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

21 Aug 2000

Volume 77, Issue 8, pp. 1071-1232

Return to All Sections
back to top
RSS Feeds

Transmittance and resistivity of semicontinuous copper films prepared by pulsed-laser deposition

S. K. So, H. H. Fong, C. F. Yeung, and N. H. Cheung

Appl. Phys. Lett. 77, 1099 (2000); http://dx.doi.org/10.1063/1.1289259 (3 pages) | Cited 7 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thin copper films were grown on glass by pulsed-laser deposition. The simultaneous in situ monitoring of the electrical resistance and optical transmittance of the growing film yielded highly reproducible and consistent data about percolation onset and film conductivity, both being useful indicators of film quality. When prepared under favorable conditions, films as thin as 1.5 nm would percolate, and became fully continuous at 5 nm, with conductivity reaching 30% of that of bulk copper. © 2000 American Institute of Physics.
Show PACS
78.66.Bz Metals and metallic alloys
73.61.At Metal and metallic alloys
68.55.-a Thin film structure and morphology
81.15.Fg Pulsed laser ablation deposition
72.15.Eb Electrical and thermal conduction in crystalline metals and alloys

Nanoquasicrystallization of binary Zr–Pd metallic glasses

B. S. Murty, D. H. Ping, and K. Hono

Appl. Phys. Lett. 77, 1102 (2000); http://dx.doi.org/10.1063/1.1289271 (3 pages) | Cited 52 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The formation of an icosahedral phase during crystallization of Zr–Pd binary amorphous alloys is reported. The icosahedral phase forms in the nanocrystalline state with a grain size of about 10 nm as a metastable transient phase during the transformation from an amorphous to a crystalline state in Zr70Pd30 and Zr65Pd35 alloys. The amorphous phase coexists with the nanoquasicrystalline phase before complete crystallization to Zr2Pd occurs. © 2000 American Institute of Physics.
Show PACS
61.43.Fs Glasses
61.44.Br Quasicrystals
64.70.K- Solid-solid transitions
81.30.Bx Phase diagrams of metals, alloys, and oxides

Reduction of threading defects in GaN grown on vicinal SiC(0001) by molecular-beam epitaxy

M. H. Xie, L. X. Zheng, S. H. Cheung, Y. F. Ng, Huasheng Wu, S. Y. Tong, and N. Ohtani

Appl. Phys. Lett. 77, 1105 (2000); http://dx.doi.org/10.1063/1.1289266 (3 pages) | Cited 27 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We observe a significant reduction of threading dislocations in GaN grown on vicinal substrates of SiC(0001). Using scanning tunneling microscopy, we find films grown on vicinal substrates maintain the surface misorientation of the substrate and display terraces with straight edges. On top of the terraces there is no spiral mound, which is the main feature found for films grown on singular substrates. Transmission electron microscopy studies confirm that threading screw dislocations are reduced by two orders of magnitude while edge dislocations are reduced by one order. © 2000 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
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)

Dispersive rotation of dipoles in amorphous media

D. J. Binks and D. P. West

Appl. Phys. Lett. 77, 1108 (2000); http://dx.doi.org/10.1063/1.1289258 (3 pages) | Cited 9 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The dispersive rotation of dipoles under the influence of an applied electric field is described simply and accurately using a time-dependent diffusion coefficient. There is excellent agreement between theory and measurement. This analysis shows that the dispersive rotational dynamic is described well by a power law in time and hence has no characteristic lifetime, unlike the conventional biexponential description. This has important implications for the characterization of the transient response of any electro-optic process or device based on the rotation of dipoles in an amorphous material such as a polymer or glass. © 2000 American Institute of Physics.
Show PACS
61.43.-j Disordered solids

Temperature dependence of the electron–hole-plasma electroluminescence from metal–oxide–silicon tunneling diodes

C. W. Liu, Miin-Jang Chen, I. C. Lin, M. H. Lee, and Ching-Fuh Lin

Appl. Phys. Lett. 77, 1111 (2000); http://dx.doi.org/10.1063/1.1289491 (3 pages) | Cited 21 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The temperature performance of metal–oxide–silicon tunneling light-emitting diodes was studied. An electron–hole-plasma model can be used to fit all the emission spectra from room temperature to 98 K. At constant voltage bias in the accumulation region, the normalized integral emission intensity slightly increases at low temperature with activation energy as low as 12 meV. From room temperature down to 98 K, the extracted band gaps are ∼80 meV lower than the value of Varshni equation, and the linewidth drops from 65 to 30 meV. The transverse optical and longitudinal optical phonons are involved in the light-emission process due to the reduction of extracted band gaps and the resemblance between electroluminescence and photoluminescence spectra at similar temperature. © 2000 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
85.60.Jb Light-emitting devices
78.66.Db Elemental semiconductors and insulators
81.05.Cy Elemental semiconductors
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
85.30.Tv Field effect devices
72.30.+q High-frequency effects; plasma effects
73.50.Mx High-frequency effects; plasma effects

Newtonian viscosity of supercooled liquid in a Pd40Ni40P20 metallic glass

Yoshihito Kawamura and Akihisa Inoue

Appl. Phys. Lett. 77, 1114 (2000); http://dx.doi.org/10.1063/1.1289502 (3 pages) | Cited 41 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The Newtonian viscosity of the supercooled liquid measured by the continuous-strain-rate tensile test was investigated in the Pd40Ni40P20 metallic glass. It was found that continuous-strain-rate tests were applicable to determine the viscosity over a wide strain-rate region, and that the measured Newtonian viscosity η0 corresponded to the equilibrium one. The viscosity η over the entire strain-rate interval could be well described by one master curve expressed with a stretched exponential function η/η0 = 1−exp(C/mathβ) in which β was 0.82. The free-volume-theory relation proposed by Cohen and Grest reproduced the equilibrium viscosity data over the entire temperature region better than the famous Vogel–Fulcher–Tammann relation. The supercooled liquid of the Pd40Ni40P20 metallic glass was classified into the relatively strong liquids as well as the other metallic glasses. The Pd40Ni40P20 metallic glass that is a metal-metalloid alloy exhibited to be more fragile than metal–metal glasses. © 2000 American Institute of Physics.
Show PACS
66.20.-d Viscosity of liquids; diffusive momentum transport
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
61.25.Mv Liquid metals and alloys

Band gap engineering in amorphous AlxGa1−xN: Experiment and ab initio calculations

Hong Chen, Kuiying Chen, D. A. Drabold, and M. E. Kordesch

Appl. Phys. Lett. 77, 1117 (2000); http://dx.doi.org/10.1063/1.1289496 (3 pages) | Cited 25 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Amorphous alloys of aluminum nitride and gallium nitride deposited at 100 K at compositions ranging from pure AlN to pure GaN with optical band gaps which vary linearly with composition from 3.27 eV (a-GaN) to 5.95 eV (a-AlN) have been synthesized. Ab initio molecular dynamics calculations for these alloys reproduce the band gap versus composition data and give specific information on the electronic localization of the band tail states. There are no midgap states in amorphous AlxGa1−xN alloys. The calculated models have mixed four-fold and three-fold coordination and have no wrong (homopolar nuclear) bonds, demonstrating the strong ionicity in amorphous AlxGa1−xN alloys. It has been found that the valence band tail states are mostly localized on the three-fold coordinated N sites while the conduction band tail states are mostly localized on the three-fold coordinated Ga or Al sites. © 2000 American Institute of Physics.
Show PACS
71.23.Cq Amorphous semiconductors, metallic glasses, glasses
78.66.Jg Amorphous semiconductors; glasses
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
71.15.Pd Molecular dynamics calculations (Car-Parrinello) and other numerical simulations
71.55.Jv Disordered structures; amorphous and glassy solids
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
78.66.Fd III-V semiconductors

Ultrafast polarized fluorescence dynamics in an organic dendrimer

O. Varnavski, G. Menkir, T. Goodson, and P. L. Burn

Appl. Phys. Lett. 77, 1120 (2000); http://dx.doi.org/10.1063/1.1289495 (3 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF


See Also: Erratum

Show Abstract
The excited state relaxation processes of a nitrogen-cored distyrylbenzene-stilbene (A-DSB) dendrimers and the analogous linear model compound (bis-MSB) were investigated by polarized fluorescence upconversion spectroscopy. The fluorescence anisotropy (FA) of A-DSB was found to decay to a value close to zero in less than 200 fs after excitation. For the model compound bis-MSB the FA initial value was close to 0.4 and showed a relatively slow decay (82 ps) corresponding to the overall rotational diffusion of the molecule. The results are interpreted in terms of fast transition dipole reorientation during relaxation of the excited states of the branched molecules. © 2000 American Institute of Physics.
Show PACS
36.20.Kd Electronic structure and spectra
33.15.Hp Barrier heights (internal rotation, inversion, rotational isomerism, conformational dynamics)
33.50.Dq Fluorescence and phosphorescence spectra
31.50.Df Potential energy surfaces for excited electronic states
36.20.Ey Conformation (statistics and dynamics)

Codoping characteristics of Zn with Mg in GaN

K. S. Kim, M. S. Han, G. M. Yang, C. J. Youn, H. J. Lee, H. K. Cho, and J. Y. Lee

Appl. Phys. Lett. 77, 1123 (2000); http://dx.doi.org/10.1063/1.1289494 (3 pages) | Cited 7 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The doping characteristics of Mg–Zn codoped GaN films grown by metalorganic chemical vapor deposition are investigated. By means of the concept of Mg–Zn codoping technique, we have grown p-GaN showing a low electrical resistivity (0.72 Ω cm) and a high hole concentration (8.5×1017 cm−3) without structural degradation of the film. It is thought that the codoping of Zn atoms with Mg raises the Mg activation ratio by reducing the hydrogen solubility in p-GaN. In addition, the measured specific contact resistance of Mg–Zn codoped GaN film is 5.0×10−4 Ω cm2, which is one order of magnitude lower than that of Mg doped only GaN film (1.9×10−3 Ω cm2). © 2000 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
61.72.uj III-V and II-VI semiconductors
73.40.Cg Contact resistance, contact potential
73.61.Ey III-V semiconductors

In situ transmission electron microscopy study of dislocations in a polycrystalline Cu thin film constrained by a substrate

Gerhard Dehm and Eduard Arzt

Appl. Phys. Lett. 77, 1126 (2000); http://dx.doi.org/10.1063/1.1289488 (3 pages) | Cited 32 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Dislocation plasticity in a thin Cu film on a SiNx/SiOx coated silicon wafer was observed by transmission electron microscopy (TEM) during thermal cycling of a cross-sectional specimen. While the in situ TEM study revealed jerky dislocation motion at low homologous temperatures, continuous dislocation glide occurred at elevated temperatures. Furthermore, dislocations were pulled into the Cu/SiNx interface, where dislocation contrast disappeared. It is assumed from these preliminary observations that the limited mobility of dislocations at low homologous temperatures rather than interfacial dislocation segments may be responsible for the high yield stress of the Cu film. © 2000 American Institute of Physics.
Show PACS
68.60.Bs Mechanical and acoustical properties
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.)
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep

Dielectric function of V2O5 nanocrystalline films by spectroscopic ellipsometry: Characterization of microstructure

Maria Losurdo, Giovanni Bruno, Davide Barreca, and Eugenio Tondello

Appl. Phys. Lett. 77, 1129 (2000); http://dx.doi.org/10.1063/1.1289658 (3 pages) | Cited 10 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spectroscopic ellipsometry over the photon energy 1.5–5.0 eV is used to derive the dielectric function of V2O5 nanocrystalline films deposited by plasma-enhanced chemical vapor deposition. The dispersion in the optical response is described by a combination of Lorentzian oscillators. The results are obtained from a microstructure-dependent model, which considers the anisotropy of the V2O5 crystallites into the bulk film, as well as the presence of interface and surface roughness layers. The variation of the V2O5 thin-film dielectric function upon film crystallinity, going from pure nanocrystalline to amorphous material, is also investigated. © 2000 American Institute of Physics.
Show PACS
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Jg Amorphous semiconductors; glasses
68.55.-a Thin film structure and morphology
61.46.-w Structure of nanoscale materials
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons
07.60.Fs Polarimeters and ellipsometers
78.40.Fy Semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)

Sintering, structure, and mechanical properties of nanophase SiC: A molecular-dynamics and neutron scattering study

Alok Chatterjee, Rajiv K. Kalia, Aiichiro Nakano, Andrey Omeltchenko, Kenji Tsuruta, Priya Vashishta, Chun-Keung Loong, Markus Winterer, and Sylke Klein

Appl. Phys. Lett. 77, 1132 (2000); http://dx.doi.org/10.1063/1.1289661 (3 pages) | Cited 16 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Structure, mechanical properties, and sintering of nanostructured SiC (n-SiC) are investigated with neutron scattering and molecular-dynamics (MD) techniques. Both MD and the experiment indicate the onset of sintering around 1500 K. During sintering, the pores shrink while maintaining their morphology: the fractal dimension is ∼2 and the surface roughness exponent is ∼0.45. Structural analyses reveal that interfacial regions in n-SiC are disordered with nearly the same number of three- and fourfold coordinated Si atoms. The elastic moduli scale with the density as ∼ ρμ, where μ = 3.4±0.1. © 2000 American Institute of Physics.
Show PACS
61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
61.66.Fn Inorganic compounds
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
68.35.B- Structure of clean surfaces (and surface reconstruction)
02.70.Ns Molecular dynamics and particle methods
71.15.Pd Molecular dynamics calculations (Car-Parrinello) and other numerical simulations

Huge differences between low- and high-angle twist grain boundaries: The case of ultrathin (001) Si films bonded to (001) Si wafers

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

Appl. Phys. Lett. 77, 1135 (2000); http://dx.doi.org/10.1063/1.1289656 (3 pages) | Cited 16 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ultrathin (001) Si films bonded onto (001) Si wafers, inducing grain boundaries with twist angles varying from 0.5° to 12°, were studied by transmission electron microscopy. A great structural difference between low (ψ<5°) and high (ψ>6°) twist angles was observed. In low twist angle grain boundaries, “twist interfacial dislocations” are dissociated and produce rough interfaces with no oxide precipitates. It is the opposite in high-angle grain boundaries: there is no dissociation, the interfaces are smoother but contain oxide precipitates. These differences are not attributed to the thin thickness of one grain, but to the large atomic differences between high- and low-angle twist grain boundaries, which is not the case for tilt grain boundaries. © 2000 American Institute of Physics.
Show PACS
61.72.Mm Grain and twin boundaries
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
64.75.-g Phase equilibria
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Optical evidence of intrinsic quantum wells in the transparent conducting oxide β-Ga2O3

Laurent Binet and Didier Gourier

Appl. Phys. Lett. 77, 1138 (2000); http://dx.doi.org/10.1063/1.1289655 (3 pages) | Cited 11 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A peculiar peak structure is observed in the optical absorption edge of β-Ga2O3 at low temperature. These peaks appear in an energy range corresponding to the excitation of the acceptor defects. It is suggested that some of these acceptors be assembled in low dimensional clusters with size about 30–40 Å and forming potential wells with depth about 0.5 eV. The extra peaks are interpreted as transitions between the discrete energy levels of these potential wells and the conduction band. © 2000 American Institute of Physics.
Show PACS
78.66.Li Other semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.40.Fy Semiconductors

Polyparaphenylene-based low-temperature carbons studied by transmission electron microscopy

T. Hayashi, M. Endo, and M. S. Dresselhaus

Appl. Phys. Lett. 77, 1141 (2000); http://dx.doi.org/10.1063/1.1289653 (3 pages) | Cited 1 time

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A comparison of the microtexture and structure of the low temperature heat-treated polyparaphenylene (PPP)-based carbons which are promising for the Li ion battery has been performed using high-resolution transmission electron microscopy and electron energy loss spectroscopy. It is found that the PPP-based carbon prepared by Kovacic method remains in suitable microtexture for high Li storage over a wider temperature range relative to that obtained by Yamamoto method. This characteristic of the Kovacic PPP-based carbon could lead to a more controlled microtexture for obtaining a higher Li storage capacity for Li ion battery applications. © 2000 American Institute of Physics.
Show PACS
81.05.ub Fullerenes and related materials
61.66.Bi Elemental solids
81.40.Gh Other heat and thermomechanical treatments
82.47.-a Applied electrochemistry
61.43.Er Other amorphous solids
79.20.Kz Other electron-impact emission phenomena

Doping of covalently bound fullerene monolayers: Ag clusters on C60/Si(111)

M. D. R. Taylor, P. Moriarty, B. N. Cotier, M. J. Butcher, P. H. Beton, and V. R. Dhanak

Appl. Phys. Lett. 77, 1144 (2000); http://dx.doi.org/10.1063/1.1289797 (3 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The deposition of silver on a C60 monolayer chemisorbed on Si(111) leads to the formation of nanoscale clusters which, as determined from valence band photoemission measurements, donate minimal charge to the adsorbed fullerene molecules. The low doping level of the C60 monolayer leads to a slow rate of Ag cluster neutralization following the emission of a photoelectron, resulting in a significant shift of the cluster Fermi level and valence band features to higher binding energy. © 2000 American Institute of Physics.
Show PACS
61.48.-c Structure of fullerenes and related hollow and planar molecular structures
68.08.-p Liquid-solid interfaces
68.43.-h Chemisorption/physisorption: adsorbates on surfaces
68.18.-g Langmuir-Blodgett films on liquids
61.46.-w Structure of nanoscale materials
73.22.-f Electronic structure of nanoscale materials and related systems
73.20.At Surface states, band structure, electron density of states
73.20.Hb Impurity and defect levels; energy states of adsorbed species

Ultrasonic investigation of Pd39Ni10Cu30P21 bulk metallic glass upon crystallization

Li Min Wang, W. H. Wang, R. J. Wang, Z. J. Zhan, D. Y. Dai, L. L. Sun, and W. K. Wang

Appl. Phys. Lett. 77, 1147 (2000); http://dx.doi.org/10.1063/1.1289801 (3 pages) | Cited 35 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Acoustic velocities of Pd39Ni10Cu30P21 bulk metallic glass (BMG) are measured by an ultrasonic technique upon annealing. The elastic constants and the Debye temperature are obtained. A large softening of the transverse phonon is exhibited in the as-quenched BMG relative to its crystallized state. Upon crystallization, the shear modulus and the Debye temperature increase by ∼ 30% and ∼ 12%, respectively; however, the density increases by only ∼ 0.6%. Some anomalous acoustic and elastic behaviors are observed near the glass transition temperature and in the supercooled liquid region of the BMG. The anomalies are explained with regard to the structural changes. © 2000 American Institute of Physics.
Show PACS
61.43.Fs Glasses
62.65.+k Acoustical properties of solids
81.40.Jj Elasticity and anelasticity, stress-strain relations
63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions
62.20.D- Elasticity
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
63.50.-x Vibrational states in disordered systems

Er3+ in strong light-confining microcavity

M. Lipson and L. C. Kimerling

Appl. Phys. Lett. 77, 1150 (2000); http://dx.doi.org/10.1063/1.1289800 (3 pages) | Cited 8 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Er3+ ions produce a sharp line emission that has small absorption cross section, long radiative lifetime, and is independent of external perturbations. These optical properties of the Er3+ ions limit the pumping efficiency and tunability of the emission line. In this work we present a study in which Er3+ emission was modified by coupling an ensemble of Er3+ ions to a microcavity resonance. The optical response of an optical cavity that consists of an Er2O3 layer confined between Si/SiO2 distributed Bragg reflectors is studied. When the cavity is in resonance with the optical transition of the Er3+ ions, the resonances in the reflectivity spectra split. The results are explained by a standard semiclassical model of atom–photon coupling. © 2000 American Institute of Physics.
Show PACS
78.66.Nk Insulators
78.55.Hx Other solid inorganic materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Formation of ultrafine nanostructure by crystallization of Zr52Al6Cu14Ni8Fe20 metallic glass

N. Mattern, U. Kühn, J. Neuefeind, and J. Eckert

Appl. Phys. Lett. 77, 1153 (2000); http://dx.doi.org/10.1063/1.1289802 (2 pages) | Cited 6 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The short-range order and the crystallization behavior of amorphous Zr52Al6Cu14Ni8Fe20 alloys have been investigated by means of calorimetry and x-ray diffraction. The amorphous structure transforms upon annealing without formation of long-range order. An ultrafine microstructure consisting of about 60 vol % cubic NiZr2 crystal-like clusters with a size of 〈D〉 ≈ 2 nm embedded in a residual amorphous matrix phase forms as a first step of crystallization resulting from high nucleation rate combined with low growth velocity. In a second step growth of the clusters to crystals up to a mean diameter of 〈D〉 ≈ 4–5 nm takes place as a distinct process. © 2000 American Institute of Physics.
Show PACS
61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
61.43.Fs Glasses
81.05.Kf Glasses (including metallic glasses)
64.70.K- Solid-solid transitions
81.40.Gh Other heat and thermomechanical treatments

Grain-size-dependent thermal conductivity of nanocrystalline yttria-stabilized zirconia films grown by metal-organic chemical vapor deposition

G. Soyez, J. A. Eastman, L. J. Thompson, G.-R. Bai, P. M. Baldo, A. W. McCormick, R. J. DiMelfi, A. A. Elmustafa, M. F. Tambwe, and D. S. Stone

Appl. Phys. Lett. 77, 1155 (2000); http://dx.doi.org/10.1063/1.1289803 (3 pages) | Cited 58 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A grain-size-dependent reduction in the room-temperature thermal conductivity of nanocrystalline yttria-stabilized zirconia is reported for the first time. Films were grown by metal-organic chemical vapor deposition with controlled grain sizes from 10 to 100 nm. For grain sizes smaller than approximately 30 nm, a substantial reduction in thermal conductivity was observed, reaching a value of less than one-third the bulk value at the smallest grain sizes measured. The observed behavior is consistent with expectations based on an estimation of the phonon mean-free path in zirconia.© 2000 American Institute of Physics.
Show PACS
68.60.Dv Thermal stability; thermal effects
66.70.-f Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.Nq Composition and phase identification
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)

Crystallization kinetics of the bulk-glass-forming Pd43Ni10Cu27P20 melt

Jan Schroers, William L. Johnson, and Ralf Busch

Appl. Phys. Lett. 77, 1158 (2000); http://dx.doi.org/10.1063/1.1289033 (3 pages) | Cited 41 times

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The crystallization of undercooled Pd43Ni10Cu27P20 melts is studied under isothermal conditions and at constant heating and cooling rates. Investigations are carried out by fluxing the melt with B2O3 and without any fluxing material. The isothermal experiments allow us to determine the complete time–temperature-transformation diagram with a minimum crystallization time of about 200 s for the fluxed melt and about 130 s for the unfluxed Pd43Ni10Cu27P20 melt. The results of the experiments at constant cooling and heating rates are summarized in a continuous heating and cooling diagram. The critical cooling rate for the fluxed alloy is determined to be 0.09 K/s, whereas the critical heating rate is 6 K/s. For the unfluxed Pd43Ni10 Cu27P20, 0.4 and 9 K/s are found, respectively. This alloy exhibits the most sluggish crystallization kinetics of all metallic systems known so far. © 2000 American Institute of Physics.
Show PACS
61.43.Fs Glasses
81.05.Kf Glasses (including metallic glasses)

Thermal wet oxidation of GaP and Al0.4Ga0.6P

J. H. Epple, K. L. Chang, G. W. Pickrell, K. Y. Cheng, and K. C. Hsieh

Appl. Phys. Lett. 77, 1161 (2000); http://dx.doi.org/10.1063/1.1286871 (3 pages)

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thermal wet oxidations of GaP and Al0.4Ga0.6P at 650 °C for various times have been performed. Comparisons are made on oxidation rates and post oxidation morphology. Transmission electron microscopy shows that when oxidizing GaP, polycrystalline monoclinic GaPO4⋅2H2O forms without noticeable loss of phosphorus. Oxidation for 6 h or more leads to poor morphology resulting in cracks and detachment. A thickness expansion of about 2.5–3 times is noticed as a result of oxidation. In contrast, oxidized Al0.4Ga0.6P exhibits much better morphology without cracks or detachment from the substrate. The oxide has an almost amorphous-like microstructure. The oxidation process shows typical diffusion-limited reaction at long anneals. Preliminary work on the oxidation of AlP indicates that the reaction leads to formation of Al2O3 and possible volatile P2O5 diffusing out of the specimen. Thus, from the structural viewpoint, AlGaP forms a better oxide suitable for device needs. © 2000 American Institute of Physics.
Show PACS
81.65.Mq Oxidation
81.05.Ea III-V semiconductors
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
82.20.Pm Rate constants, reaction cross sections, and activation energies
68.35.B- Structure of clean surfaces (and surface reconstruction)
62.20.M- Structural failure of materials
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
81.40.Gh Other heat and thermomechanical treatments
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close