduction of a porous AlN buffer underneath via metalorganic chemical vapor deposition. By modifying growth conditions, a porous AlN layer and an atomically flat AlN layer have been obtained for comparison, confirmed by atomic force microscopy. An Al0.98Ga0.02N layer was subsequently grown on both the porous AlN layer and the atomically flat AlN layer under identical conditions. Significant dislocation reduction was achieved for the Al0.98Ga0.02N layer grown on the porous AlN buffer layer, compared to the layer grown on the atomically flat AlN layer, as observed by transmission electron microscopy. Clear bubbles from the layer grown on the porous AlN buffer layer have been observed, while in contrast, there was not any bubble from the layer on the flat AlN buffer, confirming the mechanism of lateral growth for dislocation reduction. Asymmetric x-ray diffraction studies also indicated that the crystal quality was dramatically improved using the porous AlN buffer layer.
Show PACS
81.05.Ea III-V semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.55.A- Nucleation and growth
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Nanoscale multistep shear band formation by deformation-induced nanocrystallization in Zr-Al-Ni-Pd bulk metallic glass

Junji Saida, Albertus Deny Heri Setyawan, Hidemi Kato, and Akihisa Inoue

Appl. Phys. Lett. 87, 151907 (2005); http://dx.doi.org/10.1063/1.2081124 (3 pages) | Cited 65 times

Online Publication Date: 5 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A single Zr65Al7.5Ni10Pd17.5 bulk metallic glass exhibits a large plastic strain of 6.6% during the compressive deformation process, which is attributed to the deformation mode with nanoscale multistep shear bands. We have observed that nanocrystals with a metastable fcc Zr2Ni structure containing several distorted icosahedral clusters are arranged in a “bandlike” formation in the glassy matrix around the multistep shear bands. This is recognized as direct evidence of the novel phenomenon of the restraint of shear band propagation owing to the dynamic precipitation of the nanocrystals.
Show PACS
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
61.43.Fs Glasses
61.46.-w Structure of nanoscale materials

Modeling of heterogeneous precipitation of iron in silicon

A. Haarahiltunen, H. Väinölä, O. Anttila, E. Saarnilehto, M. Yli-Koski, J. Storgårds, and J. Sinkkonen

Appl. Phys. Lett. 87, 151908 (2005); http://dx.doi.org/10.1063/1.2099531 (3 pages) | Cited 6 times

Online Publication Date: 6 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A model is presented for the growth and dissolution of iron precipitates at oxygen-related defects in silicon during thermal processing. The heterogeneous nucleation of iron is taken into account by special growth and dissolution rates, which are inserted into a set of modified chemical rate equations. This approach allows us to calculate the size distribution of iron precipitates and the residual iron concentration. By comparing the simulated results with experimental ones, it is proven that this model can be used to estimate the internal gettering efficiency of iron under a variety of processing conditions.
Show PACS
81.10.Aj Theory and models of crystal growth; physics and chemistry of crystal growth, crystal morphology, and orientation
81.05.Cy Elemental semiconductors
81.30.Mh Solid-phase precipitation
64.75.-g Phase equilibria

Far-infrared absorption due to electronic transitions of N–O complexes in Czochralski-grown silicon crystals: Influence of nitrogen and oxygen concentration

H. Ch. Alt, Y. V. Gomeniuk, F. Bittersberger, A. Kempf, and D. Zemke

Appl. Phys. Lett. 87, 151909 (2005); http://dx.doi.org/10.1063/1.2099517 (3 pages) | Cited 10 times

Online Publication Date: 6 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fourier-transform infrared absorption measurements have been carried out on nitrogen-doped Czochralski-grown silicon crystals after thermal annealing at 600 °C. The strength of the electronic transitions due to N–O related shallow donors shows a square root dependence on the nitrogen concentration and donor-specific power dependences on the interstitial oxygen concentration. Based on mass action laws, chemical compositions are discussed. It is found that the N–O complexes investigated all involve one nitrogen atom but three different numbers of oxygen atoms.
Show PACS
78.30.Am Elemental semiconductors and insulators
61.72.uf Ge and Si
61.72.S- Impurities in crystals
61.72.J- Point defects and defect clusters
61.72.Cc Kinetics of defect formation and annealing
82.80.-d Chemical analysis and related physical methods of analysis

Photoluminescence from 8-hydroxy quinoline aluminum embedded in porous anodic alumina membrane

G. S. Huang, X. L. Wu, Y. Xie, F. Kong, Z. Y. Zhang, G. G. Siu, and Paul K. Chu

Appl. Phys. Lett. 87, 151910 (2005); http://dx.doi.org/10.1063/1.2099522 (3 pages) | Cited 12 times

Online Publication Date: 6 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
By immersing porous alumina membranes in 8-hydroxy quinoline aluminum (Alq3) solutions, we embed Alq3 molecules into the nanovoids of the membranes. Photoluminescence (PL) spectral examinations show that the Alq3 molecules embedded in the alumina membrane show a blueshifted luminescent spectrum compared to that of Alq3 solid film. Since the blueshift of ∼ 18 nm does not change with nanopore diameter, we consider it to be due to the confinement of nanovoids in the nanopore walls, which prevents Alq3 molecules from aggregation and thus weakens the interaction between them. Further spectral analyses suggest that the photogeneration of carriers takes place in oxygen vacancies at the surfaces of nanopore walls, whereas the radiative recombination occurs in the embedded Alq3 molecules. Förster energy transfer from oxygen vacancies to the embedded Alq3 molecules is proposed to be responsible for the enhancement of the PL intensity.
Show PACS
78.55.Mb Porous materials
82.45.Wx Polymers and organic materials in electrochemistry
82.20.Rp State to state energy transfer

Electrically induced surface instability of a conductive thin film on a dielectric substrate

Rui Huang

Appl. Phys. Lett. 87, 151911 (2005); http://dx.doi.org/10.1063/1.2099526 (3 pages)

Online Publication Date: 6 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The stability of a conductive thin film on a dielectric substrate subjected to a transverse electric field and a residual strain is analyzed. Under a uniform electric field, an equilibrium state exists with a constant thickness reduction of the substrate. The equilibrium state, however, can be unstable, depending on the intensity of the electric field, the stiffness, and Poisson’s ratio of the substrate, and on the residual strain in the film. Based on a linear perturbation analysis, the critical condition is determined, beyond which wrinkling of the film is expected.
Show PACS
77.84.-s Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials
77.55.-g Dielectric thin films
68.60.Bs Mechanical and acoustical properties
73.61.-r Electrical properties of specific thin films
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity

Spatially resolved in situ measurements of the transport of organic molecules in a polycrystalline nanoporous membrane

Weontae Oh and Sankar Nair

Appl. Phys. Lett. 87, 151912 (2005); http://dx.doi.org/10.1063/1.2093918 (3 pages) | Cited 1 time

Online Publication Date: 7 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report spatially resolved, quantitative, in situ, nondestructive measurements of the transport of organic molecules through a polycrystalline, anisotropic, nanoporous molecular sieve membrane, with micron-scale resolution. A method based on photoacoustic spectroscopy experiments during permeation through a nanoporous membrane, combined with a physical model of photoacoustic signal generation from a heterogeneous membrane, allows extraction of concentration profiles in situ. In particular, we demonstrate the steady-state concentration profiling of the organic molecules p-xylene and n-hexane during their transport through a nanoporous zeolite silicalite membrane. The implications for elucidating structure-property relationships in membrane materials for separations, catalytic, or nanotechnology applications are discussed.
Show PACS
82.75.Jn Measurements and modeling of molecule migration in zeolites
82.75.Mj Measurements and simulation of properties (optical, structural) of molecules in zeolites
43.35.Ud
62.65.+k Acoustical properties of solids
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
61.43.Gt Powders, porous materials
61.46.-w Structure of nanoscale materials

Basal plane dislocation-free epitaxy of silicon carbide

Z. Zhang and T. S. Sudarshan

Appl. Phys. Lett. 87, 151913 (2005); http://dx.doi.org/10.1063/1.2093931 (3 pages) | Cited 16 times

Online Publication Date: 7 October 2005

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Molten KOH etching was implemented on SiC substrates before growing epilayers on them. It was found that the creation of basal plane dislocation (BPD) etch pits on the substrates can greatly enhance the conversion of BPDs to threading edge dislocations during epitaxy, and thus low BPD density and BPD-free SiC epilayers are obtained by this method. The reason why BPD etch pits can promote the earlier conversion is discussed. The SiC epilayer growth by this method is very promising in overcoming forward voltage drop degradation of SiC PiN diodes.
Show PACS
81.05.Hd Other semiconductors
81.65.Cf Surface cleaning, etching, patterning
68.55.A- Nucleation and growth
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
61.72.Lk Linear defects: dislocations, disclinations
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close