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21 Dec 1998

Volume 73, Issue 25, pp. 3629-3786

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A fast-response and short-wavelength nonlinear optical chromophore for a photorefractive composite

Zhijian Chen, Feng Wang, Cong Yao, Zhiwen Huang, Qihuang Gong, Yiwang Chen, and Huiying Chen

Appl. Phys. Lett. 73, 3629 (1998); http://dx.doi.org/10.1063/1.122844 (3 pages) | Cited 3 times

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A nonlinear optical molecule, β,β-diacetyl-4-methoxylstyrene (DAMST), was synthesized and used as the electro-optic chromophore in a photorefractive polymeric composite. Its absorption peak lies at 320 nm and shows no absorption at wavelengths longer than 400 nm. In a 100 μm thickness film of DAMST:poly(N-vinylcarbazole):2,4,7-trinitro-9-fluorenone with a weight ratio of 59:40:1, two-beam coupling gain was measured as high as 32 cm−1 at a wavelength of 543 nm. A response time as short as 17 ms was estimated at an applied electric field of 84 V/μm with a writing beam intensity of 1 W/cm2. © 1998 American Institute of Physics.
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42.65.Jx Beam trapping, self-focusing and defocusing; self-phase modulation
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.70.Mp Nonlinear optical crystals
78.20.Jq Electro-optical effects

Broadband optical limiting with multiwalled carbon nanotubes

X. Sun, R. Q. Yu, G. Q. Xu, T. S. A. Hor, and W. Ji

Appl. Phys. Lett. 73, 3632 (1998); http://dx.doi.org/10.1063/1.122845 (3 pages) | Cited 83 times

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Optical limiting effects in multiwalled carbon nanotubes have been observed in the visible and infrared spectral regions with nanosecond laser pulses. The multiwalled carbon nanotubes investigated include those suspended in distilled water and embedded in polymethyl methacrylate films. Among all the samples measured, the limiting performance of the carbon nanotube suspension is the best with the limiting threshold determined to be ∼ 1, 5, and 13 J/cm2 at 532, 700, and 1064 nm, respectively. The possible mechanism for the observed effects is discussed. © 1998 American Institute of Physics.
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42.70.Gi Light-sensitive materials
78.30.Na Fullerenes and related materials
78.40.Ri Fullerenes and related materials
42.79.-e Optical elements, devices, and systems
42.70.Nq Other nonlinear optical materials; photorefractive and semiconductor materials
42.50.Md Optical transient phenomena: quantum beats, photon echo, free-induction decay, dephasings and revivals, optical nutation, and self-induced transparency

Modulation of second harmonic generation in photochromic materials by the application of electric fields and low intensity light

M. C. J. Large, F. Kajzar, and P. Raimond

Appl. Phys. Lett. 73, 3635 (1998); http://dx.doi.org/10.1063/1.122846 (3 pages) | Cited 5 times

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The simultaneous application of low intensity optical and static electric fields to photoisomerizable electro-optic materials is shown to allow manipulation of the refractive index. A dc electric field was applied to the sample by means of a corona poling mechanism, which was illuminated within the absorption band using a low power laser. The application of the optical field caused a reduction in polar order in the material, with a corresponding change in the refractive index. The change of polar order was monitored by optical second harmonic generation. For typical experimental values, the variation in refractive index was calculated to be about 1%, which is sufficient to change waveguiding conditions. Electroded samples also showed the effect. © 1998 American Institute of Physics.  
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42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
78.20.Jq Electro-optical effects
82.30.Qt Isomerization and rearrangement
82.50.-m Photochemistry

Two-photon transitions between bound-to-continuum states in AlGaAs/GaAs multiple quantum well

Jin U. Kang, Jacob B. Khurgin, C. C. Yang, H. H. Lin, and George I. Stegeman

Appl. Phys. Lett. 73, 3638 (1998); http://dx.doi.org/10.1063/1.122847 (3 pages) | Cited 4 times

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We have experimentally observed room-temperature exciton resonances resulting from interband two-photon transitions between bound-to-continuum states. The excitons exhibit reduced binding energy and broadened resonances compared to that of excitons resulting from two-photon transitions between bound states. This trend is consistent with our theoretical prediction. © 1998 American Institute of Physics.
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78.66.Fd III-V semiconductors
71.35.Cc Intrinsic properties of excitons; optical absorption spectra
73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems
78.30.Fs III-V and II-VI semiconductors

J-aggregate electroluminescence in dye doped polymer layers

E. I. Mal’tsev, D. A. Lypenko, B. I. Shapiro, M. A. Brusentseva, V. I. Berendyaev, B. V. Kotov, and A. V. Vannikov

Appl. Phys. Lett. 73, 3641 (1998); http://dx.doi.org/10.1063/1.122848 (3 pages) | Cited 12 times

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The electroluminescence (EL) of a dye nanocrystalline phase was revealed in single layer light-emitting diodes based on polymers doped with cyanine dye molecules. Observation of light emission in the visible range depended on the redox potentials of the dyes used. The 9,10-dithioanthracene-containing polyimides exhibiting efficient electron-hole transport appeared to be appropriate media for the generation of J-aggregate EL. © 1998 American Institute of Physics.
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78.66.Qn Polymers; organic compounds
78.60.Fi Electroluminescence
61.41.+e Polymers, elastomers, and plastics

Single-sided alignment of electroclinic liquid crystals for active matrix displays

A. Hermanns, C. M. Wilson, J. Y. Patel, J. W. Naciri, J. R. Lindle, and B. R. Ratna

Appl. Phys. Lett. 73, 3644 (1998); http://dx.doi.org/10.1063/1.122849 (3 pages) | Cited 3 times

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Single-sided alignment, in which only one of the two display substrates bears an alignment layer, stands to significantly simplify the manufacture and improve the yield and performance of active matrix displays. Using polybutylene terephthalate alignment layers, we show that single-sided alignment is feasible for electroclinic liquid crystals and can result in faster switching and larger tilt angle. Most importantly, single-sided alignment gave high contrast in excess of 170:1. © 1998 American Institute of Physics.
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42.79.Kr Display devices, liquid-crystal devices
42.70.Df Liquid crystals
61.30.Gd Orientational order of liquid crystals; electric and magnetic field effects on order

Effect of hydrogenation on room-temperature 1.54 μm Er3+ photoluminescent properties of erbium-doped silicon-rich silicon oxide

Jung H. Shin, Se-young Seo, and Seok-Ju Lee

Appl. Phys. Lett. 73, 3647 (1998); http://dx.doi.org/10.1063/1.122850 (3 pages) | Cited 9 times

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The effect of hydrogenation on the room-temperature 1.54 μm Er3+ photoluminescent properties of erbium-doped silicon-rich silicon oxide thin films is investigated. Two samples with 7 and 1 at. % excess silicon and 0.4 at. % erbium were prepared by electron cyclotron resonance plasma-enhanced chemical vapor deposition of SiH4 and O2 with cosputtering of erbium and subsequent rapid thermal anneal at 900 °C. Hydrogenation by exposure to D plasma doubles the 1.54 μm Er3+ luminescence intensity from the high excess silicon content sample but halves that from the low excess silicon content sample. The lifetimes and excitation power dependence of Er+ luminescence show that hydrogenation primarily affects the active erbium fraction, increasing it in case of the high excess silicon sample but decreasing it in case of the low excess silicon content sample. With proper treatments, Er3+ luminescence lifetime of over 7 ms is obtained. © 1998 American Institute of Physics.
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78.66.Nk Insulators
78.55.Hx Other solid inorganic materials
61.72.Cc Kinetics of defect formation and annealing

Low temperature periodic electrical poling of flux-grown KTiOPO4 and isomorphic crystals

G. Rosenman, A. Skliar, D. Eger, M. Oron, and M. Katz

Appl. Phys. Lett. 73, 3650 (1998); http://dx.doi.org/10.1063/1.122851 (3 pages) | Cited 43 times

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Studies of dielectric spectroscopy, dc conductivity, and polarization switching allowed the observation of phase transition from the superionic to the insulating state in flux-grown KTiOPO4 (KTP) crystals at low temperature where the high mobility of potassium ions is suppressed. A low temperature method of fabrication of engineered periodic domain structures in superionic KTP and isomorphic crystals is proposed. It enabled us to tailor homogeneous domain gratings with various periods in the range 4–39 μm for quasiphase-matched nonlinear optical converters in KTP plates over whole area of 30×30 mm2. © 1998 American Institute of Physics.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.22.Ej Polarization and depolarization
77.22.Ch Permittivity (dielectric function)
72.60.+g Mixed conductivity and conductivity transitions
77.80.Fm Switching phenomena
77.80.Dj Domain structure; hysteresis
42.79.Dj Gratings
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.79.Nv Optical frequency converters
42.70.Mp Nonlinear optical crystals
66.30.H- Self-diffusion and ionic conduction in nonmetals

Highly reflective GaN/Al0.34Ga0.66N quarter-wave reflectors grown by metal organic chemical vapor deposition

T. Someya and Y. Arakawa

Appl. Phys. Lett. 73, 3653 (1998); http://dx.doi.org/10.1063/1.122852 (3 pages) | Cited 53 times

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Quarter-wave reflectors consisting of sets of GaN and Al0.34Ga0.66N layers have been grown on sapphire substrates by atmospheric-pressure metal organic chemical vapor deposition. A periodic structure with flat interfaces was observed by high-resolution scanning electron microscopy. X-ray diffraction measurements were performed to characterize the structures, from which the Al content x in the AlxGa1−xN layers was determined to be 0.34. No cracks could be seen on the surface of the reflectors by optical microscopy. The measured peak reflectivity at 390 nm increases with the number of pairs and reaches as high as 96±2% in the 35-pair reflector. © 1998 American Institute of Physics.
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78.66.Fd III-V semiconductors
42.79.Wc Optical coatings

Ultraviolet lasing in resonators formed by scattering in semiconductor polycrystalline films

H. Cao, Y. G. Zhao, H. C. Ong, S. T. Ho, J. Y. Dai, J. Y. Wu, and R. P. H. Chang

Appl. Phys. Lett. 73, 3656 (1998); http://dx.doi.org/10.1063/1.122853 (3 pages) | Cited 212 times

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A semiconductor laser whose cavities are “self-formed” due to strong optical scattering in highly disordered gain media is demonstrated. The lasers are made of zinc oxide polycrystalline films grown on amorphous fused silica substrates. Lasing occurs at an ultraviolet wavelength of ∼380 nm under optical pumping. Actual images of the microscopic laser cavities formed by multiple scattering have been captured. These results suggest the possibility of using disordered semiconductor microstructures as alternative sources of coherent light emission. © 1998 American Institute of Physics.
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42.55.Px Semiconductor lasers; laser diodes
42.60.By Design of specific laser systems

Blue-light laser source by sum-frequency mixing in Nd:YAl3(BO3)4

D. Jaque, J. Capmany, F. Molero, and J. García Solé

Appl. Phys. Lett. 73, 3659 (1998); http://dx.doi.org/10.1063/1.122854 (3 pages) | Cited 34 times

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Sum-frequency mixing in neodymium-doped YAl3(BO3)4 of its fundamental laser line at 1062 nm and the pump light from a tunable Ti:sapphire laser has been used to generate blue radiation from 435 to 465 nm in an end-pumped configuration. In nonoptimal preliminary experiments 22 μW at 458 nm was obtained out of 200 mW absorbed power at 807 nm. Nd:YAB, therefore, emerges as a promising laser material for diode-pumped solid-state lasers in the blue spectral region. © 1998 American Institute of Physics.
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42.55.Rz Doped-insulator lasers and other solid state lasers
42.70.Hj Laser materials
42.65.Ky Frequency conversion; harmonic generation, including higher-order harmonic generation
42.70.Mp Nonlinear optical crystals
42.60.Pk Continuous operation
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MeV γ-ray yield from solid targets irradiated with fs-laser pulses

C. Gahn, G. Pretzler, A. Saemann, G. D. Tsakiris, K. J. Witte, D. Gassmann, T. Schätz, U. Schramm, P. Thirolf, and D. Habs

Appl. Phys. Lett. 73, 3662 (1998); http://dx.doi.org/10.1063/1.122855 (3 pages) | Cited 19 times

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We have investigated the MeV bremsstrahlung which is emitted when fast electrons generated by the interaction of 200 mJ, 130 fs Ti:sapphire laser pulses with a preformed plasma penetrate into a solid target. Employing different targets the dependence of the γ-ray spectrum on the atomic number was studied. We detected single γ photons with an energy up to 2.5 MeV and found a maximum conversion efficiency of the laser energy into MeV bremsstrahlung of 4×10−6. Data analysis using a Monte Carlo code revealed a fast-electron temperature of 0.9 MeV.© 1998 American Institute of Physics.
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76.80.+y Mössbauer effect; other γ-ray spectroscopy
02.50.Ng Distribution theory and Monte Carlo studies
02.70.Rr General statistical methods
78.70.-g Interactions of particles and radiation with matter
79.20.Ds Laser-beam impact phenomena
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)
78.47.-p Spectroscopy of solid state dynamics
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
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Newtonian to non-Newtonian master flow curves of a bulk glass alloy Pd40Ni10Cu30P20

Hidemi Kato, Yoshihito Kawamura, Akihisa Inoue, and H. S. Chen

Appl. Phys. Lett. 73, 3665 (1998); http://dx.doi.org/10.1063/1.122856 (3 pages) | Cited 70 times

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The viscosity and flow stress of a bulk Pd40Ni10Cu30P20 alloy glass near the glass transition were measured as a function of temperature and strain rate under compression. The steady-state viscosity of the glass for a given temperature remains constant at low strain rate, then decreases by many orders of magnitude above a critical strain rate. A master curve in term of the viscosity ratio η/ηN and the product ηNmath has been constructed, where η and ηN are, respectively, the steady-state viscosity and Newtonian viscosity, and math is the strain rate. The flow stress also can be represented in terms of the product ηNmath. The master curves are fitted with a simple stress relaxation of the form 1−exp[−t/λ] with t = math−1. © 1998 American Institute of Physics.
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66.20.-d Viscosity of liquids; diffusive momentum transport
81.40.Lm Deformation, plasticity, and creep
62.20.F- Deformation and plasticity
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
61.43.Fs Glasses
81.05.Kf Glasses (including metallic glasses)
47.50.-d Non-Newtonian fluid flows
83.10.Gr Constitutive relations

Enhancing electron emission from silicon tip arrays by using thin amorphous diamond coating

N. S. Xu, J. C. She, S. E. Huq, J. Chen, and S. Z. Deng

Appl. Phys. Lett. 73, 3668 (1998); http://dx.doi.org/10.1063/1.122857 (3 pages) | Cited 34 times

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A thin ( ∼ 2 nm thick) amorphous diamond coating was prepared on single crystal silicon tip arrays by using a filtered vacuum arc plasma deposition technique. The coating has a microscopically uniform morphology. As compared to uncoated tips, the electron emission of the coated tip arrays is enhanced, showing an increase in the total current, lower turn-on field and a lower-slope Fowler–Nordheim plot. We propose that field-emitted electrons could tunnel through such a thin coating with few scattering events. It is shown that the low potential barrier at the interface is the major cause of the enhancing effects instead of the negative surface electron affinity of the coating. © 1998 American Institute of Physics.
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79.70.+q Field emission, ionization, evaporation, and desorption
72.80.Cw Elemental semiconductors

Cubic C3N4 particles prepared in an induction thermal plasma

Yingguo Peng, Takamasa Ishigaki, and Shigeo Horiuchi

Appl. Phys. Lett. 73, 3671 (1998); http://dx.doi.org/10.1063/1.122858 (3 pages) | Cited 16 times

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Carbon nitride particles of nm size were prepared in an induction thermal plasma treatment of carbon powder including a small amount of nitrogen. Relatively large ones of about 5 nm in diameter are mostly in a dodecahedral shape. The structure was analyzed by high-resolution transmission electron microscopy and electron energy-loss spectroscopy to be a cubic C3N4, which had been predicted by a first-principles calculation as a substance with the highest bulk modulus. The lattice parameter is, however, rather large (a = 0.582 nm) as compared to the prediction. N-deficient planar defects are included in some of the particles. © 1998 American Institute of Physics.
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81.07.-b Nanoscale materials and structures: fabrication and characterization
61.46.-w Structure of nanoscale materials
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition
81.20.Ev Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation
61.66.Fn Inorganic compounds
62.20.D- Elasticity
81.40.Jj Elasticity and anelasticity, stress-strain relations
61.72.Nn Stacking faults and other planar or extended defects

Retention characteristics of SrBi2Ta2O9 thin films prepared by metalorganic decomposition

Z. G. Zhang, Y. N. Wang, J. S. Zhu, F. Yan, X. M. Lu, H. M. Shen, and J. S. Liu

Appl. Phys. Lett. 73, 3674 (1998); http://dx.doi.org/10.1063/1.122859 (3 pages) | Cited 12 times

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Polycrystalline SrBi2Ta2O9 (SBT) ferroelectric thin films were synthesized on Pt/Ti/SiO2/Si substrates by metalorganic decomposition. Electric measurements demonstrate that the polarization decay increases with increasing the write/read voltage within the first second. This could be attributed to the depolarization fields, which increases with increasing the retained polarization. However, we found that the polarization loss is insignificant with different write/read voltages over a range of 1–30 000 S. Furthermore, experiment indicates that there is weak pinning of domain walls existing in SBT, which plays an important role for SBT thin film over a range of 1–30 000 S with a low write/read voltage. © 1998 American Institute of Physics.  
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.55.-g Dielectric thin films
77.22.Ej Polarization and depolarization
77.80.Dj Domain structure; hysteresis

Effect of compression on grain growth in Al films

C. A. Volkert and C. Lingk

Appl. Phys. Lett. 73, 3677 (1998); http://dx.doi.org/10.1063/1.122860 (3 pages) | Cited 8 times

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The effect of compression on grain growth in Al and Al(Cu) films on oxidized Si substrates has been studied. Samples were compressed in a uniaxial press during annealing at 400 °C, and then examined using focused ion beam imaging. It was found that the compressed regions had a final grain size roughly a factor of 3 larger than in the uncompressed regions. This behavior is interpreted as due to a decrease in grain boundary grooving and the pinning forces associated with them, thus allowing enhanced grain growth. © 1998 American Institute of Physics.
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68.60.Bs Mechanical and acoustical properties
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.Cc Kinetics of defect formation and annealing
61.72.Mm Grain and twin boundaries
81.40.Vw Pressure treatment
81.05.Bx Metals, semimetals, and alloys

Influence of tunneling voltage on the imaging of carbon nanotube rafts by scanning tunneling microscopy

L. P. Biró, P. A. Thiry, Ph. Lambin, C. Journet, P. Bernier, and A. A. Lucas

Appl. Phys. Lett. 73, 3680 (1998); http://dx.doi.org/10.1063/1.122861 (3 pages) | Cited 5 times

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The influence of bias voltage on the quality of scanning tunneling microscopy images of carbon nanotube “rafts” was investigated in the range from −1 to 1 V in combination with scanning tunneling spectroscopy (STS) measurements. While for positive tip polarity only a slight voltage dependence was found in the image quality, for negative polarity a strong increase of the noise was observed with increasing voltage. STS showed that, for negative tip polarity, the tunneling current may be different in different locations by several orders of magnitude. © 1998 American Institute of Physics.
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61.48.-c Structure of fullerenes and related hollow and planar molecular structures
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

Lead-free high-strain single-crystal piezoelectrics in the alkaline–bismuth–titanate perovskite family

Yet-Ming Chiang, Gregory W. Farrey, and Andrey N. Soukhojak

Appl. Phys. Lett. 73, 3683 (1998); http://dx.doi.org/10.1063/1.122862 (3 pages) | Cited 144 times

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Doped alkaline–bismuth–titanate perovskite single crystals have been grown in ferroelectric phases with high piezoelectric actuation. Rhombohedral-phase Na1/2Bi1/2TiO3–BaTiO3 crystals exhibit up to 0.25% free strain with low hysteresis along the cubic 〈001〉 direction (d33 ∼ 450 pC/N). Tetragonal phase crystals exhibit free strains as high as 0.85% with greater hysteresis characteristic of domain switching; low field d33 exceeds 500 pC/N. Strain energy densities exceed those of optimized polycrystalline lead perovskites, and actuation capability is retained at compressive stresses >100 MPa. © 1998 American Institute of Physics.
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77.84.Ek Niobates and tantalates
77.84.Cg PZT ceramics and other titanates
77.65.Ly Strain-induced piezoelectric fields
77.80.Dj Domain structure; hysteresis
77.80.Fm Switching phenomena
77.22.Ch Permittivity (dielectric function)
81.05.Mh Cermets, ceramic and refractory composites
81.10.Dn Growth from solutions
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Influence of the surface morphology on the yellow and “edge” emissions in wurtzite GaN

M. Godlewski, E. M. Goldys, M. R. Phillips, R. Langer, and A. Barski

Appl. Phys. Lett. 73, 3686 (1998); http://dx.doi.org/10.1063/1.122863 (3 pages) | Cited 21 times

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In this letter we examine an influence of surface morphology on yellow and edge emissions in wurtzite phase GaN. Our cathodoluminescence measurements show that the yellow emission does not correlate with the surface morphology, but simultaneously the “edge” emission shows very strong spatial fluctuations. The observed effect is attributed to granular structures in GaN films and enhancement of the yellow emission in the interface region. © 1998 American Institute of Physics.
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78.60.Hk Cathodoluminescence, ionoluminescence
78.66.Fd III-V semiconductors
78.55.Cr III-V semiconductors
68.35.B- Structure of clean surfaces (and surface reconstruction)

Stimulated emission characteristics of InGaN/GaN multiple quantum wells: Excitation length and excitation density dependence

T. J. Schmidt, S. Bidnyk, Yong-Hoon Cho, A. J. Fischer, J. J. Song, S. Keller, U. K. Mishra, and S. P. DenBaars

Appl. Phys. Lett. 73, 3689 (1998); http://dx.doi.org/10.1063/1.122864 (3 pages) | Cited 8 times

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Optically pumped stimulated emission (SE) from InGaN/GaN multiple quantum wells (MQWs) grown by metalorganic chemical vapor deposition has been systematically studied as a function of excitation length (Lexc). Two distinct SE peaks were observed from these structures: one that originates at 425 nm at 10 K (430 nm at 300 K) and another that originates at 434 nm at 10 K (438 nm at 300 K). The SE threshold for the high-energy peak was observed to always be lower than that of the low-energy peak, but the difference was found to decrease greatly with increasing Lexc. A detailed study of the emission intensity of these two SE peaks as a function of excitation density shows that the two peaks compete for gain in the MQW active region. © 1998 American Institute of Physics.
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78.45.+h Stimulated emission
42.55.Px Semiconductor lasers; laser diodes
78.66.Fd III-V semiconductors

Fowler–Nordheim tunneling of holes through thermally grown SiO2 on p+ 6H–SiC

Richard Waters and Bart Van Zeghbroeck

Appl. Phys. Lett. 73, 3692 (1998); http://dx.doi.org/10.1063/1.122865 (3 pages) | Cited 7 times

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Fowler–Nordheim tunneling of holes through thermally grown silicon dioxide on 6H–silicon carbide is reported. Oxides of 5.2, 10, and 14.2 nm thickness were grown on the p+ face of a p+n SiC junction. The p+n junction served to separate the electron and hole tunneling currents. Hole tunneling was found to be the dominant current mechanism through the oxide. Fowler–Nordheim analysis, using a parabolic E–K relationship, was performed to extract a barrier height–effective mass product, ΦB3/2(mox/m0)1/2, for electrons and holes of 2.88%±4.9% and 2.38%±3.8% (V3/2) respectively. An estimate for the effective mass of holes within the oxide was made using both the parabolic and Franz dispersion relations. © 1998 American Institute of Physics.
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73.40.Qv Metal-insulator-semiconductor structures (including semiconductor-to-insulator)
71.18.+y Fermi surface: calculations and measurements; effective mass, g factor
73.40.Gk Tunneling
73.61.Ng Insulators

Complete suppression of boron transient-enhanced diffusion and oxidation-enhanced diffusion in silicon using localized substitutional carbon incorporation

M. S. Carroll, C-L. Chang, J. C. Sturm, and T. Büyüklimanli

Appl. Phys. Lett. 73, 3695 (1998); http://dx.doi.org/10.1063/1.122866 (3 pages) | Cited 20 times

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In this letter, we show the ability, through introduction of a thin Si1−x−yGexCy layer, to eliminate the enhancement of enhanced boron diffusion in silicon due to an oxidizing surface or ion implant damage. This reduction of diffusion is accomplished through a low-temperature-grown thin epitaxial Si1−x−yGexCy layer which completely filters out excess interstitials introduced by oxidation or ion implant damage. We also quantify the oxidation-enhanced diffusion (OED) and transient-enhanced diffusion (TED) dependence on substitutional carbon level, and further report both the observation of carbon TED and OED, and its dependence on carbon levels. © 1998 American Institute of Physics.
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66.30.J- Diffusion of impurities
61.72.J- Point defects and defect clusters
61.72.uf Ge and Si
61.80.Jh Ion radiation effects
85.40.Ry Impurity doping, diffusion and ion implantation technology
81.65.Mq Oxidation
81.05.Cy Elemental semiconductors

Radiotracer investigation of deep Ga- and Zn-related band gap states in 6H–SiC

J. Grillenberger, N. Achtziger, F. Günther, and W. Witthuhn

Appl. Phys. Lett. 73, 3698 (1998); http://dx.doi.org/10.1063/1.122867 (2 pages) | Cited 1 time

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To identify Ga- or Zn-related deep levels, deep level transient spectroscopy (DLTS) measurements were performed repeatedly during the elemental transmutation of 67Ga to 67Zn. The radioactive isotope 67Ga was recoil implanted into p-type 6H–SiC for radiotracer experiments. The DLTS spectra exhibit one peak of time-dependent height. It describes the increasing concentration of the daughter element Zn with the half life of the nuclear decay. Thus, one Zn-related level at 1.16 eV above the valence band edge is definitely identified. There is no deep level of Ga in the lower part of the band gap. © 1998 American Institute of Physics.
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71.55.Ht Other nonmetals
71.20.Nr Semiconductor compounds

Silicon nanowhiskers grown on a hydrogen-terminated silicon {111} surface

N. Ozaki, Y. Ohno, and S. Takeda

Appl. Phys. Lett. 73, 3700 (1998); http://dx.doi.org/10.1063/1.122868 (3 pages) | Cited 70 times

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Using a hydrogen-terminated Si {111} surface as a substrate, we have grown Si nanowhiskers along the 〈112〉 direction by the vapor–liquid–solid mechanism. The minimum silicon core diameter was 3 nm and the maximum length was about 2 μm. The minimum silicon core diameter is close to the critical value for visible light emission due to the quantum confinement effect. In contrast to an oxidized Si surface, the hydrogen-terminated surface facilitates the formation of small molten Au–Si catalysts at a lower temperature (500 °C) which is slightly above the eutectic temperature. The formation of catalysts and the subsequent growth at the low temperature yield thin Si nanowhiskers on a Si substrate. © 1998 American Institute of Physics.
Show PACS
68.70.+w Whiskers and dendrites (growth, structure, and nonelectronic properties)
81.05.Cy Elemental semiconductors
61.46.-w Structure of nanoscale materials
81.07.-b Nanoscale materials and structures: fabrication and characterization
82.65.+r Surface and interface chemistry; heterogeneous catalysis at surfaces
81.10.Fq Growth from melts; zone melting and refining
81.10.Bk Growth from vapor
78.55.Ap Elemental semiconductors
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