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

15 Sep 2003

Volume 83, Issue 11, pp. 2091-2291

Issue Cover Spotlight Figure

Appl. Phys. Lett. 83, 2244 (2003); http://dx.doi.org/10.1063/1.1610259 (3 pages)

X.-M. Meng, Y. Jiang, J. Liu, C.-S. Lee, I. Bello, and S.-T. Lee
Enlarge Image | Read More
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Orientation dependent microwave dielectric properties of ferroelectric Ba1−xSrxTiO3 thin films

Seung Eon Moon, Eun-Kyoung Kim, Min-Hwan Kwak, Han-Cheol Ryu, Young-Tae Kim, Kwang-Yong Kang, Su-Jae Lee, and Won-Jeong Kim

Appl. Phys. Lett. 83, 2166 (2003); http://dx.doi.org/10.1063/1.1609658 (3 pages) | Cited 49 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of anisotropic dielectric properties of ferroelectric Ba1−xSrxTiO3 (BST) films on the characteristics of the interdigital (IDT) capacitors have been studied in microwave regions at room temperature. Ferroelectric BST films with (001), (011), and (111) orientation were epitaxially grown on (001), (011), and (111) MgO substrates, respectively, by the pulsed laser deposition method. The microwave properties of orientation engineered BST films were investigated using interdigital capacitors. The calculated dielectric constant tunability with 40 V dc bias variation and the calculated dielectric quality factor values for IDT capacitors based on (001), (011), and (111) oriented BST films at 9 GHz with no dc bias were about 47%, 55%, 43%, and 12, 14, 21, respectively. © 2003 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
77.22.Ch Permittivity (dielectric function)
77.22.Gm Dielectric loss and relaxation

Electron dynamics in InNxSb1−x

I. Mahboob, T. D. Veal, and C. F. McConville

Appl. Phys. Lett. 83, 2169 (2003); http://dx.doi.org/10.1063/1.1611270 (3 pages) | Cited 6 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Electron transport properties in InNxSb1−x are investigated for a range of alloy compositions. The band structure of InNxSb1−x is modeled using a modified k⋅p Hamiltonian. This enables the semiconductor statistics for a given x value to be calculated from the dispersion relation of the E− subband. These calculations reveal that for alloy compositions in the range 0.001 ⩽ x ⩽ 0.02 there is only a small variation of the carrier concentration at a given plasma frequency. A similar trend is observed for the effective mass at the Fermi level. Measurements of the plasma frequency and plasmon lifetime for InNxSb1−x alloys enable the carrier concentration and the effective mass at the Fermi level to be determined and a lower limit for the electron mobility to be estimated. © 2003 American Institute of Physics.
Show PACS
71.20.Nr Semiconductor compounds
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
71.15.-m Methods of electronic structure calculations
72.20.Ee Mobility edges; hopping transport
72.20.Fr Low-field transport and mobility; piezoresistance

Chemistry and band offsets of HfO2 thin films for gate insulators

M. Oshima, S. Toyoda, T. Okumura, J. Okabayashi, H. Kumigashira, K. Ono, M. Niwa, K. Usuda, and N. Hirashita

Appl. Phys. Lett. 83, 2172 (2003); http://dx.doi.org/10.1063/1.1611272 (3 pages) | Cited 43 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Interfacial chemistry and band offsets of HfO2 films grown on Si(100) substrates are investigated using high-resolution angle-resolved photoelectron spectroscopy and are correlated with interfacial structures revealed by transmission electron microscope. Hf 4f and O 1s spectra show similar chemical shifts indicating the existence of a double layer structure consisting of a HfO2, upper layer and a SiO2-rich Hf1−xSixO2 lower layer. Two types of valence band offsets are clearly determined by a double subtraction method to be 3.0 and 3.8 eV that can be attributed to ΔEv1 for the upper layer HfO2/Si and ΔEv2 for the lower layer Hf1−xSixO2/Si, respectively. © 2003 American Institute of Physics.
Show PACS
73.20.At Surface states, band structure, electron density of states
79.60.Jv Interfaces; heterostructures; nanostructures
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
68.35.Ct Interface structure and roughness

Magnetic properties of heavily Mn-doped quaternary alloy ferromagnetic semiconductor (InGaMn)As grown on InP

Shinobu Ohya, Hideo Kobayashi, and Masaaki Tanaka

Appl. Phys. Lett. 83, 2175 (2003); http://dx.doi.org/10.1063/1.1610788 (3 pages) | Cited 20 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF


See Also: Publisher's Note

Show Abstract
We have studied magnetic properties of heavily Mn-doped [(In0.44Ga0.56)0.79Mn0.21]As thin films grown by low-temperature molecular-beam epitaxy on InP substrates. (InGaMn)As with high Mn content (21%) was obtained by decreasing the growth temperature to 190 °C. When the thickness of the [(In0.44Ga0.56)0.79Mn0.21]As layer is equal or thinner than 10 nm, the reflection high-energy electron diffraction pattern and transmission electron microscopy show no MnAs clustering, indicating that a homogeneous single crystal was grown. Magnetic circular dicroism characterizations, as well as transport and magnetization measurements, indicate that the Curie temperature is 125–130 K. © 2003 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
78.20.Ls Magneto-optical effects
78.66.Fd III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Determination of the electronic conductivity of polybithiophene films at different doping levels using in situ electrochemical impedance measurements

Germà Garcia-Belmonte, Juan Bisquert, and George S. Popkirov

Appl. Phys. Lett. 83, 2178 (2003); http://dx.doi.org/10.1063/1.1609657 (3 pages) | Cited 4 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This letter presents in situ electronic conductivity measurements of polybithiophene films using a twin working electrode in an electrochemical configuration. A twin electrode is made of two metallic stripes which are separated by a few micrometers by an insulating gap. As the polymer doping level depends on the bias potential maintained between counter- and working electrodes, changes of electronic density of many orders of magnitude (from 1016 up to 1020 cm−3 in the potential window investigated) can be achieved using this experimental technique. A simple impedance model based on electronic (polaronic) diffusion between absorbing contacts accounts for the measured impedance spectra. The dependence of low-frequency conductivity σdc with bias potential E at low doping levels follows the relationship ln σdc∝E/2kBT, which allows one to regard it as a double contribution, simultaneously electronic and ionic, to the thermodynamics of doping. It has also been possible to calculate the electronic chemical diffusion coefficient from the diffusion characteristic frequency ωd, which results within the range of De ∼ 4–1×10−3 cm2 s−1. © 2003 American Institute of Physics.
Show PACS
73.61.Ph Polymers; organic compounds
72.15.Nj Collective modes (e.g., in one-dimensional conductors)
71.20.Rv Polymers and organic compounds

Spin splitting in narrow InAs quantum wells with In0.75Ga0.25As barrier layers

C. H. Möller, Ch. Heyn, and D. Grundler

Appl. Phys. Lett. 83, 2181 (2003); http://dx.doi.org/10.1063/1.1610790 (3 pages) | Cited 15 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using two independent magnetotransport experiments, i.e., thermal activation and the coincidence method in tilted fields, we determine the g factor in a two-dimensional electron system in a 4-nm-wide InAs quantum well. From these independent techniques we deduce consistently an absolute value ∣gexp∣ ≅ 6. This is considerably smaller if compared to ∣g∣ = 14.8 for bulk InAs. Nonparabolicity in InAs cannot fully explain the reduced g factor. We argue that the penetration of the wave function into the In0.75Ga0.25As barriers and into the In0.75Al0.25As spacer layer plays an additional role. © 2003 American Institute of Physics.
Show PACS
73.63.Hs Quantum wells
73.21.Fg Quantum wells
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor

Probing carriers in two-dimensional systems with high spatial resolution by scanning spreading resistance microscopy

K. Maknys, O. Douhéret, and S. Anand

Appl. Phys. Lett. 83, 2184 (2003); http://dx.doi.org/10.1063/1.1611619 (3 pages) | Cited 16 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this work, cross-sectional scanning spreading resistance microscopy (SSRM) is used to profile carriers in quantum wells (QWs). The investigated structures consist of InGaAs wells of different widths sandwiched between Si-doped InP barriers. It is demonstrated that SSRM is indeed capable of detecting electrons in the quantum wells with high lateral resolution and that the SSRM signal shows a systematic trend for the different wells. Clear dips in the resistance signal are observed at the quantum wells and imply accumulated electron densities higher than in the surrounding barriers. Carrier density in the QW is found by using the calibration curve obtained from the resistance measurements on reference layers sample. It is also shown that only at certain appropriate tip-sample bias conditions the depletion regions in the barriers adjacent to the wells are resolved. Finally, we demonstrate that under very low forward biases the full width at half maximum of the observed resistance dips in SSRM data is nearly equal to the geometric QW widths. © 2003 American Institute of Physics.
Show PACS
73.63.Hs Quantum wells
84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
back to top
RSS Feeds

Microwave distribution in stacked Bi2Sr2CaCu2O8+x intrinsic Josephson junctions in a transmission-line geometry

Myung-Ho Bae, Hu-Jong Lee, Jinhee Kim, and Kyu-Tae Kim

Appl. Phys. Lett. 83, 2187 (2003); http://dx.doi.org/10.1063/1.1610258 (3 pages) | Cited 4 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The microwave distribution inside a rectangular stack (15 μm×0.72 μm×60 nm) of Bi2Sr2CaCu2O8+x intrinsic Josephson junctions (IJJs) was studied. The stack was microfabricated into a transmission-line geometry, with a-few-hundred-nm-thick Au layers deposited on the top and bottom of the stack. The microwave distribution was monitored by measuring the anomalous suppression of the tunneling critical current of the IJJs with varied microwave power at frequencies in the W band. This technique can provide valuable information on the microwave transmission modes inside the sandwiched stack of IJJs, which is utterly important for the high-frequency device applications using IJJs, such as fluxon-flow THz oscillators. © 2003 American Institute of Physics.
Show PACS
74.50.+r Tunneling phenomena; Josephson effects
84.40.Az Waveguides, transmission lines, striplines
74.72.-h Cuprate superconductors
74.25.N- Response to electromagnetic fields
74.25.Sv Critical currents

Local thermometry technique based on proximity-coupled superconductor/normal-metal/superconductor devices

Z. Jiang, H. Lim, V. Chandrasekhar, and J. Eom

Appl. Phys. Lett. 83, 2190 (2003); http://dx.doi.org/10.1063/1.1611259 (3 pages) | Cited 8 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In mesoscopic superconductor/normal-metal/superconductor heterostructures, it is known that the resistance of the normal metal between the superconductors has a strong temperature dependence. Based on this phenomenon, we have developed a type of thermometer, which dramatically enhances our ability to measure the local electron temperature Te at low temperatures. Using this technique, we have been able to measure small temperature gradients across a micron-size sample, opening up the possibility of quantitatively measuring the thermal properties of mesoscopic devices. © 2003 American Institute of Physics.
Show PACS
07.20.Dt Thermometers
74.45.+c Proximity effects; Andreev reflection; SN and SNS junctions
85.25.Cp Josephson devices

Meissner state of high-Tc oxide thin films observed by scanning superconducting quantum interference device microscopy

I. Iguchi, T. Takeda, A. Sugimoto, T. Imaizumi, H. Haibara, and T. Kawai

Appl. Phys. Lett. 83, 2193 (2003); http://dx.doi.org/10.1063/1.1599624 (3 pages)

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic level of the Meissner state in high-Tc oxide thin films is investigated using scanning superconducting quantum interference device microscopy. We find that the Meissner level observed is not uniquely determined and shifts with the temperature and depends on the doping level of individual oxide films. The result at higher temperature may be interpreted by a grain-coupled model which reflects the granular nature of high-Tc oxides and is useful for evaluation of high-Tc film quality. © 2003 American Institute of Physics.
Show PACS
74.25.Ha Magnetic properties including vortex structures and related phenomena
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
85.25.Dq Superconducting quantum interference devices (SQUIDs)

Promotion of L10 ordered phase transformation by the Ag top layer on FePt thin films

Z. L. Zhao, J. Ding, K. Inaba, J. S. Chen, and J. P. Wang

Appl. Phys. Lett. 83, 2196 (2003); http://dx.doi.org/10.1063/1.1611280 (3 pages) | Cited 43 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The influence of the deposition of an ultrathin Ag top layer on the structure and magnetic properties of FePt thin films has been investigated. Crystallographic ordering of the L10 face-centered-tetragonal (fct) FePt phase was significantly promoted when a Ag layer was deposited on top of the film. The increased fraction of hard magnetic L10 fct FePt phase led to a dramatic increase of coercivity from 1 to about 6.0 kOe. The δM curves suggested exchange decoupling of magnetic grains. A perpendicular FePt film with a coercivity of 5.0 kOe and remanent squareness of 0.98 was achieved with a CrRu underlayer and the Ag top layer. © 2003 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Bb Fe and its alloys
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
68.55.Nq Composition and phase identification
68.35.Rh Phase transitions and critical phenomena
75.30.Et Exchange and superexchange interactions

Co-doped La0.5Sr0.5TiO3−δ: Diluted magnetic oxide system with high Curie temperature

Y. G. Zhao, S. R. Shinde, S. B. Ogale, J. Higgins, R. J. Choudhary, V. N. Kulkarni, R. L. Greene, T. Venkatesan, S. E. Lofland, C. Lanci, J. P. Buban, N. D. Browning, S. Das Sarma, and A. J. Millis

Appl. Phys. Lett. 83, 2199 (2003); http://dx.doi.org/10.1063/1.1610796 (3 pages) | Cited 29 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ferromagnetism is observed at and above room temperature in pulsed laser deposited epitaxial films of Co-doped Ti-based oxide perovskite (La0.5Sr0.5TiO3−δ). The system has the characteristics of an intrinsic diluted magnetic semiconductor (metal) at low concentrations (< ∼ 2%), but develops inhomogeneity at higher cobalt concentrations. The films range from being opaque metallic to transparent semiconducting depending on the oxygen pressure during growth and are yet ferromagnetic. © 2003 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.50.Pp Magnetic semiconductors
81.15.Fg Pulsed laser ablation deposition
75.50.Dd Nonmetallic ferromagnetic materials

Indirect exchange coupling between two ferromagnetic electrodes through ZnS barrier in magnetic tunnel junctions

A. Dinia, P. Carrof, G. Schmerber, and C. Ulhacq

Appl. Phys. Lett. 83, 2202 (2003); http://dx.doi.org/10.1063/1.1610257 (3 pages)

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Room- and low-temperature magnetization measurements have been performed on magnetic tunnel junctions before patterning to evidence the presence of an indirect ferromagnetic exchange interaction between the hard and the soft ferromagnetic electrodes through the ZnS barrier. The magnetic junctions are composed of an artificial ferrimagnet CoFe/Ru/CoFe sandwich as a hard layer separated by a ZnS barrier from a soft CoFe/Fe soft layer as follows: Fe6 nmCu3 nm(CoFe)1.8 nmRu0.8 nm(CoFe)3 nmZnSx nmCoFe1 nmFe4 nmCu1 nmRu3 nm. At room temperature, a large shift of about −25 Oe is observed in a magnetization minor loop that indicates the presence of a ferromagnetic interaction. The decrease of the amplitude of this shift at low temperature provides a signature of an indirect exchange coupling mediated by spin-polarized quantum tunneling. © 2003 American Institute of Physics.
Show PACS
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
75.50.Bb Fe and its alloys
75.30.Et Exchange and superexchange interactions
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Ww Permanent magnets

Current-induced precessional magnetization reversal

H. W. Schumacher, C. Chappert, R. C. Sousa, and P. P. Freitas

Appl. Phys. Lett. 83, 2205 (2003); http://dx.doi.org/10.1063/1.1610797 (3 pages) | Cited 8 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report magnetization reversal in microscopic current-in-plane spin valves by ultrashort current pulses through the device. Current densities of the order of 1011 A/m2 with pulse durations as short as 120 ps reliably and reversibly switch the cell’s free-layer magnetization. Variations of the pulse parameters reveal the full signature of precessional switching, which is triggered by the transverse magnetic field generated by the device current. This current switching mode allows for the design of a two-terminal nonvolatile magnetic memory cell combining ultrafast access times and high magnetoresistive readout. © 2003 American Institute of Physics.
Show PACS
75.60.Jk Magnetization reversal mechanisms
75.47.De Giant magnetoresistance
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
85.75.Bb Magnetic memory using giant magnetoresistance

Microchemistry and magnetization reversal mechanism in melt-spun 2:17-type Sm-Co magnets

A. Yan, O. Gutfleisch, T. Gemming, and K.-H. Müller

Appl. Phys. Lett. 83, 2208 (2003); http://dx.doi.org/10.1063/1.1611641 (3 pages) | Cited 12 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The stability of microstructure and of microchemistry in melt-spun precipitation-hardened Sm(Co,Fe,Cu,Zr)z magnets at high temperature and its effect on the magnetic properties, especially the coercivity at room temperature, were investigated by transmission electron microscopy, nanoprobe chemical analysis, and magnetic measurements. A very large gradient of the Cu content within the 1:5-type cell boundary phase was observed in highly coercive melt-spun Sm(Co,Fe,Cu,Zr)z magnets with uniform cellular structure. After an additional isothermal aging at 850 °C for 5 min, the coercivity is reduced dramatically from 3 T to 0.16 T. This is accompanied by the disappearance of the large gradient of Cu content within the cell boundary phase. Thus, it is proposed that the high coercivity in 2:17 Sm-Co magnets originates from the large gradient of domain wall energy within the Sm(Co,Cu)5 cell boundary phase. This gradient is caused by a very rapid phase separation taking place within the cell boundary phase during slow cooling. © 2003 American Institute of Physics.
Show PACS
75.60.Jk Magnetization reversal mechanisms
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.50.Vv High coercivity materials
75.50.Bb Fe and its alloys
81.40.Cd Solid solution hardening, precipitation hardening, and dispersion hardening; aging
75.60.Ch Domain walls and domain structure
64.75.-g Phase equilibria
back to top
RSS Feeds

Ferroelectric epitaxial nanocrystals obtained by a self-patterning method

I. Szafraniak, C. Harnagea, R. Scholz, S. Bhattacharyya, D. Hesse, and M. Alexe

Appl. Phys. Lett. 83, 2211 (2003); http://dx.doi.org/10.1063/1.1611258 (3 pages) | Cited 70 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Lead zirconate titanate nanoislands were obtained by a self-patterning method making use of the instability of ultrathin films during high-temperature treatments. After high-temperature annealing, the as-deposited film breaks into islands with a narrow size distribution. The single-crystal nanoislands were studied by scanning and high-resolution transmission electron microscopy, atomic force microscopy, and x-ray diffraction. They show an epitaxial relationship with the Nb-doped (001) SrTiO3 substrate. The ferroelectric switching of several individual islands was investigated by piezoresponse force microscopy. © 2003 American Institute of Physics.
Show PACS
77.80.Fm Switching phenomena
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
61.46.-w Structure of nanoscale materials
68.37.Lp Transmission electron microscopy (TEM)
68.37.Ps Atomic force microscopy (AFM)

Ferroelectricity in Mn-implanted CdTe

D. J. Fu, J. C. Lee, S. W. Choi, C. S. Park, G. N. Panin, T. W. Kang, and X. J. Fan

Appl. Phys. Lett. 83, 2214 (2003); http://dx.doi.org/10.1063/1.1610789 (3 pages) | Cited 10 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
CdTe:Mn was prepared by implantation of CdTe with 200 keV Mn ions with a dose of 5×1016 cm−2, which produced an insulating layer in the surface region. Ferroelectric characterization of the implanted sample revealed a clear hysteresis in its polarization–voltage curves. The remnant polarization of CdTe:Mn amounts to 0.64 μC/cm2 at 400 Hz, and it decreases with increasing temperature in a continuous and diffusive manner. Capacitance measurement demonstrated a maximum capacitance at 140 °C, and fitting of the data with Curie–Weiss law shows the occurrence of a second-order-type phase transition. The ferroelectricity is accounted for by the cation size difference in CdTe:Mn. © 2003 American Institute of Physics.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.80.Dj Domain structure; hysteresis
77.22.Ej Polarization and depolarization
77.80.B- Phase transitions and Curie point
61.72.uj III-V and II-VI semiconductors

Observation of ferroelectromagnetic nature in rare-earth-substituted bismuth iron titanate

A. Srinivas, Dong-Wan Kim, Kug Sun Hong, and S. V. Suryanarayana

Appl. Phys. Lett. 83, 2217 (2003); http://dx.doi.org/10.1063/1.1610255 (3 pages) | Cited 25 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Rare earth ions; Nd, Sm, Gd, and Dy, are substituted at the bismuth site in bismuth iron titanate, a four-layered compound which belongs to bismuth layer structured ferroelectrics. A solid-state sintering route was adopted in synthesizing the materials. X-ray diffraction indicates the formation of single-phase materials. The dielectric measurements showed the anomalies at high temperatures. Dynamic magnetoelectric measurements showed magnetoelectric output at room temperature and at low temperatures. Thus, the material is ferroelectromagnetic in nature. © 2003 American Institute of Physics.
Show PACS
75.80.+q Magnetomechanical effects, magnetostriction
77.80.-e Ferroelectricity and antiferroelectricity
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates

Ferroelectric switching of strontium–barium–niobate crystals in pulsed fields

T. Volk, D. Isakov, L. Ivleva, and M. Wöhlecke

Appl. Phys. Lett. 83, 2220 (2003); http://dx.doi.org/10.1063/1.1606871 (3 pages) | Cited 18 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In strontium–barium–niobate (SBN) polarization and switching processes under pulsed field differ from those in model ferroelectrics. In most SBN crystals, the polarization changes smoothly with relaxation times up to seconds even under fields strongly exceeding the coercive field. The kinetics are described with a power law. In some samples of a variety of compositions faster changes have been observed, but their characteristics fundamentally differ from those in model ferroelectrics. The peculiarities are evidently caused by the relaxor properties of SBN. © 2003 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
77.22.Ej Polarization and depolarization
77.22.Gm Dielectric loss and relaxation

Percolation path and dielectric-breakdown-induced-epitaxy evolution during ultrathin gate dielectric breakdown transient

Chih Hang Tung, Kin Leong Pey, Lei Jun Tang, M. K. Radhakrishnan, Wen He Lin, Felix Palumbo, and Salvatore Lombardo

Appl. Phys. Lett. 83, 2223 (2003); http://dx.doi.org/10.1063/1.1611649 (3 pages) | Cited 21 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A physical model has been developed which complies with the experimental observation on the failure mechanism of ultrathin gate oxide breakdown during constant voltage stress. Dynamic equilibrium needs to be established between the percolation conductive path and the dielectric breakdown induced epitaxy (DBIE) formation during gate dielectric breakdown transient. The model is capable of linking the percolation model, soft breakdown, and hard breakdown to the DBIE growth for a variety of stress conditions and gate oxide thickness without involving new empirical parameters. © 2003 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
77.22.Jp Dielectric breakdown and space-charge effects
85.40.Qx Microcircuit quality, noise, performance, and failure analysis

Low dielectric constant porous diamond films formed by diamond nanoparticles

Hiroyuki Sakaue, Noriyoshi Yoshimura, Shoso Shingubara, and Takayuki Takahagi

Appl. Phys. Lett. 83, 2226 (2003); http://dx.doi.org/10.1063/1.1609659 (3 pages) | Cited 4 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The reduction of the dielectric constant of interlayer insulating films in ultra large scale integrated circuits is an important factor in improving resistance-capacitance delay. A “porous diamond” film, composed of nanoscale diamond particles, is proposed as a material with a low dielectric constant, and is prepared by spin coating a 5% diamond colloidal solution mixed by 4 nm diamond nanoparticles in purified water. High-resolution scanning electron microscope observations show that the film contains nanoscale pores. The mechanical strength and adhesion of the porous diamond films were improved by forming the chemical bonds between diamond nanoparticles and also between the nanoparticles and the substrate. The chemical bonds were created by introducing a bi-functional silane coupler such as hexachlorodisiloxan molecules followed by annealing at 300 °C. A low dielectric constant of 1.63, estimated from the refractive index, was obtained by using high purity diamond nanoparticles after the reinforcing process by hexachlorodisiloxan. The porous diamond films are expected to have a higher thermal stability and a superior mechanical strength compared with other porous low dielectric constant materials. © 2003 American Institute of Physics.
Show PACS
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.-g Dielectric thin films
77.22.Ch Permittivity (dielectric function)
68.60.Bs Mechanical and acoustical properties
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
81.40.Gh Other heat and thermomechanical treatments
68.60.Dv Thermal stability; thermal effects

Electrical and physical properties of HfO2 films prepared by remote plasma oxidation of Hf metal

Kazuhiko Yamamoto, Shigenori Hayashi, Masaaki Niwa, Masayuki Asai, Sadayoshi Horii, and Hironobu Miya

Appl. Phys. Lett. 83, 2229 (2003); http://dx.doi.org/10.1063/1.1609246 (3 pages) | Cited 42 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electrical and physical properties of thin hafnium oxide (HfO2) films fabricated by a remote plasma oxidation of a hafnium metal were investigated. The HfO2 capacitors with TiN electrodes exhibited excellent electrical characteristics such as equivalent oxide thickness (EOT) of 0.65 nm with leakage current density of 2.7 A/cm2 at the gate bias of Vfb-1 (V). The HfO2 thickness dependence of the EOT demonstrated that the permittivity of 19 for HfO2 layer and the interfacial layer thickness of 0.36 nm. X-ray photoelectron spectroscopy study revealed that the oxygen radicals oxidize the Hf metal selectively than Si substrate, leading to an increase of permittivity of HfO2 with reduced interfacial layer growth. © 2003 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
81.65.Mq Oxidation
52.77.-j Plasma applications
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
84.32.Tt Capacitors
77.22.Ch Permittivity (dielectric function)
back to top
RSS Feeds

High sensitive detection of near-infrared absorption by surface plasmon resonance

Akifumi Ikehata, Xiaoling Li, Tamitake Itoh, Yukihiro Ozaki, and Jian-Hui Jiang

Appl. Phys. Lett. 83, 2232 (2003); http://dx.doi.org/10.1063/1.1610812 (3 pages) | Cited 7 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter we report on an operative method for high sensitive measurement of near-infrared absorption based on a surface plasmon resonance (SPR) technique. By coupling with the SPR of a gold film, an absorption band of water near 5173 cm−1 assigned to a combination of the stretching and bending modes of OH groups is enhanced over 100 times compared with a case without the gold film. In addition, positive and negative enhancements of an absorption depending on the thickness of a gold film were observed as predicted by H. Kano et al. [Appl. Opt. 33, 5166 (1994)]. These experimental results are mathematically well reproduced by use of Fresnel multiple-reflection theory. © 2003 American Institute of Physics.
Show PACS
78.30.-j Infrared and Raman spectra
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
78.66.Bz Metals and metallic alloys
68.35.Ja Surface and interface dynamics and vibrations

Stark-shift modulation absorption spectroscopy of single quantum dots

Benito Alén, Florian Bickel, Khaled Karrai, Richard J. Warburton, and Pierre M. Petroff

Appl. Phys. Lett. 83, 2235 (2003); http://dx.doi.org/10.1063/1.1609243 (3 pages) | Cited 71 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Excitonic interband optical transitions within single InAs self-assembled quantum dots have been directly observed in a transmission experiment at 4.2 K. Using Stark shift, the excitonic energy levels of a single quantum dot are tuned into resonance with a narrow-band laser line. The Stark shift is also modulated at low frequencies. Relative changes in transmission can be detected this way down to one part per million. The oscillator strength as well the homogeneous linewidth of the transition is obtained. © 2003 American Institute of Physics.
Show PACS
78.67.Hc Quantum dots
78.20.Jq Electro-optical effects
71.35.Cc Intrinsic properties of excitons; optical absorption spectra

Sharp exciton emission from single InAs quantum dots in GaAs nanowires

Nikolay Panev, Ann I. Persson, Niklas Sköld, and Lars Samuelson

Appl. Phys. Lett. 83, 2238 (2003); http://dx.doi.org/10.1063/1.1611261 (3 pages) | Cited 41 times

Online Publication Date: 9 September 2003

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have performed photoluminescence spectroscopy on single GaAs nanowires with InAs quantum dots in the form of thin slices of InAs, possibly alloyed with Ga as InGaAs, incorporated into the GaAs. The nanowires were grown by chemical beam epitaxy using gold nanoparticles as catalysts. The photoluminescence measurements showed rich spectra consisting of sharp lines with energies and excitation power dependency behavior very similar to that observed for Stranski–Krastanow-grown InAs/GaAs quantum dots. By reducing the excitation power density we were able to obtain a quantum dot spectrum consisting of only one single sharp line—the exciton line. © 2003 American Institute of Physics.
Show PACS
73.21.La Quantum dots
78.67.Hc Quantum dots
71.35.-y Excitons and related phenomena
78.55.Cr III-V semiconductors
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close