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

29 Apr 2002

Volume 80, Issue 17, pp. 3033-3231

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

Boundary conditions in an electric current contact

O. Yu. Titov, J. Giraldo, and Yu. G. Gurevich

Appl. Phys. Lett. 80, 3108 (2002); http://dx.doi.org/10.1063/1.1473875 (3 pages) | Cited 14 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In most electronic devices, the electric current of both types (electrons and holes) flows through a junction. Usually the boundary conditions have been formulated exclusively for open circuit. The boundary conditions proposed here bypass this limitation. Besides, these boundary conditions correctly describe the current flow in a circuit, i.e., closed circuit conditions, which are the usual operation conditions for electronic devices and for the measurement of many transport properties. We also have generalized the case (as much as it is possible in a classical treatment), so self-consistent boundary conditions that describe the current flow through a contact between two arbitrary conducting media are developed in the present work. These boundary conditions take into account a recently developed theory: influence of temperature space inhomogeneity due to the interfaces and quasiparticles temperature mismatch on thermogeneration and recombination. They also take into account surface resistance, surface recombination rates, and possible temperature discontinuities at the interface due to finite surface thermoconductivity. The temperature difference between current carriers and phonon subsystems is also included in this approach. © 2002 American Institute of Physics.
Show PACS
72.10.Fk Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect)
73.40.Cg Contact resistance, contact potential

Band alignment between GaAs and partially ordered GaInP

Yong Zhang, Angelo Mascarenhas, and Lin-Wang Wang

Appl. Phys. Lett. 80, 3111 (2002); http://dx.doi.org/10.1063/1.1472478 (3 pages) | Cited 12 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
An empirical pseudopotential method is used for calculating the band structure of partially CuPt ordered GaxIn1−xP alloy with order parameter η varying from 0 to 1. Because the relative band alignments between the binaries (GaAs, GaP, and InP) are taken into account in the pseudopotential fitting, such a calculation naturally yields the conduction and valence band alignment between the GaInP alloy and GaAs, as well as shows how the alignments change with the order parameter. The band alignment is found to change from type I to type II at η = 0.46 (0.54) for x = 0.50 (0.52), which is in good agreement with experimental data. © 2002 American Institute of Physics.
Show PACS
73.20.At Surface states, band structure, electron density of states
71.15.Dx Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction)

Bias-dependent photoluminescence in CdTe photovoltaics

Diana Shvydka, V. G. Karpov, and A. D. Compaan

Appl. Phys. Lett. 80, 3114 (2002); http://dx.doi.org/10.1063/1.1475359 (3 pages) | Cited 5 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We show that external bias significantly affects the photoluminescence (PL) in CdTe photovoltaics. The main observations are: (1) reverse bias suppresses PL, (2) PL increases with moderate forward bias and tends to saturate when it is above the open-circuit voltage, and (3) PL in the region of saturation is extremely sensitive to device degradation. We attribute the observed phenomena to the competition between the field-induced separation of electrons and holes and their nonradiative recombination. We have developed a model that describes bias-dependent PL more quantitatively and forms a basis for using it as an indicator of device degradation. © 2002 American Institute of Physics.
Show PACS
78.55.Et II-VI semiconductors
78.66.Hf II-VI semiconductors
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
72.40.+w Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.80.Ey III-V and II-VI semiconductors

Extremely high room-temperature two-dimensional hole gas mobility in Ge/Si0.33Ge0.67/Si(001) p-type modulation-doped heterostructures

M. Myronov, T. Irisawa, O. A. Mironov, S. Koh, Y. Shiraki, T. E. Whall, and E. H. C. Parker

Appl. Phys. Lett. 80, 3117 (2002); http://dx.doi.org/10.1063/1.1473690 (3 pages) | Cited 30 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
To extract the room-temperature drift mobility and sheet carrier density of two-dimensional hole gas (2DHG) that form in Ge strained channels of various thicknesses in Ge/Si0.33Ge0.67/Si(001) p-type modulation-doped heterostructures, the magnetic field dependences of the magnetoresistance and Hall resistance at temperature of 295 K were measured and the technique of maximum entropy mobility spectrum analysis was applied. This technique allows a unique determination of mobility and sheet carrier density of each group of carriers present in parallel conducting multilayers semiconductor heterostructures. Extremely high room-temperature drift mobility (at sheet carrier density) of 2DHG 2940 cm2 V−1 s−1 (5.11×1011 cm−2) was obtained in a sample with a 20 nm thick Ge strained channel. © 2002 American Institute of Physics.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
73.61.Le Other inorganic semiconductors
73.61.Cw Elemental semiconductors

Transport properties of Mn δ-doped GaAs and the effect of selective doping

Ahsan M. Nazmul, S. Sugahara, and M. Tanaka

Appl. Phys. Lett. 80, 3120 (2002); http://dx.doi.org/10.1063/1.1473878 (3 pages) | Cited 23 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have grown Mn δ-doped GaAs layers on GaAs(001) substrates by molecular beam epitaxy. Secondary ion mass spectroscopy and transmission electron microscopy revealed that Mn dopants were abruptly confined. The doping profiles still retained abruptness even at elevated growth temperature up to 400 °C. Mn δ-doped GaAs samples showed high resistivity at low temperature and did not show a ferromagnetic behavior. However, in a selectively doped heterostructure (Mn δ-doped GaAs / Be-doped AlGaAs), where holes were supplied from the Be-doped AlGaAs layer, a ferromagnetic order was observed with the ferromagnetic transition temperature as high as 70 K. © 2002 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
61.72.S- Impurities in crystals
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
75.50.Pp Magnetic semiconductors

Tris-(8-hydroxyquinoline)aluminum-based organic light-emitting devices with Al/CaF2 cathode: Performance enhancement and interface electronic structures

J. Lee, Y. Park, S. K. Lee, E.-J. Cho, D. Y. Kim, H. Y. Chu, H. Lee, L.-M. Do, and T. Zyung

Appl. Phys. Lett. 80, 3123 (2002); http://dx.doi.org/10.1063/1.1474602 (3 pages) | Cited 31 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The device characteristics and the interface electronic structures of organic light-emitting devices based on tris-(8-hydroxyquinoline)aluminum were investigated with Al/CaF2, Al/LiF, and Al-only cathodes. Similar to the Al/LiF cathode, the Al/CaF2 cathode greatly improved the performance of the device over the Al-only cathode. However, a photoelectron spectroscopy study revealed that despite the performance improvement, the evolution of the new peaks during the Al/CaF2 cathode formation closely resembled those of the Al-only cathode rather than the Al/LiF cathode. © 2002 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
73.20.At Surface states, band structure, electron density of states
79.60.Jv Interfaces; heterostructures; nanostructures

Spin splitting in modulation-doped AlGaN/GaN two-dimensional electron gas

K. Tsubaki, N. Maeda, T. Saitoh, and N. Kobayashi

Appl. Phys. Lett. 80, 3126 (2002); http://dx.doi.org/10.1063/1.1474599 (3 pages) | Cited 35 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
AlGaN/GaN heterostructure devices have recently been attracting much attention because of their potential for high-performance microwave applications. Therefore, the electronic properties of a two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures have recently been discussed. We studied the magnetoresistance oscillation of the 2DEG at 0.4 K for various backgate voltages, and observed multiple oscillations resulting from spin splitting. The magnetoresistance shows clear beating due to the superposition of three oscillations. The frequency interval between the first and second largest frequencies is proportional to the total electron concentration and the measured spin-orbit interaction parameter agrees with the theoretical one. Therefore, the first and second largest frequencies are found to correspond to spin splitting by the spin-orbit interaction. © 2002 American Institute of Physics.
Show PACS
73.61.Ey III-V semiconductors
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
81.05.Ea III-V semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
72.25.Mk Spin transport through interfaces
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect

Effects of sulfur passivation on Ti/Al ohmic contacts to n-type GaN using CH3CSNH2 solution

June O Song, Seong-Ju Park, and Tae-Yeon Seong

Appl. Phys. Lett. 80, 3129 (2002); http://dx.doi.org/10.1063/1.1475773 (3 pages) | Cited 18 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We investigate the effect of CH3CSNH2 solution treatment on Ti/Al ohmic contacts to n-GaN:Si (3×1018 cm−3). It is shown that the sulfide treatment results in a drastic increase in the photoluminescence intensity, compared with that of the untreated sample. Current-voltage (I–V) results show that the sulfide treatment significantly improves the specific contact resistance. The annealing of the sulfide-treated sample (at 700 °C) results in a specific contact resistance of 3.1×10−6 Ω cm2. X-ray photoemission spectroscopy (XPS) results show that the Ga 2p core levels shift toward the higher-binding energy side by 0.2 eV for the sulfide-treated sample and by 0.4 eV for the annealed (sulfide-treated) sample, compared with that of the untreated one. It is further shown that the intensity of O 1s core level decreases with the sulfide treatment. Based on the I–V and XPS results, the sulfide and annealing treatment dependence of the specific contact resistance is discussed. © 2002 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
81.65.Rv Passivation
73.40.Ns Metal-nonmetal contacts
73.20.At Surface states, band structure, electron density of states
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
79.60.Jv Interfaces; heterostructures; nanostructures
61.72.Cc Kinetics of defect formation and annealing
73.40.Cg Contact resistance, contact potential

Zero-field spin splitting in In0.52Al0.48As/InxGa1−xAs metamorphic high-electron-mobility-transistor structures on GaAs substrates using Shubnikov–de Haas measurements

L. J. Cui, Y. P. Zeng, B. Q. Wang, Z. P. Zhu, L. Y. Lin, C. P. Jiang, S. L. Guo, and J. H. Chu

Appl. Phys. Lett. 80, 3132 (2002); http://dx.doi.org/10.1063/1.1476055 (3 pages) | Cited 10 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Shubnikov–de Haas measurements were carried out for In0.52Al0.48As/InxGa1−xAs metamorphic high-electron-mobility-transistor structures grown on GaAs substrates with different indium contents and/or different Si δ-doping concentrations. Zero-field (B→0) spin splitting was found in samples with stronger conduction band bending in the InGaAs well. It was shown that the dominant spin splitting mechanism is attributed to the contribution by the Rashba term. We found that zero-field spin splitting not only occurs in the ground electron subband, but also in the first excited electron subband for a sample with Si δ-doping concentration of 6×1012 cm−2. We propose that this In0.52Al0.48As/InxGa1−xAs metamorphic high-electron-mobility-transistor structure grown on GaAs may be a promising candidate spin-polarized field-effect transistors. © 2002 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
85.75.Hh Spin polarized field effect transistors
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
back to top
RSS Feeds

60% magnetoresistance at room temperature in Co–Fe/Al–O/Co–Fe tunnel junctions oxidized with Kr–O2 plasma

Masakiyo Tsunoda, Kazuhiro Nishikawa, Satoshi Ogata, and Migaku Takahashi

Appl. Phys. Lett. 80, 3135 (2002); http://dx.doi.org/10.1063/1.1475363 (3 pages) | Cited 41 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the mixed inert gas species for plasma oxidization process of a metallic Al layer on the tunnel magnetoresistance (TMR) was investigated for a magnetic tunnel junction (MTJ), Ta 50 Å/Cu 200 Å/Ta 200 Å/Ni–Fe 50 Å/Cu 50 Å/Mn75Ir25 100 Å/Co70Fe30 25 Å/Al–O/Co70Fe30 25 Å/Ni–Fe 100 Å/Cu 200 Å/Ta 50 Å. Using Kr–O2 plasma, a 58.8% of TMR ratio was obtained at room temperature after annealing the junction at 300 °C, while the achieved TMR ratio of the MTJ fabricated with usual Ar–O2 plasma remained 48.6%. A faster oxidization rate of the Al layer by using Kr–O2 plasma is a possible cause to prevent the over oxidization of the Al layer, which depolarizes the surface of the underlaid ferromagnetic electrode, and to realize a large magnetoresistance. © 2002 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.47.De Giant magnetoresistance
73.61.At Metal and metallic alloys
81.05.Bx Metals, semimetals, and alloys
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
73.40.Rw Metal-insulator-metal structures
61.72.Cc Kinetics of defect formation and annealing
52.77.-j Plasma applications
81.65.Mq Oxidation

Anomalous Hall effect in La1−xCaxCoO3

S. A. Baily, M. B. Salamon, Y. Kobayashi, and K. Asai

Appl. Phys. Lett. 80, 3138 (2002); http://dx.doi.org/10.1063/1.1473866 (3 pages) | Cited 13 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
La1−xCaxCoO3 films show the largest anomalous Hall effect of any ferromagnetic metal. The anomalous Hall coefficient increases as x decreases. At doping below 0.2 La1−xCaxCoO3 is insulating and shows spin-glass behavior at low temperature. We have measured the Hall effect and magnetic behavior of an x = 0.15 crystal. It shows cluster-glass or correlated-spin-glass behavior at intermediate temperatures. The anomalous Hall effect does not depend on the total magnetization, M, but on the ferromagnetic correlations of the glass. © 2002 American Institute of Physics.
Show PACS
72.20.My Galvanomagnetic and other magnetotransport effects
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Lk Spin glasses and other random magnets
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects

Local magnetic ordering in La1−xCaxMnO3 determined by spin-polarized x-ray absorption spectroscopy

Q. Qian, T. A. Tyson, C.-C. Kao, M. Croft, and A. Yu. Ignatov

Appl. Phys. Lett. 80, 3141 (2002); http://dx.doi.org/10.1063/1.1473700 (3 pages) | Cited 8 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A systematic study of spin-dependent Mn K-edge x-ray absorption spectra was performed on La1−xCaxMnO3. By examining the changes in the pre-edge spectra with the temperature, a model of the excitation process is developed and used to predict the temperature dependent changes in the local magnetic ordering about Mn sites. The approach is of general applicability to perovskite systems. It can be used to determine the change in the local magnetic order (ferromagnetic versus antiferromagnetic) about a transition metal site upon going through a transition or as the result of external perturbations. © 2002 American Institute of Physics.
Show PACS
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.47.Gk Colossal magnetoresistance
78.70.Dm X-ray absorption spectra

Spin-coherent transport in ferromagnetically contacted carbon nanotubes

B. Zhao, I. Mönch, H. Vinzelberg, T. Mühl, and C. M. Schneider

Appl. Phys. Lett. 80, 3144 (2002); http://dx.doi.org/10.1063/1.1471570 (3 pages) | Cited 71 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The spin-coherent quantum transport through multiwall carbon nanotubes contacted by ferromagnetic Co pads is investigated experimentally. At 4.2 K, the devices show a remarkable increase of the magnetoresistance (MR) ratio with decreasing junction bias, reaching a maximum MR ratio of 30% at a junction bias current of 1 nA. The experimental results suggest the transport to be dominated by spin-dependent tunneling processes at the Co/nanotube interfaces and governed by the local magnetization. We also observe an asymmetry of the magnetoresistance peak position and width which is attributed to a local exchange biasing in the electrode material. © 2002 American Institute of Physics.
Show PACS
72.25.Mk Spin transport through interfaces
73.63.Fg Nanotubes
75.50.Cc Other ferromagnetic metals and alloys
75.45.+j Macroscopic quantum phenomena in magnetic systems

Resonant terahertz radiation from Tl2Ba2CaCu2O8+δ thin films by ultrafast optical pulse excitation

Yukihiro Tominari, Toshihiko Kiwa, Hironaru Murakami, Masayoshi Tonouchi, Hagen Wald, Paul Seidel, and Henrik Schneidewind

Appl. Phys. Lett. 80, 3147 (2002); http://dx.doi.org/10.1063/1.1475770 (3 pages) | Cited 16 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have observed the free-space radiation of the resonant terahertz wave from c-axis oriented Tl2Ba2CaCu2O8+δ thin films by femtosecond optical pulse excitation under a radial magnetic field of about 100 Oe nearly parallel to the c axis of the thin film. The observed wave form showed clear oscillations up to 80 K. The frequency was shifted from ∼ 620 GHz at 24 K to ∼ 300 GHz at 80 K, corresponding to an increase in c-axis penetration depth, λc, from ∼ 26 μm to ∼ 53 μm, and disappeared above TC as expected for the Josephson plasma resonance. © 2002 American Institute of Physics.
Show PACS
74.72.-h Cuprate superconductors
74.78.-w Superconducting films and low-dimensional structures
74.25.N- Response to electromagnetic fields
74.50.+r Tunneling phenomena; Josephson effects
74.25.Ha Magnetic properties including vortex structures and related phenomena

Stroboscopic single-shot detection of the flux state in a radio frequency superconducting quantum interference device

C. Cosmelli, F. Sciamanna, M. G. Castellano, R. Leoni, G. Torrioli, P. Carelli, and F. Chiarello

Appl. Phys. Lett. 80, 3150 (2002); http://dx.doi.org/10.1063/1.1474605 (3 pages) | Cited 10 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The flux states of a rf superconducting quantum interference device (SQUID) can be used to investigate macroscopic quantum effects, the most challenging of which is the detection of quantum coherent oscillations, and are promising candidates for the implementation of quantum computing. The use of a proper readout system is of utmost importance for these purposes. In this letter we present experimental evidence of the possibility of using an underdamped, hysteretic dc SQUID to read out stroboscopically the flux states of a rf SQUID, allowing a single shot discrimination with an efficiency of 98%. The devices are all integrated on chip. © 2002 American Institute of Physics.
Show PACS
85.25.Dq Superconducting quantum interference devices (SQUIDs)
03.67.Lx Quantum computation architectures and implementations

Fluxon insertion into annular Josephson junctions

Alexey V. Ustinov

Appl. Phys. Lett. 80, 3153 (2002); http://dx.doi.org/10.1063/1.1474617 (3 pages) | Cited 30 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A technique of inserting magnetic fluxons into annular Josephson junctions is proposed and demonstrated experimentally. The method is based on local injection of current into one of the superconducting electrodes of the junction. The residual pinning of fluxons in the junction can be eliminated by choosing an appropriate injection current, which depends on the spacing between the injectors. The reported technique resolves the long-standing problem of a controlled preparation of fluxon states in annular Josephson junctions and can be used in various fluxon devices. © 2002 American Institute of Physics.
Show PACS
85.25.Cp Josephson devices
74.50.+r Tunneling phenomena; Josephson effects
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
74.45.+c Proximity effects; Andreev reflection; SN and SNS junctions

Spin valves with interlayer coupling domain biasing

Z. Q. Lu and G. Pan

Appl. Phys. Lett. 80, 3156 (2002); http://dx.doi.org/10.1063/1.1471930 (3 pages) | Cited 4 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spin valves with structure of sub/Ta/NiFe/FeMn/NiFe/Mo/NiFe/Cu/NiFe/CrMnPt/Ta were developed. In this configuration, a longitudinal-biasing field from interlayer coupling stabilized the magnetic domains of the free layer. Planar Hall effect was used to study the magnetization reversal process of the free layer. It was shown that by adjusting the thickness of Mo layer, the interlayer coupling biasing field can provide domain stabilization and was sufficiently strong to constrain the magnetization in coherent rotation. This can prevent Barkhausen noises associated with magnetization reversal. Such a spin valve sensor structure is particularly attractive for high density read heads. © 2002 American Institute of Physics.
Show PACS
75.47.De Giant magnetoresistance
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.60.Jk Magnetization reversal mechanisms
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
85.70.Kh Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
back to top
RSS Feeds

Fast time-resolved x-ray diffraction in BaTiO3 films subjected to a strong high-frequency electric field

E. Zolotoyabko, J. P. Quintana, B. H. Hoerman, and B. W. Wessels

Appl. Phys. Lett. 80, 3159 (2002); http://dx.doi.org/10.1063/1.1476057 (3 pages) | Cited 16 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The pulsed synchrotron radiation from the Advanced Photon Source of Argonne National Laboratory was used to measure the dynamic structural response in 200-nm-thick BaTiO3 ferroelectric films, in situ, under the application of a high-frequency electric field. X-ray diffraction measurements were performed in the stroboscopic mode, i.e., by synchronizing the x-ray bursts with the electric-field periodicity. Time-dependent variations of lattice parameters were derived from the electric-field-induced distortions of the diffraction profiles. Drastic reduction of the relaxation time, from 6.9 ns at 71.69 MHz down to 0.7 ns at 521.36 MHz, was found with an increase of the electric-field frequency. © 2002 American Institute of Physics.
Show PACS
68.55.-a Thin film structure and morphology
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.65.Bn Piezoelectric and electrostrictive constants

Field-cooled static nonlinear response of relaxor ferroelectrics

Z. Kutnjak, R. Pirc, and R. Blinc

Appl. Phys. Lett. 80, 3162 (2002); http://dx.doi.org/10.1063/1.1475771 (3 pages) | Cited 25 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The third-order static field-cooled nonlinear dielectric permittivity in relaxor ferroelectric PbMg1/3Nb2/3O3 has been measured as a function of temperature. It is shown that the observed behavior can be explained by a mechanism of nonlinear response within the framework of the spherical random bond-random field model. © 2002 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.80.-e Ferroelectricity and antiferroelectricity
77.22.Ch Permittivity (dielectric function)

Polarized Raman scattering of epitaxial PbTiO3 thin film with coexisting c and a domains

Sun-Hwa Lee, Hyun M. Jang, Seong M. Cho, and Gyu-Chul Yi

Appl. Phys. Lett. 80, 3165 (2002); http://dx.doi.org/10.1063/1.1473864 (3 pages) | Cited 14 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Effects of the orientation of ferroelectric domains on the characteristics of polarized Raman spectra were studied using an epitaxially grown PbTiO3 thin film in which the c-axis oriented domains coexist with the a-axis oriented domains on MgO (001). To obtain polarized spectra for both two distinctive c and a domains, we have employed scattering configurations in which the relevant phonon wave vector, k, is perpendicular to the c axis of the tetragonal unit cell. Compared with the mode frequencies of single-crystal PbTiO3, a softening of the E(TO) phonons was evident for both c and a domains, suggesting the presence of a strong tensile film stress. In addition to this, we observed a splitting of the degenerate “silent” mode into two distinctive B1 and E modes in an epitaxially grown film on MgO (001). © 2002 American Institute of Physics.
Show PACS
78.30.Hv Other nonmetallic inorganics
77.55.-g Dielectric thin films
78.66.Nk Insulators
77.80.Dj Domain structure; hysteresis
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
63.70.+h Statistical mechanics of lattice vibrations and displacive phase transitions

Bi3.25La0.75Ti3O12 thin films on ultrathin Al2O3 buffered Si for ferroelectric memory application

San-Yuan Chen, Chia-Liang Sun, Shi-Bai Chen, and Albert Chin

Appl. Phys. Lett. 80, 3168 (2002); http://dx.doi.org/10.1063/1.1471937 (3 pages) | Cited 13 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the physical and electrical properties of Bi3.25La0.75Ti3O12 (BLT) thin films on Pt/Ti/SiO2/Si and on Al2O3(6 nm)/Si, which are used for one-transistor-one-capacitor and one-transistor ferroelectric memory, respectively. The BLT thin films on both substrates show good capacitance–voltage characteristics and the same threshold voltage shift of 1.6 V at applied ±10 V bias. However, the leakage current of BLT on Al2O3/Si at −100 kV/cm is two orders of magnitude lower than that on Pt. The comparable memory characteristics and much reduced leakage current of BLT on Al2O3/Si are the strong advantages as compared with BLT on Pt because it is directly related to switching energy and device scaling down. © 2002 American Institute of Physics.
Show PACS
85.50.Gk Non-volatile ferroelectric memories
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Na0.5K0.5NbO3 thin films for voltage controlled acoustoelectric device applications

Choong-Rae Cho, Ilia Katardjiev, Michael Grishin, and Alex Grishin

Appl. Phys. Lett. 80, 3171 (2002); http://dx.doi.org/10.1063/1.1473689 (3 pages) | Cited 20 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Perovskite Na0.5K0.5NbO3 (NKN) thin films have been prepared on Y+36° cut single crystal quartz substrates using the pulsed laser ablation technique. X-ray diffraction θ–2θ and ω-scan data demonstrate almost perfectly c-axis oriented film textures with narrow mosaic broadening. Radio frequency dielectric spectroscopy showed that the films possess relatively high dielectric permittivities, low dielectric losses, and low frequency dispersions. Capacitance–voltage (C–V) measurements for a 2 μm slot NKN/quartz interdigital capacitor yield 23.1% tunability by applying 40 V bias at 1 MHz, while C–V hysteresis indicates polarization reversal. The considerable voltage tunability with superior crystallinity in piezoelectric NKN films on quartz substrates suggests their potential use for novel voltage tunable acoustoelectric devices. © 2002 American Institute of Physics.
Show PACS
72.50.+b Acoustoelectric effects
77.65.Dq Acoustoelectric effects and surface acoustic waves (SAW) in piezoelectrics
73.50.Rb Acoustoelectric and magnetoacoustic effects

Piezoelectric properties and phase transitions of 〈001〉-oriented Pb(Zn1/3Nb2/3)O3–PbTiO3 single crystals

W. Ren, S-F. Liu, and B. K. Mukherjee

Appl. Phys. Lett. 80, 3174 (2002); http://dx.doi.org/10.1063/1.1474600 (3 pages) | Cited 36 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electric-field-induced phase transitions and piezoelectric properties of 〈001〉-oriented Pb(Zn1/3Nb2/3)O3–xPbTiO3 single crystals for x = 4.5% and 8% (PZN–4.5%PT and PZN–8%PT) have been investigated as a function of temperature. It was found that the piezoelectric properties and phase transitions for both crystals are strongly dependent on temperature. The measurements of polarization and strain as a function of unipolar electric field show that the field for the rhombohedral–tetragonal phase transition decreases linearly with temperature in the range between 25 and 105 °C. Thus, raising the temperature can stabilize the tetragonal phase in 〈001〉-oriented PZN–PT crystals. Longitudinal piezoelectric constant d33 in the rhombohedral phase increases with temperature for both crystals; in PZN–4.5%PT the slope itself increases significantly at temperatures over 60 °C. In the field-induced tetragonal phase, there is little change in d33 for PZN–8%PT within the temperature range investigated, while in PZN–4.5%PT a slight increase of d33 with temperature was observed at temperatures above 80 °C. © 2002 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.65.Bn Piezoelectric and electrostrictive constants
64.70.K- Solid-solid transitions
77.80.-e Ferroelectricity and antiferroelectricity
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
77.22.Ej Polarization and depolarization

Suppressed boron penetration in p+ polycrystalline-Si/Al2O3/Si metal–oxide–semiconductor structures

Heung-Jae Cho, Dae-Gyu Park, Kwan-Yong Lim, Jung-Kyu Ko, In-Seok Yeo, Jin Won Park, and Jae-Sung Roh

Appl. Phys. Lett. 80, 3177 (2002); http://dx.doi.org/10.1063/1.1474603 (3 pages) | Cited 7 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a suppressed boron penetration in p+ polycrystalline-Si (poly-Si)/Al2O3/n-Si metal–oxide–semiconductor (MOS) capacitors using a remote plasma nitridation (RPN) of Al2O3 surface. The B penetration was sufficiently suppressed for temperature to 850 °C in N2 for 30 min as manifested by the negligible flat band shift (ΔVFB) and insignificant B diffusion. The nitrogen (N) incorporation in Al2O3 surface appears to effectively impede the B diffusion into the Si channel. Increased gate leakage current for the n+ poly-Si/RPN-Al2O3/p-Si n-type MOS capacitors was observed and attributed to the reduced band gap energy of RPN-Al2O3 due to the formation of AlN and bulk defects due to RPN. Optimization of N concentration is required for the suppressed B penetration and leakage reduction. © 2002 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.40.Ty Semiconductor-insulator-semiconductor structures
84.32.Tt Capacitors
66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.Fx Diffusion; interface formation

Determination of the optimal cation composition of ferroelectric (ZnxCd1−x)S thin films for applications to silicon-based nonvolatile memories

Y. Hotta, E. Rokuta, J.-H. Jhoi, H. Tabata, H. Kobayashi, and T. Kawai

Appl. Phys. Lett. 80, 3180 (2002); http://dx.doi.org/10.1063/1.1476710 (3 pages) | Cited 18 times

Online Publication Date: 22 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Thin films of ferroelectric binary mixed II–VI compounds such as (ZnxCd1−x)S, as well as (ZnyCd1−y)Te and (ZnzCd1−z)Se (0 ⩽ x,y,z ⩽ 1), were examined from the standpoint of the application to Si-based nonvolatile memories. Electronic-band discontinuities at the ferroelectric–Si interface decreased significantly with increase in the atomic number of the constituent chalcogenide atoms, which favored (ZnxCd1−x)S as the most potential gate ferroelectrics among the three compounds. Polarization-field (P–E) characteristics of the (ZnxCd1−x)S films were found to largely depend on the cation composition. No hysteretic behaviors in the P–E curves were observed for high-Zn concentrations above x = 0.5, while the P–E curves traced hysteretic loops due to the ferroelectricity for x<0.5. The remnant polarization was greatly dependent on the Zn concentration, and yielded a maximum of 0.03 μC/cm2 for x = 0.3. On the other hand, the coercive field was not composition dependent, and was approximately 12 kV/cm. © 2002 American Institute of Physics.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
68.55.Nq Composition and phase identification
77.55.-g Dielectric thin films
85.50.Gk Non-volatile ferroelectric memories
73.61.Ga II-VI semiconductors
77.80.Dj Domain structure; hysteresis
77.22.Ej Polarization and depolarization
73.20.At Surface states, band structure, electron density of states
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close