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

5 Aug 2002

Volume 81, Issue 6, pp. 951-1149

Page 2 of 3 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Formation and crystallization of Ti–Hf–Ni metallic glasses

V. T. Huett and K. F. Kelton

Appl. Phys. Lett. 81, 1026 (2002); http://dx.doi.org/10.1063/1.1497724 (3 pages) | Cited 4 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The formation of a Ti25Hf50Ni25 metallic glass and the phase evolution upon crystallization (devitrification) are reported. The glass is strongly metastable, with a 65 °C separation between the glass transition temperature, Tg = 335 °C, and the onset temperature for primary crystallization to a nanoscale microstructure consisting of an icosahedrally symmetric ordered phase, that can not be reported as the icosahedral phase (i-phase). There is no distinction between an i-phase and a high-order crystal rational approximant for such small grains, since the unit cell size of a reasonable high-order approximant is of the order of the grain size. Upon annealing at higher temperatures, the metastable icosahedrally symmetric phase transforms to a stable Ti2Ni-type crystal phase. © 2002 American Institute of Physics.
Show PACS
61.43.Fs Glasses
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
81.40.Gh Other heat and thermomechanical treatments
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization

Bias-assisted photoelectrochemical oxidation of n-GaN in H2O

J. W. Seo, C. S. Oh, H. S. Jeong, J. W. Yang, K. Y. Lim, C. J. Yoon, and H. J. Lee

Appl. Phys. Lett. 81, 1029 (2002); http://dx.doi.org/10.1063/1.1498863 (3 pages) | Cited 14 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Growth of gallium oxide on n-GaN was realized in H2O by bias-assisted photoelectrochemical (PEC) oxidation using Al as a counterelectrode instead of a Pt commonly used in the PEC process. Although the growth of the oxide was not observed at below 2 V, the initial oxide growth rate of 8.7 nm/min was shown at a bias of 15 V and ultraviolet light intensity of 300 mW/cm2. However, the growth rate lowered and oxide thickness was saturated to 340 nm. The saturated oxide thickness and initial growth rate were increased with the applied bias. The homogeneous oxide growth and near stoichiometric composition of Ga2O3 were observed in Auger electron spectroscopy analysis results. © 2002 American Institute of Physics.
Show PACS
81.65.Mq Oxidation
82.45.Jn Surface structure, reactivity and catalysis
82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
back to top
RSS Feeds

Investigation of the energy band structure of orthorhombic BaSi2 by optical and electrical measurements and theoretical calculations

Tomoyuki Nakamura, Takashi Suemasu, Ken-ichiro Takakura, Fumio Hasegawa, Akihiro Wakahara, and Motoharu Imai

Appl. Phys. Lett. 81, 1032 (2002); http://dx.doi.org/10.1063/1.1498865 (3 pages) | Cited 25 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical and electrical properties of polycrystalline orthorhombic BaSi2 prepared by arc melting in Ar atmosphere were investigated. The optical absorption spectra measured at room temperature showed that indirect and direct absorption edges were 1.15 and 1.25 eV, respectively. The activation energy estimated from temperature dependence of the resistivity was 1.10 eV. These results agreed well with a calculated band structure of the orthorhombic BaSi2 by first principles calculation using density functional theory. © 2002 American Institute of Physics.
Show PACS
71.20.Nr Semiconductor compounds
71.15.Mb Density functional theory, local density approximation, gradient and other corrections
78.66.Li Other semiconductors
73.61.Le Other inorganic semiconductors
78.40.Fy Semiconductors
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Epitaxial MgO layer for low-resistance and coupling-free magnetic tunnel junctions

E. Popova, J. Faure-Vincent, C. Tiusan, C. Bellouard, H. Fischer, M. Hehn, F. Montaigne, M. Alnot, S. Andrieu, A. Schuhl, E. Snoeck, and V. da Costa

Appl. Phys. Lett. 81, 1035 (2002); http://dx.doi.org/10.1063/1.1498153 (3 pages) | Cited 32 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Epitaxially grown magnetic tunnel junctions MgO(100)/Fe/MgO/Fe/Co/Pd have been elaborated by molecular beam epitaxy, with insulating layer thickness down to 0.8 nm. The continuity of this layer was checked at different spatial scales by means of morphological (high resolution transmission electronic microscopy), electric (local impedance), and magnetic (magnetoresistance and hysteresis loop) measurements. These junctions show a low resistance (4 kΩ μm2), tunnel magnetoresistance up to 17%, and a very small interlayer magnetic coupling. © 2002 American Institute of Physics.
Show PACS
75.47.De Giant magnetoresistance
73.40.Gk Tunneling
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.65.Ac Multilayers
75.50.Bb Fe and its alloys
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
72.15.Gd Galvanomagnetic and other magnetotransport effects
68.35.Ct Interface structure and roughness
68.37.Lp Transmission electron microscopy (TEM)
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Achieving highly conductive AlGaN alloys with high Al contents

K. B. Nam, J. Li, M. L. Nakarmi, J. Y. Lin, and H. X. Jiang

Appl. Phys. Lett. 81, 1038 (2002); http://dx.doi.org/10.1063/1.1492316 (3 pages) | Cited 23 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Si-doped n-type AlxGa1−xN alloys were grown by metalorganic chemical vapor deposition on sapphire substrates. We have achieved highly conductive n-type AlxGa1−xN alloys for x up to 0.7. A conductivity (resistivity) value of 6.7 Ω−1 cm−1 (0.15 Ω cm) (with free electron concentration 2.1×1018 cm−3 and mobility of 20 cm2/Vs at room temperature) has been achieved for Al0.65Ga0.35N, as confirmed by Hall-effect measurements. Our experimental results also revealed that (i) the conductivity of AlxGa1−xN alloys continuously increases with an increase of Si doping level for a fixed value of Al content and (ii) there exists a critical Si-dopant concentration of about 1×1018 cm−3 that is needed to convert insulating AlxGa1−xN with high Al content (x ≥ 0.4) to n-type. © 2002 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
81.05.Ea III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
72.20.Fr Low-field transport and mobility; piezoresistance
back to top
RSS Feeds

A multipurpose torsional magnetometer with optical detection

M. R. Schaapman, P. C. M. Christianen, J. C. Maan, D. Reuter, and A. D. Wieck

Appl. Phys. Lett. 81, 1041 (2002); http://dx.doi.org/10.1063/1.1498152 (3 pages) | Cited 12 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have developed a sensitive, multipurpose torsional magnetometer with optical detection of the torque. The use of a feedback system with a current coil mounted with the sample allows direct, quantitative determination of the magnetization with a sensitivity of 10−12 J/T in a Bitter-magnet and 2×10−13 J/T at 15 T in a superconducting magnet. The system can be used over a wide range of temperatures and up to high magnetic fields. To demonstrate the sensitivity and versatility of our magnetometer, we present magnetization measurements of a multisubband two-dimensional electron gas (3×1011 spins) and of a 0.13 mg crystal of the organic conductor κ-(BEDT-TTF)2Cu(NCS)2. © 2002 American Institute of Physics.
Show PACS
07.55.Jg Magnetometers for susceptibility, magnetic moment, and magnetization measurements
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
72.15.Nj Collective modes (e.g., in one-dimensional conductors)
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems

Spin valves using insulating cobalt ferrite exchange-spring pinning layers

M. J. Carey, S. Maat, P. Rice, R. F. C. Farrow, R. F. Marks, A. Kellock, P. Nguyen, and B. A. Gurney

Appl. Phys. Lett. 81, 1044 (2002); http://dx.doi.org/10.1063/1.1494859 (3 pages) | Cited 25 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Cobalt ferrite, CoFe2O4, thin films are explored as pinning layers for read sensor applications. High ΔR/R values, 12.8%, and high pinning fields, 1500 Oe, are observed. Unlike other coercivity based pinning layers, the soft properties of the free layer are not compromised. The properties of the cobalt ferrite layers are strongly dependent on the microstructure, which, in turn, depends on the reactive sputtering process. © 2002 American Institute of Physics.
Show PACS
75.47.De Giant magnetoresistance
75.30.Et Exchange and superexchange interactions
81.15.Cd Deposition by sputtering
85.70.Kh Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
68.55.-a Thin film structure and morphology

Approach for the fabrication of MgB2 superconducting tape with large in-field transport critical current density

K. Komori, K. Kawagishi, Y. Takano, H. Fujii, S. Arisawa, H. Kumakura, M. Fukutomi, and K. Togano

Appl. Phys. Lett. 81, 1047 (2002); http://dx.doi.org/10.1063/1.1495087 (3 pages) | Cited 37 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The letter reports the fabrication of MgB2 superconducting tape using a flexible metallic substrate as well as its strong pinning force, which was verified by direct measurement of transport critical current density. The tape was prepared by depositing MgB2 film on a Hastelloy tape buffered with an yttria-stabilized-zirconia layer. The Jc of the tape exceeds 105 A/cm2 at 4.2 K and 10 T, which is considered as a common benchmark for magnet application. The Jc dependence on magnetic field remains surprisingly very small up to 10 T, suggesting that the tape has much better magnetic field characteristic than conventional Nb–Ti wires in liquid helium. © 2002 American Institute of Physics.
Show PACS
84.71.Mn Superconducting wires, fibers, and tapes
74.72.-h Cuprate superconductors
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
74.25.Sv Critical currents
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)

Preparation and magnetic properties of highly coercive FePt films

T. Shima, K. Takanashi, Y. K. Takahashi, and K. Hono

Appl. Phys. Lett. 81, 1050 (2002); http://dx.doi.org/10.1063/1.1498504 (3 pages) | Cited 99 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetization processes of highly ordered FePt(001) films with large perpendicular magnetic anisotropy have been studied. The film morphology was controlled from isolated particles to continuous film by varying the nominal thickness (tN) of the FePt film sputter deposited directly on a MgO(001) substrate at an elevated temperature. A drastic change in the coercivity by one order of magnitude has been found at the critical thickness (tN = 45 nm) where the film morphology changes from a particulate to a continuous state. A huge coercivity exceeding 40 kOe has been achieved in the film with tN = 10 nm, which comprises single domain particles with an average lateral size of approximately 50 nm. © 2002 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
81.15.Cd Deposition by sputtering
68.55.-a Thin film structure and morphology
81.05.Bx Metals, semimetals, and alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Gw Magnetic anisotropy
75.50.Vv High coercivity materials
75.50.Bb Fe and its alloys
75.70.Kw Domain structure (including magnetic bubbles and vortices)
back to top
RSS Feeds

Internal photoemission of electrons and holes from (100)Si into HfO2

V. V. Afanas’ev, A. Stesmans, F. Chen, X. Shi, and S. A. Campbell

Appl. Phys. Lett. 81, 1053 (2002); http://dx.doi.org/10.1063/1.1495088 (3 pages) | Cited 83 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electron energy band alignment at the Si/HfO2 interfaces with different interlayers (Si3N4, SiON, and SiO2) is directly determined using internal photoemission of electrons and holes from Si into the Hf oxide. Irrespective of the interlayer type, the energy barrier for the Si valence electrons was found to be equal 3.1±0.1 eV, yielding the conduction band offset of 2.0±0.1 eV. Photoemission of holes is effectively suppressed by SiON and SiO2 interlayers, yet it is observed to occur across the Si3N4 interlayer with a barrier of 3.6±0.1 eV, which corresponds to a Si/HfO2 valence band offset of 2.5±0.1 eV. The HfO2 band gap width of 5.6 eV, thus derived from the band offsets, coincides with the bulk value obtained from the oxide photoconductivity spectra. © 2002 American Institute of Physics.
Show PACS
79.60.Jv Interfaces; heterostructures; nanostructures
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
72.40.+w Photoconduction and photovoltaic effects

Ferroelastic phase in SrBi2Ta2O9 and study of the ferroelectric phase-transition dynamics

S. Kamba, J. Pokorný, V. Porokhonskyy, J. Petzelt, M. P. Moret, A. Garg, Z. H. Barber, and R. Zallen

Appl. Phys. Lett. 81, 1056 (2002); http://dx.doi.org/10.1063/1.1498005 (3 pages) | Cited 26 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polarized microscope observation of ferroelastic domains in a SrBi2Ta2O9 (SBT) single crystal reveals the presence of domains up to Tc1 ≃ 770 K, which supports the ferroelasticity and Amam symmetry of the intermediate phase between ferroelectric and paraelectric phases. Far-infrared spectra of SBT ceramics, single crystal and thin films show a well underdamped optical soft mode at 28 cm−1, which partially softens to 21 cm−1 near the ferroelectric transition temperature (Tc2 ≅ 600 K). This softening does not explain the entire anomaly of low-frequency permittivity observed near Tc2. On the basis of high-frequency measurements, which do not show a significant dispersion, central-mode-type dispersion in the 10–100 GHz range is proposed as an explanation. So, the phase transition at Tc2 apparently shows a crossover behavior between the displacive and the order–disorder type. © 2002 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
62.20.D- Elasticity
77.80.B- Phase transitions and Curie point
78.30.Hv Other nonmetallic inorganics
77.22.Ch Permittivity (dielectric function)
63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions

Pyroelectric nanoporous films: Synthesis and properties

Ganesh Suyal, Andreas Seifert, and Nava Setter

Appl. Phys. Lett. 81, 1059 (2002); http://dx.doi.org/10.1063/1.1498008 (3 pages) | Cited 8 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
PbZrxTi1−xO3 (x = 0.45) and PbxCa1−xTiO3 (PCT) (x = 0.75) porous thin films were deposited on platinized silicon wafers by chemical solution deposition route using a polymer as a volatile phase. The introduction of pores creates a matrix-void composite resulting in a high figure of merit for pyroelectric applications. The figures of merit Fv and Fd for PCT films are shown to be as high as 4.8 and 250 μC/m2 K, respectively. © 2002 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.70.+a Pyroelectric and electrocaloric effects
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
61.46.-w Structure of nanoscale materials
81.07.Bc Nanocrystalline materials
81.05.Rm Porous materials; granular materials
77.22.Ch Permittivity (dielectric function)
77.22.Gm Dielectric loss and relaxation

Epitaxial PbZr.52Ti.48O3 films on SrTiO3/(001)Si substrates deposited by sol–gel method

A. A. Talin, S. M. Smith, S. Voight, J. Finder, K. Eisenbeiser, D. Penunuri, Z. Yu, P. Fejes, T. Eschrich, J. Curless, D. Convey, and A. Hooper

Appl. Phys. Lett. 81, 1062 (2002); http://dx.doi.org/10.1063/1.1498006 (3 pages) | Cited 12 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on the sol–gel deposition and characterization of high-quality, epitaxial films of PbZr.52Ti.48O3 (PZT) on (001)Si substrates, with a thickness range of 400 Å to 1 μm. The epitaxial growth of PZT on (001)Si is achieved using a thin template layer of SrTiO3, grown by molecular-beam epitaxy. The sol–gel PZT films have a typical surface roughness of 5 Å and exhibit well defined reflective high-energy electron diffraction patterns characteristic of smooth, epitaxial films. Using high-resolution transmission electron microscopy and double-crystal x-ray diffraction, we find that the PZT films are oriented with the c axis normal to the (001)Si plane and with the a axis lying along 〈110〉Si direction. Finally, we measure the electromechanical coupling coefficients and the surface acoustic wave velocities for our films as a function of thickness and compare our experimental data to previously published theoretical values for this system. © 2002 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
68.55.A- Nucleation and growth
77.80.-e Ferroelectricity and antiferroelectricity
77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
68.35.Iv Acoustical properties

HfO2 gate dielectric with 0.5 nm equivalent oxide thickness

H. Harris, K. Choi, N. Mehta, A. Chandolu, N. Biswas, G. Kipshidze, S. Nikishin, S. Gangopadhyay, and H. Temkin

Appl. Phys. Lett. 81, 1065 (2002); http://dx.doi.org/10.1063/1.1495882 (3 pages) | Cited 42 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Hafnium dioxide films have been deposited using reactive electron beam evaporation in oxygen on hydrogenated Si(100) surfaces. The capacitance–voltage curves of as-deposited metal(Ti)–insulator–semiconductor structures exhibited large hysteresis and frequency dispersion. With post-deposition annealing in hydrogen at 300 °C, the frequency dispersion decreased to less than 1%/decade, while the hysteresis was reduced to 20 mV at flatband. An equivalent oxide thickness of 0.5 nm was achieved for HfO2 thickness of 3.0 nm. We attribute this result to a combination of pristine hydrogen saturated silicon surfaces, room temperature dielectric deposition, and low temperature hydrogen annealing. © 2002 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.Cc Kinetics of defect formation and annealing

Stress-induced polarization-graded ferroelectrics

Joseph V. Mantese, Norman W. Schubring, Adolph L. Micheli, Margarita P. Thompson, Ratna Naik, Gregory W. Auner, I. Burc Misirlioglu, and S. Pamir Alpay

Appl. Phys. Lett. 81, 1068 (2002); http://dx.doi.org/10.1063/1.1498506 (3 pages) | Cited 33 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Polarization-graded ferroelectrics and their electrically active embodiments, graded ferroelectric devices and transpacitors, have been formed from a variety of material systems, both by grading the composition of the ferroelectric and by imposing temperature gradients normal to the electrode surfaces. In this letter, we show how these same devices can be formed from homogeneous ferroelectric films of lead strontium titanate by imposing stress gradients on the material normal to their electrode surfaces. © 2002 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
77.65.Ly Strain-induced piezoelectric fields
77.80.Dj Domain structure; hysteresis
77.22.Ej Polarization and depolarization
77.22.Ch Permittivity (dielectric function)
62.20.F- Deformation and plasticity
81.40.Lm Deformation, plasticity, and creep
68.60.Bs Mechanical and acoustical properties

Dielectric characteristics of Al2O3–HfO2 nanolaminates on Si(100)

M.-H. Cho, Y. S. Roh, C. N. Whang, K. Jeong, H. J. Choi, S. W. Nam, D.-H. Ko, J. H. Lee, N. I. Lee, and K. Fujihara

Appl. Phys. Lett. 81, 1071 (2002); http://dx.doi.org/10.1063/1.1499223 (3 pages) | Cited 63 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The structural characteristics and the chemical state of a HfO2–Al2O3 nanolaminate structure, depending on the postannealing temperature, were examined by x-ray diffraction and x-ray photoelectron spectroscopy. The structural stability is significantly enhanced up to 870 °C and so is able to sustain its amorphous and laminate structure. However, the laminate structure is drastically broken at the annealing temperature of 920 °C and the crystallization is locally generated. In particular, the formation of the interfacial layer during the postannealing treatment is effectively suppressed in the nanolaminated structure. The dielectric constant of the nanolaminate structure calculated from the accumulation capacitance increases from ∼10 to ∼17 as the annealing temperature increases. This change is closely related to the degree of the mixture composed by Al2O3 and HfO2. © 2002 American Institute of Physics.
Show PACS
77.22.Ch Permittivity (dielectric function)
61.46.-w Structure of nanoscale materials
79.60.Jv Interfaces; heterostructures; nanostructures

Boron penetration studies from p+ polycrystalline Si through HfSixOy

M. A. Quevedo-Lopez, M. El-Bouanani, M. J. Kim, B. E. Gnade, R. M. Wallace, M. R. Visokay, A. LiFatou, M. J. Bevan, and L. Colombo

Appl. Phys. Lett. 81, 1074 (2002); http://dx.doi.org/10.1063/1.1498872 (3 pages) | Cited 31 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present detailed B penetration studies from B-doped polysilicon through alternate gate dielectric candidate HfSixOy films. No detectible B penetration is observed for annealing times as long as 20 s after 950 °C. Considerable B incorporation into the Si substrate is observed for annealing temperatures higher than 950 °C. By modeling the B depth profiles, we calculated the B diffusivities through HfSixOy to be higher than the corresponding diffusivities for SiO2. B diffusion through grain boundaries after HfSixOy crystallization is proposed to be responsible for the enhanced B diffusivity observed. © 2002 American Institute of Physics.
Show PACS
61.72.uf Ge and Si
66.30.J- Diffusion of impurities
61.72.Cc Kinetics of defect formation and annealing
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
85.40.Ry Impurity doping, diffusion and ion implantation technology
81.05.Cy Elemental semiconductors
61.72.Mm Grain and twin boundaries

Field-induced effects in the relaxor ferroelectric Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 studied by micro-Brillouin scattering

Jae-Hyeon Ko and Seiji Kojima

Appl. Phys. Lett. 81, 1077 (2002); http://dx.doi.org/10.1063/1.1496136 (3 pages) | Cited 7 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Field-induced changes of Brillouin scattering spectra in a relaxor-based ferroelectric Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 single crystal have been examined under an electric field oriented along the pseudocubic [001] direction. A complete cycle of the Brillouin shift-electric field loop shows that sound velocities of one longitudinal and two transverse modes are softened during the polarization reversal. In particular, one transverse mode, which corresponds to the (c11−c12)/2 elastic stiffness coefficient, becomes markedly soft from 18.6 to 14 GHz and then restores its initial value at two distinct electric fields. In addition, two peaks have also been observed in the field dependence of the full width at half maximum of this mode. It implies that, at least two kinds of polarization rotation process are involved in the switching process, which seems to be related with the existence of intermediate monoclinic symmetry during the field-induced phase transition from rhombohedral to tetragonal phase. © 2002 American Institute of Physics.
Show PACS
77.80.Fm Switching phenomena
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
78.35.+c Brillouin and Rayleigh scattering; other light scattering
77.22.Ej Polarization and depolarization
63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions
64.70.K- Solid-solid transitions
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
77.80.B- Phase transitions and Curie point
62.65.+k Acoustical properties of solids
back to top
RSS Feeds

Ordered arrays of vertically correlated GaAs and AlAs quantum wires grown on a GaAs(311)A surface

D. Litvinov, A. Rosenauer, D. Gerthsen, N. N. Ledentsov, D. Bimberg, G. A. Ljubas, V. V. Bolotov, V. A. Volodin, M. D. Efremov, V. V. Preobrazhenskii, B. R. Semyagin, and I. P. Soshnikov

Appl. Phys. Lett. 81, 1080 (2002); http://dx.doi.org/10.1063/1.1497994 (3 pages) | Cited 10 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We study GaAs–AlAs short-period superlattices (SPSLs) grown on a GaAs(311)A surface using plan-view transmission electron microscopy (TEM). A strong in-plane compositional modulation with a period of 3.2 nm along the [0math1] direction is revealed by TEM under chemically sensitive imaging conditions and in high-resolution TEM. Our results confirm the formation of highly ordered vertically aligned arrays of GaAs and AlAs quantum wires formed via self-organized growth. Bright photoluminescence (PL) at room temperature in the green and yellow spectral range is observed. © 2002 American Institute of Physics.
Show PACS
68.65.La Quantum wires (patterned in quantum wells)
68.65.Cd Superlattices
78.67.Lt Quantum wires
78.55.Cr III-V semiconductors

Field emission from individual B–C–N nanotube rope

P. Dorozhkin, D. Golberg, Y. Bando, and Z.-C. Dong

Appl. Phys. Lett. 81, 1083 (2002); http://dx.doi.org/10.1063/1.1497194 (3 pages) | Cited 22 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The field-emission characteristics of individual ropes made of B–C–N nanotubes were measured in situ in a low-energy electron point source microscope. The tungsten field emission tip of the microscope was used as a movable electrode, approaching the rope, and acting as an anode during field-emission measurements. The atomic structure and chemical composition of the ropes were analyzed by high-resolution transmission electron microscopy and electron energy-loss spectroscopy. The tubes assembled within the ropes typically revealed open-tip ends, a small number of layers and zigzag chirality. We found that the field-emission properties of the B–C–N nanotube ropes are competitive with conventional C nanotubes, with the expected additional benefit that the B–C–N ropes exhibit higher environmental stability. © 2002 American Institute of Physics.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
61.46.-w Structure of nanoscale materials
79.20.Uv Electron energy loss spectroscopy

Why do (2×4) GaAs and InAs (001) surfaces exposed to phosphorus have so different behavior? Elastic strain arguments

X. Wallart, C. Priester, D. Deresmes, T. Gehin, and F. Mollot

Appl. Phys. Lett. 81, 1086 (2002); http://dx.doi.org/10.1063/1.1499230 (3 pages) | Cited 2 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
When exposed to phosphorus, the (2×4) GaAs surface tends rapidly to roughen whereas it is not the case for the (2×4) InAs one, even after long exposure times. X-ray photoemission measurements show that the incorporated phosphorus amount is similar in both cases. The elastic energy difference between these two materials with incorporated phosphorus, calculated within the valence force field approximation, appears to be strong enough to explain this phenomenon. The role of surface reconstruction, mainly dimerization, on phosphorus incorporation is also emphasized. © 2002 American Institute of Physics.
Show PACS
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.05.Ea III-V semiconductors
68.35.Gy Mechanical properties; surface strains
79.60.Dp Adsorbed layers and thin films
62.20.F- Deformation and plasticity
68.35.Md Surface thermodynamics, surface energies

Growth front roughening of room-temperature deposited copper nanocluster films

G. Palasantzas, S. A. Koch, and J. Th. M. De Hosson

Appl. Phys. Lett. 81, 1089 (2002); http://dx.doi.org/10.1063/1.1497200 (3 pages) | Cited 9 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Growth front aspects of copper nanocluster films deposited with low energy onto silicon substrates at room temperature are investigated by atomic force microscopy. Analyses of the height-difference correlation function yield a roughness exponent H of 0.45±0.05. The root-mean-sqaure roughness amplitude w evolves with deposition time as a power law, w∝tβ (β = 0.62±0.07), leading also to a power-law increase of the local surface slope ρ, ρ∝tc (c = 0.73±0.09). These scaling exponents, in combination with an asymmetrical height distribution, point at a complex nonlinear roughening mechanism dominated by the formation of voids resulting in a highly porous film. © 2002 American Institute of Physics.
Show PACS
68.55.A- Nucleation and growth
81.07.Bc Nanocrystalline materials
61.46.-w Structure of nanoscale materials
81.16.Ta Atom manipulation
68.37.Ps Atomic force microscopy (AFM)
61.72.Qq Microscopic defects (voids, inclusions, etc.)

Electron charging and discharging in amorphous silicon quantum dots embedded in silicon nitride

Nae-Man Park, Suk-Ho Choi, and Seong-Ju Park

Appl. Phys. Lett. 81, 1092 (2002); http://dx.doi.org/10.1063/1.1497444 (3 pages) | Cited 20 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electron charging and discharging were produced in metal-insulator-semiconductor structures containing amorphous silicon quantum dots (a-Si QDs) by increasing the applied voltage in a stepwise fashion without changing its sign. The metal-insulator-semiconductor structure was fabricated using an insulating silicon nitride film containing a-Si QDs by plasma-enhanced chemical vapor deposition. This charging behavior suggests that a-Si QDs in the silicon nitride are positively charged due to nitrogen dangling bonds. The surface state of the a-Si QDs is considered to play a dominant role in the charging properties such as electron storage and charge-loss rate in the a-Si QDs. © 2002 American Institute of Physics.
Show PACS
73.21.La Quantum dots
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Blackbody radiation from resistively heated multiwalled carbon nanotubes during field emission

M. Sveningsson, M. Jönsson, O. A. Nerushev, F. Rohmund, and E. E. B. Campbell

Appl. Phys. Lett. 81, 1095 (2002); http://dx.doi.org/10.1063/1.1498493 (3 pages) | Cited 24 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report the observation of blackbody radiation from aligned multiwalled carbon nanotubes undergoing field emission. The light intensity correlates with fluctuations in the emission current. The onset of light emission occurs at an emission current of 1 mA/cm2 and corresponds to a temperature on the order of 1550 K. Beyond this critical current irreversible changes occur in the nanotube film. The correlation between light intensity and emission current provides convincing evidence for Joule heating and stable operation for nanotube temperatures up to at least 2000 K and emission current densities on the order of 10 mA/cm2. © 2002 American Institute of Physics.
Show PACS
78.60.Fi Electroluminescence
81.07.De Nanotubes
79.70.+q Field emission, ionization, evaporation, and desorption
73.63.Fg Nanotubes
78.67.Ch Nanotubes
44.40.+a Thermal radiation

Secondary electron emission from magnesium oxide on multiwalled carbon nanotubes

Won Seok Kim, Whikun Yi, SeGi Yu, Jungna Heo, Taewon Jeong, Jeonghee Lee, Chang Soo Lee, J. M. Kim, Hee Jin Jeong, Young Min Shin, and Young Hee Lee

Appl. Phys. Lett. 81, 1098 (2002); http://dx.doi.org/10.1063/1.1498492 (3 pages) | Cited 20 times

Online Publication Date: 30 July 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated effects of electric fields on the yield of secondary electron emission (SEE) from the primary electron bombardment on magnesium oxide (MgO) covering vertically grown multiwalled carbon nanotubes (MWCNTs). We observe that the yield of SEE increases up to at least 22 000 at a special condition. The strong local field generated by the sharp tip of vertically grown MWCNTs accelerates secondary electrons generated by primary electrons. This eventually gives rise to so called Townsend avalanche effect, generating huge number of secondary electrons in a MgO film. Emission mechanism for such a high SEE will be further discussed with energy spectrum analysis. © 2002 American Institute of Physics.
Show PACS
79.20.Hx Electron impact: secondary emission
73.50.Fq High-field and nonlinear effects
77.22.Jp Dielectric breakdown and space-charge effects
81.07.De Nanotubes
73.61.Ng Insulators
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close