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

8 Sep 1997

Volume 71, Issue 10, pp. 1285-1432

Page 2 of 2 Pages Previous Page | Jump to Page

Evolution of stress relaxation and yellow luminescence in GaN/sapphire by Si incorporation

In-Hwan Lee, In-Hoon Choi, C. R. Lee, and S. K. Noh

Appl. Phys. Lett. 71, 1359 (1997); http://dx.doi.org/10.1063/1.119893 (3 pages) | Cited 59 times

Full Text: | Download PDF

Show Abstract
We report a systematic study accomplished with a series of undoped and Si-doped GaN epilayers grown on sapphire (0001) with the carrier concentration of 4.0×1017−1.6×1019 cm−3 in order to investigate the evolution of stress relaxation and yellow luminescence by Si incorporation. As the Si doping becomes higher, the bound exciton peaks are gradually shifted to lower energy due to relaxation of the thermal residual stress with the linear coefficient of ΔE/Δσ∥ = 42 meV/GPa. The present results show that both the full width at half maximum of double-crystal x-ray diffractometry and the photoluminescence intensity ratio of the yellow luminescence to edge emission gradually increase as the Si incorporation becomes heavier. We suggest that the Si doping in GaN epilayers induces overall defects and gives rise to stress relaxation during the cool-down process, and the yellow luminescence may be originated from a complex of VGa and the Si-induced defect. © 1997 American Institute of Physics.
Show PACS
68.60.Bs Mechanical and acoustical properties
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
78.55.Cr III-V semiconductors
71.35.Cc Intrinsic properties of excitons; optical absorption spectra
61.72.uj III-V and II-VI semiconductors

Measurement of the depth distribution of ion beam etching-induced damage in AlGaAs/GaAs multiple quantum well structure

F. Frost, K. Otte, A. Schindler, F. Bigl, G. Lippold, and V. Gottschalch

Appl. Phys. Lett. 71, 1362 (1997); http://dx.doi.org/10.1063/1.119894 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The defect depth distribution caused by a 500 eV nitrogen ion beam etching (IBE) of an Al0.35Ga0.65As/GaAs multiple quantum well (MQW) structure was investigated by confocal photoluminescence (PL) measurements on a beveled section of the sample. The beveled section with an extremely small inclination angle necessary for the high depth resolution was fabricated by the IBE itself. Compared to other ion beam or plasma assisted etching processes reported, e.g., Ar-IBE, the 500 eV nitrogen IBE yields a very low defect density. A model including diffusion effects for the description of the profile gives a value of 4×10−15 cm2 /s for the defect diffusion coefficient. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
73.61.Ey III-V semiconductors
81.65.Cf Surface cleaning, etching, patterning
78.66.Fd III-V semiconductors
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
85.35.Be Quantum well devices (quantum dots, quantum wires, etc.)
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

Growth of AlN and GaN on 6H–SiC(0001) using a helium supersonic beam seeded with ammonia

V. M. Torres, M. Stevens, J. L. Edwards, David J. Smith, R. B. Doak, and I. S. T. Tsong

Appl. Phys. Lett. 71, 1365 (1997); http://dx.doi.org/10.1063/1.119895 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
We have grown AlN and GaN layers on 4° off-axis 6H–SiC (0001) substrates using He supersonic beams seeded with NH3. The AlN films were used as buffer layers for GaN growth at 800°C. We estimate 39% incorporation of the NH3 molecules impinging on the substrate surface during GaN film growth. High structural quality of the epitaxial GaN layers was confirmed by transmission electron microscopy and electron channeling patterns. The GaN films, which had a thickness of ∼ 105 nm, contained a defect density of ∼ 2×1010 cm−2. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy

Effects of well thickness and Si doping on the optical properties of GaN/AlGaN multiple quantum wells

K. C. Zeng, J. Y. Lin, H. X. Jiang, A. Salvador, G. Popovici, H. Tang, W. Kim, and H. Morkoç

Appl. Phys. Lett. 71, 1368 (1997); http://dx.doi.org/10.1063/1.119896 (3 pages) | Cited 37 times

Full Text: | Download PDF

Show Abstract
Effects of well thickness and Si doping on the optical properties of GaN/AlGaN (MQWs) have been investigated by picosecond time-resolved photoluminescence (PL) measurements. Our results have yielded that (i) the optical transitions in nominally undoped MQWs with narrow well thicknesses (Lw<40 Å) were blue shifted with respect to the GaN epilayer due to quantum confinement, however, no such blue shift was evident for the MQWs with well thicknesses larger than 40 Å, (ii) the band-to-impurity transitions were the dominant emission lines in nominally undoped MQWs of large well thicknesses (Lw>40 Å) at low temperatures, and (iii) Si doping improved significantly the crystalline quality of MQWs of large well thicknesses (Lw>40 Å). The implications of these results on the device applications based on III-nitride MQWs have been discussed. © 1997 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
78.47.-p Spectroscopy of solid state dynamics

Low-temperature nitridation of silicon surface using NH3-decomposed species in a catalytic chemical vapor deposition system

Akira Izumi and Hideki Matsumura

Appl. Phys. Lett. 71, 1371 (1997); http://dx.doi.org/10.1063/1.119897 (2 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
This letter reports a procedure for low-temperature nitridation of silicon surfaces using species produced by NH3 catalytic decomposition on heated tungsten in a catalytic chemical vapor deposition system. The surface of Si(100) was nitrided at temperatures as low as 200 °C. Silicon oxinitride films are obtained with a stoichiometry Si:N:O=1:0.9:0.3, a maximum thickness as high as 4.8 nm and an electrical breakdown field of 6 MV/cm. © 1997 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
77.22.Jp Dielectric breakdown and space-charge effects

Negative differential resistance in InGaAs/AlAsSb/InGaAs single-barrier heterostructure

W. K. Chen, R. H. Cheng, and J. Ou

Appl. Phys. Lett. 71, 1373 (1997); http://dx.doi.org/10.1063/1.119898 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
We have observed negative differential resistance in InP lattice-matched InGaAs/AlAsSb/InGaAs single-barrier tunneling heterostructure. With a 10-nm-thick barrier, the diode exhibits a peak-to-valley current ratio of 4.2 (1.2) and peak current density of 54 (158) A/cm2 at 100 K (300 K). © 1997 American Institute of Physics.
Show PACS
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
85.30.Kk Junction diodes
73.61.Ey III-V semiconductors
81.05.Ea III-V semiconductors

In situ optical second-harmonic-generation monitoring of disilane adsorption and hydrogen desorption during epitaxial growth on Si(001)

X. F. Hu, Z. Xu, D. Lim, M. C. Downer, P. S. Parkinson, B. Gong, G. Hess, and J. G. Ekerdt

Appl. Phys. Lett. 71, 1376 (1997); http://dx.doi.org/10.1063/1.119927 (3 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
The kinetics of disilane adsorption and hydrogen desorption during low-temperature, ultrahigh vacuum chemical vapor deposition on Si(001) is investigated in situ in real time by monitoring the instantaneous hydrogen coverage using optical second-harmonic generation. A simple two-site adsorption model and first-order desorption are used to establish a reactive sticking coefficient and to predict the Si(001) epitaxial growth rate. The reactive sticking coefficient is temperature independent between 740 and 920 K and equal to 0.04±0.01. Predicted growth rates are in agreement with published growth rates obtained from gas-source molecular-beam epitaxy of Si(001). © 1997 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
68.03.Fg Evaporation and condensation of liquids
68.43.Mn Adsorption kinetics
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation

Trivalent behavior of palladium in silicon

J.-U. Sachse, W. Jost, J. Weber, and H. Lemke

Appl. Phys. Lett. 71, 1379 (1997); http://dx.doi.org/10.1063/1.119899 (3 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
Palladium is known to exhibit an acceptor state at EC−0.22 eV in n-type Si and a donor state at EV+0.31 eV in p-type Si. We have identified a third level at EV+(0.140±0.005) eV and attribute it to the double donor state of substitutional Pd. The Pd level positions are very similar to the corresponding levels for Pt. The double donor states of both metals show an electric field dependence of the emission rates and a thermal activation of the hole capture cross sections. © 1997 American Institute of Physics.
Show PACS
71.55.Cn Elemental semiconductors

Optical data storage in InGaN/GaN heterostructures

I. K. Shmagin, J. F. Muth, R. M. Kolbas, R. D. Dupuis, P. A. Grudowski, C. J. Eiting, J. Park, B. S. Shelton, and D. J. H. Lambert

Appl. Phys. Lett. 71, 1382 (1997); http://dx.doi.org/10.1063/1.119900 (3 pages) | Cited 7 times

Full Text: | Download PDF

Show Abstract
Optical storage data was realized using an InGaN/GaN single heterostructure. It was observed that exposure to a high power density ultraviolet light temporarily changes the optical properties of the InGaN epitaxial layer. The photo-induced changes can be observed under an optical microscope with low intensity ultraviolet excitation. This effect was used to create high contrast optical patterns on the sample at room temperature and 77 K. The photo-induced changes completely disappear in about four hours at room temperature. After the recorded pattern is erased, the information can be rewritten without a change in efficiency or retention time. © 1997 American Institute of Physics.
Show PACS
42.79.Vb Optical storage systems, optical disks
42.70.Gi Light-sensitive materials
78.55.Cr III-V semiconductors
78.66.Fd III-V semiconductors
78.45.+h Stimulated emission

The process and efficiency of ultraviolet generation from gallium nitride blue light emitting diodes

J. P. Basrur, F. S. Choa, P.-L. Liu, J. Sipior, G. Rao, G. M. Carter, and Y. J. Chen

Appl. Phys. Lett. 71, 1385 (1997); http://dx.doi.org/10.1063/1.119901 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
To obtain small size, high speed ultraviolet sources, we studied the ultraviolet (UV) generation process and efficiency of gallium nitride (GaN) blue light emitting diodes (LEDs). The blue and UV emissions follow a four-level recombination model. Depending on the pump pulse amplitude, the UV-to-blue generation ratio increases and then saturates with increasing pump pulse duration. High efficiency, up to 450 μW UV power at 380 nm, can be obtained from a 1.2 mW blue LED. © 1997 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
42.72.Bj Visible and ultraviolet sources
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
78.60.Fi Electroluminescence
85.30.De Semiconductor-device characterization, design, and modeling

Organic–inorganic heterojunction light emitting diodes based on poly(p-phenylenevinylene)/cadmium sulfide thin films

N. Deepak Kumar, Mukesh P. Joshi, Christopher S. Friend, Paras N. Prasad, and Ryszard Burzynski

Appl. Phys. Lett. 71, 1388 (1997); http://dx.doi.org/10.1063/1.120196 (3 pages) | Cited 28 times

Full Text: | Download PDF

Show Abstract
We report on a solution processed novel electroluminescent heterostructure device consisting of an inorganic semiconductor, CdS, and a polymer emitter, poly(p-phenylene vinylene) (PPV). This configuration provides the advantage of excellent charge transporting properties of an inorganic semiconductor and the high luminescence quantum efficiency of an organic emitter. The electroluminescence spectrum obtained from this hetrostructure device is similar to the emission spectrum of pure PPV. Even with aluminum electrode, we have achieved stable electroluminescence at very low threshold voltage (3 V) and overall quantum efficiency of about 1% in these devices. The device emitted bright electroluminescence radiation (150 cd/m2) at a driving voltage of 10 V under the forward bias condition. © 1997 American Institute of Physics.
Show PACS
85.60.Jb Light-emitting devices
78.60.Fi Electroluminescence
78.66.Hf II-VI semiconductors
78.66.Qn Polymers; organic compounds

Photoluminescence of ozone oxidized and HF etched porous silicon and the multiple source quantum well model

L. Jia, S. P. Wong, I. H. Wilson, S. K. Hark, S. L. Zhang, Z. F. Liu, and S. M. Cai

Appl. Phys. Lett. 71, 1391 (1997); http://dx.doi.org/10.1063/1.119902 (3 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
Porous silicon (PS) samples were alternately oxidized in an ozone atmosphere and etched in HF solution. The variation of the corresponding photoluminescence (PL) implies that there is more than one origin responsible for the PL of PS. These results are explained by a multiple source quantum well model, where the nanoscale Si units and their covering oxide layers both contribute to the PL in different situations. © 1997 American Institute of Physics.
Show PACS
78.66.Db Elemental semiconductors and insulators
78.55.Mb Porous materials
81.05.Cy Elemental semiconductors
81.05.Rm Porous materials; granular materials
78.66.Jg Amorphous semiconductors; glasses
81.65.Cf Surface cleaning, etching, patterning
81.65.Mq Oxidation

Photoluminescence of InGaAs/GaAs single quantum well adjacent to a selectively oxidized AlAs layer

A. R. Pratt, T. Takamori, and T. Kamijoh

Appl. Phys. Lett. 71, 1394 (1997); http://dx.doi.org/10.1063/1.119903 (3 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
Photoluminescence (PL) has been used to characterize an InGaAs/GaAs single quantum well (SQW) adjacent to a selectively oxidized AlAs layer. For a direct interface between the SQW and AlAs, the room temperature PL intensity is drastically reduced after oxidation indicating the presence of an efficient non-radiative pathway. However, a 20 nm AlGaAs layer grown between the SQW and the AlAs effectively isolates the SQW and yields a luminescence efficiency after oxidation identical to that of the as grown material. © 1997 American Institute of Physics.
Show PACS
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
81.65.Mq Oxidation
81.05.Ea III-V semiconductors

Solid-phase epitaxial growth of AlxGa1−xAs alloys as a function of Al content

S. M. Hogg, D. J. Llewellyn, H. H. Tan, and M. C. Ridgway

Appl. Phys. Lett. 71, 1397 (1997); http://dx.doi.org/10.1063/1.119904 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The solid-phase epitaxial growth (SPEG) of amorphized AlxGa1−xAs alloys has been investigated as a function of Al content (0 ⩽ x ⩽ 0.46). Time-resolved reflectivity and Rutherford backscattering spectrometry in combination with channeling (RBS/C) were used to determine the recrystallization kinetics over the temperature range 220–310 °C. Residual disorder was characterized with RBS/C and cross-sectional transmission electron microscopy. At a given temperature, both the average velocity and nonplanarity of the amorphous/crystalline interface increased as the Al content increased. In contrast, an Al-content dependence was not observed for residual disorder—for all compositions, single-crystal regrowth was apparent for ∼ 25 nm followed by the onset of twinning. The SPEG kinetics exhibited an Arrhenius-type temperature behavior with an average activation energy Eact value of 1.60 eV independent of Al content. Also, the validity of a recrystallization mechanism based on the collective reorganization of groups of atoms was verified—Debye frequency values derived from experimental Eact results were in excellent agreement with theoretical predictions. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
81.15.Np Solid phase epitaxy; growth from solid phases
78.47.-p Spectroscopy of solid state dynamics
78.66.Fd III-V semiconductors
61.85.+p Channeling phenomena (blocking, energy loss, etc.)
61.72.Mm Grain and twin boundaries

Preservation of rectangular-patterned InP gratings overgrown by gas source molecular beam epitaxy

E. M. Koontz, M. H. Lim, V. V. Wong, G. S. Petrich, L. A. Kolodziejski, Henry I. Smith, K. M. Matney, G. D. U’Ren, and M. S. Goorsky

Appl. Phys. Lett. 71, 1400 (1997); http://dx.doi.org/10.1063/1.119905 (3 pages) | Cited 4 times

Full Text: | Download PDF

Show Abstract
The ability to preserve a grating profile during epitaxial overgrowth is vital to the design and operation of devices such as planar waveguide-coupled Bragg-resonant filters. Intentional preservation of rectangular-patterned InP gratings during gas source molecular beam epitaxial overgrowth has been accomplished. The use of a low temperature atomic hydrogen-assisted oxide removal technique alleviates the dependence on elevated temperatures for desorption of the native oxide, and is crucial to the preservation of the patterned profile. Confirmation of the overgrown grating fidelity is demonstrated via scanning electron microscopy and triple axis x-ray diffractometry. © 1997 American Institute of Physics.
Show PACS
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
72.80.Ey III-V and II-VI semiconductors
81.05.Ea III-V semiconductors
42.79.Dj Gratings

Growth and characterization of InAs/GaSb photoconductors for long wavelength infrared range

H. Mohseni, E. Michel, Jan Sandoen, M. Razeghi, W. Mitchel, and G. Brown

Appl. Phys. Lett. 71, 1403 (1997); http://dx.doi.org/10.1063/1.119906 (3 pages) | Cited 42 times

Full Text: | Download PDF

Show Abstract
In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 μm and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of 1.33×109 cm Hz1/2/W at 10.3 μm at 78 K. © 1997 American Institute of Physics.
Show PACS
81.05.Ea III-V semiconductors
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
85.60.Gz Photodetectors (including infrared and CCD detectors)

Measurements of quasi-Fermi energies by scanning electron beam

S. Mil’shtein

Appl. Phys. Lett. 71, 1406 (1997); http://dx.doi.org/10.1063/1.119907 (3 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
Scanning electron microscopy dark voltage contrast (DVC) was used to define quasi-Fermi energies in a silicon p-n junction either under illumination or forward bias conditions. Quantitative DVC measurements have proven to be a precise method of locating quasi-Fermi levels (QFLs) in any operating device. By simultaneously using light and electron beams we have obtained accurate measurements of the position of QFLs by DVC in an illuminated p-n junction. © 1997 American Institute of Physics.
Show PACS
73.20.At Surface states, band structure, electron density of states
73.40.Lq Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
68.37.Hk Scanning electron microscopy (SEM) (including EBIC)
68.37.Lp Transmission electron microscopy (TEM)
73.61.Cw Elemental semiconductors

Self-formed silicon quantum wires on ultrasmooth sapphire substrates

Shun-ichi Yanagiya, Shunsuke Kamimura, Masanori Fujii, Makoto Ishida, Yoshitaka Moriyasu, Masahiro Matsui, Mamoru Yoshimoto, Tsuyoshi Ohnishi, Kenji Yoshida, Kenji Sasaki, and Hideomi Koinuma

Appl. Phys. Lett. 71, 1409 (1997); http://dx.doi.org/10.1063/1.119908 (3 pages) | Cited 11 times

Full Text: | Download PDF

Show Abstract
We have observed step-flow growth of Si on sapphire, for the first time, by gas-source molecular beam epitaxy using ultrasmooth sapphire substrates, and self-formed Si quantum wires were fabricated on the substrates. The wires were aligned along the substrate steps and formed uniformly with 50 nm width and 1 nm height. Visible photoluminescence from the wires was observed at 9 and 300 K. The optical properties of the wires were very similar to those observed in conventional porous silicon and other nanostructured silicon. © 1997 American Institute of Physics.
Show PACS
81.05.Cy Elemental semiconductors
68.55.-a Thin film structure and morphology
78.55.Ap Elemental semiconductors
78.66.Db Elemental semiconductors and insulators

Observation of coherent modes of Josephson vortices in Bi2Sr2CaCu2Ox

J. U. Lee, P. Guptasarma, D. Hornbaker, A. El-Kortas, D. Hinks, and K. E. Gray

Appl. Phys. Lett. 71, 1412 (1997); http://dx.doi.org/10.1063/1.119909 (3 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
We report strong evidence for coherent modes of moving Josephson vortices in mesas patterned on the surface of Bi2Sr2CaCu2Ox single crystals. The vortex flow current–voltage curves are characterized by a sharp up-turn and the appearance of multiple branches as the current is ramped up and down at a fixed magnetic field and temperature. These results are consistent with weakly damped motion of Josephson vortices in which different coherent modes can occur in a close stack of Josephson coupled multilayers. © 1997 American Institute of Physics.
Show PACS
74.72.-h Cuprate superconductors
74.25.Uv Vortex phases (includes vortex lattices, vortex liquids, and vortex glasses)
74.78.Fk Multilayers, superlattices, heterostructures
74.50.+r Tunneling phenomena; Josephson effects

Voltage responses to optical pulses of unbiased normal and superconducting samples

D. Van Vechten, K. S. Wood, G. G. Fritz, J. S. Horwitz, G. M. Daly, J. B. Thrasher, D. M. Photiadis, J. Ding, J. F. Pinto, M. G. Blamire, G. Burnell, A. L. Gyulamiryan, V. H. Vartanyan, R. B. Akopyan, and A. M. Gulian

Appl. Phys. Lett. 71, 1415 (1997); http://dx.doi.org/10.1063/1.119910 (3 pages)

Full Text: | Download PDF

Show Abstract
The direct transformation of the energy of an incident high-energy photon into a measurable potential difference within an absorbing metal is investigated. Experimental evidence is presented that the effect arises from the inherent energy dependence of the electronic density of states, rather than from a simple temperature excursion. The similarities between the results on Al and YBa2Cu3O7 samples indicate that the effect is universal in nature. We assert it may be used as the basis of a fast, energy resolving, individual photon detector for the ultraviolet radiation and x-rays. © 1997 American Institute of Physics.
Show PACS
74.72.-h Cuprate superconductors
72.40.+w Photoconduction and photovoltaic effects
71.20.Gj Other metals and alloys
85.60.Gz Photodetectors (including infrared and CCD detectors)
71.20.Ps Other inorganic compounds

Theory of magnetic dissipation imaging

Y. Liu, B. Ellman, and P. Grütter

Appl. Phys. Lett. 71, 1418 (1997); http://dx.doi.org/10.1063/1.119911 (3 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
A model is presented for magnetic dissipation imaging and magnetic force gradient imaging obtained with a vibrating ferromagnetic tip and a ferromagnetic thin film sample. Results of calculations are compared to recent experiments and show good agreement using known bulk values for the magnetic parameters of tip and sample. We suggest that oscillations of domain wall width result in magnetoelastic emission of phonons. These phonons carry energy from the tip, leading to image contrast at domain walls. We also discuss the energy dissipation resulting from eddy current losses in the tip and sample. © 1997 American Institute of Physics.
Show PACS
68.37.Ef Scanning tunneling microscopy (including chemistry induced with STM)
68.37.Ps Atomic force microscopy (AFM)
68.37.Rt Magnetic force microscopy (MFM)
68.37.Uv Near-field scanning microscopy and spectroscopy
75.70.Kw Domain structure (including magnetic bubbles and vortices)
75.80.+q Magnetomechanical effects, magnetostriction

Magnetoresistance in the oxygen deficient LnBaCo2O5.4 (Ln=Eu, Gd) phases

C. Martin, A. Maignan, D. Pelloquin, N. Nguyen, and B. Raveau

Appl. Phys. Lett. 71, 1421 (1997); http://dx.doi.org/10.1063/1.119912 (3 pages) | Cited 141 times

Full Text: | Download PDF

Show Abstract
New “112” phases, LnBaCo2O5.4, with an ordered oxygen deficient perovskite structure, derived from the YBaFeCuO5-type were studied for Ln=Eu, Gd. The appearance of giant negative magnetoresistance in this structural type is demonstrated. Resistance ratio R0/R7 T reaches at least 10 at 10 K, i.e., is significantly larger than those observed in the other cobalt perovskites, such as La1−xSrxCoO3. These properties are linked to an original magnetic behavior of these materials that exhibit two types of transition—antiferromagnetic to ferromagnetic, and ferromagnetic to paramagnetic—as T increases. This magnetic behavior may be related to a possible I.S. and L.S. spin ordering of trivalent cobalt in pyramidal and octahedral coordinations, respectively. © 1997 American Institute of Physics.
Show PACS
72.20.My Galvanomagnetic and other magnetotransport effects
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)

Simultaneous electronic and magnetic transitions in La1−xKxMnO3 thin films

Chun-Che Chen and Alex de Lozanne

Appl. Phys. Lett. 71, 1424 (1997); http://dx.doi.org/10.1063/1.119913 (3 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
We have fabricated perovskite La1−xKxMnO3 (x = 0.14 and 0.2) thin films on SrTiO3 (100) by e-beam/thermal coevaporation. From the electrical and magnetic studies, we found a simultaneous occurrence of the paramagnetic to ferromagnetic state and insulating to metallic state, as predicted by the double exchange theory. The magnetoresistance is relatively small compared to that of the divalent cation doped La1−xAxMnO3 in fields up to 5 T. © 1997 American Institute of Physics.
Show PACS
75.70.Ak Magnetic properties of monolayers and thin films
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
71.30.+h Metal-insulator transitions and other electronic transitions
75.47.De Giant magnetoresistance
73.50.Jt Galvanomagnetic and other magnetotransport effects (including thermomagnetic effects)
73.61.Ng Insulators

Nanolithography with metastable neon atoms: Enhanced rate of contamination resist formation for nanostructure fabrication

S. J. Rehse, A. D. Glueck, S. A. Lee, A. B. Goulakov, C. S. Menoni, D. C. Ralph, K. S. Johnson, and M. Prentiss

Appl. Phys. Lett. 71, 1427 (1997); http://dx.doi.org/10.1063/1.119914 (3 pages) | Cited 21 times

Full Text: | Download PDF

Show Abstract
We report a sevenfold improvement in the rate of contamination resist formation over previous experiments by using metastable neon atoms for nanolithography. Chemically assisted ion beam etching was used to transfer the resist pattern into the substrate. We demonstrate the fabrication of 50-nm-wide features in GaAs with well-defined edges and an aspect ratio >2:1. These are the best resolution and highest aspect ratio features that have been achieved with metastable atom lithography. The resist formation rate by the metastable neon atoms and the etch selectivity of the contamination resist with GaAs were measured. © 1997 American Institute of Physics.
Show PACS
85.40.Hp Lithography, masks and pattern transfer
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices
81.65.Cf Surface cleaning, etching, patterning
81.05.Ea III-V semiconductors

Field emission from tetrahedral amorphous carbon

B. S. Satyanarayana, A. Hart, W. I. Milne, and J. Robertson

Appl. Phys. Lett. 71, 1430 (1997); http://dx.doi.org/10.1063/1.119915 (3 pages) | Cited 178 times

Full Text: | Download PDF

Show Abstract
Field emission has been measured from a series of tetrahedrally bonded amorphous carbon (ta-C) films produced by the filtered cathodic vacuum arc. The threshold field and current densities achievable have been studied as a function of their sp3 content and of nitrogen incorporation. Typical undoped ta-C films are found to have a threshold field of 10–20 V/μm, decreasing with increasing sp3 content, and optimally nitrogen doped films exhibit threshold fields as low as 3–5 V/μm. © 1997 American Institute of Physics.
Show PACS
79.70.+q Field emission, ionization, evaporation, and desorption
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy
Page 2 of 2 Pages Previous Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close