共查询到20条相似文献,搜索用时 31 毫秒
1.
G.W. Meng X.S. Peng Y.W. Wang C.Z. Wang X.F. Wang L.D. Zhang 《Applied Physics A: Materials Science & Processing》2003,76(1):119-121
Aligned SiOx nanowire arrays standing on a Si substrate were successfully synthesized using a simple method by heating a single-crystalline
Si slice covered with SiO2 nanoparticles at 1000 °C in a flowing Ar atmosphere. The SiOx nanowire arrays were characterized by scanning electron microscopy and transmission electron microscopy. The SiOx nanowires become progressively thinner from bottom to top. The formation process of the SiOx nanowire arrays is closely related to a vapor–solid mechanism. Room-temperature photoluminescence measurements under excitation
at 260 nm showed that the SiOx nanowire arrays had a strong blue–green emission at 500 nm (about 2.5 eV), which may be related to oxygen defects.
Received: 29 April 2002 / Accepted: 30 April 2002 / Published online: 10 September 2002
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ID="*"Corresponding author. Fax: +86-551-559-1434, E-mail: gwmeng@mail.issp.ac.cn 相似文献
2.
C. Moreau E. Therssen P. Desgroux J.F. Pauwels A. Chapput M. Barj 《Applied physics. B, Lasers and optics》2003,76(5):597-602
The potential of Laser Induced Fluorescence detection of the CH radical using C–X (0–0) excitation is investigated in a sooting
methane/air diffusion flame at atmospheric pressure. Fluorescence is detected using the very narrow (<0.4 nm) Q-branch of
the C–X (0–0) band, which enables the measurement of CH in sooting flames without interference from PAH fluorescence and soot
emissions. Absolute concentrations are obtained using Cavity Ring Down Spectroscopy. 1D CH profiles in the sooting zone are
recorded using a CCD camera with an excellent signal-to-noise ratio. The C–X (0–0) excitation associated with Q-branch detection
is shown to be three times more efficient than the B–X scheme.
Received: 4 March 2002 / Revised version: 5 November 2002 / Published online: 5 May 2003
RID="*"
ID="*"Corresponding author. Fax: +33-3/2033-6463, E-mail: eric.therssen@univ-lille1.fr 相似文献
3.
Z.J. Li H.J. Li X.L. Chen A.L. Meng K.Z. Li Y.P. Xu L. Dai 《Applied Physics A: Materials Science & Processing》2003,76(4):637-640
Large quantities of high-purity crystalline β-SiC nanowires have been synthesized at relatively low temperature via a new
simple method, the chemical-vapor-reaction approach, in a home-made graphite reaction cell. A mixture of milled Si and SiC
powders and C3H6 were employed as the starting materials. The results show that the nanowires with diameters of about 10–35 nm are single
crystalline β-SiCwithout any wrapping of amorphous material, and the nanowire axes lie along the 〈111〉 direction. Some unique
properties are found in the Raman scattering from the β-SiC nanowires, which are different from previous observations of β-SiC
materials. A possible growth mechanism for the β-SiC nanowires is proposed.
Received: 27 August 2002 / Accepted: 28 August 2002 / Published online: 4 December 2002
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ID="*"Corresponding author. Fax: +86-29/8491-000, E-mail: zjli-sohu@sohu.com 相似文献
4.
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
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ID="*"Corresponding author. Fax: 86-25/359-5535, E-mail: xhzhu@public1.ptt.js.cn 相似文献
5.
A. Costela I. García-Moreno C. Gómez O. García R. Sastre 《Applied physics. B, Lasers and optics》2002,75(8):827-833
We report on the laser action of rhodamine 6G (Rh6G) incorporated into new hybrid organic–inorganic monolithic materials.
The synthesis of these materials proceeded via the simultaneous sol-gel process of the inorganic part (tetraethoxysilane or
tetramethoxysilane) and the free-radical polymerization of an organic monomer part (2-hydroxypropyl methacrylate, 2-hydroxyethyl
methacrylate and a 1:1 v/v copolymer of this monomer with methyl methacrylate). The wt. % proportion of the alkoxide was systematically
varied in each organic formulation, and the effect of each organic–inorganic composition on the lasing properties of Rh6G
was evaluated. The laser samples were transversely pumped and the influence on the laser action of dye concentration, pump
wavelength and pump repetition rate was analyzed. Lasing efficiencies of up 26% and good stabilities, with a 90% drop in the
initial laser output of up to 12000 pump pulses at 2.5 Hz, were obtained when the samples were pumped at 355 nm with 5.5 mJ/pulse
from the third harmonic of a Q-switched Nd:YAG laser.
Received: 31 July 2002 / Revised version: 14 October 2002 / Published online: 20 December 2002
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ID="*"Corresponding author. Fax: +34-91/564-4853, E-mail: ogarcia@ctp.csic.es 相似文献
6.
G. Tsilimis J. Kutzner H. Zacharias 《Applied Physics A: Materials Science & Processing》2003,76(5):743-749
An extreme ultraviolet (EUV) laser light source based on high-harmonic generation is presented. Coherent radiation in the
photon energy range hν=20–120 eV is produced in the conversion media argon, neon and helium. High-harmonic radiation in the
energy range 20–50 eV is applied to investigate photoemission spectra of Pt (111) and CO/Pt (111). In the photoemission spectra
of the clean surface, new secondary electron emission structures are found which influence the cross section analysis of the
CO states. When taking these Pt resonances into consideration, the 4σ and 5σ CO shape resonances are found at photon energies
of 37 eV and 28 eV, respectively. Additionally, a resonance at hν=31 eV is also observed for the CO 1π state, in contrast
to formerly published experimental data. Experimental and theoretical data suggest that this resonance is not connected to
the well-known shape resonances in the σ-channel. Based on theoretical approaches, it is identified as an autoionization resonance.
Received: 8 April 2002 / Accepted: 22 May 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +49-251/833-3604, E-mail: kutzner@uni-muenster.de 相似文献
7.
S.H. Sun G.W. Meng Y.W. Wang T. Gao M.G. Zhang Y.T. Tian X.S. Peng L.D. Zhang 《Applied Physics A: Materials Science & Processing》2003,76(2):287-289
Tin dioxide (SnO2) nanobelts have been successfully synthesized in bulk quantity by a simple and low-cost process based on the thermal evaporation
of tin powders at 800 °C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations reveal
that the nanobelts are uniform, with lengths from several-hundred micrometers to a few millimeters, widths of 60 to 250 nm
and thicknesses of 10 to 30 nm. X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and selected-area electron
diffraction analysis (SAED) indicate that the nanobelts are tetragonal rutile structure of SnO2. The SnO2 nanobelts grow via a vapor–solid (VS) process.
Received: 3 June 2002 / Accepted: 10 June 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-551/559-1434, E-mail: gwmeng@mail.issp.ac.cn 相似文献
8.
Q. Ren D. Xu Y.T. Chow Z.H. Lü C.B. Ma G.H. Zhang H.P. Chan P.L. Chu 《Applied Physics A: Materials Science & Processing》2003,76(2):183-186
Composite thin films of PbTiO3 nanocrystals and high-transparency PEKc polymer for applications in electro-optical devices were prepared using the spin
coating technique. The size of the PbTiO3 nanocrystals was estimated to be 30–40 nm using a transmission electron microscope. The transmission technique, a simple
method for measuring the electro-optic coefficients of poled composite polymer films was developed. The electro-optic coefficient
γ33 of poled PbTiO3/PEKc composite polymer films was measured to be 18.34 pm V-1 at 633 nm under room temperature. The index at 633 nm and the dielectric constant at 100 kHz under room temperature were
determined to be 1.65248 and 7.32, respectively. The figure of merit F2=n7γ2/ε was estimated to be 1546, showing very good electro-optical properties.
Received: 5 February 2002 / Accepted: 12 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Corresponding author. Fax: +852/2788-7791, E-mail: eeytc@cityu.edu.hk 相似文献
9.
K.-H. Shim M.C. Paek B.T. Lee C. Kim J.Y. Kang 《Applied Physics A: Materials Science & Processing》2001,72(4):471-474
Effects of thermal treatments on the electrical properties and microstructures of indium–tin oxide (ITO)/GaN contacts have
been investigated using a rf-magnetron sputter deposition followed by rapid thermal annealing. ITO films annealed at 800 °C
revealed Schottky contact characteristics with a barrier height corresponding to ITO’s work function of 4.62 eV. The evolution
of electrical properties of ITO/GaN contacts was attributed to the preferential regrowth of In2O3 (222)//GaN (0001) with an ideal metal–semiconductor Schottky contact. The feasible use of ITO/GaN as a transparent Schottky
contact would be realized by the enhanced regrowth of In2O3 at high temperature.
Received: 1 September 2000 / Accepted: 15 November 2000 / Published online: 28 February 2001 相似文献
10.
We report on germania/organically modified silane (ormosil) hybrid materials produced by the sol–gel technique for photonic
applications. Acid-catalyzed solutions of γ-glycidoxypropyltrimethoxysilane mixed with germanium isopropoxide have been used
as precursors for the hybrid materials. Planar waveguide films with a thickness of about 2 μm have been prepared by a single
spin-coating process and low-temperature heat treatment from these high germanium content hybrid materials. Atomic force microscopy,
thermal gravimetric analysis, UV–visible spectroscopy, and Fourier-transform infrared spectroscopy have been used to investigate
the optical and structural properties of the films. The results have indicated that a dense, low absorption, and high transparency
(in the visible range) waveguide film could be achieved at a low temperature. A strong UV-absorption region at short wavelengths
∼200 nm, accompanied by a shoulder peaked at ∼240 nm, has been noticed due to the neutral oxygen monovacancy defects. The
propagation mode and loss properties of the planar waveguide films have also been investigated by using a prism-coupling technique.
Received: 5 November 2002 /
Revised version: 27 December 2002 / Published online: 19 March 2003
RID="*"
ID="*"Corresponding author. Fax: +65-67909081, E-mail: ewxque@ntu.edu.sg 相似文献
11.
K. Yamasaki S. Juodkazis T. Lippert M. Watanabe S. Matsuo H. Misawa 《Applied Physics A: Materials Science & Processing》2003,76(3):325-329
We report the reversible micro-structuring of a synthetic rubber polymer (cis1,4-polybutadiene (PB)) by femtosecond laser
illumination. Visco-elastic relaxation of the optically damaged region was observed. The recovery time, typically 102–104 ms, can be varied by changing the irradiation pulse energy. Multi-shot-induced damage recovers on the much longer scale of
101–102 s. It was found that the doping of PB by 4 wt. % of pentazadiene ([4-NO2]–phenyl–N=N–N(C3H7)–N=N–phenyl–[4-NO2]) reduces the threshold of light-induced photo-modification by 20%. This is explained by photo-induced (homolytic) cleavage
of the pentazadiene bonds and formation of gaseous N2, which facilitates material failure at the irradiated spot.
The recovery of optical transmission can be applied to optical memory, optical and micro-mechanical applications. The underlying
mechanism of the phenomenon is discussed in terms of anelastic α- and β-relaxation (polymer backbone and chains/coils relaxation,
respectively).
Received: 11 October 2001 / Accepted: 9 July 2002 / Published online: 25 October 2002
RID="*"
ID="*"Corresponding author. Fax: +81-88/656-7598, E-mail: misawa@eco.tokushima-u.ac.jp 相似文献
12.
X.Y. Chen B. Yang T. Zhu K.H. Wong J.M. Liu Z.G. Liu 《Applied Physics A: Materials Science & Processing》2002,74(4):567-569
(110)-textured MgO films were grown on Si (100) with etching and without etching by pulsed laser deposition. The deposited
MgO films were shown to be droplets-free. The MgO film was used as a buffer layer to further grow Pt film on Si (100). A completely
(110)-oriented Pt film was obtained on such a buffer layer and its surface is very smooth with a roughness of about 7.5 nm
over 5×5 μm. This can be used as a new oriented Pt electrode on silicon for devices.
Received: 23 January 2001 / Accepted: 27 April 2001 / Published online: 27 June 2001 相似文献
13.
Highly oriented GaN nanowire arrays have been achieved by the catalytic reaction of gallium with ammonium. The resulting materials
were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), energy dispersive X-ray
spectroscopy (EDS), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). SEM images show
that the resulting materials are nanowire arrays with a uniform length of about 10 μm. XRD, EDS, TEM and SAED indicate that
the nanowire arrays are single-crystal hexagonal GaN with a wurtzite structure. They have diameters of 10 to 20 nm.
Received: 2 October 2002 / Accepted: 7 October 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. E-mail: wwwangjc@sina.com 相似文献
14.
J.S. Gibb G. Hancock A. Hutchinson R. Peverall G.A.D. Ritchie 《Applied physics. B, Lasers and optics》2003,76(1):97-105
A simple technique is demonstrated for the accurate determination of pressure-induced line shifts of water in air. High- and
low-pressure water samples are simultaneously probed on selected overtone transitions at 1.32 μm using a current-modulated
distributed-feedback diode laser and harmonic detection. The resultant profiles yield an average line shift of -293±30 MHz/atm
for the 3,3,0 (002)2,2,1 (000)transition at 227251 GHz and -134±7 MHz/atm for the 3,2,1 (002)2,1,2 (000) transition at 227027 GHz.
Comparisons are made between first- and second-harmonic detection, and wavelength- and frequency-modulation regimes. The effect
of modulation broadening on the returned line shifts is quantified.
Received: 12 August 2002 / Revised version: 21 October 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +44-01865/275410, E-mail: gus.hancock@chemistry.ox.ac.uk 相似文献
15.
C.L. Wang S.Z. Lin Y. Niu W.T. Wu Z.L. Zhao 《Applied Physics A: Materials Science & Processing》2003,76(2):157-163
A bulk nanocrystallined Ag50Ni alloy has been prepared by hot-pressing the mechanically pre-alloyed powders at 620 °C under
a normal pressure of 58 MPa in vacuum. The microstructural characteristics of the alloy were studied by X-ray diffraction
(XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of the precise determination
of the lattice parameters of the phases in the powders and in the alloy by XRD show that, after mechanical alloying for 200 h,
the solid solubility of Ag in Ni reaches 4.85±0.21 at %, while that of Ni in Ag reaches 0.84±0.30 at %. After hot pressing,
the Ag- and Ni-rich phases in the alloy still show a certain degree of supersaturation, with a solid solubility of 0.45±0.11 at %
of Ag in Ni. After further annealing of the alloy at 700 °C for 24 h, the solubility decreases to a value of 0.21±0.11 at %
for Ag in Ni and to less than 0.1 at % for Ni in Ag. The grain size of the mechanically alloyed powders was of ca 6 nm. After
hot pressing, the grain size of the alloy increased to 40–60 nm and then grew further to 100–110 nm after annealing. The influence
of the variation of the grain size and the internal stress on the line breadth of the X-ray diffraction peaks has been evaluated
in detail. Finally, the role of the nanocrystalline structure in the fast densification process of the powders is also discussed.
Received: 12 September 2001 / Accepted: 18 Febraury 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-24/2389-3624, E-mail: wwt@icpm.syb.ac.cn 相似文献
16.
E. Majkova S. Luby R. Senderak Y. Chushkin M. Jergel I. Zergioti D. Papazoglou A. Manousaki C. Fotakis 《Applied Physics A: Materials Science & Processing》2003,76(5):763-766
The sub-picosecond laser microstructuring of multilayer gratings is presented in this paper. A micromachining system operating
with a 0.5 ps KrF laser at 248 nm was used to etch grating structures with a groove width of 1–2 μm in Mo/Si and Si/Mo multilayers.
Atomic force microscopy, scanning electron microscopy and X-ray reflectivity were used to characterize the microetched patterns.
The ω-scans around the 1st Bragg maximum show symmetric satellites up to 3rd order, with positions corresponding to the grating
period. The use of sub-picosecond laser pulses minimizes the thermally affected zone and enhances the quality of the etched
features. Short pulse laser processing is advantageous for the fabrication of high spatial resolution microstructures required
in X-ray optics.
Received: 21 May 2002 / Accepted: 19 August 2002 / Published online: 15 January 2003
RID="*"
ID="*"Corresponding author. Email: dpapa@iesl.forth.gr 相似文献
17.
Efficient room-temperature operation of 4
F
3/24
I
9/2 transitions in diode-end-pumped Nd:YAG lasers at 946 nm and 938.5 nm is reported. 7.0-W continuous-wave output power at 946 nm
and 3.9 W at 938.5 nm have been obtained. An analytical model has been developed for the quasi-three-level laser including
the influence of energy-transfer upconversion. Frequency doubling of these transitions in periodically poled KTP generated
blue light at 473 nm and 469 nm. Both single-pass extra-cavity as well as intracavity schemes have been investigated.
Received: 31 July 2002 / Published online: 5 February 2003
RID="*"
ID="*"Corresponding author. Fax: +46-8/750-5430, E-mail: stefan.bjurshagen@acreo.se 相似文献
18.
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
19.
C. Dölle C. Reinhardt P. Simon B. Wellegehausen 《Applied physics. B, Lasers and optics》2002,75(6-7):629-634
. Investigations of the efficient generation of powerful coherent radiation at 82.8 nm by frequency tripling of short-pulse
KrF laser radiation are presented. Argon gas is selected as nonlinear medium due to the resonantly enhanced 3rd-order susceptibility
χ(3)(-3ω,ω,ω,ω). Pulse energies of 100 μJ at 82.8 nm have been measured for a pump pulse energy of 14 mJ. An upscaling to more
than 500 μJ is expected with available more powerful pump lasers. Features of this XUV source and possible applications are
discussed.
Received: 26 July 2002 / Published online: 15 November 2002
RID="*"
ID="*"Corresponding author. Fax: +49-511/7622211, E-mail: reinhardt@iqo.uni-hannover.de 相似文献
20.
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