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25 Oct 2004

Volume 85, Issue 17, pp. 3657-3939

Issue Cover Spotlight Figure

Appl. Phys. Lett. 85, 3851 (2004); http://dx.doi.org/10.1063/1.1808886 (3 pages)

P. Guha, S. Kar, and S. Chaudhuri
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Fluorine-enhanced low-temperature wafer bonding of native-oxide covered Si wafers

Q.-Y. Tong, Q. Gan, G. Fountain, P. Enquist, R. Scholz, and U. Gösele

Appl. Phys. Lett. 85, 3731 (2004); http://dx.doi.org/10.1063/1.1809279 (3 pages) | Cited 7 times

Online Publication Date: 29 October 2004

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The bonding energy of bonded native-oxide-covered silicon wafers treated in the HNO3∕H2O∕HF or the HNO3∕HF solution prior to room-temperature contact is significantly higher than bonded standard RCA1 cleaned wafer pairs after low-temperature annealing. The bonding energy reaches over 2000 mJ∕m2 after annealing at 100 °C. The very slight etching and fluorine in the chemically grown oxide are believed to be the main contributors to the enhanced bonding energy. Transmission-electron-microscopic images have shown that the chemically formed native oxide at bonding interface is embedded with many flake-like cavities. The cavities can absorb the by-products of the interfacial reactions that result in covalent bond formation at low temperatures allowing the strong bond to be retained.
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81.65.Cf Surface cleaning, etching, patterning
61.72.Cc Kinetics of defect formation and annealing

Periodic precipitation of crystalline Ge nanoparticles in Ge–B–SiO2 thin glass films

Hiroaki Nishiyama, Isamu Miyamoto, Shin-ichi Matsumoto, Mitsunori Saito, Kohei Fukumi, Kenji Kintaka, and Junji Nishii

Appl. Phys. Lett. 85, 3734 (2004); http://dx.doi.org/10.1063/1.1812369 (3 pages) | Cited 5 times

Online Publication Date: 29 October 2004

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Crystalline 20- to 40-nm-diam Ge nanoparticles were precipitated periodically in Ge–B–SiO2 thin glass films fabricated by the plasma-enhanced chemical vapor deposition method. Such a periodic structure was created by exposure to an interference pattern with a KrF excimer laser (248 nm wavelength) and successive annealing at 600°C. Nanoparticles were precipitated predominantly in the unirradiated region after photoinduced refractive index change was erased completely after annealing up to 500°C.
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81.05.Kf Glasses (including metallic glasses)
61.43.Fs Glasses
61.46.-w Structure of nanoscale materials
68.55.A- Nucleation and growth
81.30.Mh Solid-phase precipitation
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.40.Gh Other heat and thermomechanical treatments
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.66.Jg Amorphous semiconductors; glasses
81.65.Cf Surface cleaning, etching, patterning

Visualization of graphite atomic arrangement by stereo atomscope

Fumihiko Matsui, Hiroshi Daimon, Fang Zhun Guo, and Tomohiro Matsushita

Appl. Phys. Lett. 85, 3737 (2004); http://dx.doi.org/10.1063/1.1810214 (3 pages) | Cited 19 times

Online Publication Date: 29 October 2004

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The direct visualization of an atomic arrangement is essential for understanding the nature of materials. The rotation of forward focusing peaks in photoelectron angular distribution (PEAD) patterns excited by circularly polarized light with the opposite helicities are found to be the same as the parallax in stereo view. Taking advantage of this phenomenon of PEAD circular dichroism, the three-dimensional atomic arrangement image of graphite crystal was realized. Taking a stereo picture around carbon atom, which has been thought difficult due to a small angular momentum of photoelectron, proved that this method is applicable to all materials including biomolecules.
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78.20.Fm Birefringence
79.60.-i Photoemission and photoelectron spectra
61.66.Bi Elemental solids

Characterization of light-induced modification of the nonlinear refractive index using a one-laser-shot nonlinear imaging technique

G. Boudebs and Cid B. de Araújo

Appl. Phys. Lett. 85, 3740 (2004); http://dx.doi.org/10.1063/1.1810624 (3 pages) | Cited 11 times

Online Publication Date: 29 October 2004

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We report the exploitation of a one-laser-shot measurement technique to study photo-induced effects in semiconductor-doped glasses. The technique, based on the use of a phase object in a 4f coherent imaging system, allows one to characterize the kinetics of the nonlinear refractive index of samples versus the light exposure time.
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42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
61.82.Fk Semiconductors
61.82.Rx Nanocrystalline materials
61.46.-w Structure of nanoscale materials
42.65.-k Nonlinear optics
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation

Determination of the nitrogen distribution in InGaNAs∕GaAs quantum wells by transmission electron microscopy

D. Litvinov, D. Gerthsen, A. Rosenauer, M. Hetterich, A. Grau, Ph. Gilet, and L. Grenouillet

Appl. Phys. Lett. 85, 3743 (2004); http://dx.doi.org/10.1063/1.1810643 (3 pages) | Cited 10 times

Online Publication Date: 29 October 2004

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We report on measurements of the nitrogen-concentration profile in an InGaNAs heterostructure by high-resolution transmission electron microscopy. Two samples grown by gas-source molecular-beam epitaxy on GaAs(001) substrates were investigated which contain InGaAs and InGaNAs wells with the same thickness and In concentration. The indium concentration was determined by high-resolution x-ray diffractometry. Indium-concentration profiles were obtained with the composition evaluation by lattice fringe analysis (CELFA) technique from the sample with the InGaAs wells exploiting the chemical sensitivity of the diffracted (002) beam. Nitrogen-concentration profiles were measured in the InGaNAs wells by comparison of the CELFA results observed in the samples with and without nitrogen.
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81.07.St Quantum wells
81.05.Ea III-V semiconductors
68.65.Fg Quantum wells
61.72.S- Impurities in crystals
68.35.Ct Interface structure and roughness
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
78.67.De Quantum wells
78.55.Cr III-V semiconductors
68.37.Lp Transmission electron microscopy (TEM)

Study on the growth mechanism of pentacene thin films by the analysis of island density and island size distribution

M. Tejima, K. Kita, K. Kyuno, and A. Toriumi

Appl. Phys. Lett. 85, 3746 (2004); http://dx.doi.org/10.1063/1.1812591 (3 pages) | Cited 13 times

Online Publication Date: 29 October 2004

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The growth mechanism of pentacene thin films on a thermally grown SiO2 on Si(100) substrate is examined in detail for a wide substrate temperature range (223–342 K) by analyzing the saturated island density and island size distribution. It is found that the log plot of the saturated island density as a function of inverse substrate temperature can be well represented by two straight lines and that these two regions have different critical cluster sizes for nucleation which is independently confirmed by island size distribution analysis. It is concluded that the nucleation behavior of pentacene thin films can be explained by the diffusion-mediated growth model well known in inorganic thin-film growth.
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68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
81.15.Aa Theory and models of film growth
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
68.35.B- Structure of clean surfaces (and surface reconstruction)

Effect of stacking fault energy on plastic deformation of nanocrystalline face-centered cubic metals

F. Ebrahimi, Z. Ahmed, and H. Li

Appl. Phys. Lett. 85, 3749 (2004); http://dx.doi.org/10.1063/1.1810629 (3 pages) | Cited 21 times

Online Publication Date: 29 October 2004

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The effect of stacking fault energy (SFE) on the tensile stress–strain behavior of nanocrystalline face-centered cubic (fcc) metals was investigated. The stacking fault energy of nickel was decreased by alloying with copper or iron. It was found that, as predicted by a recent simulation study, decreasing the SFE increases the strain hardening rate of the nanocrystalline fcc metals. The effect was more pronounced in the nickel–copper alloy, which had a smaller average grain size.
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81.07.Bc Nanocrystalline materials
61.72.Nn Stacking faults and other planar or extended defects
62.25.-g Mechanical properties of nanoscale systems
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
81.40.Ef Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization
61.46.-w Structure of nanoscale materials

Axial strain redistribution resulting from off-axis ply cracking in polymer composites

Dionisis G. Katerelos and Costas Galiotis

Appl. Phys. Lett. 85, 3752 (2004); http://dx.doi.org/10.1063/1.1811395 (3 pages) | Cited 10 times

Online Publication Date: 29 October 2004

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The initial mode of damage in multidirectional composites is the accumulation of matrix cracks in the off-axis plies. Remote laser Raman spectroscopy, using aramid (Kevlar 49®) fibers as Raman strain sensors, has been employed to monitor the local strains in cracked crossply composites. The strain magnification in the 0° ply caused by 90° matrix cracking are measured at different levels of loading. A relationship between the values of strain magnification and the distance between the position of the fibers sensors vis-à-vis the crack front has been established. The effect of damage progression within the 0° plies on the remaining∕surviving glass fibers is modeled satisfactorily and verified against predictions on the basis of a generalized plane strain model by assuming that the 90° ply “expands” in relative size against the 0° ply thickness.
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81.05.Qk Reinforced polymers and polymer-based composites
81.40.Np Fatigue, corrosion fatigue, embrittlement, cracking, fracture, and failure
62.20.M- Structural failure of materials

Electronic structure of secondary phases in Cu-rich CuGaSe2 solar cell devices

D. Fuertes Marrón, Th. Glatzel, A. Meeder, Th. Schedel-Niedrig, S. Sadewasser, and M. Ch. Lux-Steiner

Appl. Phys. Lett. 85, 3755 (2004); http://dx.doi.org/10.1063/1.1812582 (3 pages) | Cited 10 times

Online Publication Date: 29 October 2004

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Kelvin probe force microscopy in ultrahigh vacuum was used to image the electronic structure of thin-film solar cell cross sections based on as-grown Cu-rich CuGaSe2 absorbers. We observe different secondary phases in the absorber film. A p-type degenerate Cu2−xSe phase is identified by a higher work function (Φ∼5.35 eV) than CuGaSe2 (Φ∼5.1 eV), allowing good contrast mappings of both phases within the absorber film. Besides entire Cu2−xSe crystallites we also observed this secondary phase segregated as an interfacial layer along CuGaSe2 grain boundaries. An additional high-work function phase at the CuGaSe2∕window junction is attributed to the formation of an improper CuS buffer layer during chemical bath processing. The detrimental effect of these secondary phases on the solar cell performance is discussed.
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84.60.Jt Photoelectric conversion
71.20.Nr Semiconductor compounds
61.72.Mm Grain and twin boundaries
73.30.+y Surface double layers, Schottky barriers, and work functions

The influence of scandium in effecting fragile to strong glass transition in aluminium-based alloys

Dmitri V. Louzguine, Shintaro Sobu, and Akihisa Inoue

Appl. Phys. Lett. 85, 3758 (2004); http://dx.doi.org/10.1063/1.1808502 (2 pages) | Cited 15 times

Online Publication Date: 29 October 2004

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The “fragile”–“strong glass” transition in Al-based alloys is observed as a function of Sc content. The Sc-bearing alloys suffer glass transition as well as Sc-free Al0.84Y0.09Ni0.05Co0.02 alloy, however, the value of ΔCp decreases drastically and comes within the variation of the baseline at higher than 2 at. % of Sc. The studied glasses are free from pre-existing nuclei.
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81.05.Kf Glasses (including metallic glasses)
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
61.43.Fs Glasses

Photon-directed colloidal crystallization

Tieying Gong and David W. M. Marr

Appl. Phys. Lett. 85, 3760 (2004); http://dx.doi.org/10.1063/1.1808471 (3 pages) | Cited 11 times

Online Publication Date: 29 October 2004

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We have recently shown that electric fields can be used to induce rapid three-dimensional colloidal crystallization from isotropic colloidal dispersions through a combination of dielectrophoretic and electro-osmotic mechanisms. In this letter we demonstrate that light itself can be used to drive colloidal crystallization in a local and directed fashion under applied electric fields, allowing one to effectively write colloidal crystals in arbitrary and reversible patterns. This ability will provide great flexibility in the construction of colloid-based devices and allow their reversible operation as a function of an applied optical or electric field.
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82.70.Dd Colloids
64.70.D- Solid-liquid transitions
82.45.-h Electrochemistry and electrophoresis
78.35.+c Brillouin and Rayleigh scattering; other light scattering
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Influence of image force potential on the shot noise properties of field emitters

K. Rangaswamy, M. Cahay, and K. L. Jensen

Appl. Phys. Lett. 85, 3763 (2004); http://dx.doi.org/10.1063/1.1811790 (3 pages) | Cited 6 times

Online Publication Date: 29 October 2004

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The shot noise power spectrum of the emission current from planar metallic cathodes is calculated taking into account the effects of the image force potential in front of the cathode. For metals with low work function, the Fano factor which characterizes the reduction of the shot noise power SIem below the Schottky result 2 qIem (where q is the magnitude of the charge of the electron and Iem is the time average of the emitted current) is calculated as a function of the applied external electric field and is found to be reduced substantially below the value calculated when the effects of the image charge potential are neglected. A study of the temperature dependence of the Fano factor can be used to estimate the temperature dependence of the work function of the cathode material.
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79.60.Bm Clean metal, semiconductor, and insulator surfaces
79.70.+q Field emission, ionization, evaporation, and desorption
72.70.+m Noise processes and phenomena
73.30.+y Surface double layers, Schottky barriers, and work functions
77.22.Jp Dielectric breakdown and space-charge effects

Giant low-temperature piezoresistance effect in AlAs two-dimensional electrons

Y. P. Shkolnikov, K. Vakili, E. P. De Poortere, and M. Shayegan

Appl. Phys. Lett. 85, 3766 (2004); http://dx.doi.org/10.1063/1.1808883 (3 pages) | Cited 14 times

Online Publication Date: 29 October 2004

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We present piezoresistance measurements in modulation doped AlAs quantum wells where the two-dimensional electron system occupies two conduction band valleys with elliptical Fermi contours. Our data demonstrate that, at low temperatures, the strain gauge factor (the fractional change in resistance divided by the sample’s fractional length change) in this system exceeds 10 000. Moreover, in the presence of a moderate magnetic field perpendicular to the plane of the two-dimensional system, gauge factors up to 56 000 can be achieved. The piezoresistance data can be explained qualitatively by a simple model that takes into account intervalley charge transfer.
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73.63.Hs Quantum wells
73.21.Fg Quantum wells
71.70.Di Landau levels

Transport properties of highly conductive n-type Al-rich AlxGa1−xN (x⩾0.7)

M. L. Nakarmi, K. H. Kim, K. Zhu, J. Y. Lin, and H. X. Jiang

Appl. Phys. Lett. 85, 3769 (2004); http://dx.doi.org/10.1063/1.1809272 (3 pages) | Cited 23 times

Online Publication Date: 29 October 2004

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We report here the growth and transport studies of conductive n-type AlxGa1−xN alloys with high Al contents (x⩾0.7). Si-doped AlxGa1−xN alloys were grown by metalorganic chemical vapor deposition on AlN-epilayer∕sapphire substrates with very smooth surface. Low n-type resistivities have been obtained for Al-rich AlxGa1−xN alloys. The resistivity was observed to increase rapidly with increasing x due to the deepening of the Si donor energy level. Transport measurements have indicated that we have achieved n-type conduction in pure AlN. From the temperature dependence of the resistivity, the donor activation energy was estimated to vary from 23 to 180 meV as x was increased from 0.7 to 1.0.
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81.05.Ea III-V semiconductors
68.55.A- Nucleation and growth
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
73.61.Ey III-V semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.S- Impurities in crystals
71.55.Eq III-V semiconductors
61.72.uj III-V and II-VI semiconductors

Modification of drain current on metal–oxide–semiconductor field-effect transistor by magnetic field induced by remanent magnetization

Naoki Wakiya, Kan Shimizu, Satoshi Mizukami, Kazuo Shinozaki, and Nobuyasu Mizutani

Appl. Phys. Lett. 85, 3772 (2004); http://dx.doi.org/10.1063/1.1812382 (3 pages) | Cited 1 time

Online Publication Date: 29 October 2004

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We propose a concept of drain current (Ids) modification in a metal–oxide–semiconductor field-effect transistor (MOSFET) using the Lorentz force from an external magnetic field and a magnetic field induced by remanent magnetization. We fabricated a Pt∕MZF∕YSZ∕MOSFET structure (MZF: Mn0.60Zn0.30Fe2.10O4, YSZ: Y0.15Zr0.85O1.93), based on this concept and examined the effect of the magnetic field on electrical properties. The magnetic field increased the Ids when the carriers were pushed away from the interface. A magnetic field of the opposite direction increased Ids slightly. This phenomenon is related to the potential change and carrier mobility. It may be useful for use in memory devices.
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85.30.Tv Field effect devices
81.15.Fg Pulsed laser ablation deposition
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
73.61.Ng Insulators

Low-contact-resistance and smooth-surface Ti∕Al∕Nb∕Au ohmic electrode on AlGaN∕GaN heterostructure

T. Nakayama, H. Miyamoto, Y. Ando, Y. Okamoto, T. Inoue, K. Hataya, and M. Kuzuhara

Appl. Phys. Lett. 85, 3775 (2004); http://dx.doi.org/10.1063/1.1810210 (2 pages) | Cited 14 times

Online Publication Date: 29 October 2004

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We have achieved both low contact resistance and smooth surface morphology by using Ti∕Al∕Nb∕Au formed on an Al0.3Ga0.7N∕GaN heterostructure. A low contact resistance of less than 0.6 Ω∕mm was reproducibly recorded after thermal treatment with a wide range of annealing temperature from 830 to 1000 °C and annealing time from 10 to 300 s. It was found that root-mean square surface roughness of under 35 nm was obtained with all the annealing conditions investigated. In consideration of surface roughness and reproducibility, the most suitable annealing condition was 850 °C for 100 s, which leads to a contact resistance and a specific contact resistivity of 0.48 Ω∕mm and 5×10−6 Ω∕cm2, respectively.
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68.55.A- Nucleation and growth
73.40.Cg Contact resistance, contact potential
81.40.Gh Other heat and thermomechanical treatments
73.40.Ns Metal-nonmetal contacts
81.05.Ea III-V semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

Room temperature ferromagnetism in cubic GaN epilayers implanted with Mn+ ions

V. A. Chitta, J. A. H. Coaquira, J. R. L. Fernandez, C. A. Duarte, J. R. Leite, D. Schikora, D. J. As, K. Lischka, and E. Abramof

Appl. Phys. Lett. 85, 3777 (2004); http://dx.doi.org/10.1063/1.1812590 (3 pages) | Cited 29 times

Online Publication Date: 29 October 2004

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Mn ions were implanted in p-type cubic GaN at doses from 0.6 to 2.4×1016 cm−2 at 200 keV energy. A 200-nm-thick epitaxial layer, grown by molecular beam epitaxy on GaAs(001) substrate, is used for the Mn implantation. The Mn implanted samples were subjected to an annealing at 950 °C for 1–5 min. The structural quality of the samples was investigated by high resolution x-ray diffraction and Raman spectroscopy. The annealing procedure leads to a significant increasing of the crystalline quality of the samples. Hysteresis loops were observed for all cubic GaMnN annealed samples and ferromagnetism was detected up to room temperature.
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81.05.Ea III-V semiconductors
75.50.Pp Magnetic semiconductors
75.50.Dd Nonmetallic ferromagnetic materials
75.70.Ak Magnetic properties of monolayers and thin films
68.55.-a Thin film structure and morphology
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
75.30.Cr Saturation moments and magnetic susceptibilities
61.72.uj III-V and II-VI semiconductors
61.72.Cc Kinetics of defect formation and annealing
78.66.Fd III-V semiconductors
78.30.Fs III-V and II-VI semiconductors

Low temperature annealing of electron irradiation induced defects in 4H-SiC

Antonio Castaldini, Anna Cavallini, Lorenzo Rigutti, and Filippo Nava

Appl. Phys. Lett. 85, 3780 (2004); http://dx.doi.org/10.1063/1.1810627 (3 pages) | Cited 16 times

Online Publication Date: 29 October 2004

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Low temperature annealing of electron irradiation-induced deep levels in 4H-SiC is reported. The major deep level transient spectroscopy peak S2 associated with the energy level at Ec−0.39 eV disappears in the temperature range 360–400 K, and some rearrangement of the peak S3, associated with the defect Z1∕Z2 with energy level at Ec−0.5∕Ec−0.65 eV occurs in the temperature interval 400–470 K. A net free charge carrier concentration increase goes along with the disappearance of peak S2 at Ec−0.39 eV, whereas the charge collection efficiency of the diode does not experience any significant change. An interpretation of the annealing of peak S2 on a microscopic scale is given.
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85.30.Kk Junction diodes
61.72.Cc Kinetics of defect formation and annealing
61.80.Fe Electron and positron radiation effects
61.82.Fk Semiconductors
71.55.Ht Other nonmetals

Nitric acid oxidation of silicon at ∼120 °C to form 3.5-nm SiO2∕Si structure with good electrical characteristics

Asuha, Shigeki Imai, Masao Takahashi, and Hikaru Kobayashi

Appl. Phys. Lett. 85, 3783 (2004); http://dx.doi.org/10.1063/1.1804255 (3 pages) | Cited 23 times

Online Publication Date: 29 October 2004

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3.5-nm-thick SiO2 layers can be formed at 120 °C by immersion of Si in 40 wt % nitric acid (HNO3) followed by immersion in an azeotropic mixture (i.e., 68 wt % HNO3). The former immersion produces a 1.1-nm SiO2 layer with a low atomic density of 2.19×1022∕cm2, where the layer acts as a catalyst for the decomposition of HNO3. The latter immersion results in a 3.5-nm SiO2 layer with a higher atomic density of 2.22×1022∕cm2. When the postmetalization annealing treatment at 250 °C in hydrogen is performed on the 〈Al∕3.5-nm SiO2∕Si(100)〉 metal-oxide semiconductor diodes, interface states are passivated and a low leakage current density (e.g., 8×10−4 A∕cm2 at the forward gate bias of 1.5 V) is achieved.
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73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
85.40.Ls Metallization, contacts, interconnects; device isolation
81.65.Mq Oxidation
81.65.Rv Passivation

Effect of Al∕N ratio during nucleation layer growth on Hall mobility and buffer leakage of molecular-beam epitaxy grown AlGaN∕GaN heterostructures

D. F. Storm, D. S. Katzer, S. C. Binari, B. V. Shanabrook, Lin Zhou, and David J. Smith

Appl. Phys. Lett. 85, 3786 (2004); http://dx.doi.org/10.1063/1.1808496 (3 pages) | Cited 15 times

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AlGaN∕GaN high electron mobility transistor structures have been grown by plasma-assisted molecular beam epitaxy on semi-insulating 4H-SiC utilizing an AlN nucleation layer. The electron Hall mobility of these structures increases from 1050 cm2∕V s to greater than 1450 cm2∕V s when the Al∕N flux ratio during the growth of the nucleation layer is increased from 0.90 to 1.07. Buffer leakage currents increase abruptly by nearly three orders of magnitude when the Al∕N ratio increases from below to above unity. Transmission electron microscopy indicates that high buffer leakage is correlated with the presence of stacking faults in the nucleation layer and cubic phase GaN in the buffer, while low mobilities are correlated with high dislocation densities.
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85.30.Tv Field effect devices
68.55.A- Nucleation and growth
73.61.Ey III-V semiconductors
72.20.My Galvanomagnetic and other magnetotransport effects
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)
68.55.-a Thin film structure and morphology
68.37.Lp Transmission electron microscopy (TEM)
61.72.Nn Stacking faults and other planar or extended defects

A simple method for the preparation of transparent p-type Ca-doped CuInO2 films: Pulsed-laser deposition from air-sintered Ca-doped Cu2In2O5 targets

Charles W. Teplin, Tatiana Kaydanova, David L. Young, John D. Perkins, David S. Ginley, Aiko Ode, and Dennis W. Readey

Appl. Phys. Lett. 85, 3789 (2004); http://dx.doi.org/10.1063/1.1808498 (3 pages) | Cited 12 times

Online Publication Date: 29 October 2004

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We report the deposition of single-phase undoped and Ca-doped CuInO2 thin films from a readily synthesized source target of Cu2In2O5—circumventing the very difficult fabrication of CuInO2 targets. X-ray diffraction shows that single-phase materials were obtained over a range of substrate temperatures and deposition pressures. p-type conductivities are measured to be ∼3×10−3 S∕cm, comparable to the best films previously reported. The optical properties of the films were measured by spectroscopic ellipsometry.
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68.55.A- Nucleation and growth
81.05.Hd Other semiconductors
68.55.-a Thin film structure and morphology
81.15.Fg Pulsed laser ablation deposition
73.61.Le Other inorganic semiconductors
78.66.Li Other semiconductors
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Paramagnetic defects in annealed ultrathin layers of SiOx, Al2O3, and ZrO2 on (100)Si

A. Stesmans and V. V. Afanas’ev

Appl. Phys. Lett. 85, 3792 (2004); http://dx.doi.org/10.1063/1.1787152 (3 pages) | Cited 12 times

Online Publication Date: 29 October 2004

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Electron spin resonance (ESR) measurements on (100)Si∕SiOx∕ZrO2 and (100)Si∕Al2O3∕ZrO2 stacks with nm-thick dielectric layers reveal, upon postdeposition oxidation (PDO) in the range of 650–800 °C, the appearance of various SiO2-characteristic defects, including E′ and EX centers and a 95‐G doublet. These defects generally grow during PDO treatment, attesting to significant modification of the SiOx interlayer, and∕or additional SiOx interlayer growth. The ESR results on E′ indicate that the SiOx interlayer formed in (100)Si∕SiOx∕ZrO2 is drastically inferior to standard thermal (100)Si∕SiO2, exhibiting over one order of magnitude more O-deficiency centers. The (100)Si∕Al2O3 system appears more robust in terms of SiOx interlayer growth, and has better interlayer properties.
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77.84.Bw Elements, oxides, nitrides, borides, carbides, chalcogenides, etc.
77.55.-g Dielectric thin films
68.55.A- Nucleation and growth
61.72.J- Point defects and defect clusters
81.65.Mq Oxidation
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
76.30.Mi Color centers and other defects
61.72.Cc Kinetics of defect formation and annealing
81.40.Gh Other heat and thermomechanical treatments
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
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Suppression of spin accumulation in nonmagnet due to ferromagnetic ohmic contact

T. Kimura, J. Hamrle, Y. Otani, K. Tsukagoshi, and Y. Aoyagi

Appl. Phys. Lett. 85, 3795 (2004); http://dx.doi.org/10.1063/1.1811801 (2 pages) | Cited 17 times

Online Publication Date: 29 October 2004

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We experimentally demonstrate that the ohmic contact of a Ni–Fe wire additionally connected to a Cu strip between an injector and detector in a nonlocal spin-valve structure signicantly suppresses the spin polarization induced in the Cu strip. This behavior is attributable to spin current absorption into the connected additional Ni–Fe wire.
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85.70.Kh Magnetic thin film devices: magnetic heads (magnetoresistive, inductive, etc.); domain-motion devices, etc.
75.50.Bb Fe and its alloys
72.25.Mk Spin transport through interfaces

Anistropic photoinduced magnetism of a RbjCok[Fe(CN)6]l⋅nH2O thin film

J.-H. Park, E. Čižmár, M. W. Meisel, Y. D. Huh, F. Frye, S. Lane, and D. R. Talham

Appl. Phys. Lett. 85, 3797 (2004); http://dx.doi.org/10.1063/1.1807963 (3 pages) | Cited 15 times

Online Publication Date: 29 October 2004

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A magneto-optically active thin film of RbjCok[Fe(CN)6]l⋅nH2O has been prepared using a sequential assembly method. Upon irradiation with light and at 5 K, the net magnetization of the film increased when the surface of the film was oriented parallel to the external magnetic field of 0.1 T. However, when the surface of the film was perpendicular to the field, the net magnetization decreased upon irradiation. The presence of dipolar fields and the low-dimensional nature of the system are used to describe the orientation dependence of the photoinduced magnetization. The ability to increase or decrease the photoinduced magnetization by changing the orientation of the system with respect to the field is a phenomenon that may be useful in future device applications.
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78.20.Ls Magneto-optical effects
75.50.Xx Molecular magnets
75.20.Ck Nonmetals
75.50.Gg Ferrimagnetics
75.70.Ak Magnetic properties of monolayers and thin films
68.55.A- Nucleation and growth
68.55.-a Thin film structure and morphology
75.30.Gw Magnetic anisotropy
81.15.Lm Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids)

Precipitate-free films of La1−xSrxMnO3 grown on the substrates with artificial step edges

Y. Ishii, H. Sato, A. Sawa, T. Yamada, H. Akoh, K. Endo, M. Kawasaki, and Y. Tokura

Appl. Phys. Lett. 85, 3800 (2004); http://dx.doi.org/10.1063/1.1807969 (3 pages) | Cited 6 times

Online Publication Date: 29 October 2004

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We have fabricated precipitate-free La0.7Sr0.3MnO3 (LSMO) films by locating precipitate nucleation at artificial step edges patterned on SrTiO3 substrates and absorbing excess species of off-stoichiometry by getter effect. The precipitate-free and atomically flat area of about 10 μm width can be obtained along the step edges by pulsed-laser deposition at a substrate temperature Ts of ∼900 °C. Thermally activated processes are shown to be involved in such chemical reactions between the precipitates and surface migrating species. LSMO∕SrTiO3∕LSMO tunnel junctions fabricated by this method showed an excellent uniformity of the junction resistances.
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68.55.A- Nucleation and growth
61.72.Yx Interaction between different crystal defects; gettering effect
61.66.Bi Elemental solids
61.66.Dk Alloys
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
81.30.Mh Solid-phase precipitation
81.15.Fg Pulsed laser ablation deposition
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