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

6 May 2002

Volume 80, Issue 18, pp. 3247-3450

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

Phonons on GaN(110)

H. M. Tütüncü, R. Miotto, G. P. Srivastava, and J. S. Tse

Appl. Phys. Lett. 80, 3322 (2002); http://dx.doi.org/10.1063/1.1476401 (3 pages) | Cited 1 time

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present results of adiabatic bond-charge model calculations for the vibrational properties of the GaN(110) surface using electronic and structural data obtained from a first-principles pseudopotential method. It is found that in order to relate the energy locations of optical phonon modes on this surface with corresponding modes on nonnitride III–V(110) and II–VI(110) surfaces, it is necessary to consider scaling of results with the lattice constant in addition to the reduced mass. © 2002 American Institute of Physics.
Show PACS
68.35.Ja Surface and interface dynamics and vibrations

In situ ordering of FePt thin films with face-centered-tetragonal (001) texture on Cr100−xRux underlayer at low substrate temperature

Yingfan Xu, J. S. Chen, and J. P. Wang

Appl. Phys. Lett. 80, 3325 (2002); http://dx.doi.org/10.1063/1.1476706 (3 pages) | Cited 114 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In situ ordered FePt thin films with face-centered-tetragonal (fct)-(001) texture have been prepared by magnetron sputtering the FePt layer onto the Cr100−xRux underlayer at relatively low temperature. The dependence of FePt texture on the Ru content in the Cr underlayer and the substrate temperature is investigated. Addition of Ru in Cr underlayer results in the formation of the FePt ordered phase in a lower substrate temperature (350 °C) with c-axis orientation perpendicular to the film plane. Good perpendicular magnetic properties are obtained in films with Cr91Ru9 underlayer. A thin Pt intermediate layer is introduced between the FePt layer and the CrRu underlayer, which is found to effectively resist the Cr diffusion from the CrRu underlayer into the FePt layer and results in better FePt fct-(001) texture and improved magnetic properties. © 2002 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Ss Magnetic recording materials
81.15.Cd Deposition by sputtering
68.55.-a Thin film structure and morphology
75.30.Gw Magnetic anisotropy
68.35.Fx Diffusion; interface formation

Lattice distortions and the transmuted-Ge related luminescence in neutron-transmutation-doped GaN

K. Kuriyama, T. Tokumasu, Jun Takahashi, H. Kondo, and M. Okada

Appl. Phys. Lett. 80, 3328 (2002); http://dx.doi.org/10.1063/1.1477269 (3 pages) | Cited 12 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The lattice distortion and the transmuted-Ge related luminescence in neutron-transmutation-doped (NTD) GaN are studied by combining Rutherford backscattering spectroscopy/channeling, Raman scattering, and photoluminescence methods. The lattice displacement of Ga atoms of ∼ 0.12 Å from the 〈0001〉 row is estimated from the normalized angular yield profiles, preserving the single crystallinity in as-irradiated GaN with a minimum yield (χmin) of 7%. A 2.84 eV emission band observed in 600 °C annealed NTD-GaN is associated with the Ga interstitial, supporting the lattice distortion. Two emission bands at 2.90 eV and 2.25 eV observed in 1000 °C annealed NTD-GaN are assigned to a negatively charged DX-like center of Ge at Ga site and a complex defect attributed to Ge at Ga site and Ga vacancy, respectively. © 2002 American Institute of Physics.
Show PACS
61.72.uj III-V and II-VI semiconductors
61.82.Fk Semiconductors
78.55.Cr III-V semiconductors
61.80.Hg Neutron radiation effects
71.55.Eq III-V semiconductors
78.30.Fs III-V and II-VI semiconductors
78.66.Fd III-V semiconductors
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
61.72.J- Point defects and defect clusters
61.72.Cc Kinetics of defect formation and annealing
back to top
RSS Feeds

G-quartet biomolecular nanowires

A. Calzolari, R. Di Felice, E. Molinari, and A. Garbesi

Appl. Phys. Lett. 80, 3331 (2002); http://dx.doi.org/10.1063/1.1476700 (3 pages) | Cited 31 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We present a first-principle investigation of quadruple helix nanowires, consisting of stacked planar hydrogen-bonded guanine tetramers. Our results show that long wires form and are stable in potassium-rich conditions. We present their electronic band structure and discuss the interpretation in terms of effective wide-band-gap semiconductors. The microscopic structural and electronic properties of the guanine quadruple helices make them suitable candidates for molecular nanoelectronics. © 2002 American Institute of Physics.
Show PACS
85.65.+h Molecular electronic devices

Si–SiO2 barrier height and its temperature dependence in metal-oxide-semiconductor structures with ultrathin gate oxide

A. Hadjadj, O. Simonetti, T. Maurel, G. Salace, and C. Petit

Appl. Phys. Lett. 80, 3334 (2002); http://dx.doi.org/10.1063/1.1476709 (3 pages) | Cited 4 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The potential distribution across n+ polycristalline silicon (poly-Si)/SiO2/Si(p) structures, with an oxide layer thinner than 4 nm, was determined using a full quantum self-consistent model. When applied to capacitance–voltage measurements, it allows an accurate determination of the oxide thickness tox to be made. When applied to current–voltage measurements, in the Fowler–Nordheim regime, it leads to an accurate determination of the barrier height Φ at the interface between the emitting poly-Si gate electrode and the oxide, over a temperature range 20–250 °C. The results show a constant Φ(0 K) for 3 nm<tox ⩽ 9 nm. However, the temperature sensitivity ∣dΦ/dT∣ increases from 0.35 to 0.7 meV/K with tox reduction. © 2002 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
73.40.Gk Tunneling
73.50.Fq High-field and nonlinear effects
71.15.Mb Density functional theory, local density approximation, gradient and other corrections

Estimation of the impact of electrostatic discharge on density of states in hydrogenated amorphous silicon thin-film transistors

Natasa Tosic Golo, Siebrigje van der Wal, Fred G. Kuper, and Ton Mouthaan

Appl. Phys. Lett. 80, 3337 (2002); http://dx.doi.org/10.1063/1.1476394 (3 pages) | Cited 2 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The objective of this letter is to give an estimation of the impact of an electrostatic discharge (ESD) stress on the density of states (DOS) within the energy gap of hydrogenated amorphous silicon (a-Si:H) thin-film transistors. ESD stresses were applied by means of a transmission line model tester. The DOS in the a-Si:H was determined by Suzuki’s algorithm using field-effect conductance measurements. A comparison of stressed and unstressed devices shows that there is a threshold ESD stress voltage, below which there is no damage. Above the threshold stress level, first an increase of the deep gap states is found and when stress is increased further, also in the tail states. © 2002 American Institute of Physics.
Show PACS
85.30.Tv Field effect devices
71.23.Cq Amorphous semiconductors, metallic glasses, glasses
41.20.Cv Electrostatics; Poisson and Laplace equations, boundary-value problems
85.30.De Semiconductor-device characterization, design, and modeling
71.55.Jv Disordered structures; amorphous and glassy solids

Combining a scanning near-field optical microscope with a picosecond streak camera: Statistical analysis of exciton kinetics in GaAs single-quantum wells

U. Neuberth, L. Walter, G. von Freymann, B. Dal Don, H. Kalt, M. Wegener, G. Khitrova, and H. M. Gibbs

Appl. Phys. Lett. 80, 3340 (2002); http://dx.doi.org/10.1063/1.1477274 (3 pages) | Cited 10 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Combining a low-temperature scanning near-field optical microscope with a picosecond streak camera allows us to measure the complete wavelength-time behavior at one spot on the sample within about 13 min at excitation powers of 100 nW. We use this instrument to measure the variation of relaxation times in disordered single-GaAs quantum wells with sample position. © 2002 American Institute of Physics.
Show PACS
73.21.Fg Quantum wells
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
71.35.Lk Collective effects (Bose effects, phase space filling, and excitonic phase transitions)
68.37.Uv Near-field scanning microscopy and spectroscopy
78.47.-p Spectroscopy of solid state dynamics
07.68.+m Photography, photographic instruments; xerography

Interaction between low-energy electrons and defects created by hot holes in ultrathin silicon dioxide

Eric M. Vogel, Dawei Heh, and Joseph B. Bernstein

Appl. Phys. Lett. 80, 3343 (2002); http://dx.doi.org/10.1063/1.1471376 (3 pages) | Cited 4 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The interaction of injected electrons with defects created by hot holes in 2.0-nm-thick silicon dioxide is studied using substrate hot hole injection and concomitant electron tunneling. The ratio of injected hot holes to electrons is varied from approximately 10−3 to 100 by changing the forward biased substrate hot hole injector voltage. Increased bulk and interfacial degradation caused by the interaction of concomitantly injected electrons with defects created by hole injection is not observed for the experimental conditions studied. The ability of defects to produce catastrophic breakdown is also not affected. The results suggest that the interaction of tunneling electrons with defects created by hot holes is not a viable mechanism for explaining the catastrophic breakdown of the oxide layer in field-effect transistors. © 2002 American Institute of Physics.
Show PACS
73.61.Ng Insulators
73.50.Fq High-field and nonlinear effects
71.55.Ht Other nonmetals
73.50.Gr Charge carriers: generation, recombination, lifetime, trapping, mean free paths
73.40.Gk Tunneling
77.22.Jp Dielectric breakdown and space-charge effects
85.30.Tv Field effect devices

Size and grain-boundary effects of a gold nanowire measured by conducting atomic force microscopy

Alexander Bietsch and Bruno Michel

Appl. Phys. Lett. 80, 3346 (2002); http://dx.doi.org/10.1063/1.1473868 (3 pages) | Cited 27 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The resistivities of thin metal films and wires are highly sensitive to their polycrystalline structure and surface morphology because grain boundaries and surfaces provide additional scattering sites compared to bulk materials. Here, we investigated polycrystalline gold wires of nanometer-scale diameter that were—at some locations—connected through single grain boundaries. A detailed topography of the wires was recorded by atomic force microscopy. A Pt-coated tip in a conducting atomic force microscopy setup served as a mobile electrode to probe the resistance of a wire. Analyzing the topographical cross section and the resistance data allowed us to evaluate the effective specific resistivity of the wire as well as reflection coefficients of single grain boundaries. © 2002 American Institute of Physics.
Show PACS
73.63.Bd Nanocrystalline materials
61.46.-w Structure of nanoscale materials
61.72.Mm Grain and twin boundaries
68.37.Ps Atomic force microscopy (AFM)
85.40.Ls Metallization, contacts, interconnects; device isolation
68.35.B- Structure of clean surfaces (and surface reconstruction)
72.20.Fr Low-field transport and mobility; piezoresistance

Photoluminescence and photoluminescence excitation studies of as-grown and P-implanted GaN: On the nature of yellow luminescence

H. Y. Huang, C. H. Chuang, C. K. Shu, Y. C. Pan, W. H. Lee, W. K. Chen, W. H. Chen, and M. C. Lee

Appl. Phys. Lett. 80, 3349 (2002); http://dx.doi.org/10.1063/1.1476400 (3 pages) | Cited 8 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied optical and electronic properties of isoelectronic P-implanted GaN films grown by metalorganic chemical vapor phase epitaxy. After rapid thermal annealing, a strong emission band around 430 nm was observed, which is attributed to the recombination of exciton bound to isoelectronic P-hole traps. From the Arrhenius plot, the hole binding energy of ∼ 180 meV and the exciton localization energy of 28 meV were obtained. According to first-principle total-energy calculations, the implantation process likely introduced NI and P-related defects. By using photoluminescence excitation technique, we found that the P-implantation-induced localized states not only increase the yellow luminescence but also suppress the transitions from the free carriers to deep levels. © 2002 American Institute of Physics.
Show PACS
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
71.55.Eq III-V semiconductors
81.05.Ea III-V semiconductors
61.72.uj III-V and II-VI semiconductors
61.80.Jh Ion radiation effects
61.72.Cc Kinetics of defect formation and annealing
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
71.35.-y Excitons and related phenomena
71.15.Nc Total energy and cohesive energy calculations

Band line-up and mechanisms of current flow in n-GaN/p-SiC and n-AlGaN/p-SiC heterojunctions

A. Y. Polyakov, N. B. Smirnov, A. V. Govorkov, E. A. Kozhukhova, B. Luo, J. Kim, R. Mehandru, F. Ren, K. P. Lee, S. J. Pearton, A. V. Osinsky, and P. E. Norris

Appl. Phys. Lett. 80, 3352 (2002); http://dx.doi.org/10.1063/1.1477273 (3 pages) | Cited 6 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The properties of n-GaN/p-SiC and n-AlGaN/p-SiC heterojunctions (HJ) prepared by hydride vapor phase epitaxy (HVPE) on 4H SiC substrates are reported. It is shown that the GaN/p-SiC HJ is staggered type II with the conduction bandoffset and the valence bandoffset values, respectively, ΔEc = −0.49 eV and ΔEv = 0.65 eV. When changing GaN for AlGaN with Al mole fraction of x = 0.25–0.3 the band alignment becomes normal type I with ΔEc = 0.2 eV and ΔEv = 0.6 eV. Current–voltage characteristics of both heterojunctions bear evidence of strong tunneling via defect states. The tunneling was found to be more pronounced in the AlGaN/SiC HJs even though these showed no evidence of formation of dark line defects at the interface, in contrast to GaN/SiC. © 2002 American Institute of Physics.
Show PACS
73.20.At Surface states, band structure, electron density of states
73.20.Hb Impurity and defect levels; energy states of adsorbed species
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.40.Gk Tunneling
81.15.Kk Vapor phase epitaxy; growth from vapor phase

Anisotropy in breakdown field of 4H–SiC

Shun-ichi Nakamura, Hironori Kumagai, Tsunenobu Kimoto, and Hiroyuki Matsunami

Appl. Phys. Lett. 80, 3355 (2002); http://dx.doi.org/10.1063/1.1477271 (3 pages) | Cited 9 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The breakdown fields along the 〈11math0〉 and 〈03math8〉 directions in 4H–SiC have been measured. For the measurements, epitaxial p+n diodes with mesa structures were fabricated on the (11math0) and (03math8) faces, and they showed good rectification properties and avalanche breakdown. The breakdown fields along these directions calculated from the breakdown voltage were found to be about three quarters of that along the 〈0001〉 direction in 4H–SiC. The cause of the anisotropy in breakdown field is discussed. © 2002 American Institute of Physics.
Show PACS
85.30.Kk Junction diodes
73.50.Fq High-field and nonlinear effects
73.40.Ei Rectification
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
back to top
RSS Feeds

Effects of rapid thermal annealing on the ferromagnetic properties of sputtered Zn1−x(Co0.5Fe0.5)xO thin films

Young Mok Cho, Woong Kil Choo, Hyojin Kim, Dojin Kim, and YoungEon Ihm

Appl. Phys. Lett. 80, 3358 (2002); http://dx.doi.org/10.1063/1.1478146 (3 pages) | Cited 124 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the effects of rapid thermal annealing under vacuum on the CoFe-doped ZnO [Zn1−x(Co0.5Fe0.5)xO] films grown by reactive magnetron co-sputtering. At least up to x = 0.15, the films have the single phase of the same wurtzite structure as pure ZnO. Ferromagnetism was observed for the CoFe-doped ZnO films. We found that rapid thermal annealing leads to a remarkable increase in the spontaneous magnetization of the CoFe-doped ZnO as well as the electron concentration. The annealing also leads to a significant increase in the Curie temperature (TC), resulting in room temperature ferromagnetism with TC>300 K for the CoFe-doped ZnO films. © 2002 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.50.Pp Magnetic semiconductors
81.05.Dz II-VI semiconductors
81.40.Rs Electrical and magnetic properties related to treatment conditions
61.72.Cc Kinetics of defect formation and annealing
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Fk Semiconductors
68.55.-a Thin film structure and morphology
75.50.Dd Nonmetallic ferromagnetic materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.40.-s Critical-point effects, specific heats, short-range order

Magnetic anisotropy of ferromagnetic La0.7Sr0.3MnO3 epitaxial thin films: Dependence on temperature and film thickness

K. Steenbeck, T. Habisreuther, C. Dubourdieu, and J. P. Sénateur

Appl. Phys. Lett. 80, 3361 (2002); http://dx.doi.org/10.1063/1.1473870 (3 pages) | Cited 34 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic anisotropy of (001) oriented La0.7Sr0.3MnO3 films of thickness t = 7–156 nm, deposited on LaAlO3 substrates, was measured by torque magnetometry in the temperature range T = 10–300 K. For t ≥ 50 nm and H rotating out of plane the anisotropy Ku agrees well with shape anisotropy. For thinner films, Ku is reduced and its sign is reversed for t = 7 nm and T<70 K; this can be explained by a perpendicular anisotropy Kuϵ due to lattice strain. The crystal anisotropy constant K1 was determined from the biaxial in-plane anisotropy. At T = 100 K K1 differed by no more than 50% from the mean value −8 kJ/m3 in the thickness region investigated. K1 was much less dependent on the thickness t and strain relaxation in the films than Kuϵ. © 2002 American Institute of Physics.
Show PACS
75.50.Dd Nonmetallic ferromagnetic materials
75.30.Gw Magnetic anisotropy
75.70.Ak Magnetic properties of monolayers and thin films
68.60.Bs Mechanical and acoustical properties
68.55.-a Thin film structure and morphology

Room temperature operation of a high output current magnetic tunnel transistor

Sebastiaan van Dijken, Xin Jiang, and Stuart S. P. Parkin

Appl. Phys. Lett. 80, 3364 (2002); http://dx.doi.org/10.1063/1.1474610 (3 pages) | Cited 50 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The structure and properties of a magnetic tunnel transistor with high current output at room temperature are presented. The transistor marries a two-terminal magnetic tunnel junction with an Al2O3 tunnel barrier and a GaAs collector. The output current depends on the spin-dependent transport of hot electrons in the base layer of the transistor, which is formed from a single ultrathin ferromagnetic film. At a bias voltage of 1.4 V across the tunnel barrier, output currents larger than 1 μA and magnetocurrent changes of 64% are obtained at room temperature. © 2002 American Institute of Physics.
Show PACS
85.75.Mm Spin polarized resonant tunnel junctions
85.70.Kh Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
75.50.Bb Fe and its alloys

Large low-field magnetoresistance of phase-separated single-crystalline Pr0.7Pb0.3MnO3

Run-Wei Li, Zhi-Hong Wang, Wei-Ning Wang, Ji-Rong Sun, Qing-An Li, Shao-Ying Zhang, Zhao-Hua Cheng, Bao-Gen Shen, and Ben-Xi Gu

Appl. Phys. Lett. 80, 3367 (2002); http://dx.doi.org/10.1063/1.1477940 (3 pages) | Cited 12 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A large low-field magnetoresistance (MR) slightly above the metal–insulator transition temperature (234 K) was observed in single-crystalline Pr0.7Pb0.3MnO3. Combining the temperature dependence of magnetization, resistance, and electron spin resonance spectra, it was suggested that phase separation occurs above the Curie temperature; ferromagnetic metallic clusters imbedding in the insulating paramagnetic matrix, and spin-polarized electron tunneling between isolated ferromagnetic clusters should be responsible for the large low-field MR observed. Undoubtedly, this observation opens a window to explore large low-field MR at high temperature, which is very important for the practical application of colossal MR effect. © 2002 American Institute of Physics.
Show PACS
64.75.-g Phase equilibria
72.25.-b Spin polarized transport
72.60.+g Mixed conductivity and conductivity transitions
72.20.My Galvanomagnetic and other magnetotransport effects
75.47.Gk Colossal magnetoresistance
71.30.+h Metal-insulator transitions and other electronic transitions
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
72.20.Fr Low-field transport and mobility; piezoresistance
72.80.Sk Insulators
76.30.-v Electron paramagnetic resonance and relaxation
back to top
RSS Feeds

Structure and piezoelectric properties of sol–gel-derived 0.5 Pb[Yb1/2Nb1/2]O3–0.5 PbTiO3 thin films

Q. Q. Zhang, Q. F. Zhou, and S. Trolier-McKinstry

Appl. Phys. Lett. 80, 3370 (2002); http://dx.doi.org/10.1063/1.1472476 (3 pages) | Cited 10 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
0.5 Pb[Yb1/2Nb1/2]O3–0.5 PbTiO3 thin films were deposited on (111) Pt/Ti/SiO2/Si substrates by sol–gel processing using a thin Pb(Zr0.52Ti0.48)O3 seed layer. X-ray diffraction analysis and scanning electron microscopy revealed that the films were strongly (111) oriented, mimicking the orientation of the (111) Pt/Ti/SiO2/Si substrate. No pyrochlore phase was observed by x-ray diffraction and the films had a uniform grain size of about 50–60 nm. The dielectric permittivity and loss factor varied only slightly with frequency in the range of 100–10 000 Hz. At 1 kHz, the dielectric permittivity was 1025 and dielectric loss was 0.028. The films exhibited good ferroelectric and piezoelectric properties. The remanent polarization (Pr) was 30 μC/cm2. The effective transverse piezoelectric e31,f coefficient (−4.8 C/m2) of the films was measured using a modified wafer flexure method. © 2002 American Institute of Physics.
Show PACS
77.55.-g Dielectric thin films
81.05.Je Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides)
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
68.55.-a Thin film structure and morphology
77.80.-e Ferroelectricity and antiferroelectricity
77.65.Bn Piezoelectric and electrostrictive constants
81.10.Dn Growth from solutions
81.10.Fq Growth from melts; zone melting and refining
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
77.22.Ch Permittivity (dielectric function)
77.22.Gm Dielectric loss and relaxation

Depoling a ferroelectric capacitor

M. J. Higgins, A. Krishnan, M. M. J. Treacy, and S. Bhattacharya

Appl. Phys. Lett. 80, 3373 (2002); http://dx.doi.org/10.1063/1.1476063 (3 pages) | Cited 5 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A “shrinking hysteresis loop” method, analogous to degaussing a ferromagnet, is used to depolarize a ferroelectric thin film and reach the origin, nominally the zero polarization-zero applied field state. Scanning piezoresponse imaging of the depoled state shows fragmentation into domains of up and down polarization that constitute the zero polarization state. Furthermore, the depoling method improves the left–right symmetry of the coercive field in “imprinted” samples. © 2002 American Institute of Physics.
Show PACS
84.32.Tt Capacitors
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
77.22.Ej Polarization and depolarization
77.80.Dj Domain structure; hysteresis
77.55.-g Dielectric thin films
77.65.-j Piezoelectricity and electromechanical effects

Epitaxial growth and planar dielectric properties of compositionally graded (Ba1−xSrx)TiO3 thin films prepared by pulsed-laser deposition

Xinhua Zhu, Nui Chong, Helen Lai-Wah Chan, Chung-Loong Choy, Kin-Hung Wong, Zhiguo Liu, and Naiben Ming

Appl. Phys. Lett. 80, 3376 (2002); http://dx.doi.org/10.1063/1.1475367 (3 pages) | Cited 37 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have heteroepitaxially deposited compositionally graded (Ba1−xSrx)TiO3 (BST) thin films with increasing x from 0.0 to 0.25 on (100)-oriented MgO substrates using pulsed-laser deposition. The compositional gradients along the depth in the graded films were characterized by Rutherford backscattering spectroscopy. By using surface interdigital electrodes, the planar dielectric response of epitaxial graded BST films was measured as a function of frequency, temperature, and dc applied voltage. At room temperature, the dielectric constant of the graded BST film was about 450 with a dielectric loss, tan δ of 0.007 at 100 kHz. Measurements varying the dc bias voltage showed hysteresis of the dielectric response and a tunability of 25% at an applied electric field of 80 kV/cm. The graded BST films undergo a diffuse phase transition with a broad and flat profile of the capacitance versus temperature. Such behavior of the dielectric response in graded BST films is attributed to the presence of the compositional and/or residual strain gradients in the epitaxial graded films. With such a graded structure, it is possible to a build a dielectric thin-film capacitor with a low-temperature dependence of the capacitor over a broad temperature regime. © 2002 American Institute of Physics.
Show PACS
68.55.A- Nucleation and growth
68.55.Nq Composition and phase identification
77.55.-g Dielectric thin films
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
81.15.Kk Vapor phase epitaxy; growth from vapor phase
77.80.-e Ferroelectricity and antiferroelectricity
61.66.Bi Elemental solids
61.66.Dk Alloys
81.15.Fg Pulsed laser ablation deposition
77.22.Ch Permittivity (dielectric function)
77.22.Gm Dielectric loss and relaxation
82.80.Yc Rutherford backscattering (RBS), and other methods of chemical analysis
68.49.Sf Ion scattering from surfaces (charge transfer, sputtering, SIMS)
84.32.Tt Capacitors
68.60.Bs Mechanical and acoustical properties

Time-resolved study of SrTiO3 homoepitaxial pulsed-laser deposition using surface x-ray diffraction

G. Eres, J. Z. Tischler, M. Yoon, B. C. Larson, C. M. Rouleau, D. H. Lowndes, and P. Zschack

Appl. Phys. Lett. 80, 3379 (2002); http://dx.doi.org/10.1063/1.1477279 (3 pages) | Cited 25 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Homoepitaxy of SrTiO3 by pulsed-laser deposition has been studied using in situ time-resolved surface x-ray diffraction in the temperature range of 310 °C to 780 °C. Using a two-detector configuration, surface x-ray diffraction intensities were monitored simultaneously at the (0 0 ½) specular and the (0 1 ½) off-specular truncation rod positions. Abrupt intensity changes in both the specular and off-specular rods after laser pulses indicated prompt crystallization into SrTiO3 layers followed by slower intra- and interlayer surface rearrangements on time scales of seconds. Specular rod intensity oscillations indicated layer-by-layer growth, while off-specular rod intensity measurements suggested the presence of transient in-plane lattice distortions for depositions above 600 °C. © 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.Fg Pulsed laser ablation deposition
68.35.B- Structure of clean surfaces (and surface reconstruction)
77.80.-e Ferroelectricity and antiferroelectricity
68.55.-a Thin film structure and morphology
78.47.-p Spectroscopy of solid state dynamics
68.49.Uv X-ray standing waves

Resonant tunneling through metal (Ag–Ti)/insulator (MgO) triple barrier structures

T. Kado

Appl. Phys. Lett. 80, 3382 (2002); http://dx.doi.org/10.1063/1.1476707 (3 pages) | Cited 1 time

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Resonant tunneling through metal (Ag–Ti)/insulator (MgO) triple barrier structures has been demonstrated. The multilayers with the triple barrier structures were epitaxially grown on MgO (001) substrates under 473 K by the electron beam evaporation method. For the measurement of current–voltage characteristics, the mesa-isolated diodes were fabricated by photolithography. The observed current peaks in the current–voltage characteristics of the diodes could be explained as the resonant tunneling current. © 2002 American Institute of Physics.
Show PACS
73.40.Ns Metal-nonmetal contacts
73.40.Rw Metal-insulator-metal structures
73.40.Gk Tunneling
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Excellent thermal stability of Al2O3/ZrO2/Al2O3 stack structure for metal–oxide–semiconductor gate dielectrics application

Hyo Sik Chang, Sanghun Jeon, Hyunsang Hwang, and Dae Won Moon

Appl. Phys. Lett. 80, 3385 (2002); http://dx.doi.org/10.1063/1.1477266 (3 pages) | Cited 12 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The thermal stability of a nanolaminate (Al2O3/ZrO2/Al2O3) gate stack prepared by atomic layer chemical vapor deposition was investigated using medium-energy ion scattering spectroscopy, and x-ray photoelectron spectroscopy. We observed that the structure was stable up to 1000 °C under ultrahigh vacuum conditions. However, annealing in a nitrogen or oxygen ambient at 1 atm yielded the formation of an interfacial Zr–Al silicate layer at much lower temperatures. The growth of the interfacial silicate layer could be significantly reduced during furnace annealing via the use of plasma nitridation. © 2002 American Institute of Physics.
Show PACS
68.60.Dv Thermal stability; thermal effects
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
61.72.Cc Kinetics of defect formation and annealing
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation

Rapid biaxial texture development during nucleation of MgO thin films during ion beam-assisted deposition

Rhett T. Brewer and Harry A. Atwater

Appl. Phys. Lett. 80, 3388 (2002); http://dx.doi.org/10.1063/1.1476385 (3 pages) | Cited 16 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We propose a mechanism for the nucleation of highly aligned biaxially textured MgO on amorphous Si3N4 during ion beam-assisted deposition. Using transmission electron microscopy, reflection high-energy electron diffraction, energy dispersive x-ray analysis, and ellipsometery, we have observed that highly aligned biaxially textured grains emerge from a “diffraction-amorphous” film when the film thickens from 3.5 to 4.5 nm. Transmission electron microscopy dark-field images also show the onset of rapid grain growth during this same film thickness interval. These results suggest biaxial texturing through aligned solid phase crystallization. © 2002 American Institute of Physics.
Show PACS
81.15.Jj Ion and electron beam-assisted deposition; ion plating
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology

Dielectric nonlinearity and stochastic effects in strontium titanate

Alp T. Findikoğlu, Roberto Camassa, Grant Lythe, and Q. X. Jia

Appl. Phys. Lett. 80, 3391 (2002); http://dx.doi.org/10.1063/1.1477278 (3 pages) | Cited 8 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on experiments using compact coplanar waveguide devices, incorporating thin-film superconducting YBa2Cu3O7 electrodes. The substrate is strontium titanate, whose nonlinear dielectric properties are dependent on temperature and applied electric field. Close to zero dc bias, the frequency-doubled microwave power output increases by several orders of magnitude with modest broadband noise input. Experimental results are supported by analytical and numerical calculations based on a nonlinear wave equation. © 2002 American Institute of Physics.
Show PACS
84.40.Az Waveguides, transmission lines, striplines
85.25.Qc Superconducting surface acoustic wave devices and other superconducting devices
74.78.-w Superconducting films and low-dimensional structures
74.72.-h Cuprate superconductors
77.22.Gm Dielectric loss and relaxation
77.22.Ch Permittivity (dielectric function)

Optical limiting in SrBi2Ta2O9 and PbZrxTi1−xO3 ferroelectric thin films

Pingxiong Yang, Jianfeng Xu, John Ballato, Robert W. Schwartz, and David L. Carroll

Appl. Phys. Lett. 80, 3394 (2002); http://dx.doi.org/10.1063/1.1477618 (3 pages) | Cited 28 times

Online Publication Date: 29 April 2002

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Optical limiting effects in SrBi2Ta2O9 (SBT) and PbZrxTi1−xO3 (PZT) ferroelectric thin films have been observed with nanosecond laser pulses at 1.064 μm. Limiting thresholds were found to be 5.84 J/cm2 for SBT and between 4.53 and 5.93 J/cm2 for PZT, depending on composition, whereas saturation thresholds for the films were about 2.92 J/cm2 and between 2.27 J/cm2 to 2.97 J/cm2, respectively. Damage thresholds around 10.0 J/cm2 and between 10.37 J/cm2 to 10.54 J/cm2, respectively for SBT and PZT, were also determined. A possible mechanism for the observed limiting, nonlinear optical scattering from the ferroelectric domains, is discussed. These results elucidate the origin of the nonlinear optical properties in perovskite-type ferroelectric thin films and show the potential role such materials can play in photonic devices based on nonlinear optical effects. © 2002 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
42.70.Qs Photonic bandgap materials
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency
77.80.Dj Domain structure; hysteresis
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close