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1.
Ester-functionalized soluble single-walled carbon nanotubes 总被引:2,自引:0,他引:2
M.A. Hamon H. Hui P. Bhowmik H.M.E. Itkis R.C. Haddon 《Applied Physics A: Materials Science & Processing》2002,74(3):333-338
We report the preparation of soluble ester- functionalized single-wall carbon nanotubes (sSWNT-COO(CH2)17CH3). By use of solution phase IR spectroscopy we are able to compare the ratio of the carbon atoms in the SWNT backbone to the
carbon atoms in the ester and amide functionalities of s-SWNTs.
Received: 16 July 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
2.
N+BF<Subscript>2</Subscript> and N+C+BF<Subscript>2</Subscript> high-dose co-implantation in silicon
L. Barbadillo M. Cervera M.J. Hernández P. Rodríguez J. Piqueras S.I. Molina A. Ponce F.M. Morales 《Applied Physics A: Materials Science & Processing》2003,76(5):791-800
Nitrogen and boron BF2, and nitrogen, carbon, and boron BF2 high-dose (6×1016–3×1017 cm-2) co-implantation were performed at energies of about 21–77 keV. Subsequent high-temperature annealing processes (600, 850,
and 1200 °C) lead to the formation of three and two surface layers respectively. The outer layer mainly consists of polycrystalline
silicon and some amorphous material and Si3N4 inclusions. The inner layer is highly defective crystalline silicon, with some inclusions of Si3N4 too. In the N+B-implanted sample the intermediate layer is amorphous. Co-implantation of boron with nitrogen and with nitrogen
and carbon prevents the excessive diffusivity of B and leads to a lattice-parameter reduction of 0.7–1.0%.
Received: 10 January 2002 / Accepted: 30 May 2002 / Published online: 4 November 2002
RID="*"
ID="*"Corresponding author. Fax: +34-91/3974895; E-mail: Lucia.Barbadillo@uam.es 相似文献
3.
T. Sameshima Y. Kaneko N. Andoh 《Applied Physics A: Materials Science & Processing》2002,74(6):719-723
We analyzed the rapid heating properties of 50-nm-thick silicon films via 250-nm-thick SiO2 intermediate layers by heat diffusion from joule heating induced by electrical current flow in chromium strips. Numerical
heat-flow simulation resulted in that the silicon films were heated to the melting point by a joule-heating intensity above
1 MW/cm2. A marked increase in electrical conductance associated with silicon melting was experimentally detected. Taper-shaped chromium
strips detected the temperature gradient in the lateral direction caused by the spatial distribution of the joule-heating
intensity. Crystallization occurred according to the temperature gradient. A 2–4-μm lateral crystalline grain growth was demonstrated
for the silicon films.
Received: 20 November 2001 / Accepted: 22 November 2001 / Published online: 20 March 2002 相似文献
4.
G.F. Cerofolini 《Applied Physics A: Materials Science & Processing》2003,76(1):49-52
The thermodynamic and kinetic stabilities of the Si–H bonds at the Si–SiO2 interface are studied on the basis of high-level quantum-mechanical calculations in the framework of density-functional theory.
In the absence of an applied electric field, the silanic bond is shown to be stable with respect to both hole capture from
the top of the silicon valence band and electron loss to the bottom of the silicon conduction band, but unstable with respect
to hole capture from the top of the SiO2 conduction band. The positively charged hydrogen does not shift spontaneously to protonate a neighbouring siloxanic bridge
unless it contains one adsorbed water molecule at least. The protonated siloxanic site thus formed may restore the original
silanic site (via simultaneous electron capture from the conduction band and hydron shift to silicon) but also evolve spontaneously
to a hydrogen atom via simple electron capture.
Received: 2 November 2001 / Accepted: 6 January 2002 / Published online: 20 March 2002 / Published online: 20 March 2002
RID="*"
ID="*"Also at: STMicroelectronics, 20041 Agrate MI, Italy (E-mail: gianfranco.cerofolini@st.com) 相似文献
5.
Phonon conductivity in intermediately doped n-type silicon still remains unexplained. In this paper we have calculated the
phonon conductivity in Li-doped silicon for Nex < Nc using Mikoshiba's inhomogeneity model. We have introduced spherical polar coordinates for the phonon polarization vectors
in Sota and Suzuki's theory in order to take into account the realistic picture of the scattered phonons. Deformation potential
for different polarizations λ has been evaluated for the metallic region. Present calculations show that Mikoshiba's inhomogeneity
model is able to explain the phonon conductivity of Li-doped silicon having intermediate donor concentration very well.
Received 18 May 2001 / Received in final form 4 July 2002 Published online 19 December 2002
RID="a"
ID="a"e-mail: mkroy@ctgu.edu 相似文献
6.
G.F. Cerofolini C. Bongiorno M. Camalleri G.G. Condorelli I.L. Fragalà C. Galati S. Lorenti L. Renna C. Spinella O. Viscuso 《Applied Physics A: Materials Science & Processing》2002,75(5):585-590
Nitridation of hydrogen-terminated silicon in a diluted N2:N2O atmosphere was studied by X-ray photoemission spectroscopy and high-resolution electron microscopy. Our analysis showed
that the broad N(1s) peak of width 1.5 eV at 398–399 eV, usually reported in the literature, is preceded by the formation
of a narrow peak of width around 1.0 eV at 397.5 eV, attributed to the moiety Si3N in which silicon is only marginally oxidized, and two other peaks at 400.0 eV and 401.5 eV, attributed to the moieties Si2NOSi and SiNO, respectively.
Received: 11 July 2001 / Accepted: 19 September 2001 / Published online: 20 December 2001 相似文献
7.
CVD synthesis and purification of single-walled carbon nanotubes on aerogel-supported catalyst 总被引:3,自引:0,他引:3
Single-walled carbon nanotubes (SWNTs) were synthesized by disproportionation of carbon monoxide on an aerogel-supported Fe/Mo
catalyst. A simple acidic treatment followed by an oxidation process produced a high purity (>99%) of SWNTs. The nanotubes
obtained are bundled SWNTs and free of amorphous-carbon coating. Several factors that affect the yield and the quality of
the SWNTs were also studied. This method shows great promise for large-scale production of SWNTs.
Received: 30 August 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
8.
V.L. Kalashnikov V.G. Shcherbitsky N.V. Kuleshov S. Girard R. Moncorgé 《Applied physics. B, Lasers and optics》2002,75(1):35-39
An approach to the energy optimization of the passively Q-switchedEr:glass laser is considered. The optimization procedure
is represented in the maximally verifiable and usable graphical form, which is applied to the flash-lamp pumped Er:glass laser
passively Q-switchedwith the Co2+-doped MgAl2O4 and LaMgAl11O19 saturable absorbers.
Received: 6 December 2001 / Revised version: 5 March 2002 / Published online: 8 August 2002 相似文献
9.
A method for the experimental determination of the net charge distribution over the atoms in a large class of compounds is
described. The method is based on X-ray photoemission spectroscopy and requires the determination of two core-level energies
per constituting atomic species. Two special cases of large conceptual and practical interest are discussed: the silicon charge
in CoSi2, Si1-xGex (0≤x≤0.3), SiC, Si3N4 and SiO2, and the aluminum charge in aluminum-doped zeolites.
Received: 20 March 2000 / Accepted: 28 March 2000 / Published online: 21 March 2001 相似文献
10.
M.J. Ariza F. Martín D. Leinen 《Applied Physics A: Materials Science & Processing》2001,73(5):579-584
X-ray photoelectron spectroscopy (XPS) has been applied to surfaces of silicon wafers in the different stages of the assembly
line for large-scale monocrystalline silicon solar cell manufacturing (ISOFOTON, Malaga, Spain). XPS results have shown that
a considerable amount of carbon is present on the pyramidal-textured monocrystalline silicon surface. This amount decreases
slightly but is still present after the process of phosphor diffusion (p-n junction), as well as after subsequent calcination
in humid air for SiO2 film formation (passivation). This amount of carbon may be buried during the process of CVD coating an anti-reflection TiO2 film. After calcination of the film in order to obtain the TiO2 rutile phase, an even higher amount of carbon is detected on the TiO2 anti-reflection coating surface. This indicates that not all organics from the tetra-isopropile ortho-titanate (TPT) precursor
were released from the film. Furthermore, in this case phosphor is found in excess on the SiO2 wafer surface (dead layer) and also on the rutile TiO2 surface, indicating that an extra phosphor diffusion from the bulk silicon through the TiO2 film has taken place during calcination. These results demonstrate how thermal treatments applied in the solar cell manufacturing
assembly line can influence and may change the intended compositional distribution. These treatments may also introduce defects
that act as recombination centres for charge carriers in the solar cell device.
Received: 13 September 2000 / Accepted: 10 January 2001 / Published online: 3 May 2001 相似文献
11.
A theoretical model for the growth of single-wall carbon nanotubes produced by metal-catalyzed decomposition of hydrocarbons
and fullerenes is presented. The growth process is treated as a thermodynamic equilibrium between carbon in the gas phase
and carbon in the nanotube. The minimum possible nanotube diameters based on several published experimental conditions are
calculated by combining the free energy of the reaction with an equation derived from elastic theory. The model predicts the
possibility of generating nanotubes with extremely small diameters that are smaller than in the corresponding experiments.
Received: 18 July 2001 / Accepted: 19 November 2001 / Published online: 4 March 2002 相似文献
12.
In this work, an analytical expression for the complex dielectric function is proposed, which includes both discrete and continuum
exciton effects. We have introduced Lorentzian broadening in Elliott’s formula and compare our model to other models based
on Elliott’s formula. The results show that our model is superior to other models for the dielectric function of ZnO in the
literature. Excellent agreement with experimental data for the dielectric function of ZnO for both perpendicular and parallel
polarizations has been obtained using our model.
Received: 18 April 2001 / Accepted: 19 December 2001 / Published online: 20 March 2002 / Published online: 20 March 2002
RID="*"
ID="*"Corresponding author. (Fax: +852-2559-8738, E-mail: dalek@eee.hku.hk) 相似文献
13.
This paper reports the photo-assisted formation of ZrO2 layers derived by sol–gel processing at low temperatures using intense radiation from ultraviolet (UV) excimer lamps. Excellent
layer properties can be readily obtained for these sol–gel layers after 5-min exposure to the UV irradiation at around 300 °C.
Analyses of the as-deposited sol–gel layers by UV/VIS spectrophotometry show that the organic species contained in the layers
have been removed to a large extent after 5-min irradiation. This is further confirmed by X-ray photoelectron spectroscopy
analyses of the same irradiated layers, which indicate the formation of ZrO2 with little carbon contamination contributed by the organic species and less oxidation of Si at the interface. Electrical
measurements of these layers are also reported.
Received: 31 July 2001 / Accepted: 6 September 2001 / Published online: 17 October 2001 相似文献
14.
M. Morstein P.R. Willmott H. Spillmann M. Döbeli 《Applied Physics A: Materials Science & Processing》2002,75(6):647-654
High-quality thin films of ZrCyN1-y and the novel tribological material Zr0.8Al0.2CyN1-y have been grown by pulsed reactive crossed-beam laser ablation using Zr and Zr–Al ablation targets, respectively, and a pulsed
gas. The gas mixture provided the carbon and nitrogen for the solid-solution films. Control of the stoichiometry (i.e. y)
was determined by the relative partial pressures of the nitrogen- and carbon-containing gases. It was found that optimal control
of the film chemistry was achieved by using the least thermally reactive gases. In this manner, it was possible to activate
the gas species exclusively by collisions in the gas phase with the ablation-plume particles, thereby decoupling the chemistry
from surface processes. The films were characterized for their chemical, crystallographic, optical, and tribological properties.
All the films had very low impurity levels and a cubic rock salt crystal structure over the entire investigated temperature
range between 100 and 600 °C. Exceedingly high quality epitaxial films could be grown on MgO (001) at 600 °C. Films grown
on stainless steel were polycrystalline. The hardness of the films showed a maximum for both sets for stoichiometries predicted
by a recent theoretical model for hardness based on band-structure calculations. In addition, all the films had an exceptionally
low coefficient of friction versus steel.
Received: 22 August 2001 / Accepted: 3 March 2002 / Published online: 19 July 2002 相似文献
15.
Ion synthesis and laser annealing of Cu nanoparticles in Al2O3 总被引:1,自引:0,他引:1
A.L. Stepanov V.N. Popok D.E. Hole I.B. Khaibullin 《Applied Physics A: Materials Science & Processing》2002,74(3):441-446
Al2O3 samples with Cu nanoparticles, synthesised by ion implantation at 40 keV with a dose of 1×1017 ion/cm2 and a current density from 2.5 to 12.5 μA/cm2, were annealed using ten pulses from a KrF excimer laser with a single pulse fluence of 0.3 J/cm2. The copper depth distribution, formation and modification of metal nanoparticles under the ion implantation and laser treatment
were studied by Rutherford backscattering (RBS), energy dispersive X-ray (EDX) analysis, atomic force microscopy (AFM) and
optical spectroscopy. It was found that laser annealing leads to a reduction in the nanoparticle size without diffusion of
metal atoms into the bulk. The change in particle size and the possibility for oxidation of the copper particles are examined
in the framework of Mie theory. Calculations presented show that under excimer laser treatment, Cu nanoparticles are more
likely to be reduced in size than to undergo oxidation.
Received: 19 April 2001 / Accepted: 7 November 2001 / Published online: 23 January 2002 相似文献
16.
R. Rosentsveig A. Margolin Y. Feldman R. Popovitz-Biro R. Tenne 《Applied Physics A: Materials Science & Processing》2002,74(3):367-369
In this paper, the synthesis of multigram portions of WS2 nanotubes and large foils consisting of aligned nanotubes is described. For this purpose, a fluidized bed reactor, in which
WO3 powder is fed from the top and the reaction gases are blown from below maintaining the powder aloft, is described. The reaction
mechanism is briefly discussed.
Received: 20 August 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
17.
D.-H. Lee Y. Yoon B. Kim J.Y. Lee Y.S. Yoo J.W. Hahn 《Applied physics. B, Lasers and optics》2002,74(4-5):435-440
A simple and reliable method is presented for optimizing the mode matching of a laser beam to the high-finesse cavity used
in pulsed cavity ringdown spectroscopy (CRDS). The method is based on minimizing the excitation of higher-order transverse
cavity modes through monitoring the non-degenerate transverse mode beating which becomes visible with induced cavity asymmetry
caused by slight misalignment. No additional instrument is required other than a pinhole aperture, thus this method can be
applied for CRDS experiments in the whole wavelength range. Measurements of the CRDS absorption spectrum of acetylene (C2H2) near 571 nm demonstrate that the mode-matching optimization improves the sensitivity of pulsed CRDS.
Received: 22 October 2001 / Revised version: 16 January 2002 / Published online: 14 March 2002 相似文献
18.
We emphasize the importance of the new design concept for diffusion barriers in high-density memory capacitors. RuTiN and
RuTiO films are proposed as sacrificial oxygen diffusion barriers. They showed much lower sheet resistance up to 800 °C than
various barriers including binary and ternary nitrides, reported by others. The contact resistance for both the Pt/RuTiN/TiSix/n++poly-plug/n+channel layer/Si and the Pt/RuTiO/RuTiN/TiSix/n++poly-plug/n+channel layer/Si contact structures, the most important electrical parameter for the diffusion barrier in the bottom-electrode
structure of capacitors, exhibited values as low as 5 kΩ, even after annealing up to 750 °C. When each RuTiN and TiN film
is inserted as a glue layer between the bottom electrode Pt layer in the CVD–BST simple stack-type structure, the thermal
stability of the RuTiN glue layer is observed to be 150 °C higher than that of the TiN glue layer. Moreover, the capacitance
of the PVD–BST simple stack-type structure with a TiN glue layer initially degrades after annealing at 500 °C, and thereafter
failed completely. In the case of RuTiN and the RuTiO/RuTiN glue layers, however, the capacitance continuously increased up
to 550 °C. These new experimental results accommodate the introduction of the sacrificial design concept of diffusion barriers
against oxygen in high-density memory capacitors.
Received: 6 February 2002 / Accepted: 4 March 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +82-31/360-4545, E-mail: dongsoo.yoon@hynix.com 相似文献
19.
A.B. Djurišić C.Y. Kwong T.W. Lau E.H. Li Z.T. Liu H.S. Kwok L.S.M. Lam W.K. Chan 《Applied Physics A: Materials Science & Processing》2003,76(2):219-223
Optical functions of tris (8-hydroxyquinoline) aluminum (Alq3) have been studied in the spectral range from 1.55 eV to 5 eV using spectroscopic ellipsometry. The samples have been deposited
by thermal evaporation on glass substrates. Optical functions of Alq3 deposited on unheated substrates and on substrates kept at 100 °C have been determined. The optical functions have been modeled
using point-to-point fitting, with the conventional oscillator model and modified oscillator model. It has been found that
point-to-point fitting gives the best agreement with the experimental data, and that the modified oscillator model yields
better agreement with the experimental data than the conventional oscillator model.
Received: 3 September 2001 / Accepted: 22 March 2002 / Published online: 5 July 2002
RID="*"
ID="*"Corresponding author. Fax: +852-2559/8738, E-mail: dalek@eee.hku.hk 相似文献
20.
X. Zhu S. Lu H.L.W. Chan C.L. Choy K.H. Wong 《Applied Physics A: Materials Science & Processing》2003,76(2):225-229
Compositionally graded (Ba1-xSrx)TiO3 (BST) (x:0.0∼0.25) thin films were grown on Pt (111)/TiO2/SiO2/Si (100) substrates using layer-by-layer pulsed laser deposition in the temperature range 550–650 °C. Both downgraded (Ba/Sr
ratio varying from 100/0 at the bottom surface to 75/25 at the top surface) and upgraded (Ba/Sr ratio varying from 75/25 at
the bottom surface to 100/0 at the top surface) BST films were prepared. Their microstructures were systematically studied
by X-ray diffractometry and scanning electron microscopy. A grain morphology transition from large ‘rosettes’ (>0.30 μm) to
small compact grains (70–110 nm) was observed in the downgraded BST films as the deposition temperature was increased from
550 to 650 °C. No such grain morphology transition was detected in the upgraded BST films. Dielectric measurements with metal
electrodes revealed an enhanced dielectric behavior in the downgraded films. This enhancement is mainly attributed to the
large compressive stress field built up near the interface between the downgraded film and substrate. Furthermore, the BaTiO3 layer in the downgraded BST films not only serves as a bottom layer but also as an excellent seeding layer for enhancing
the crystallization of the subsequent film layers in the downgraded films.
Received: 10 December 2001 / Accepted: 12 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Corresponding author. Fax: 86-25/359-5535, E-mail: xhzhu@public1.ptt.js.cn 相似文献