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31 Jan 2000

Volume 76, Issue 5, pp. 523-656

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Multiple gratings simultaneously formed in holographic polymer-dispersed liquid-crystal displays

Chris C. Bowley, Adam K. Fontecchio, Gregory P. Crawford, Jau-Jeng Lin, Le Li, and Sadeg Faris

Appl. Phys. Lett. 76, 523 (2000); http://dx.doi.org/10.1063/1.125836 (3 pages) | Cited 32 times

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We report single-layer holographic polymer-dispersed liquid-crystal materials with multiple reflection and/or diffraction gratings. Three switchable gratings are observed in a single film formed in a three-beam interference pattern. Two reflection gratings and one transmission grating are formed, corresponding to each of the three possible two-beam interference fringes. We present scanning electron microscopy and electro-optic results which are in good agreement with our model based on matrix methods and coupled-wave theory. © 2000 American Institute of Physics.
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42.79.Wc Optical coatings
42.40.Eq Holographic optical elements; holographic gratings
42.79.Kr Display devices, liquid-crystal devices
78.20.Jq Electro-optical effects
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation

Near-field spectroscopy of selectively oxidized vertical cavity surface emitting lasers

J. Kim, J. T. Boyd, Howard E. Jackson, and K. D. Choquette

Appl. Phys. Lett. 76, 526 (2000); http://dx.doi.org/10.1063/1.125807 (3 pages) | Cited 9 times

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Selectively oxidized vertical cavity surface emitting lasers (VCSELs) have been studied by spectrally resolved near-field scanning optical microscopy. We have obtained spatially and spectrally resolved images of both subthreshold emission and lasing emission from a selectively oxidized VCSEL operating at a wavelength of 850 nm. Below threshold, highly local high gain regions, emitting local intensity maxima within the active area, were observed; these were found to serve as lasing centers just above threshold. Above threshold, the near-field spatial modal distributions of low order transverse modes were identified by spectrally analyzing the emission; these were found to be complex and somewhat different from those measured in the far field. © 2000 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.Da Resonators, cavities, amplifiers, arrays, and rings
07.79.Fc Near-field scanning optical microscopes
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

Improved characteristics of InGaN multiple-quantum-well laser diodes grown on laterally epitaxially overgrown GaN on sapphire

M. Hansen, P. Fini, L. Zhao, A. C. Abare, L. A. Coldren, J. S. Speck, and S. P. DenBaars

Appl. Phys. Lett. 76, 529 (2000); http://dx.doi.org/10.1063/1.125808 (3 pages) | Cited 37 times

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InGaN multiple-quantum-well laser diodes have been fabricated on fully coalesced laterally epitaxially overgrown (LEO) GaN on sapphire. The laterally overgrown “wing” regions as well as the coalescence fronts contained few or no threading dislocations. Laser diodes fabricated on these low-dislocation-density regions showed a reduction in threshold current density from 10 to 4.8 kA/cm2 compared to those on conventional planar GaN on sapphire. The internal quantum efficiency also improved from 3% for laser diodes on conventional GaN on sapphire to 22% for laser diodes on LEO GaN on sapphire. © 2000 American Institute of Physics.
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81.05.Ea III-V semiconductors
42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
61.72.Ff Direct observation of dislocations and other defects (etch pits, decoration, electron microscopy, x-ray topography, etc.)

Radiation losses of waveguide-based two-dimensional photonic crystals: Positive role of the substrate

H. Benisty, D. Labilloy, C. Weisbuch, C. J. M. Smith, T. F. Krauss, D. Cassagne, A. Béraud, and C. Jouanin

Appl. Phys. Lett. 76, 532 (2000); http://dx.doi.org/10.1063/1.125809 (3 pages) | Cited 106 times

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Radiation losses occurring in photonic crystals etched into planar waveguides are analyzed using a first-order perturbation approximation. Assuming the incoherent scattering limit, the model indicates that losses diminish as the cladding index approaches the core index. A simple scheme is devised to include these losses into purely two-dimensional calculations by using an imaginary index. Such calculations are shown to agree with corresponding experimental transmission through near-infrared photonic crystals, reproducing the contrasting behavior of the “dielectric” and “air” band edges. © 2000 American Institute of Physics.
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42.70.Qs Photonic bandgap materials
42.79.Gn Optical waveguides and couplers
42.82.Et Waveguides, couplers, and arrays

Stability of the single-mode output of a laser diode array with phase conjugate feedback

S. Juul Jensen, M. Løbel, and P. M. Petersen

Appl. Phys. Lett. 76, 535 (2000); http://dx.doi.org/10.1063/1.125810 (3 pages) | Cited 5 times

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The stability of the output of a single-mode laser diode array with frequency selective phase conjugate feedback has been investigated experimentally. Both the long-term stability of the laser output and the sensitivity to feedback generated by external reflection of the output beam are examined. The output power and the center wavelength are found to be extremely stable in a 100 h stability measurement. External feedback of the output beam into the laser is seen to decrease both the spatial and the temporal coherence of the output significantly. We outline an approach to obtain a stable single-mode output when external feedback is present using spatial filtering in the path of the output beam. © 2000 American Institute of Physics.
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42.60.Da Resonators, cavities, amplifiers, arrays, and rings
42.55.Px Semiconductor lasers; laser diodes
42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.79.Ci Filters, zone plates, and polarizers

Large enhancement of second harmonic generation in polymer films by microcavities

H. Cao, D. B. Hall, J. M. Torkelson, and C.-Q. Cao

Appl. Phys. Lett. 76, 538 (2000); http://dx.doi.org/10.1063/1.125811 (3 pages) | Cited 23 times

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We report significant enhancement of second-harmonic-generation intensity in a nonlinear optical polymer by strongly confining the fundamental light in a planar microcavity. Employing a microcavity formed by a distributed Bragg reflector and a silver layer, we have observed up to a factor of 50 increase of second-harmonic light intensity in polymer thin films. © 2000 American Institute of Physics.
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42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.70.Jk Polymers and organics
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.65.An Optical susceptibility, hyperpolarizability
78.66.Qn Polymers; organic compounds
42.79.Bh Lenses, prisms and mirrors

Direct measurement of optical phase in the near field

P. L. Phillips, J. C. Knight, J. M. Pottage, G. Kakarantzas, and P. St. J. Russell

Appl. Phys. Lett. 76, 541 (2000); http://dx.doi.org/10.1063/1.125812 (3 pages) | Cited 15 times

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To fully characterize photonic crystal guided wave optical devices, one needs to measure the spatial variation of both the phase and amplitude of the electromagnetic field. In this work, we simultaneously measure the intensity and phase in the near field of both propagating and evanescent fields by incorporating a scanning near-field optical microscope into one arm of a Mach–Zehnder interferometer. We demonstrate the technique by imaging the phase fronts of an evanescent wave formed by total internal reflection and by measuring the phase variation in the LP11 mode in an overmoded optical fiber. © 2000 American Institute of Physics.
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42.70.Qs Photonic bandgap materials
07.79.Fc Near-field scanning optical microscopes
07.60.Ly Interferometers
42.50.-p Quantum optics
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
42.81.Cn Fiber testing and measurement of fiber parameters
42.87.-d Optical testing techniques
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Vacuum emission and breakdown characteristics of a planar He–Xe microdischarge

Olivier B. Postel and Mark A. Cappelli

Appl. Phys. Lett. 76, 544 (2000); http://dx.doi.org/10.1063/1.125813 (3 pages) | Cited 9 times

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Vacuum emission, breakdown, and current–voltage characteristics of a large surface area-to-volume ratio planar dc microdischarge have been measured for different He–Xe mixtures in the range of 10%–100% Xe and pressures in the range of 60–500 Torr. The electrical measurements show that the Paschen breakdown curves and the current–voltage characteristics are primarily controlled by the xenon concentration in the mixture. A study of the vacuum ultraviolet emission of xenon atoms at 147 nm and of xenon dimers at 150 nm normalized to the discharge power reveals the presence of local maxima in the emitted intensity as a function of discharge pressure and xenon concentration, indicative of complex excited-state atomic and excimer kinetic processes. © 2000 American Institute of Physics.
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52.80.Hc Glow; corona
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Electron temperature control by varying size of slits made in a grid

Kohgi Kato, Tetsuji Shimizu, Satoru Iizuka, and Noriyoshi Sato

Appl. Phys. Lett. 76, 547 (2000); http://dx.doi.org/10.1063/1.125814 (3 pages) | Cited 18 times

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Electron temperature is controlled by varying the length of slits made in a grid immersed in a weakly ionized discharge plasma. The grid, which is kept at floating potential, has six slits in this experiment. With a decrease in the slit length from 6 to 0 cm, the electron temperature decreases from 2.1 to 0.09 eV, being accompanied by an electron-density increase from 0.32×109 to 1.53×109 cm−3 at argon gas pressure of 1.5 mTorr. This method of electron–temperature control is applicable to reactive plasmas in which grids are often covered by insulators. © 2000 American Institute of Physics.
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52.25.Jm Ionization of plasmas
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
52.80.-s Electric discharges
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Growth and characterization of hypothetical zinc-blende ZnO films on GaAs(001) substrates with ZnS buffer layers

A. B. M. Almamun Ashrafi, Akio Ueta, Adrian Avramescu, Hidekazu Kumano, Ikuo Suemune, Young-Woo Ok, and Tae-Yeon Seong

Appl. Phys. Lett. 76, 550 (2000); http://dx.doi.org/10.1063/1.125851 (3 pages) | Cited 60 times

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A stable wurtzite phase of ZnO is commonly observed. In this letter, we report the growth and characterization of zinc-blende ZnO on GaAs(001) substrates. The ZnO films grown on GaAs(001) substrates using microwave-plasma-assisted metalorganic molecular-beam epitaxy were characterized by reflection high-energy electron diffraction, x-ray diffraction, transmission electron microscope, and atomic force microscope measurements. The use of a ZnS buffer layer was found to lead to the growth of the zinc-blende ZnO films. Although the zinc-blende ZnO films were polycrystalline with columnar structures, they showed bright band-edge luminescence at room temperature. © 2000 American Institute of Physics.
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68.55.-a Thin film structure and morphology
81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.05.Dz II-VI semiconductors
78.66.Hf II-VI semiconductors
78.55.Et II-VI semiconductors

First-principles study of NH3 exposed Si(001)2×1: Relation between N 1s core-level shifts and atomic structure

G.-M. Rignanese and Alfredo Pasquarello

Appl. Phys. Lett. 76, 553 (2000); http://dx.doi.org/10.1063/1.125815 (3 pages) | Cited 33 times

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Using a first-principles approach, we assign N 1s core-level shifts at ammonium exposed Si(001)2×1 surfaces to definite bonding configurations of N atoms. Model structures are obtained by fully relaxing the atomic positions of N atoms in different bonding configurations. Calculated values of N 1s core-level shifts of N-Si3, N-Si2H, and N-SiH2 structural units show a linear dependence on the number of nearest-neighbor H atoms, in good agreement with data from photoemission experiments. Our results support the picture in which NH3 is adsorbed dissociatively as NH2 and H. © 2000 American Institute of Physics.
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81.05.Cy Elemental semiconductors
81.65.Lp Surface hardening: nitridation, carburization, carbonitridation
68.35.B- Structure of clean surfaces (and surface reconstruction)
73.20.At Surface states, band structure, electron density of states

High-power quantum-dot lasers at 1100 nm

F. Heinrichsdorff, Ch. Ribbat, M. Grundmann, and D. Bimberg

Appl. Phys. Lett. 76, 556 (2000); http://dx.doi.org/10.1063/1.125816 (3 pages) | Cited 40 times

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High-power semiconductor laser diodes based on multiple InGaAs/GaAs quantum-dot layers grown by metal–organic chemical-vapor deposition are demonstrated. The devices exhibit a peak power of 3 W (4.5 W) at 1100 nm (1068 nm), respectively, during pulsed operation at room temperature and show slope efficiencies of 57% (66%). © 2000 American Institute of Physics.
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42.60.By Design of specific laser systems
42.55.Px Semiconductor lasers; laser diodes
78.66.Fd III-V semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
78.55.Cr III-V semiconductors

Layer-by-layer growth of ZnO epilayer on Al2O3(0001) by using a MgO buffer layer

Yefan Chen, Hang-Ju Ko, Soon-Ku Hong, and Takafumi Yao

Appl. Phys. Lett. 76, 559 (2000); http://dx.doi.org/10.1063/1.125817 (3 pages) | Cited 116 times

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By introducing a thin MgO buffer, layer-by-layer growth of ZnO epilayers on Al2O3(0001) substrates is achieved by plasma-assisted molecular beam epitaxy. The MgO buffer is very effective on the improvement of surface morphology during the initial growth stage, which eventually leads to an atomically flat surface. As a result, (3×3) surface reconstruction of ZnO is observed and reflection high-energy electron diffraction intensity oscillations are recorded. Structural analysis indicates that the twin defect with a 30° in-plane crystal orientation misaligned is completely eliminated, while the total dislocation density is reduced. Free exciton emissions at 3.3774 eV (XA) and 3.383 eV (XB) are observed in photoluminescence at 4.2 K further indicating the high quality of the resulting ZnO epilayers. © 2000 American Institute of Physics.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
81.05.Dz II-VI semiconductors
78.55.Et II-VI semiconductors
78.66.Hf II-VI semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.55.-a Thin film structure and morphology
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.15.Kk Vapor phase epitaxy; growth from vapor phase
68.35.B- Structure of clean surfaces (and surface reconstruction)
68.35.Rh Phase transitions and critical phenomena
61.72.Mm Grain and twin boundaries
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
71.35.Cc Intrinsic properties of excitons; optical absorption spectra

Chemical vapor deposition of Si nanowires nucleated by TiSi2 islands on Si

T. I. Kamins, R. Stanley Williams, Y. Chen, Y.-L. Chang, and Y. A. Chang

Appl. Phys. Lett. 76, 562 (2000); http://dx.doi.org/10.1063/1.125852 (3 pages) | Cited 70 times

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Silicon “nanowires” can be formed by chemical vapor deposition of Si onto Si substrates on which nanometer-scale, Ti-containing islands have been grown. At the growth temperatures used, the Ti-containing islands remain solid and anchored to the substrate, while the Si nanowires grow out from the islands, which remain at their bases. The nanowire growth mechanism, therefore, differs from the usual vapor-liquid-solid process and provides a potential route for the formation of oriented Si nanostructures or semiconductor-metal-semiconductor structures compatible with Si integrated circuits. © 2000 American Institute of Physics.
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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
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
81.05.Cy Elemental semiconductors
61.46.-w Structure of nanoscale materials
85.40.Sz Deposition technology
61.72.Cc Kinetics of defect formation and annealing

Ortho-molecular hydrogen in hydrogenated amorphous silicon

Tining Su, P. C. Taylor, Shenlin Chen, R. S. Crandall, and A. H. Mahan

Appl. Phys. Lett. 76, 565 (2000); http://dx.doi.org/10.1063/1.125818 (3 pages) | Cited 1 time

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Using a Jeener–Broekaert three-pulse sequence to measure directly the concentration of o-H2 by 1H nuclear magnetic resonance (NMR), we find that this concentration is one order of magnitude larger than that previously inferred from spin-lattice relaxation time (T1) measurements. At 300 K, this concentration of o-H2 contributes at most 30% to the narrow 1H NMR line attributed to hydrogen bonded to silicon. For a plasma-enhanced-chemical-vapor-deposition (PECVD) sample, two distinct values of T1 for o-H2 are found, only one of which contributes to the T1 for bonded hydrogen. In hot-wire-chemical-vapor-deposition samples, the line shape of o-H2 exhibits motional narrowing at lower temperatures, suggesting a more ordered structure than in a typical PECVD sample. © 2000 American Institute of Physics.
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61.43.Dq Amorphous semiconductors, metals, and alloys
76.60.Es Relaxation effects
76.60.Lz Spin echoes
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
81.05.Gc Amorphous semiconductors
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)

Comparison of nitrogen incorporation in SiO2/SiC and SiO2/Si structures

K. McDonald, M. B. Huang, R. A. Weller, L. C. Feldman, J. R. Williams, F. C. Stedile, I. J. R. Baumvol, and C. Radtke

Appl. Phys. Lett. 76, 568 (2000); http://dx.doi.org/10.1063/1.125819 (3 pages) | Cited 25 times

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The nitrogen content of SiO2/SiC (4H) structures annealed in NO and N2O has been measured using nuclear reaction analysis. Samples were annealed in 15N18O or 15N2O at 1000 °C at a static pressure of 10 mbar for either 1 or 4 h. Annealing in N2O incorporates ∼ 1013 cm−2 of N and annealing in NO incorporates ∼ 1014 cm−2, both of which are an order of magnitude lower than in SiO2/Si. In the NO anneal, N is predominantly incorporated near the SiO2/SiC interface with an atomic concentration of ∼0.5%. As in the nitridation of SiO2/Si, two features are observed in SiO2/SiC after the NO anneal: a surface exchange of O in the oxide with the gas phase and NO diffusion and reaction at the interface. The surface exchange reaction in SiO2/SiC is similar to SiO2/Si, but there is a large difference in the incorporation of N at the interface. © 2000 American Institute of Physics.
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81.65.Lp Surface hardening: nitridation, carburization, carbonitridation
61.72.Cc Kinetics of defect formation and annealing
61.72.S- Impurities in crystals
68.35.Dv Composition, segregation; defects and impurities
82.80.Jp Activation analysis and other radiochemical methods
66.30.Ny Chemical interdiffusion; diffusion barriers
82.30.Hk Chemical exchanges (substitution, atom transfer, abstraction, disproportionation, and group exchange)

The dependence of arsenic transient enhanced diffusion on the silicon substrate temperature during ultralow energy implantation

S. Whelan, J. A. Van den Berg, S. Zhang, D. G. Armour, and R. D. Goldberg

Appl. Phys. Lett. 76, 571 (2000); http://dx.doi.org/10.1063/1.125820 (3 pages) | Cited 7 times

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The redistribution of As during high-temperature annealing has been investigated as a function of the Si(100) substrate temperature (−120 °C, +25 °C, and +300 °C) during 2.5 keV implantation (to 1.5×1015atoms/cm2). Each implant produced a damaged near-surface region, the extent of which varied with implant temperature. Samples implanted at each temperature were annealed in a nitrogen ambient with a few percent oxygen for 10 s at 550, 925, and 975 °C. The changes in implant damage and dopant distributions both prior to and following annealing were investigated using medium energy ion scattering and secondary ion mass spectrometry. Transient enhanced diffusion (TED) of the dopant was observed for all implant temperatures after 925 °C annealing with the 25 °C implant showing the deepest diffusion. Between 925 and 975 °C annealing, the As diffusion rate in the 300 °C exceeded that of the 25 °C implant. Significantly, the −120 °C implant displayed less TED of As compared to the higher temperature implants following annealing at 975 °C. The results indicate that the diffusion is affected by the nature of the post-implant damage and the high arsenic concentrations. © 2000 American Institute of Physics.
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66.30.J- Diffusion of impurities
81.05.Cy Elemental semiconductors
61.72.uf Ge and Si
61.80.Jh Ion radiation effects
61.72.Cc Kinetics of defect formation and annealing
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Implantation damage effect on boron annealing behavior using low-energy polyatomic ion implantation

Jian-Yue Jin, Jiarui Liu, Paul A. W. van der Heide, and Wei-Kan Chu

Appl. Phys. Lett. 76, 574 (2000); http://dx.doi.org/10.1063/1.125821 (3 pages) | Cited 5 times

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We have studied ion-implantation damage effects on boron clustering and transient enhanced diffusion (TED) by using polyatomic boron (Bn−, n = 1–3) ion implantation with the same atomic boron dose and energy. This Bn− series implantation can produce different amounts of damage with the same boron as-implanted profile and same amount of excess interstitials, hence a net effect of implantation damage can be extracted. Secondary ion mass spectrometry measurements indicate that for 1 keV boron atomic energy implantation and 10 s 1050 °C rapid thermal annealing, B1− implantation has less TED and less boron–interstitial clustering than B2− and B3− implantation. A boron trapping peak at the SiO2/Si interface is also speculated since the amount of boron trapped is correlated to the size of implanted ions. © 2000 American Institute of Physics.
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61.72.uf Ge and Si
61.80.Jh Ion radiation effects
61.82.Fk Semiconductors
61.72.Cc Kinetics of defect formation and annealing
66.30.J- Diffusion of impurities
61.72.J- Point defects and defect clusters
61.72.Yx Interaction between different crystal defects; gettering effect

Characterization of InGaN thin films using high-resolution x-ray diffraction

L. Görgens, O. Ambacher, M. Stutzmann, C. Miskys, F. Scholz, and J. Off

Appl. Phys. Lett. 76, 577 (2000); http://dx.doi.org/10.1063/1.125822 (3 pages) | Cited 24 times

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Wurtzite InGaN thin films grown by metalorganic chemical vapor deposition on sapphire substrates with and without GaN buffer layers are investigated by high-resolution x-ray diffraction measurements. The structural quality, lattice constants, strain, and indium composition of 100 nm thick films with In concentrations up to 33% are evaluated by measuring symmetric (00.2) and asymmetric (20.5) reflexes. The quality of the InGaN layers with widely different biaxial stress is measured and compared. An analytical solution for the determination of the In content of strained epitaxial layers is introduced. The results show that neglecting the strain can result in a severe miscalculation of the In concentration. © 2000 American Institute of Physics.
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68.55.-a Thin film structure and morphology
81.15.Gh Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.)
68.55.Nq Composition and phase identification
68.60.Bs Mechanical and acoustical properties
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Drift mobility of semiconductive La0.5Sr0.5CoO3 films measured using the traveling wave method

J. Yin, L. Wang, J. M. Liu, K. J. Chen, Z. G. Liu, and Q. Huang

Appl. Phys. Lett. 76, 580 (2000); http://dx.doi.org/10.1063/1.125823 (3 pages)

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The conductivity and the drift mobility of La0.5Sr0.5CoO3 films deposited on fused silica substrates at 650 °C by pulsed-laser deposition have been measured by using the traveling-wave method. At room temperature, La0.5Sr0.5CoO3 films with semiconductivity have a hole density of 1×1021 cm−3, and drift mobility of 0.01 cm2/V s. The films underwent a paraferromagnetic transition around 240 K. The hopping process and tunneling effect of small polarons may be responsible for the conductive behavior above the Curie temperature. © 2000 American Institute of Physics.
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73.61.Le Other inorganic semiconductors
73.50.Dn Low-field transport and mobility; piezoresistance
75.50.Pp Magnetic semiconductors
75.70.Ak Magnetic properties of monolayers and thin films
72.20.Ee Mobility edges; hopping transport
75.30.Kz Magnetic phase boundaries (including classical and quantum magnetic transitions, metamagnetism, etc.)
75.47.De Giant magnetoresistance

A full-band Monte Carlo model for the temperature dependence of electron and hole transport in silicon

Björn Fischer and Karl R. Hofmann

Appl. Phys. Lett. 76, 583 (2000); http://dx.doi.org/10.1063/1.125824 (3 pages) | Cited 9 times

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A full-band Monte Carlo transport model for silicon is presented that achieves excellent quantitative agreement with the temperature, field, and crystal direction dependences of experimental electron and hole drift velocities from 20 to 500 K. The model is based on wave-vector-dependent phonon scattering rates, for which a unique set of only two empirical deformation potentials for each carrier type has been determined from the experiments. Numerical accuracy is obtained by a variable Brillouin zone discretization. We discuss discrepancies between different experimental low-field electron mobilities at 77 K showing that the value should be 26 100 cm2/(V s) instead of the often quoted 20 800 cm2/(V s). For holes, we show that the inclusion of inelastic intravalley acoustic phonons cannot be restricted to low temperatures, but is essential for a correct transport description even at room temperature. © 2000 American Institute of Physics.
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72.80.Cw Elemental semiconductors
72.20.Fr Low-field transport and mobility; piezoresistance
72.10.Di Scattering by phonons, magnons, and other nonlocalized excitations
02.50.Ng Distribution theory and Monte Carlo studies
02.70.Rr General statistical methods

Optical and acoustic phonon modes in self-organized Ge quantum dot superlattices

J. L. Liu, G. Jin, Y. S. Tang, Y. H. Luo, K. L. Wang, and D. P. Yu

Appl. Phys. Lett. 76, 586 (2000); http://dx.doi.org/10.1063/1.125825 (3 pages) | Cited 32 times

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Raman scattering measurements were carried out in self-organized Ge quantum dot superlattices. The samples consisted of 25 periods of Ge quantum dots with different dot sizes sandwiched by 20 nm Si spacers, and were grown using solid-source molecular-beam epitaxy. Optical phonon modes were found to be around 300 cm−1, and a dependence of the Raman peak frequency on the size of dots was evidenced in good agreement with a prediction based on phonon confinement and strain effects. Acoustic phonons related to the Ge quantum dots have also been observed. © 2000 American Institute of Physics.
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63.22.-m Phonons or vibrational states in low-dimensional structures and nanoscale materials
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
78.30.Am Elemental semiconductors and insulators
78.66.Db Elemental semiconductors and insulators

Two-dimensional growth of InSb thin films on GaAs(111)A substrates

K. Kanisawa, H. Yamaguchi, and Y. Hirayama

Appl. Phys. Lett. 76, 589 (2000); http://dx.doi.org/10.1063/1.125826 (3 pages) | Cited 20 times

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Heteroepitaxy of high-quality InSb films was performed directly on GaAs surfaces by using molecular beam epitaxy. Despite the 14.6% lattice mismatch, two-dimensionally grown InSb on GaAs(111)A substrates were obtained from the initial stage, but not on (001) substrates. A conductive layer was formed from the early stage of the growth on the (111)A surface, and the mobilities and carrier concentrations of InSb on (111)A substrates suggested a low defect density due to confinement of the dislocations to the interface. © 2000 American Institute of Physics.
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81.15.Hi Molecular, atomic, ion, and chemical beam epitaxy
73.61.Ey III-V semiconductors
72.80.Ey III-V and II-VI semiconductors
81.05.Ea III-V semiconductors
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.35.Ct Interface structure and roughness
61.72.Hh Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.)
61.72.Lk Linear defects: dislocations, disclinations
73.25.+i Surface conductivity and carrier phenomena
72.20.Ee Mobility edges; hopping transport
72.20.Fr Low-field transport and mobility; piezoresistance
73.50.Dn Low-field transport and mobility; piezoresistance

1/f noise through the metal–nonmetal transition in percolating composites

A. J. Breeze, S. A. Carter, G. B. Alers, and M. B. Heaney

Appl. Phys. Lett. 76, 592 (2000); http://dx.doi.org/10.1063/1.125827 (3 pages) | Cited 11 times

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We have measured the 1/f noise through the metal–nonmetal transition in carbon black/polymer composites as a function of temperature and doping. At the electronic transition, the resistivity power spectrum Sρ varies as Sρ ∼ ρQ, with Q = 2.77, in agreement with classical three-dimensional percolation. At lower temperatures, a crossover to tunneling-dominated transport occurs with Sρ ∼ ln Sρ/ρ2. Our results show that 1/f noise can be a more sensitive technique than resistivity itself for probing transport behavior near a percolation-induced electronic transition. © 2000 American Institute of Physics.
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72.70.+m Noise processes and phenomena
71.30.+h Metal-insulator transitions and other electronic transitions
72.60.+g Mixed conductivity and conductivity transitions
72.80.Tm Composite materials

Defined crystallization of amorphous-silicon films using contact printing

Sanghoon Bae and Stephen J. Fonash

Appl. Phys. Lett. 76, 595 (2000); http://dx.doi.org/10.1063/1.125828 (3 pages) | Cited 9 times

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Patterned Ni layers are printed on amorphous-silicon (a-Si) films and, during this printing, the metal patterns induce lateral crystallization of the precursor a-Si layer. The printing process consists of simultaneously pressing the Ni printing plate to an a-Si layer and annealing at 550 °C. Printing times of 1 and 3 h are explored. The growth rate of the Ni-induced lateral crystallization is about 8 μm/h in this process. After this printing, Raman spectra show that the resulting polycrystalline-silicon (poly-Si) regions have the characteristic transverse-optical 519 cm−1 phonon peak typical of crystalline silicon. The nonprinted, noncrystallized a-Si areas have the Raman signature of a-Si; i.e., they do not have any peak. The resulting laterally crystallized Si area shows a morphological texture (i.e., a strip-like morphology) originating from the printed Ni area and growing in one direction in transmission electron microscope imaging. In terms of the selective area diffraction pattern (i.e., diffraction spot position and crystal structure), the signature of the area directly contacted by the Ni cannot be distinguished from that of the surrounding laterally crystallized silicon film. This printing approach can be used for channel crystallization/device isolation resulting in a saving of device fabrication steps. © 2000 American Institute of Physics.
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61.43.Dq Amorphous semiconductors, metals, and alloys
61.72.Cc Kinetics of defect formation and annealing
78.66.Jg Amorphous semiconductors; glasses
78.30.Am Elemental semiconductors and insulators
78.35.+c Brillouin and Rayleigh scattering; other light scattering
68.55.-a Thin film structure and morphology
78.66.Db Elemental semiconductors and insulators
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