APL Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

5 Apr 2004

Volume 84, Issue 14, pp. 2473-2706

Issue Cover Spotlight Figure

Appl. Phys. Lett. 84, 2244 (2004); http://dx.doi.org/10.1063/1.1690471 (3 pages)

David R. Smith, David Schurig, Jack J. Mock, Pavel Kolinko, and Patrick Rye
Enlarge Image | Read More
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds

Observation of coherent interfacial optical phonons in GaInP/GaAs/GaInP single quantum wells

Y.-M. Chang, H. H. Lin, C. T. Chia, and Y. F. Chen

Appl. Phys. Lett. 84, 2548 (2004); http://dx.doi.org/10.1063/1.1704859 (3 pages) | Cited 4 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Coherent phonon spectroscopy of GaInP/GaAs/GaInP single quantum wells is demonstrated with time-resolved second-harmonic generation. Coherent longitudinal optical phonons are impulsively launched via transient pump-induced field screening and stimulated Raman scattering in the well and barrier regions. A phonon mode at 9.4 THz is identified as interfacial phonon localized in the GaAs/GaInP hetero-interface. The free induced dephasing of this coherent interfacial phonon is analyzed with window-gated Fourier transform. Its dephasing time is used to characterize the interface quality of semiconductor heterostructures. © 2004 American Institute of Physics.
Show PACS
63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
78.66.Fd III-V semiconductors
78.67.De Quantum wells
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.Dr Stimulated Raman scattering; CARS
42.65.Es Stimulated Brillouin and Rayleigh scattering

Bulk-surface vacancy exchange on Pt(111)

Bene Poelsema, J. B. Hannon, N. C. Bartelt, and G. L. Kellogg

Appl. Phys. Lett. 84, 2551 (2004); http://dx.doi.org/10.1063/1.1695434 (3 pages) | Cited 8 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have used low-energy electron microscopy to study atomic exchange between the bulk and the (111) surface of Pt above 1100 K. We find that the area of two-dimensional surface islands increases when the temperature is raised and decreases when the temperature is lowered, suggesting that thermal bulk vacancies are created at the surface. By measuring the temperature dependence of the change in area of the islands, we determine a Pt bulk vacancy formation energy of 1.54±0.07 eV, consistent with previous measurements and calculations. © 2004 American Institute of Physics.
Show PACS
61.72.J- Point defects and defect clusters
68.35.B- Structure of clean surfaces (and surface reconstruction)

Modification of GaN(0001) growth kinetics by Mg doping

E. Monroy, T. Andreev, P. Holliger, E. Bellet-Amalric, T. Shibata, M. Tanaka, and B. Daudin

Appl. Phys. Lett. 84, 2554 (2004); http://dx.doi.org/10.1063/1.1705719 (3 pages) | Cited 20 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have studied the effect of Mg doping on the surface kinetics of GaN during growth by plasma-assisted molecular-beam epitaxy. Mg tends to segregate on the surface of GaN, inhibiting the formation of the self-regulated Ga film which is used as a surfactant for the growth of undoped and Si-doped GaN. The growth window is hence significantly reduced. Higher growth temperatures lead to an enhancement of Mg segregation and an improvement of the surface morphology. © 2004 American Institute of Physics.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.05.Ea III-V semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.47.Fg Semiconductor surfaces
68.55.A- Nucleation and growth
52.77.Dq Plasma-based ion implantation and deposition
68.55.-a Thin film structure and morphology
61.72.uj III-V and II-VI semiconductors
68.35.Dv Composition, segregation; defects and impurities
back to top
RSS Feeds

Low-band-gap, sublimable rhenium(I) diimine complex for efficient bulk heterojunction photovoltaic devices

H. L. Wong, L. S. M. Lam, K. W. Cheng, K. Y. K. Man, W. K. Chan, C. Y. Kwong, and A. B. Djurišić

Appl. Phys. Lett. 84, 2557 (2004); http://dx.doi.org/10.1063/1.1682676 (3 pages) | Cited 21 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The use of chlorotricarbonyl rhenium(I) diimine complex as photosensitizing molecule in photovoltaic cells is demonstrated. Unlike other transition-metal-based sensitizers, the complex is sublimable and has low band gap. It also exhibits bipolar charge transport character with relatively high carrier mobilities on the order of 10−3 cm2 V−1 s−1. Multilayer heterojunction and bulk heterojunction devices with fullerene as the electron accepting molecule were prepared. For the bulk heterojunction devices, the fill factor and power conversion efficiency under simulated solar light illumination were 0.56 and 0.48%, respectively. Atomic force microscopic images showed that the complex dispersed evenly with fullerene molecules in solid state. © 2004 American Institute of Physics.
Show PACS
85.65.+h Molecular electronic devices
85.60.Bt Optoelectronic device characterization, design, and modeling
68.37.Ps Atomic force microscopy (AFM)
73.50.Dn Low-field transport and mobility; piezoresistance

Low-resistance tunnel junctions on GaAs substrates using GaInNAs

D. E. Mars, Y.-L. Chang, M. H. Leary, S. D. Roh, and D. R. Chamberlin

Appl. Phys. Lett. 84, 2560 (2004); http://dx.doi.org/10.1063/1.1691193 (3 pages) | Cited 5 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Using molecular-beam epitaxy, we have fabricated p-n tunnel junctions lattice matched to GaAs substrates that consist of highly C-doped Ga0.93In0.07As on the p side, and highly Si-doped Ga0.93In0.07N0.02As0.98 on the n side. The introduction of N on the n side of the tunnel junction: (1) lowers the conduction band edge while leaving the valence band edge unchanged, (2) allows the introduction of In to further lower the band gap while remaining lattice matched to GaAs, and (3) increases the maximum Si donor activation that can be achieved. All three of these effects increase the tunneling probability for carriers across the junction and decrease the specific resistance. We estimate the active C acceptors on the p side to be 1.5×1020 cm−3 and the active Si donors on the n side to be 1.8×1019 cm−3. Because of the mutual passivation effect between N and Si atoms, the Si doping level was increased to 1.0×1020 cm−3 to achieve this active net donor concentration. The specific resistance of test tunnel junctions has been measured to be <1×10−5 Ω cm2 corresponding to <0.1 V drop at a current density of 10 kA/cm2. These results are a substantial improvement over corresponding test structures without N on the n side of the junction. The experimental results are in good agreement with model calculations. © 2004 American Institute of Physics.
Show PACS
71.20.Nr Semiconductor compounds
73.40.Gk Tunneling
61.72.uj III-V and II-VI semiconductors
61.72.uf Ge and Si
71.15.-m Methods of electronic structure calculations
81.65.Rv Passivation

High-quality single-crystal Ge on insulator by liquid-phase epitaxy on Si substrates

Yaocheng Liu, Michael D. Deal, and James D. Plummer

Appl. Phys. Lett. 84, 2563 (2004); http://dx.doi.org/10.1063/1.1691175 (3 pages) | Cited 59 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Ge on insulator (GOI) is desired to obtain metal-oxide-semiconductor transistors with high performance and low leakage current. We have developed a method to make GOI based on liquid-phase epitaxial (LPE) growth on Si substrates and a defect necking technique in which defects are confined to a very short distance. Self-aligned microcrucibles were used to hold the Ge liquid. High-quality single-crystal (100) as well as (111) oriented GOI structures were obtained with a process compatible with Si-based fabrication. No dislocations or stacking faults were found in the LPE Ge films on insulator. The orientation of the Ge crystals was controlled by the seeding Si substrate. This method opens up the possibility of integrating Ge device structures in a baseline Si integrated circuit process. © 2004 American Institute of Physics.
Show PACS
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)
81.05.Cy Elemental semiconductors
68.55.-a Thin film structure and morphology
85.40.-e Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)

Fabrication of GaN cantilevers on silicon substrates for microelectromechanical devices

S. Davies, T. S. Huang, M. H. Gass, A. J. Papworth, T. B. Joyce, and P. R. Chalker

Appl. Phys. Lett. 84, 2566 (2004); http://dx.doi.org/10.1063/1.1695196 (3 pages) | Cited 18 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The fabrication of free-standing GaN cantilevers on Si(111) is demonstrated, and the growth of III-nitride epilayers on silicon (111) using an AlN buffer layer is characterized. Mechanically releasing GaN structures from Si(111) required a combination of two dry inductively coupled plasma etch processes using Cl2/Ar and CF4/Ar/O2 chemistries, and a potassium hydroxide (KOH) aqueous etch. Scanning transmission electron microscopy reveals a columnar growth habit for the nitrides. Electron energy loss spectroscopy imaging of an AlGaN/GaN interface indicates columnar growth may strongly influence the potential piezoelectric properties of III-nitride cantilever microelectromechanical devices. © 2004 American Institute of Physics.
Show PACS
52.77.Bn Etching and cleaning
81.65.Cf Surface cleaning, etching, patterning
07.10.Cm Micromechanical devices and systems
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
81.05.Ea III-V semiconductors
68.37.Lp Transmission electron microscopy (TEM)
79.20.Uv Electron energy loss spectroscopy
68.55.A- Nucleation and growth
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Acoustic manipulation of electron–hole pairs in GaAs at room temperature

M. M. de Lima, R. Hey, J. A. H. Stotz, and P. V. Santos

Appl. Phys. Lett. 84, 2569 (2004); http://dx.doi.org/10.1063/1.1695636 (3 pages) | Cited 7 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We demonstrate the optically detected long-range (>100 μm) ambipolar transport of photogenerated electrons and holes at room temperature by surface acoustic waves (SAWs) in (In,Ga)As-based quantum well structures coupled to an optical microcavity. We also show the control of the propagation direction of the carriers by a switch composed of orthogonal SAW beams, which can be used as a basic control gate for information processing based on ambipolar transport. © 2004 American Institute of Physics.
Show PACS
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
72.20.Fr Low-field transport and mobility; piezoresistance
68.35.Iv Acoustical properties
72.50.+b Acoustoelectric effects
73.63.Hs Quantum wells

Fabrication and characteristics of C84 fullerene field-effect transistors

Kana Shibata, Yoshihiro Kubozono, Takayoshi Kanbara, Tomoko Hosokawa, Akihiko Fujiwara, Yasuhiro Ito, and Hisanori Shinohara

Appl. Phys. Lett. 84, 2572 (2004); http://dx.doi.org/10.1063/1.1695193 (3 pages) | Cited 22 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Fullerene field-effect transistors (FETs) were fabricated with thin films of C84, which showed n-channel normally-on depletion-type FET characteristics. The C84 FET device exhibited the highest mobility, μ, of 2.1×10−3 cm2 V−1 s−1 among normally-on fullerene FETs. The carrier transport of this FET device can be interpreted as thermally activated hopping transport. Carrier type (n-channel) and transport mechanism (hopping) reflect the electronic properties of the C84 molecule. © 2004 American Institute of Physics.
Show PACS
85.65.+h Molecular electronic devices
72.20.Ee Mobility edges; hopping transport
85.30.Tv Field effect devices

Influence of Al doping on lattice strain and electrical properties of epitaxial GaN films grown by metalorganic chemical vapor deposition on Al2O3 substrate

Jae Kyeong Jeong, Jung-Hae Choi, Cheol Seong Hwang, Hyeong Joon Kim, Jae-Hoon Lee, Jung-Hee Lee, and Chang-Soo Kim

Appl. Phys. Lett. 84, 2575 (2004); http://dx.doi.org/10.1063/1.1702135 (3 pages) | Cited 1 time

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of the isoelectronic Al doping of epitaxial GaN films grown by metalorganic chemical vapor deposition on a (0001) Al2O3 single crystal substrate were investigated. It was found that the threading screw and edge dislocation densities of the GaN film decreased to less than half of that of the undoped GaN film up to Al doping concentration of 0.45%. The in-plane and out-of-plane strains were simultaneously reduced with the decrease in dislocation density as a result of the solution hardening effect. Accordingly, the electron mobility of the 0.45% Al-doped GaN film (524 cm2/Vs) was greatly improved compared to that of the undoped GaN film (178 cm2/Vs). However, the threading dislocation densities and strains were increased at a 0.64% Al concentration, and the electron mobility decreased accordingly. Therefore, the improvement in the electron mobility by Al doping up to 0.45% is the result of a decrease in the threading dislocation density and not a decrease in the number of point defects (Ga-site vacancy) as suggested earlier [Lee et al., Appl. Phys. Lett. 83, 917 (2003)]. © 2004 American Institute of Physics.
Show PACS
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.uj III-V and II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
72.20.Fr Low-field transport and mobility; piezoresistance
73.61.Ey III-V semiconductors
61.72.J- Point defects and defect clusters

Effect of nucleation layer on the magnetic properties of GaMnN

G. Thaler, R. Frazier, B. Gila, J. Stapleton, M. Davidson, C. R. Abernathy, S. J. Pearton, and Carlos Segre

Appl. Phys. Lett. 84, 2578 (2004); http://dx.doi.org/10.1063/1.1695207 (3 pages) | Cited 19 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effects of nucleation layer and growth temperature on the magnetic properties of GaMnN have been investigated. It was found that the largest magnetic moment was measured in films prepared on metalorganic chemical vapor deposition (MOCVD) GaN buffers at a growth temperature of 700 °C. Extended x ray absorption fine structure measurements indicate that the improved magnetic quality of the films grown on MOCVD layers versus gas source molecular beam epitaxy nucleation layers is not due to a change in the lattice position of the Mn and is more likely due to a reduction in defect density. Growth temperature was also found to have a significant impact on the magnetic properties, with the optimal growth temperature found to be 700 °C. © 2004 American Institute of Physics.
Show PACS
75.30.Cr Saturation moments and magnetic susceptibilities
75.50.Pp Magnetic semiconductors
75.70.Ak Magnetic properties of monolayers and thin films
68.55.A- Nucleation and growth
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
78.70.Dm X-ray absorption spectra
81.15.Kk Vapor phase epitaxy; growth from vapor phase
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
75.50.Dd Nonmetallic ferromagnetic materials

A distributed charge storage with GeO2 nanodots

T. C. Chang, S. T. Yan, C. H. Hsu, M. T. Tang, J. F. Lee, Y. H. Tai, P. T. Liu, and S. M. Sze

Appl. Phys. Lett. 84, 2581 (2004); http://dx.doi.org/10.1063/1.1697627 (3 pages) | Cited 26 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In this study, a distributed charge storage with GeO2 nanodots is demonstrated. The mean size and aerial density of the nanodots embedded in SiO2 are estimated to be about 5.5 nm and 4.3×1011 cm−2, respectively. The composition of the dots is also confirmed to be GeO2 by x-ray absorption near-edge structure analyses. A significant memory effect is observed through the electrical measurements. Under the low voltage operation of 5 V, the memory window is estimated to ∼ 0.45 V. Also, a physical model is proposed to demonstrate the charge storage effect through the interfacial traps of GeO2 nanodots. © 2004 American Institute of Physics.
Show PACS
61.46.-w Structure of nanoscale materials
78.70.Dm X-ray absorption spectra
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods

Modified transmission line model and its application to aluminum ohmic contacts with n-type GaN

N. C. Chen, P. H. Chang, A. P. Chiu, M. C. Wang, W. S. Feng, G. M. Wu, C. F. Shih, and K. S. Liu

Appl. Phys. Lett. 84, 2584 (2004); http://dx.doi.org/10.1063/1.1704855 (3 pages) | Cited 4 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A modified transmission line model (MTLM) of ohmic contact measurement is presented. This model preserves the simplicity of the circular transmission line model but eliminates the shortcoming of the possibility of obtaining misleading results. This model was applied to n-type GaN ohmic contacts and results similar to those obtained by Hall measurement were obtained. The ohmic contact pattern used in MTLM method occasionally exists during the fabrication of several devices. In such cases, the method can be used to determine the device processing quality without the need for any other test pattern. © 2004 American Institute of Physics.
Show PACS
72.80.Ey III-V and II-VI semiconductors
73.40.Ns Metal-nonmetal contacts
back to top
RSS Feeds

High-speed operation of quasi-one junction superconducting quantum interference device based on high-Tc multilayer technology

H. Sugiyama, H. Wakana, S. Adachi, Y. Tarutani, and K. Tanabe

Appl. Phys. Lett. 84, 2587 (2004); http://dx.doi.org/10.1063/1.1690496 (3 pages) | Cited 7 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We designed a quasi-one junction superconducting quantum interference device (QOS) based on single-flux-quantum technology using high-Tc superconductors. A circuit containing 10 interface-engineered ramp-edge Josephson junctions was fabricated on a La-substituted YBa2Cu3Oy ground plane. The output voltage as a function of the input current for the QOS indicated correct operation as a periodic comparator at clock frequency of 94 and 77 GHz at 35 and 40 K, respectively. A comparison of the observed maximum operating frequency with the product of the critical current and normal resistance for the junctions suggests that comparator operation above 100 GHz at 40 K is possible if one optimizes the junction parameters. © 2004 American Institute of Physics.
Show PACS
74.72.-h Cuprate superconductors
74.78.-w Superconducting films and low-dimensional structures
85.25.Dq Superconducting quantum interference devices (SQUIDs)
74.78.Fk Multilayers, superlattices, heterostructures
68.65.Ac Multilayers
74.25.Sv Critical currents

Magnetic anisotropy control of SrRuO3 films by tunable epitaxial strain

C. U. Jung, Hiroyuki Yamada, M. Kawasaki, and Y. Tokura

Appl. Phys. Lett. 84, 2590 (2004); http://dx.doi.org/10.1063/1.1695195 (3 pages) | Cited 24 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We have investigated the effect of anisotropic structural modification through epitaxial strain on the magnetic properties in an itinerant ferromagnet SrRuO3. For giving tunable and anisotropic in-plane strain, variable thickness CaHfO3 buffer layer and SrTiO3 (STO) (110) substrate were employed, respectively. The strain could be tuned from compressive to tensile along in-plane STO[001]∥ direction, while keeping slightly compressive and coherent along another in-plane STO[1-10]∥ direction. Magnetic easy axis can always be aligned with elongated lattice direction either parallel or perpendicular to the surface, due to strong spin–orbit coupling. © 2004 American Institute of Physics.
Show PACS
75.50.Dd Nonmetallic ferromagnetic materials
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Gw Magnetic anisotropy
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
71.70.Ej Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect
75.80.+q Magnetomechanical effects, magnetostriction

Giant planar Hall effect in colossal magnetoresistive La0.84Sr0.16MnO3 thin films

Y. Bason, L. Klein, J.-B. Yau, X. Hong, and C. H. Ahn

Appl. Phys. Lett. 84, 2593 (2004); http://dx.doi.org/10.1063/1.1695197 (3 pages) | Cited 26 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The transverse resistivity in thin films of La0.84Sr0.16MnO3 (LSMO) exhibits sharp field-symmetric jumps below TC. We show that a likely source of this behavior is the giant planar Hall effect combined with biaxial magnetic anisotropy. The effect is comparable in magnitude to that observed recently in the magnetic semiconductor Ga(Mn)As. It can be potentially used in applications such as magnetic sensors and nonvolatile memory devices. © 2004 American Institute of Physics.
Show PACS
75.50.Dd Nonmetallic ferromagnetic materials
75.47.Gk Colossal magnetoresistance
75.70.Ak Magnetic properties of monolayers and thin films
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
75.30.Gw Magnetic anisotropy
73.61.Ng Insulators

High-coercivity Co-ferrite thin films on (100)-SiO2 substrate

Y. C. Wang, J. Ding, J. B. Yi, B. H. Liu, T. Yu, and Z. X. Shen

Appl. Phys. Lett. 84, 2596 (2004); http://dx.doi.org/10.1063/1.1695438 (3 pages) | Cited 52 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Co-ferrite films were deposited on SiO2 single-crystal substrates. The as-deposited films were amorphous. The crystallization required an annealing at 700 °C or higher. Magnetic properties were found to be strongly dependent on annealing temperature, annealing duration, and film thickness. A small film thickness can restrict the formation of large particles. A coercivity as high as 9.3 kOe was achieved in the 50 nm film after annealing at 900 °C for 15 min deposited on (100)-SiO2 substrate. The high coercivity was associated with a nanostructure, lattice strain, and larger Raman shift with a relatively sharp peak. © 2004 American Institute of Physics.
Show PACS
75.50.Vv High coercivity materials
75.50.Gg Ferrimagnetics
75.50.Kj Amorphous and quasicrystalline magnetic materials
75.50.Tt Fine-particle systems; nanocrystalline materials
75.70.Ak Magnetic properties of monolayers and thin films
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
64.70.K- Solid-solid transitions
81.30.Hd Constant-composition solid-solid phase transformations: polymorphic, massive, and order-disorder
81.40.Gh Other heat and thermomechanical treatments
78.30.Hv Other nonmetallic inorganics
81.15.Cd Deposition by sputtering

On the origin of spin loss in GaMnN/InGaN light-emitting diodes

I. A. Buyanova, M. Izadifard, W. M. Chen, J. Kim, F. Ren, G. Thaler, C. R. Abernathy, S. J. Pearton, C.-C. Pan, G.-T. Chen, J.-I. Chyi, and J. M. Zavada

Appl. Phys. Lett. 84, 2599 (2004); http://dx.doi.org/10.1063/1.1695100 (3 pages) | Cited 22 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Spin polarization of GaMnN/InGaN light-emitting diodes grown by molecular beam epitaxy is analyzed. In spite of the ferromagnetic behavior of the GaMnN spin injector, the diodes are shown to exhibit very low efficiency of spin injection. Based on resonant optical orientation spectroscopy, the spin loss in the structures is shown to be largely due to fast spin relaxation within the InGaN spin detector, which itself destroys any spin polarization generated by optical spin orientation or electrical spin injection. © 2004 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
75.50.Dd Nonmetallic ferromagnetic materials
72.25.Dc Spin polarized transport in semiconductors
72.25.Rb Spin relaxation and scattering
78.60.Fi Electroluminescence
78.55.Cr III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.66.Fd III-V semiconductors

Ferromagnetism at room temperature with a large magnetic moment in anatase V-doped TiO2 thin films

Nguyen Hoa Hong, Joe Sakai, and Awatef Hassini

Appl. Phys. Lett. 84, 2602 (2004); http://dx.doi.org/10.1063/1.1703848 (3 pages) | Cited 69 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
V-doped TiO2 thin films were grown by laser ablation on LaAlO3 substrates. In the chosen range of the growth conditions, all V:TiO2 films have an anatase structure and exhibit semiconducting and ferromagnetic behaviors at room temperature. V:TiO2 films have a giant magnetic moment and they seem to be far better ferromagnetic than Co/Fe/Ni-doped TiO2 films. This study has proved that a few percent of V substituting for Ti in TiO2 can result in a potential diluted magnetic semiconductor. © 2004 American Institute of Physics.
Show PACS
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Cr Saturation moments and magnetic susceptibilities
81.15.Fg Pulsed laser ablation deposition
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
61.72.up Other materials
68.55.-a Thin film structure and morphology

On the feasibility of “measuring” crystal field parameters in a rotating-sample magnetometer

M. D. Kuz’min

Appl. Phys. Lett. 84, 2605 (2004); http://dx.doi.org/10.1063/1.1699470 (3 pages)

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
It is argued that the crystal field parameters (CFPs) of rare-earth magnets can be determined by means of a rotating-sample magnetometer (RSM), recording the harmonics of magnetization Mn, n = 2,4,6, in a constant magnetic field, as temperature varies. The process of “measuring” individual CFP of order n can be as direct as observing the slope of the Mn-vs-T−n dependence at sufficiently high temperatures, necessarily in the paramagnetic region. Although the basic idea of the RSM is anything but new, its implementation is greatly facilitated by the recent technological developments, such as digital lock-in amplifiers, miniature stepper motors, and high-performance permanent magnets. © 2004 American Institute of Physics.
Show PACS
07.55.Ge Magnetometers for magnetic field measurements
71.70.Ch Crystal and ligand fields

Spatial distribution and electronic state of Co in epitaxial anatase CoxTi1−xO2 thin films grown by reactive sputtering

B.-S. Jeong, Y. W. Heo, D. P. Norton, J. G. Kelly, R. Rairigh, A. F. Hebard, J. D. Budai, and Y. D. Park

Appl. Phys. Lett. 84, 2608 (2004); http://dx.doi.org/10.1063/1.1691499 (3 pages) | Cited 29 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The magnetic and phase properties of CoxTi1−xO2 anatase thin films grown epitaxially on (001) LaAlO3 by a reactive rf magnetron cosputter deposition have been examined. CoxTi1−xO2 (x = 0.07) thin films exhibit room-temperature ferromagnetism, as evidenced by hysteresis in M–H loop. Chemical mapping indicates segregation of the Co dopant atoms in these films. However, x-ray photoelectron spectroscopy suggests that the segregated Co is not metallic, but in the Co+2 state. These results are consistent with a segregated Ti–Co–O phase being responsible for the ferromagnetic behavior. © 2004 American Institute of Physics.
Show PACS
75.50.Dd Nonmetallic ferromagnetic materials
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
64.75.-g Phase equilibria
68.55.Nq Composition and phase identification
75.70.Ak Magnetic properties of monolayers and thin films
81.30.Mh Solid-phase precipitation
81.15.Cd Deposition by sputtering
79.60.-i Photoemission and photoelectron spectra
75.50.Tt Fine-particle systems; nanocrystalline materials

Manganite-based heterojunction and its photovoltaic effects

J. R. Sun, C. M. Xiong, B. G. Shen, P. Y. Wang, and Y. X. Weng

Appl. Phys. Lett. 84, 2611 (2004); http://dx.doi.org/10.1063/1.1702128 (3 pages) | Cited 33 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A heterojunction is fabricated by growing a La0.29Pr0.38Ca0.33MnO3 (LPCM) film on the 0.5 wt % Nb-doped SrTiO3 (STON) substrate, and its properties have been experimentally studied. In addition to fairly good rectifying behavior, the heterojunction exhibits a significant photovoltaic effect. The photovoltage on the two electrodes LPCM and STON increases almost linearly with the power of the laser beam (λ = 532 nm) at a rate of ∼0.19 V/W, and no tendency to saturation is observed up to the light power of 100 mW. The lifetime of the extra carriers is between 7 and 9 ms (slightly pulse laser energy dependent), obtained from the decay of photovoltage after shutting down light illumination. The present work shows a great potential of the manganite-based heterojunction as photoelectric devices. © 2004 American Institute of Physics.
Show PACS
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
73.50.Pz Photoconduction and photovoltaic effects
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
back to top
RSS Feeds

Lithography-modulated self-assembly of small ferroelectric Pb(Zr,Ti)O3 single crystals

S. Bühlmann, P. Muralt, and S. Von Allmen

Appl. Phys. Lett. 84, 2614 (2004); http://dx.doi.org/10.1063/1.1690873 (3 pages) | Cited 24 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Triangular (111) and square-shaped (100) Pb(Zr,Ti)O3 single crystallites with lateral dimensions down to 50 nm and thickness of 20 nm have been grown using lithography-modulated self-assembly in an in situ sputter process. Epitaxial (111)-oriented Pt on a SrTiO3 single crystal served as the substrate. An epitaxial 2 nm thick rutile TiO2 film was grown and patterned into 100–200 nm wide attachment sites by electron beam lithography. The perovskite nucleation density was 60 times higher on TiO2 seeds than on bare Pt(111). © 2004 American Institute of Physics.
Show PACS
77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.80.-e Ferroelectricity and antiferroelectricity
77.55.-g Dielectric thin films

Bias-temperature stability of ultrathin parylene-capped dielectrics: influence of surface oxygen on copper ion diffusion

Jay J. Senkevich, Pei-I. Wang, Chris J. Wiegand, and T.-M. Lu

Appl. Phys. Lett. 84, 2617 (2004); http://dx.doi.org/10.1063/1.1691488 (3 pages) | Cited 7 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
The effect of interfacial oxygen on copper ion penetration was investigated with metal–insulator–semiconductor capacitor (MISCAP) structures with and without an ultrathin (50 Å) polymer-capping layer. The amount of interfacial oxygen and hence the degree of copper ion penetration could be affected by the thermal annealing of the MISCAPs at 150 and 250 °C and in inert and reducing environments. The bias-temperature stressing (BTS) of a Cu/50 Å parylene-N/3000 Å plasma-enhanced tetraethoxysilane (PETEOS)/200 Å thermal SiO2/Si MISCAP at 150 °C and 1 MV/cm and previously annealed at 250 °C in Ar-3%H2 resulted in no flatband voltage shift from as-annealed to 180 min of BTS. The lack of flatband voltage shift is indicative of no copper ion penetration and a stable dielectric. Under higher electric fields (1.5–2 MV/cm) and at 150 °C, the polymer-capped PETEOS dielectric hindered copper ion penetration, but did not prevent it. © 2004 American Institute of Physics.
Show PACS
84.32.Tt Capacitors
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
61.72.Cc Kinetics of defect formation and annealing
73.61.Ph Polymers; organic compounds
66.30.Ny Chemical interdiffusion; diffusion barriers
68.35.Fx Diffusion; interface formation
77.84.Jd Polymers; organic compounds

Thermal stability of LaAlO3/Si deposited by laser molecular-beam epitaxy

X. B. Lu, X. Zhang, R. Huang, H. B. Lu, Z. H. Chen, W. F. Xiang, M. He, B. L. Cheng, H. W. Zhou, X. P. Wang, C. Z. Wang, and B. Y. Nguyen

Appl. Phys. Lett. 84, 2620 (2004); http://dx.doi.org/10.1063/1.1690880 (3 pages) | Cited 24 times

Online Publication Date: 1 April 2004

Full Text: Read Online (HTML) | Download PDF

Show Abstract
High-k gate dielectric material LaAlO3 (LAO) films were deposited directly onto silicon substrates by laser molecular-beam epitaxy. The thermodynamic stability of LAO films deposited at different substrate temperatures and of LAO films postannealed at 1000 °C was studied by high-resolution transmission electron microscopy and capacitor–voltage measurements. These studies show that the interfacial reaction between the LAO film and silicon substrate is strongly correlated to the substrate temperature and ambient conditions. In oxygen containing ambient, the interfacial reaction often occurs not only during film deposition but also during the course of postannealing. LAO films annealed at 1000 °C in nitrogen ambient have better thermal stability with silicon than LAO films annealed in oxygen ambient do. Both kinds of films remain amorphous after 1000 °C annealing. © 2004 American Institute of Physics.
Show PACS
73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
77.55.-g Dielectric thin films
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.60.Dv Thermal stability; thermal effects
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
61.72.Cc Kinetics of defect formation and annealing
61.43.Er Other amorphous solids
77.22.Ch Permittivity (dielectric function)
Page 2 of 4 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close