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

16 Aug 2004

Volume 85, Issue 7, pp. 1095-1302

Issue Cover Spotlight Figure

Appl. Phys. Lett. 85, 1277 (2004); http://dx.doi.org/10.1063/1.1783021 (3 pages)

Katsuhiko Nishiguchi, Hiroshi Inokawa, Yukinori Ono, Akira Fujiwara, and Yasuo Takahashi
Enlarge Image | Read More
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Zn0.9Mg0.1O∕ZnO p–n junctions grown by pulsed-laser deposition

K. Ip, Y. W. Heo, D. P. Norton, S. J. Pearton, J. R. LaRoche, and F. Ren

Appl. Phys. Lett. 85, 1169 (2004); http://dx.doi.org/10.1063/1.1783015 (3 pages) | Cited 44 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electrical characteristics of Zn0.9Mg0.1O∕ZnO p–n junctions grown by pulsed-laser deposition on bulk, single-crystal ZnO substrates are reported. The forward turn-on voltage of the junctions was in the range 3.6–4 V for Pt∕Au metallization used for the p-Ohmic contact on Zn0.9Mg0.1O.The reverse breakdown voltage is as high as 9 V, but displays a small negative temperature coefficient of −0.1–0.2 V K−1 over the range 30–200°C. The achievement of acceptable rectification in the junctions required growth of an n-type ZnO buffer on the ZnO substrate prior to growth of the p-type, phosphorus-doped Zn0.9mg0.1O.Without this buffer, the junctions showed very high leakage current.
Show PACS
81.05.Dz II-VI semiconductors
73.61.Ga II-VI semiconductors
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.40.Ns Metal-nonmetal contacts
81.15.Fg Pulsed laser ablation deposition
85.40.Ls Metallization, contacts, interconnects; device isolation
61.72.S- Impurities in crystals

Influences of oligomer length on carrier-transport properties of oligofluorenes

Chung-Chih Wu, Tsung-Li Liu, Yu-Ting Lin, Wen-Yi Hung, Tung-Huei Ke, Ken-Tsung Wong, and Teng-Chih Chao

Appl. Phys. Lett. 85, 1172 (2004); http://dx.doi.org/10.1063/1.1784031 (3 pages) | Cited 14 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, carrier-transport properties of a homologous series of oligofluorenes with C9 diaryl substitution have been examined. These substituted oligofluorenes possess stable amorphous states, ambipolar carrier-transport properties, and processability to thin films for a range of oligomer lengths, rendering feasible investigating dependence of carrier transport on oligomer length in disordered systems. It is found that carrier mobilities of these oligofluorenes show a clear decreasing trend with the oligomer length. Such findings are in contrast with previous observations for crystalline oligomers and impose certain implications in carrier transport of conjugated polymers and oligomers.
Show PACS
73.61.Ph Polymers; organic compounds
72.20.Fr Low-field transport and mobility; piezoresistance
73.50.Dn Low-field transport and mobility; piezoresistance

Type-I Ge∕Ge1−x−ySixSny strained-layer heterostructures with a direct Ge bandgap

J. Menéndez and J. Kouvetakis

Appl. Phys. Lett. 85, 1175 (2004); http://dx.doi.org/10.1063/1.1784032 (3 pages) | Cited 44 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electronic properties of Ge∕Ge1−x−ySixSny strained-layer heterostructures are predicted theoretically. It is found that a lattice-matched system with fully strained Ge layers and relaxed Ge1−x−ySixSny alloys can have a direct fundamental bandgap with spatial localization in the Ge layers (type I). The Si and Sn concentrations for which such a direct bandgap obtains are close to those that have already been experimentally demonstrated [M. Bauer, C. Ritter, P. A. Crozier, J. Ren, J. Menendez, G. Wolf, and J. Kouvetakis, Appl. Phys. Lett. 83, 2163 (2003)]. The required level of tensile strain in the Ge layers is compatible with Si–Ge technology. The predicted direct bandgap values are as high as 0.6 eV.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
68.60.Bs Mechanical and acoustical properties

Oxygen precipitate denuded zone in polycrystalline sheet silicon

Jinggang Lu, George Rozgonyi, James Rand, and Ralf Jonczyk

Appl. Phys. Lett. 85, 1178 (2004); http://dx.doi.org/10.1063/1.1781369 (3 pages) | Cited 3 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The spatial variation of oxygen precipitation across the thickness of polycrystalline sheet silicon has been investigated by Fourier transform infrared (FTIR) microspectroscopy and preferential etching/optical microscopy. FTIR shows that interstitial oxygen is depleted near the top surface of the as-grown sample, thereby suppressing oxygen precipitation during subsequent annealing. Preferential etching and electron-beam-induced current imaging of polished cross sections revealed a 250-μm-wide precipitate denuded zone near the top surface. Evidently, growth-induced near-surface reduction of the oxygen profile keeps the oxygen supersaturation below a critical level for precipitate nucleation. Considering that the minority carrier diffusion length of current finished sheet silicon solar cells ranges from 50 to 100 μm, it is anticipated that optimization of the 250-μm-wide precipitate denuded zone will improve solar cell performance.
Show PACS
61.72.J- Point defects and defect clusters
61.72.Cc Kinetics of defect formation and annealing
81.30.Mh Solid-phase precipitation
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
84.60.Jt Photoelectric conversion
81.65.Cf Surface cleaning, etching, patterning
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
81.40.Gh Other heat and thermomechanical treatments
78.30.Am Elemental semiconductors and insulators
78.66.Db Elemental semiconductors and insulators

Electrical transport in amorphous semiconducting AlMgB14 films

Y. Tian, G. Li, J. Shinar, N. L. Wang, B. A. Cook, J. W. Anderegg, A. P. Constant, A. M. Russell, and J. E. Snyder

Appl. Phys. Lett. 85, 1181 (2004); http://dx.doi.org/10.1063/1.1781738 (3 pages) | Cited 5 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The electrical transport properties of semiconducting AlMgB14 films deposited at room temperature and 573 K are reported in this letter. The as-deposited films are amorphous, and they exhibit high n-type electrical conductivity, which is believed to stem from the conduction electrons donated by Al, Mg, and/or Fe impurities in these films. The film deposited at 573 K is less conductive than the room-temperature-deposited film. This is attributed to the nature of donor or trap states in the band gap related to the different deposition temperatures.
Show PACS
73.61.Jc Amorphous semiconductors; glasses
72.20.Fr Low-field transport and mobility; piezoresistance
73.50.Dn Low-field transport and mobility; piezoresistance
71.55.Jv Disordered structures; amorphous and glassy solids

Optically patterned nuclear doughnuts in GaAs∕MnAs heterostructures

J. Stephens, J. Berezovsky, R. K. Kawakami, A. C. Gossard, and D. D. Awschalom

Appl. Phys. Lett. 85, 1184 (2004); http://dx.doi.org/10.1063/1.1781743 (3 pages) | Cited 3 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a scheme for optically patterning nuclear-spin polarization in semiconductor∕ferromagnet heterostructures. A scanning time-resolved Kerr rotation microscope is used to image the nuclear-spin polarization that results when GaAs∕MnAs epilayers are illuminated with a focused laser having a Gaussian profile. Rather than tracking the intensity profile of the laser spot, these images reveal that the nuclear polarization forms an annular lateral structure having circular symmetry with a dip rather than a peak at its center.
Show PACS
75.50.Dd Nonmetallic ferromagnetic materials
75.50.Pp Magnetic semiconductors
78.20.Ls Magneto-optical effects
78.47.-p Spectroscopy of solid state dynamics
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)

Effect of thermal excitation on intermolecular charge transfer efficiency in conducting polyaniline

Guofeng Li, Mira Josowicz, Jiří Janata, and Steve Semancik

Appl. Phys. Lett. 85, 1187 (2004); http://dx.doi.org/10.1063/1.1779948 (3 pages) | Cited 4 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A conductometric gas-sensing platform with temperature control has been adopted to probe temperature-dependent phenomena in conducting polymers. This letter describes our recent observation of thermal effects on the intermolecular charge transfer efficiency of conducting polyaniline at both ends of the charge transfer—either as a donor or as an acceptor, upon exposure to gaseous analytes. When polyaniline is serving as a donor, the thermal excitation of electrons in polyaniline facilitates the charge transfer. However, if polyaniline assumes the role of an acceptor, the charge transfer becomes less efficient at higher temperatures. Furthermore, a simplified band structure model is employed to elucidate such discriminative behavior.
Show PACS
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
71.20.Rv Polymers and organic compounds
82.35.Cd Conducting polymers
61.41.+e Polymers, elastomers, and plastics
73.20.At Surface states, band structure, electron density of states
71.55.Jv Disordered structures; amorphous and glassy solids

Influence of manganese contamination on high-mobility GaAs∕AlGaAs heterostructures

K. Wagenhuber, H.-P. Tranitz, M. Reinwald, and W. Wegscheider

Appl. Phys. Lett. 85, 1190 (2004); http://dx.doi.org/10.1063/1.1782262 (3 pages) | Cited 3 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Photoluminescence and magnetotransport measurements have been performed to assess the quality of modulation-doped GaAs∕AlGaAs heterostructures. The temporal evolution of the low-temperature electron mobility of samples prepared in a molecular-beam-epitaxy chamber containing manganese as a source material was studied. Mn contamination was identified to be responsible for the reduction of the electron mobility to 1×106 cm2∕V s and the appearance of a distinct photoluminescence band. In contrast, structures in which this signal is absent reach mobility values of 5.4×106 cm2∕V s. This directly proves that the epitaxy of high-mobility electron systems and structures containing GaMnAs layers, in principle, can be combined in one growth chamber.
Show PACS
73.61.Ey III-V semiconductors
78.66.Fd III-V semiconductors
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.55.Cr III-V semiconductors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Dn Low-field transport and mobility; piezoresistance
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
back to top
RSS Feeds

Comparative study of magnetization reversal in isolated and strayfield coupled microcontacts

Guido Meier, René Eiselt, Markus Bolte, Miriam Barthelmeß, Thomas Eimüller, and Peter Fischer

Appl. Phys. Lett. 85, 1193 (2004); http://dx.doi.org/10.1063/1.1777824 (3 pages) | Cited 7 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ferromagnetic microcontacts are key components for future spintronic devices in full metal as well as in hybrid ferromagnet/semiconductor systems. Control of the micromagnetic behavior and especially the reversal process is crucial for the functionality of such devices. We have prepared isolated and strayfield coupled micron sized rectangular Ni∕Fe double layer contacts on silicon nitride membranes. High-resolution magnetic microscopy studies in external fields are performed on identical samples comparing full field magnetic transmission x-ray microscopy and magnetic-force microscopy. The results of both techniques are in good agreement. We find evidence for a strayfield-induced coupling of the domain structure in adjacent contacts in accordance with micromagnetic simulations.
Show PACS
75.50.Bb Fe and its alloys
75.60.Jk Magnetization reversal mechanisms
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.60.Ch Domain walls and domain structure
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)
68.37.Rt Magnetic force microscopy (MFM)
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)

Measurements of low-frequency noise spectral densities for a small-sized stack of intrinsic Josephson junctions of Bi2Sr2CaCu2Oy single crystal

A. Saito, H. Ishida, K. Hamasaki, A. Irie, and G. Oya

Appl. Phys. Lett. 85, 1196 (2004); http://dx.doi.org/10.1063/1.1780601 (3 pages) | Cited 4 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We measured the low-frequency-voltage noise properties of a small-sized stack of intrinsic Josephson junctions formed on the surface of a cleaved Bi2Sr2CaCu2Oy (Bi-2212) single crystal, containing a few intrinsic Josephson junctions. A stack with an area of 2×2 μm was fabricated by electron-beam lithography and argon-ion-milling. The current–voltage (I–V) characteristics along the c-axis direction of the stack were measured by a three-terminal method. The stack showed (I–V) and dV∕dI-V curves without backbending due to heating effects. Five discrete resistive branches with hysteresis were observed in the low-voltage region of these curves. The measured noise-voltage spectral density SV(f) had a 1∕f dependence on frequency. We estimated the magnitude of the 1∕f noise parameter η from SV(f) in a Bi-2212 stack and found that above the sum-gap voltage in a small-sized stack η was almost the same as that for low-Tc Nb∕Al+AlOx∕Nb high-quality tunnel junctions.
Show PACS
74.72.-h Cuprate superconductors
74.40.-n Fluctuation phenomena
74.50.+r Tunneling phenomena; Josephson effects
74.81.Fa Josephson junction arrays and wire networks
81.65.Cf Surface cleaning, etching, patterning

Stress-induced magnetization for epitaxial spinel ferrite films through interface engineering

Naoki Wakiya, Kazuo Shinozaki, and Nobuyasu Mizutani

Appl. Phys. Lett. 85, 1199 (2004); http://dx.doi.org/10.1063/1.1780603 (3 pages) | Cited 18 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
This study found “stress-induced magnetization” for epitaxial ferrite films with spinel structure. We grew (111)- and (001)-epitaxial Ni0.17Zn0.23Fe2.60O4(NZF) films on CeO2∕Y0.15Zr0.85O1.93(YSZ)∕Si(001) and oxide single-crystal substrates, respectively. There is a window of lattice mismatch (between 0 and 6.5%) to achieve bulk saturation magnetization (Ms). An NZF film grown on CeO2∕YSZ∕∕Si(001) showed tensile stress, but that stress was relaxed by introducing a ZnCo2O4(ZC) buffer layer. NZF films grown on SrTiO3(ST)(001) and (La,Sr)(Al,Ta)O3(LSAT)(001) had compressive stress, which was enhanced by introducing a ZC buffer layer. In both cases, bulk Ms was achieved by introducing the ZC buffer layer. This similarity suggests that magnetization can be controlled by the stress.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.80.+q Magnetomechanical effects, magnetostriction
68.60.Bs Mechanical and acoustical properties
68.55.A- Nucleation and growth
75.50.Gg Ferrimagnetics
81.15.Fg Pulsed laser ablation deposition
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances

Midgap state-based π-junctions for digital applications

G. Testa, A. Monaco, E. Esposito, E. Sarnelli, D.-J. Kang, S. H. Mennema, E. J. Tarte, and M. G. Blamire

Appl. Phys. Lett. 85, 1202 (2004); http://dx.doi.org/10.1063/1.1781744 (3 pages) | Cited 12 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Midgap state-based YBa2Cu3O7−x π-junctions have been fabricated by a focused ion-beam system using 45° symmetric [001] tilt SrTiO3 bicrystal substrates. Measurements, performed by inserting the junctions in a superconducting loop (as a double-phase sensitive test), show both an unconventional nonmonotonic temperature dependence of the Josephson current, with a local minimum at a crossover temperature T* and, around T*, a half flux quantum shift in the critical current versus magnetic field modulations, clear signs of a 0–π crossover with temperature. Such results demonstrate that conventional 45° symmetric grain boundary junctions may have potential for applications, from digital circuits to quantum computing.
Show PACS
85.25.Dq Superconducting quantum interference devices (SQUIDs)
74.25.Sv Critical currents
74.50.+r Tunneling phenomena; Josephson effects
74.70.Dd Ternary, quaternary, and multinary compounds (including Chevrel phases, borocarbides, etc.)
81.15.Fg Pulsed laser ablation deposition

Spin-transfer effects in nanoscale magnetic tunnel junctions

G. D. Fuchs, N. C. Emley, I. N. Krivorotov, P. M. Braganca, E. M. Ryan, S. I. Kiselev, J. C. Sankey, D. C. Ralph, R. A. Buhrman, and J. A. Katine

Appl. Phys. Lett. 85, 1205 (2004); http://dx.doi.org/10.1063/1.1781769 (3 pages) | Cited 125 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report measurements of magnetic switching and steady-state magnetic precession driven by spin-polarized currents in nanoscale magnetic tunnel junctions with low-resistance, <5 Ω μm2, barriers. The current densities required for magnetic switching are similar to values for all-metallic spin-valve devices. In the tunnel junctions, spin-transfer-driven switching can occur at voltages that are high enough to quench the tunnel magnetoresistance, demonstrating that the current remains spin polarized at these voltages.
Show PACS
72.25.Mk Spin transport through interfaces
75.50.Bb Fe and its alloys
75.50.Tt Fine-particle systems; nanocrystalline materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
72.15.Gd Galvanomagnetic and other magnetotransport effects
75.47.Np Metals and alloys
75.25.-j Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.)
81.40.Gh Other heat and thermomechanical treatments

Electric-pulse-induced reflectance change in the thin film of perovskite manganite

K. Aoyama, K. Waku, A. Asanuma, Y. Uesu, and T. Katsufuji

Appl. Phys. Lett. 85, 1208 (2004); http://dx.doi.org/10.1063/1.1782268 (3 pages) | Cited 26 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate a nonvolatile, reversible change of infrared reflectance from the thin film of perovskite manganite (Pr1−xCaxMnO3) by applying electric pulse. The result provides a possibility to use the electric-pulse-induced phenomena of this compound in optical devices.
Show PACS
78.66.Nk Insulators
78.30.Hv Other nonmetallic inorganics
75.70.-i Magnetic properties of thin films, surfaces, and interfaces
78.20.Jq Electro-optical effects
back to top
RSS Feeds

Dielectric characteristics of nanocrystalline Ag–Ba0.5Sr0.5TiO3 composite thin films

K. P. Jayadevan, C. Y. Liu, and T. Y. Tseng

Appl. Phys. Lett. 85, 1211 (2004); http://dx.doi.org/10.1063/1.1780596 (3 pages) | Cited 9 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Nanocrystalline Ag–Ba0.5Sr0.5TiO3 (Ag–BST) composite thin films are deposited on Pt/Ti/SiO2/Si substrates by a sol-gel method. The voltage-dependent capacitance (C–V) and dielectric loss of the films decrease with increasing Ag up to 2 mol % due to a series configuration involving low dielectric interface layers and dense microstructures. The evidence for asymmetric distribution of charge carriers in the Ag–BST film is derived from C–V measurements. The dielectric tunability of BST film with 1 mol % Ag is comparable to that of pure BST.
Show PACS
77.84.Lf Composite materials
81.07.Bc Nanocrystalline materials
77.55.-g Dielectric thin films
73.61.Ng Insulators
61.46.-w Structure of nanoscale materials
77.22.Gm Dielectric loss and relaxation
77.22.Ej Polarization and depolarization
77.22.Ch Permittivity (dielectric function)
61.72.Mm Grain and twin boundaries
68.35.B- Structure of clean surfaces (and surface reconstruction)

Electrical and optical properties of Bi2Ti2O7 thin films prepared by metalorganic decomposition method

Yun Hou, Tie Lin, Zhiming Huang, Genshui Wang, Zhigao Hu, Junhao Chu, Xiaohong Xu, and Min Wang

Appl. Phys. Lett. 85, 1214 (2004); http://dx.doi.org/10.1063/1.1777823 (3 pages) | Cited 9 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Highly (111) oriented Bi2Ti2O7 thin films have been grown on Pt∕Ti∕SiO2∕Si and Al2O3 substrates by metalorganic decomposition method at 550°C. The structural properties of the films were examined by x-ray diffraction. The Bi2Ti2O7 films exhibit good insulating property and the leakage current density of the film on Pt∕Ti∕SiO2∕Si is only about 1.56×10−8 A∕cm2 at 200 kV∕cm. The refractive index and extinction coefficient of Bi2Ti2O7 thin films were determined by fitting the infrared spectroscopic ellipsometric data using a classical dielectric function formula. As the wavelength increases, the refractive index decreases, while the extinction coefficient increases. And the band-gap energy Eg was obtained from the optical transmission spectra of Bi2Ti2O7 thin films.
Show PACS
77.55.-g Dielectric thin films
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
84.32.Tt Capacitors
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
73.61.Ng Insulators
78.66.Nk Insulators
77.80.Dj Domain structure; hysteresis
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.30.Hv Other nonmetallic inorganics
71.45.Gm Exchange, correlation, dielectric and magnetic response functions, plasmons

Hetero-epitaxy of perovskite oxides on GaAs(001) by molecular beam epitaxy

Y. Liang, J. Kulik, T. C. Eschrich, R. Droopad, Z. Yu, and P. Maniar

Appl. Phys. Lett. 85, 1217 (2004); http://dx.doi.org/10.1063/1.1783016 (3 pages) | Cited 21 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Hetero-epitaxy of single-crystal perovskite SrTiO3 on GaAs(001) was achieved using molecular beam epitaxy. The growth was accomplished by deposition of a submonolayer of titanium on GaAs(001), followed by the co-deposition of strontium and titanium initiated at a low-temperature, low-oxygen-pressure condition. X-ray photoelectron spectroscopy showed that the Ti prelayer reacted with As and formed TiAs-like species on the As terminated GaAs(001) surface. Reflection-high-energy-electron diffraction showed that SrTiO3 grew coherently on the GaAs(001) at early stage of growth. This coherent behavior began to degrade when SrTiO3 thickness exceeded 20 math. Cross-sectional transmission electron microscopy revealed an abrupt interface between SrTiO3 and GaAs and good crystallinity of the SrTiO3 film. An epitaxial relationship between SrTiO3 and GaAs was further confirmed by x-ray diffraction. The success of growth of SrTiO3 on GaAs paves the way for integration of various functional perovskite oxides with GaAs.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
68.35.Ct Interface structure and roughness
79.60.Bm Clean metal, semiconductor, and insulator surfaces
68.35.B- Structure of clean surfaces (and surface reconstruction)

Uniform field-induced strain in a∕b-axes-oriented Bi3.9Pr0.1Ti3O12 thick films on IrO2∕Si substrates for lead-free piezoelectric microdevice applications

Hirofumi Matsuda, Sachiko Ito, and Takashi Iijima

Appl. Phys. Lett. 85, 1220 (2004); http://dx.doi.org/10.1063/1.1783020 (3 pages) | Cited 11 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We grew 1.5-μm-thick Bi3.9Pr0.1Ti3O12 (BPT) polycrystalline films with a∕b-axes orientation on IrO2∕Si substrates from chemical solutions and measured electric-field-induced strain ϵ by a double-beam laser doppler vibrometer and atomic-force microscopy (AFM). The results reflected uniform film growth and elimination of elastic deformation of the substrate, and the microscopic piezoelectric response in AFM measurements agreed well with the macroscopic response evaluated by laser vibrometer. A large longitudinal ϵ=0.3% was observed at 400 kV∕cm and 10 Hz, and the piezoelectric coefficient d33=dϵ∕dE∣0=60 pm∕V was calculated. X-ray diffraction analyses revealed that the (200)∕(020) peak of BPT was comprised of 40% a domain and led to the reduced values of ferroelectric polarizations of 2Pr=35 and Psat=23 μC∕cm2. This suggests that applying an electric field did not cause fraction reconfiguration of a- and b-domains, and, therefore, the measured large strain was achieved without contribution from the 90°-domain-wall motion in a∕b-axes-oriented BPT thick films.
Show PACS
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
77.55.-g Dielectric thin films
77.80.Dj Domain structure; hysteresis
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
68.55.A- Nucleation and growth
62.20.D- Elasticity
62.20.F- Deformation and plasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
68.37.Ps Atomic force microscopy (AFM)
77.22.Ej Polarization and depolarization

Metal piezoelectric semiconductor field effect transistors for piezoelectric strain sensors

Yuh-Renn Wu and Jasprit Singh

Appl. Phys. Lett. 85, 1223 (2004); http://dx.doi.org/10.1063/1.1784039 (3 pages) | Cited 16 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this letter, we examine the potential of a functional device that can have good transistor and stress sensor properties. The device examined is based on the use of a thin oxide with high piezoelectric coefficients under the gate region. Channel charge and current are controlled by gate voltage or by stress. We examine the performance of two classes of heterostructures that are important semiconductor technologies: (i) Si∕SiO2∕BaTiO3 heterostructure junctions that would be an important breakthrough for silicon sensor technology and (ii) GaN∕AlN∕BaTiO3 heterostructure field effect transistors. The calculations show that with a very thin piezoelectric layer we can have a highly sensitive stress sensor and transistor. For optimum performance, the piezoelectric layer thickness should be ∼30–60 Å.
Show PACS
85.30.Tv Field effect devices
85.50.-n Dielectric, ferroelectric, and piezoelectric devices
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
07.10.Pz Instruments for strain, force, and torque
77.80.-e Ferroelectricity and antiferroelectricity

Piezoelectric d33 coefficient of cellular polypropylene subjected to expansion by pressure treatment

X. Zhang, J. Hillenbrand, and G. M. Sessler

Appl. Phys. Lett. 85, 1226 (2004); http://dx.doi.org/10.1063/1.1781388 (3 pages) | Cited 27 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The piezoelectric activity of charged cellular polypropylene films of originally 40 and 50 μm thickness can be significantly increased by thickness expansion due to an exposure to high pressure for time periods of the order of hours. After such a treatment, the d33 coefficient, measured by quasistatic and interferometric methods, is found to be as high as 1200 pC∕N at 0.001 Hz, decreasing to 350 pC∕N just below resonance. At the resonance, which is located in the range of 150–400 kHz for differently treated samples, d33 coefficients up to 1400 pC∕N are found. The high d33 coefficients result from a decrease of Young’s modulus Y and an increase of the chargeability of the material due to the expansion, while the decrease of d33 with frequency up to resonance is related to a corresponding increase of Y. Static pressures up to 10 kPa have little influence on d33, but higher pressures result in a reversible decrease.
Show PACS
77.65.Bn Piezoelectric and electrostrictive constants
77.55.-g Dielectric thin films
81.40.Jj Elasticity and anelasticity, stress-strain relations
62.20.D- Elasticity
77.84.Jd Polymers; organic compounds
62.50.-p High-pressure effects in solids and liquids
81.40.Vw Pressure treatment

Structure and thickness-dependent lattice parameters of ultrathin epitaxial Pr2O3 films on Si(001)

T. Schroeder, T.-L. Lee, J. Zegenhagen, C. Wenger, P. Zaumseil, and H.-J. Müssig

Appl. Phys. Lett. 85, 1229 (2004); http://dx.doi.org/10.1063/1.1771465 (3 pages) | Cited 12 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Pr2O3 grown heteroepitaxially on Si(001) is a promising candidate for applications as a high-k dielectric in future silicon-based microelectronics devices. The technologically important thickness range from 1 to 10 nm has been investigated by synchrotron radiation-grazing incidence x-ray diffraction. The oxide film grows as cubic Pr2O3 phase with its (101) plane on the Si(001) substrate in form of two orthogonal rotation domains. Monitoring the evolution of the oxide unit-cell lattice parameters as a function of film thickness from 1 to 10 nm, the transition from almost perfect pseudomorphism to bulk values is detected.
Show PACS
68.55.-a Thin film structure and morphology
77.55.-g Dielectric thin films
77.22.Ch Permittivity (dielectric function)
77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
64.70.K- Solid-solid transitions
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder

Near-infrared femtosecond laser-induced crystallization of amorphous silicon

Jia-Min Shieh, Zun-Hao Chen, Bau-Tong Dai, Yi-Chao Wang, Alexei Zaitsev, and Ci-Ling Pan

Appl. Phys. Lett. 85, 1232 (2004); http://dx.doi.org/10.1063/1.1782267 (3 pages) | Cited 24 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Amorphous silicon (a-Si) was crystallized by femtosecond laser annealing (FLA) using a near-infrared (λ≈800 nm) ultrafast Ti:sapphire laser system. The intense ultrashort laser pulses lead to efficient nonlinear photoenergy absorption and the generation of very dense photoexcited plasma in irradiated materials, enabling nonlinear melting on transparent silicon materials. We studied the structural characteristics of recrystallized films and found that FLA assisted by spatial scanning of laser strip spot constitutes superlateral epitaxy that can crystallize a-Si films with largest grains of ∼800 nm, requiring laser fluence as low as ∼45 mJ∕cm2, and low laser shots. Moreover, the optimal annealing conditions are observed with a significant laser-fluence window (∼30%).
Show PACS
68.55.-a Thin film structure and morphology
64.70.K- Solid-solid transitions
61.43.Dq Amorphous semiconductors, metals, and alloys
81.05.Gc Amorphous semiconductors
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
back to top
RSS Feeds

Absolute determination of film thickness from photoemission: Application to atomically uniform films of Pb on Si

M. H. Upton, T. Miller, and T.-C. Chiang

Appl. Phys. Lett. 85, 1235 (2004); http://dx.doi.org/10.1063/1.1783019 (3 pages) | Cited 10 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We report on a method to unequivocally determine the thickness of a film in terms of atomic layers, as demonstrated by a study of Pb growth on Si(111). Deposition at low temperatures on a pretreated Si substrate results in atomically uniform Pb films. These films exhibit large monolayer-by-monolayer variations in electronic structure as observed by angle-resolved photoemission. Intense and sharp peaks derived from quantum-well states are observed for odd film thicknesses N=5, 7, and 9 monolayers, but not for the adjacent even film thicknesses N=4, 6, 8, and 10 monolayers. The dramatic differences facilitate an accurate calibration of the amount of Pb deposited.
Show PACS
79.60.Bm Clean metal, semiconductor, and insulator surfaces
68.55.A- Nucleation and growth
73.21.Fg Quantum wells
81.07.St Quantum wells
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
71.20.Gj Other metals and alloys
73.20.At Surface states, band structure, electron density of states

Strained layer instabilities on vicinal surfaces: Ge0.8Si0.2 epitaxy on laser textured Si(001)

Fumiya Watanabe, David G. Cahill, Sukwon Hong, and Joseph E. Greene

Appl. Phys. Lett. 85, 1238 (2004); http://dx.doi.org/10.1063/1.1780604 (3 pages) | Cited 13 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Laser textured substrates enable a combinatorial study of strained layer growth morphology as a function of substrate miscut. Si(001) substrates with miscut θ<15° off (001) are produced by texturing with nanosecond laser pulses. Ge0.8Si0.2 growth rates are varied over a wide range, 1.7–90 monolayers per minute, at a fixed substrate temperature of 600 °C. Film morphologies at all growth rates show strong dependence on the local miscut θ within the dimpled regions of the substrate: the results demonstrate the importance of anisotropy in surface stiffness for the formation of epitaxial nanostructures. The length scales of all structures display a similar trend of decreasing size with increasing growth rate due to the suppression of coarsening at high growth rates.
Show PACS
81.05.Hd Other semiconductors
68.55.-a Thin film structure and morphology
68.35.B- Structure of clean surfaces (and surface reconstruction)
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
79.20.Ds Laser-beam impact phenomena
68.60.Bs Mechanical and acoustical properties
61.82.Fk Semiconductors
68.55.A- Nucleation and growth
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Fabrication of single nanofluidic channels in poly(methylmethacrylate) films via focused-ion beam milling for use as molecular gates

Donald M. Cannon, Bruce R. Flachsbart, Mark A. Shannon, Jonathan V. Sweedler, and Paul W. Bohn

Appl. Phys. Lett. 85, 1241 (2004); http://dx.doi.org/10.1063/1.1780605 (3 pages) | Cited 18 times

Online Publication Date: 10 August 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Focused-ion beam (FIB) milling provides rapid fabrication of individual cylindrical submicrometer channels with reproducible dimensions (±5% diameters) through 8‐μm thick poly(methylmethacrylate) (PMMA) films. PMMA films are spincast on sacrificial Si carriers and sputter-coated with Au before the 30‐kV gallium FIB milling process. By adding a trace amount of poly(ethyleneoxide) and poly(dimethylsiloxane) to the PMMA solution before casting, the films can be released for subsequent mounting in microfluidic devices to create hybrid microfluidic-nanofluidic multilevel architectures. In situ FIB sectioning demonstrates the smooth cylindrical surface within the pore. Placing a milled film in contact with an aqueous fluorescein solution fills the channel by capillary action, as verified by confocal fluorescence microscopy. Confocal fluorescence of dyed films reveals that the pores span the thickness of the PMMA film. Small arrays of channels with a defined number and density and arbitrary in-plane spatial arrangement are fabricated with this process, allowing a unique testbed for high aspect ratio nanofluidic devices.
Show PACS
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
68.55.A- Nucleation and growth
78.55.-m Photoluminescence, properties and materials
81.15.Cd Deposition by sputtering
Page 2 of 3 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close