共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
I. Vrejoiu J.D. Pedarnig M. Dinescu S. Bauer-Gogonea D. Bäuerle 《Applied Physics A: Materials Science & Processing》2002,74(3):407-409
BaTiO3–polymer composite layers have been produced by the spin-on technique (thickness 3–10 μm). The dielectric permittivity of
the layers at room temperature can be tuned from 2.8 to approximately 33 by varying the ceramic filling from 0 to 60% by volume.
The dielectric properties of the films are almost insensitive to temperature variations in the range 20–180 °C. Free-standing
composite layers with ceramic content ≤50% are flexible without noticeable change of permittivity after repeated mechanical
bending.
Received: 22 November 2001 / Accepted: 24 November 2001 / Published online: 23 January 2002 相似文献
3.
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
4.
Size dependence of non-linear optical properties of SiO2 thin films containing InP nanocrystals 总被引:1,自引:0,他引:1
M.J. Zheng L.D. Zhang J.G. Zhang 《Applied Physics A: Materials Science & Processing》2001,73(2):183-187
SiO2 composite thin films containing InP nanocrystals were fabricated by radio-frequency magnetron co-sputtering technique. The
microstructure of the composite thin films was characterized by X-ray diffraction and Raman spectrum. The optical absorption
band edges exhibit marked blueshift with respect to bulk InP due to strong quantum confinement effect. Non-linear optical
absorption and non-linear optical refraction were studied by a Z-scan technique using a single Gaussian beam of a He-Ne laser
(632.8 nm). We observed the saturation absorption and two-photon absorption in the composite films. An enhanced third-order
non-linear optical absorption coefficient and non-linear optical refractive index were achieved in the composite films. The
nonlinear optical properties of the films display the dependence on InP nanocrystals size.
Received: 27 June 2000 / Accepted: 27 June 2000 / Published online: 13 September 2000 相似文献
5.
Y. Liu D. Li R.Y. Zhu G.J. You S.X. Qian Y. Yang J.L. Shi 《Applied physics. B, Lasers and optics》2003,76(4):435-439
Au-core CdS-shell composite nanoparticles were synthesized by a direct self-assembly process and integrated into BaTiO3 thin films. Characterization by transmission electron microscopy showed that the average diameter of these composite nanoparticles
was about 8 nm. Using the femtosecond time-resolved optical Kerr effect method, we investigated the third-order nonlinear
optical response of the Au@CdS nanoparticles embedded in the BaTiO3 thin films at a wavelength of 800 nm. An ultrafast nonlinear response and a large effective third-order nonlinear susceptibility
of χ(3)=7.7×10-11 esu were observed. We attributed the enhancement of the third-order optical nonlinearity to a localized electric field effect
originating from the core-shell structure under off-surface-plasmon resonance conditions.
Received: 13 May 2002 / Revised version: 23 October 2002 / Published online: 3 April 2003
RID="*"
ID="*"Corresponding author. Fax: +86-21/6510-4949, E-mail: sxqian@fudan.ac.cn 相似文献
6.
溶剂处理对Pr4VOPc染料掺杂聚合物薄膜光谱的影响 总被引:1,自引:0,他引:1
制备了Pr4VOPc染料掺掺杂的聚合物PMMA(DIP)薄膜。Pr4VOPc在染料掺杂聚合物薄膜形成阶段形成玻璃态Ⅰ,经有机溶剂蒸汽处理后,Pr4VOPc形成了热力学更稳定的相Ⅱ。 相似文献
7.
Jerome P. Ferrance Kenith E. Meissner John W. Pettit 《Journal of nanoparticle research》2010,12(2):405-415
Optical signals were used to modulate the resistance of single-walled carbon nanotube–polymer composite films for development
of optical switching devices. Films were fabricated from nanotubes dispersed in poly(2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene)
(MEH-PPV) solutions in either tetrahydrofuran (THF) or toluene. MEH-PPV was affected by the solvent choice, with THF causing
an absorbance shift to shorter wavelengths. Composite films formed from THF dispersions showed 1–4% resistance decreases when
illuminated with a green diode laser. Illumination of toluene-based films showed up to 5.4% resistance decreases, smaller
than expected based on the polymer solution absorbance. Fluorescent emission from the polymer in toluene appears to inhibit
charge transfer from the polymer to the nanotubes. THF films were unaffected by illumination with a red diode laser, while
toluene dispersion films showed resistance decreases up to 1%. Nanotube dispersion and film formation reproducibility, evaluated
for both the solvents, showed that the solvent affected film resistance and dispersion stability. 相似文献
8.
Polypyrrole (PPy)–indium phosphide (InP) composite material was electrochemically prepared by the incorporation of InP into
a PPy matrix during electrochemical synthesis (cycling) under magnetic stirring from the acetonitrile/LiClO4 electrolyte containing
the Py and InP particles. The PPy–InP composite material was designed to explore new approaches to improve light-collection
efficiency in polymer photovoltaic. The samples were characterised by cyclic voltammetry, impedance spectroscopy measurement,
scanning electron microscopy, energy dispersive X-ray spectroscopy, UV–visible and photoelectrochemical measurements. It was
observed that the photocurrent of the composites was higher than that of the single PPy films and increased with InP concentration.
The study showed that the presence of InP particles in the polymeric film improves the optical and the photovoltaic properties
of PPy and give information on the use possibility of these films for photovoltaic cells' application. 相似文献
9.
Stress anisotropy in circular planar magnetron sputter deposited molybdenum films and its annealing effect 总被引:2,自引:0,他引:2
Y.G. Wu E.H. Cao Z.S. Wang J.M. Wei W.X. Tang L.Y. Chen 《Applied Physics A: Materials Science & Processing》2003,76(2):147-152
As part of the program to develop a free-standing thin-film filter for soft X-ray optics application, stress anisotropy in
the molybdenum films deposited by dc circular planar magnetron sputtering were studied by X-ray diffraction (XRD) as a function
of sputtering argon gas pressure over a range of 0.8–1.5 Pa. Surface morphology of the films has been investigated by optical
microscopy and scanning tunneling microscopy (STM). It is found that, for the film deposited at 0.8 Pa pressure, the stresses
are more compressive in the tangential than in the radial direction; the highest compressive stress exists in the center area.
The film deposited at 1.5 Pa pressure has the highest stress anisotropy, and the stresses are less tensile in the tangential
than in the radial direction. Annealing in vacuum is more effective in reducing tensile stress and stress anisotropy in the
tensile stressed film than in the compressively stressed film.
Received: 14 September 2001 / Accepted: 21 January 2002 / Published online: 5 July 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/6598-6323, E-mail: ygwu@mail.tongji.edu.cn 相似文献
10.
S.R. Sershen S.L. Westcott J.L. West N.J. Halas 《Applied physics. B, Lasers and optics》2001,73(4):379-381
Metal nanoshells, which are nanoparticles consisting of a dielectric core surrounded by a metal shell, have an optical response
dictated by the plasmon resonance. This optical resonance leads to large extinction cross-sections, which are typically several
times the physical cross-section of the particles. The wavelength at which the resonance occurs depends on the core and shell
sizes, allowing nanoshells to be tailored for applications. In this paper, we demonstrate how incorporating nanoshells transforms
a thermoresponsivepolymer into a photothermally responsive nanoshell–polymer composite. When the thermoresponsive polymer,
co-N-isopropylacrylamide-acrylamide (NIPAAm-co-AAm), is heated, the polymer undergoes a reversible decrease in volume. Pristine
NIPAAm-co-AAm does not inherently absorb visible or near infrared light. However, by incorporating metal nanoshell particles
with a resonance that has been placed at 832 nm into the NIPAAm-co-Aam, nanoshell–polymer composite hydrogels are fabricated.
When the composite is illuminated with a diode laser at 832 nm, the nanoshells absorb light and convert it to heat. This induces
a reversible and repeatable light-driven collapse of the composite with a weight change of 90% after illumination at 1.8 Wcm-2.
Received: 18 July 2001 / Published online: 10 October 2001 相似文献
11.
J. Gonzalo O. Sanz A. Perea J.M. Fernández-Navarro C.N. Afonso J. García López 《Applied Physics A: Materials Science & Processing》2003,76(6):943-946
Heavy metal oxide thin films of the ternary system Nb2O5–GeO2–PbO have been prepared by pulsed laser deposition in an O2 environment from either glassy or crystalline bulk samples. The range of ([Pb]+[Nb]) content in which the films are optically
homogeneous and transparent is much broader (0.5–1.0) than that of the bulk samples considered in the present work (0.55–0.62).
The imaginary part of the refractive index is very low in all cases (k<10-3), whereas the real part increases linearly with the ([Pb]+[Nb]) content up to values as high as 2.35. The optical energy
gap has been found to be strongly dependent on [Pb], whereas it is almost independent of [Nb]. This dependence is discussed
in terms of the role of Pb and Nb as network modifiers or formers.
Received: 5 August 2002 / Accepted: 8 August 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. Fax: +34-91/564-5557, E-mail: j.gonzalo@io.cfmac.csic.es 相似文献
12.
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
13.
Y. Du M.-S. Zhang J. Wu L. Kang S. Yang P. Wu Z. Yin 《Applied Physics A: Materials Science & Processing》2003,76(7):1105-1108
SrTiO3 thin films were prepared on a fused-quartz substrate by pulsed laser deposition (PLD). Dense and homogeneous films with a
thickness of 260 nm were prepared. Optical constants (refractive index n and extinction coefficient k) were determined from
the transmittance spectra using the envelope method. The optical band gap energy of the films was found to be 3.58 eV, higher
than the 3.22 eV for bulk SrTiO3, attributable to the film stress exerted by the substrate. The dispersion relation of the refractive index vs. wavelength
follows the single electronic oscillator model. The refractive index and the packing density for the PLD-prepared SrTiO3 thin films are higher than those for the SrTiO3 films prepared by physical vapor deposition, sol–gel and RF sputtering.
Received: 18 March 2002 / Accepted: 7 October 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: mszhang@nju.edu.cn 相似文献
14.
G.S. Wang X.J. Meng Z.Q. Lai J. Yu J.L. Sun S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2003,76(1):83-86
Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been grown on Pt/Ti/SiO2/Si substrates by chemical solution methods. X-ray diffraction analysis shows that BLT thin films are polycrystalline with
(171)-preferential orientation. Atomic force microscopy investigation shows that they have large grains about 120 nm in size.
A Pt/BLT/Pt capacitor has been fabricated and showed excellent ferroelectricity, with a remnant polarization and coercive
field of 24 μC/cm2 and 116 kV/cm, respectively. The capacitor shows no polarization fatigue up to 109 switching cycles. The optical constants (n,k) of the BLT thin films in the wavelength range 0.35–1.7 μm were obtained by
spectroscopic ellipsometry measurements, and the band-gap energy was found to be about 3.25 eV.
Received: 16 October 2001 / Accepted: 6 January 2002 / Published online: 3 June 2002
RID="*"
ID="*"Corresponding author. Fax: +86-21/65830-734, E-mail: gswang@mail.sitp.ac.cn 相似文献
15.
We present an experimental study of non-linear selective reflection (SR) at a quartz–Cs-vapor interface in a V-type three-level
scheme. The non-linear selective reflection at the Cs D2 resonance line (6
S
1/2F=4→6
P
3/2) is monitored with and without pumping. The sub-Doppler reflection spectrum is observed and the effect of pumping on the
signal of the selective reflection is investigated. The experimental result is in agreement with the theoretical calculation.
Received: 16 April 2002 / Revised version: 12 June 2002 / Published online: 25 September 2002
RID="*"
ID="*"Corresponding author. Fax: +86-351/701-1500, E-mail: zhaojm@sxu.edu.cn 相似文献
16.
W. Holzer A. Penzkofer T. Pertsch N. Danz A. Bräuer E.B. Kley H. Tillmann C. Bader H.-H. Hörhold 《Applied physics. B, Lasers and optics》2002,74(4-5):333-342
Wave-guided thin-film distributed-feedback (DFB) polymer lasers are fabricated by spin coating a PPV-derived semiconducting
polymer, thianthrene-DOO-PPV, onto oxidised silicon wafers with corrugated second-order periodic gratings. The gratings are
written by reactive ion beam etching. Laser action is achieved by transverse pumping with picosecond laser pulses (wavelength
347.15 nm, duration 35 ps). The DFB-laser surface emission and edge emission are analysed. Outside the grating region the
polymer film is used for comparative wave-guided travelling wave laser (amplified spontaneous emission (ASE)) studies. The
pump pulse threshold energy density for wave-guided DFB-laser action (4–9 μJ cm-2) is found to be approximately a factor of two lower than the threshold for wave-guided travelling wave laser action. The
spectral width of the DFB laser (down to ΔλDFB≈0.07 nm) is considerably narrower than that of the travelling wave laser (ΔλTWL≈14 nm). The DFB-laser emission is highly linearly polarised transverse to the grating axis (TE mode). Only at high pump pulse
energy densities does an additional weak TM mode build up. The surface-emitted DFB-laser radiation has a low divergence along
the grating direction. For both the DFB lasers and the travelling wave lasers, gain saturation occurs at high excitation energy
densities.
Received: 7 January 2002 / Revised version: 15 February 2002 / Published online: 14 March 2002 相似文献
17.
T.J. Rinke R.B. Bergmann J.H. Werner 《Applied Physics A: Materials Science & Processing》1999,68(6):705-707
Thermal crystallization of a double layer porous Si film creates a monocrystalline Si film with a thin separation layer between
the Si film and the reusable starting wafer. The process enables transfer of thin monocrystalline Si films to foreign substrates,
whereby devices may be formed before or after separation of the film. Sub-micrometer thick films are almost compact, while
films with a thickness of several μm contain voids, and are therefore termed “quasi-monocrystalline”. Internal voids strongly
enhance optical absorption by light scattering. The hole mobility is 78 cm2 V-1 s-1 at a p-type starting wafer resistivity of 0.05 Ω cm.
Received: 24 March 1999 / Accepted: 29 March 1999 / Published online: 5 May 1999 相似文献
18.
J. Liao X.J. Zhang F. Xu X.Z. Fan H.T. Wang N.B. Ming 《Applied physics. B, Lasers and optics》2002,75(8):865-869
Optical bistable behavior in a quasi-waveguide containing non-linear film has been experimentally investigated in several
publications in the past years; however, the physical mechanism for optical bistability has not been theoretically explained.
In the present letter, we propose a theoretical model and successfully explain the observed optical bistability of both the
reflected light and the scattered light (m-lines) in a non-linear quasi-waveguide. The optical bistability in the non-linear quasi-waveguide is due to the scattering-type
wavevector mismatch mechanism.
Received: 10 July 2002 / Revised version: 10 September 2002 / Published online: 20 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: htwang@nju.edu.cn 相似文献
19.
Polyvinyl alcohol (PVA) and potassium hydroxide (KOH) have been used to prepare alkaline solid polymer electrolytes (ASPE) films. The films were stored in a dry environment for 30 and 100 days. The highest room temperature conductivity for the PVA:KOH film with weight percentage ratio of 1:0.67 during storage for 30 and 100 days were (8.5±0.2)×10−4 and (1.3±0.1)×10−7 S cm−1, respectively. The conductivity–temperature behaviour after 30 and 100 days of storage of the alkaline polymer electrolytes is Arrhenian and liquid-like. The structural, morphological and thermal studies of the ASPE films are also presented in this paper. 相似文献
20.
Kuo-Sheng Kao Shang-Hao Chang Po-Tsung Hsieh Chih-Ming Wang Da-Long Cheng 《Applied Physics A: Materials Science & Processing》2009,96(2):529-533
Three-layered ZnO/Ag–Ti/ZnO structures were prepared using both the sol-gel technique and DC magnetron sputtering. This study
focuses on the electrical and optical properties of the ZnO/Ag–Ti/ZnO multilayers with various thicknesses of the Ag–Ti layer.
The ZnO thin film prepared by the sol–gel method was dried at 300°C for 3 minutes, and a fixed thickness of 20 nm was obtained.
The thickness of the Ag–Ti thin film was controlled by varying the sputtering time. The Ag–Ti layer substantially reduced
the electrical resistivity of the sol–gel-sprayed ZnO thin films. The sheet resistance of the Ag–Ti layer decreased dramatically
and then became steady beyond a sputtering time of 60 s. The sputtering time of Ag–Ti thin film deposition was determined
to be 60 s, taking into account the optical transmittance. Consequently, the transmittance of the ZnO/Ag–Ti/ZnO multilayer
films was 71% at 550 nm and 60% at 350 nm. The sheet resistance was 4.2 Ω/sq. 相似文献