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1.
Jiagang Wu Dingquan Xiao Jiliang Zhu Jianguo Zhu Junzhe Tan 《Applied Surface Science》2007,253(20):8365-8370
The (Pb0.90La0.10)Ti0.975O3/PbTiO3 (PLT/PT), PbTiO3/(Pb0.90La0.10)Ti0.975O3/PbTiO3 (PT/PLT/PT) multilayered thin films with a PbOx buffer layer were in situ deposited by RF magnetron sputtering at the substrate temperature of 600 °C. With this method, highly (1 0 0)-oriented PLT/PT and PT/PLT/PT multilayered thin films were obtained. The PbOx buffer layer leads to the (1 0 0) orientation of the films. The dielectric, ferroelectric and pyroelectric properties of the PLT multilayered thin films were investigated. It is found that highly (1 0 0)-oriented PT/PLT/PT multilayered thin films possess higher remnant polarization 2Pr (44.1 μC/cm2) and better pyroelectric coefficient at room temperature p (p = 2.425 × 10−8 C/cm2 K) than these of PLT and PLT/PT thin films. These results indicate that the design of the PT/PLT/PT multilayered thin films with a PbOx buffer layer should be an effective way to enhance the dielectric, ferroelectric and pyroelectric properties. The mechanism of the enhanced ferroelectric properties was also discussed. 相似文献
2.
Takeshi Kanashima Osamu Maida Masaki Okumoto Satoshi Kitai Haruhiko Ohashi 《Applied Surface Science》2006,252(22):7774-7780
Fluorocarbon films were deposited by soft X-ray ablation of polytetrafluoroethylene (PTFE) and characterized as low-dielectric-constant interlayer dielectrics. Very rapid deposition of such films at approximately 1500 nm/min could be achieved at room temperature. Fourier-transform infrared spectroscopy (FT-IR) measurement results suggest that the films deposited are primarily formed as one-dimensional chains of (-CF2-)n which are partially cross-linked. The cross-link density increases with increasing deposition temperature, which improves the thermal stability. However, the dielectric constant of the films increased abruptly above 300 °C. The dielectric constant and leakage current at 1.0 MV/cm of the film deposited at room temperature were approximately 2.1 and 2.0×10−9 A/cm2, respectively. 相似文献
3.
J. Xu W. Li T. Ma Z. Li W. Lu K. Chen 《Applied Physics A: Materials Science & Processing》2000,71(6):651-655
Thin layers of hydrogenated amorphous carbon were prepared by using organic hydrocarbon source, xylene (C8H10), in plasma-enhanced chemical vapor deposition (PECVD) system. The microstructures were characterized by using Fourier-transform
infrared and Raman scattering spectra. The appearance of a sharp vibration signal in 1600 cm-1 strongly suggests the existence of sp2 carbon clusters with aromatic rings. With increasing the deposition rf power, the content of these aromatic structures is
increased in the films. In contrast to a broad single PL peak in methane (CH4)-baseda-C:H films, the PL band of xylene-based a-C:H films contains multiple peaks in blue-green light region, which is influenced
by rf power. We tentatively attributed it to the radiative recombination of electron-hole pairs through some luminescent centers
associated with aromatic structures.
Received: 26 April 2000 / Accepted: 9 May 2000 / Published online: 13 September 2000 相似文献
4.
Structure-related infrared optical properties of BaTiO3 thin films grown on Pt/Ti/SiO2/Si substrates
Z.G. Hu G.S. Wang Z.M. Huang J.H. Chu 《Journal of Physics and Chemistry of Solids》2003,64(12):2445-2450
BaTiO3 thin films with different thickness have been grown on Pt/Ti/SiO2/Si substrates by a modified sol-gel method. X-ray diffraction analyses show that the BaTiO3 thin films are polycrystalline. The crystalline quality of the films is improved with increasing thickness. The infrared optical properties of the BaTiO3 thin films have been investigated using an infrared spectroscopic ellipsometry in the wave number range of 800-4000 cm−1 (2.5-12.5 μm). By fitting the measured pseudodielectric functions with a three-phase model (Air/BaTiO3/Pt), and a derived classical dispersion relation for the thin films, the optical constants and thicknesses of the thin films have been simultaneously obtained. The refractive index of the BaTiO3 thin films increases and on the other hand, the extinction coefficient does not change with increasing thickness in the entirely measured wave number range. The dependence of the refractive index on the film thickness has been discussed in detail and was mainly due to both the crystalline quality of the films and packing density. Finally, the absorption coefficient was calculated in the infrared region for applications in the pyroelectric IR detectors. 相似文献
5.
Enhanced fatigue property of PZT thin films using LaNiO3 thin layer as bottom electrode 总被引:2,自引:0,他引:2
X.J. Meng J.L. Sun J. Yu G.S. Wang S.L. Guo J.H. Chu 《Applied Physics A: Materials Science & Processing》2001,73(3):323-325
A highly (100)-oriented metallic LaNiO3 film was prepared directly on a Si substrate by a simple metalorganic decomposition (MOD) technique using lanthanum nitrate
and nickel acetate as the starting sources. Subsequent Pb(Zr,Ti)O3 (PZT) thin films deposited on the LaNiO3-coated Si substrate were obtained by a modified sol–gel method. It was found that the PZT thin films began to form a single
perovskite phase at a low annealing temperature of 530 °C, and exhibited highly (100) orientation. A ferroelectric capacitor
of Pt/Pb(Zr,Ti)O3/LaNiO3/Si annealed at 600 °C displayed a good P-E hysteresis characteristic and was fatigue-free even after 1011 switching cycles.
Received: 25 May 2000 / Accepted: 9 August 2000 / Published online: 30 November 2000 相似文献
6.
W.X. Que Y. Zhou Y.L. Lam C.H. Kam J. Zhou K. Pita Y.C. Chan S. Buddhudu L.H. Gan G.R. Deen 《Applied Physics A: Materials Science & Processing》2001,73(4):485-488
Neodymium (III) oxide nanocrystal/titania/organically-modified silane (ormosil) composite thin films have been prepared using
a chemical approach consisting of a combination of inverse microemulsion and sol-gel techniques at low temperature. Transmission
electron microscopy shows that the neodymium (III) oxide nanoparticles have a needle-like nanocrystal structure. A strong
room temperature emission at 1064 nm, corresponding to the 4
F
3/2?4
I
11/2 transition, has been observed as a function of the heat treatment temperature used for the production of the composite thin
films. In addition to this emission, two other main emissions at 890 nm and at 1336 nm have also been observed. In particular,
there was a clear shoulder peak at 1145 nm, probably be due to the host matrix, which was observed in all the measured samples
and this shoulder peak gave a maximum intensity after heat treatment at 300 °C.
Received: 6 September 2000 / Accepted: 15 November 2000 / Published online: 20 June 2001 相似文献
7.
W. Künstler M. Wegener M. Seiß R. Gerhard-Multhaupt 《Applied Physics A: Materials Science & Processing》2001,73(5):641-645
Films of poly(vinylidene fluoride-hexafluoropropylene) copolymer [P(VDF-HFP)] were cast from a dimethylsulfoxide (DMSO)/acetone
solution of Solef?85-15 P(VDF-HFP) copolymer powder grade 21508. Undrawn and uniaxially drawn cast copolymer films were investigated
with respect to their piezo- and pyroelectric properties. Quasistatic charge integration was employed for the determination
of the poling-field dependence of the piezoelectric d31 and pyroelectric p3 coefficients. In addition, the thermal stability of the pyroelectric effect was studied with a combination of thermally stimulated
discharge (TSD) and temperature-modulation techniques. Cast copolymer films could withstand electrical poling fields of up
to 400 MV/m. The maximum values of d31=30 pC/N and p3=49 μC/(m2K) for uniaxially drawn samples are similar to those found on commercial PVDF films and much higher than those on pure PVDF
films cast from solution. Samples kept for 5 min at 150 °C still exhibit 30–40% of the initial pyroelectric effect [up to
around 20 μC/(m2K)]. After this annealing step, no further decay of the pyroelectric coefficient could be observed during storage at 120 °C
for several hours.
Received: 5 July 2001 / Accepted: 27 July 2001 / Published online: 2 October 2001 相似文献
8.
J.-G. Cheng X.-J. Meng J. Tang S.-L. Guo J.-H. Chu 《Applied Physics A: Materials Science & Processing》2000,70(4):411-414
Barium strontium titanate (Ba0.8Sr0.2TiO3) films with good ferroelectricity have been obtained by a developed sol-gel processing, using a 0.05-M spin-on solution.
X-ray diffraction and Raman spectroscopy investigations showed that the Ba0.8Sr0.2TiO3 film exhibited a tetragonal structure at room temperature. Field-emission scanning electron microscopy measurements revealed
that large columnar grains with the size of 100 to 200 nm in the film were formed from the highly dilute spin-on solution
with layer-by-layer homoepitaxy. Electrical measurements for the prepared Ba0.8Sr0.2TiO3 film showed a remnant polarization of 3.5 μC/cm2, a coercive field of 53 kV/cm, two distinctive phase transitions, lower dissipation factor, and good insulating properties.
These results indicate the sol-gel-derived Ba0.8Sr0.2TiO3 film from a 0.05-M solution is suitable for uncooled infrared detector applications.
Received: 19 August 1999 / Accepted: 11 October 1999 / Published online: 1 March 2000 相似文献
9.
A. von Keudell M. Meier T. Schwarz-Selinger 《Applied Physics A: Materials Science & Processing》2001,72(5):551-556
Methyl radicals (CH3) and atomic hydrogen (H) are dominant radicals in low-temperature plasmas from methane. The surface reactions of these radicals
are believed to be key steps leading to deposition of amorphous hydrogenated carbon (a-C:H) films or polycrystalline diamond
in these discharges. The underlying growth mechanism is studied, by exposing an a-C:H film to quantified radical beams of
H and CH3. The deposition or etching rate is monitored via ellipsometry and the variation of the stoichiometry is monitored via isotope
labeling and infrared spectroscopy. It was shown recently that, at 320 K, methyl radicals have a sticking coefficient of 10-4 on a-C:H films, which rises to 10-2 if an additional flux of atomic hydrogen is present. This represents a synergistic growth mechanism between H and CH3. From the interpretation of the infrared data, a reaction scheme for this type of film growth is developed: atomic hydrogen
creates dangling bonds by abstraction of bonded hydrogen within a surface layer corresponding to the range of H in a-C:H films.
These dangling bonds serve at the physical surface as adsorption sites for incoming methyl radicals and beneath the surface
as radicalic centers for polymerization reactions leading to carbon–carbon bonds and to the formation of a dense a-C:H film.
Received: 18 July 2000 / Accepted: 12 December 2000 / Published online: 3 April 2001 相似文献
10.
W. Que Y. Zhou Y.L. Lam K. Pita Y.C. Chan C.H. Kam 《Applied Physics A: Materials Science & Processing》2001,73(2):209-213
Luminescence properties from erbium (III) oxide nanocrystals dispersed in titania/organically modified silane composite thin
films were studied. Erbium oxide nanocrystals were prepared by an inverse microemulsion technique. A strong room-temperature
photoluminescence was observed at 1.531 μm, with the full width at half maximum (FWHM) of 22 nm due to intra-atomic transitions
between 4
I
13/2 and 4
I
15/2 levels in the erbium (III) ion. The shape, peak position, and FWHM of the photoluminescence signals from the composite thin
films were quite comparable to those prepared by other methods. The photoluminescence peak of the composite thin films showed
a maximum intensity at the heat-treatment temperature of 300 °C. A room-temperature green up-conversion emission at 543 nm
(4
S
3/2?4
I
15/2) was observed for the composite thin films with different heat-treatment temperatures upon excitation at 993 nm. The up-conversion
emission mechanism was explained by means of an energy-level diagram and the lifetime of the visible up-conversion emission
was measured.
Received: 10 July 2000 / Accepted: 11 July 2000 / Published online: 5 October 2000 相似文献
11.
Uncooled pyroelectric infrared detectors based on ferroelectric single crystals 0.74Pb(Mg1/3Nb2/3)O3–0.26PbTiO3 (PMN–0.26PT) were fabricated. The performances of pyroelectric detectors dependence on detector fabrication temperature, absorption layer, and element thickness were compared. The room-temperature voltage responsivity (Rv) of 200 V/W and specific detectivity (D*) of 108 cm Hz1/2/W at 12.5 Hz have been achieved. The results reveal that the better pyroelectric response can be expected by controlling temperature below 70 °C during the fabrication of the pyroelectric detectors, selecting absorption layer with high absorption coefficient, and decreasing the thickness of the elements. 相似文献
12.
CoC composite films and Co/C multilayer films have been prepared by a method incorporating ion beam sputtering and plasma
chemical vapor deposition. It has been found that the structure and magnetic properties of both the Co-C composite and the
Co/C multilayer films depend strongly on the substrate temperature during deposition. The Co-C composite film deposited at
room temperature is amorphous, with relatively low saturation magnetization and coercivity. On the other hand, the film deposited
at 250 °C is composed of fine Co crystallites separated by amorphous C or Co-C phase. As a result, both the saturation magnetization
and coercivity are increased compared with the film deposited at room temperature. When deposited at room temperature, the
Co/C multilayer film exhibits good periodicity, with a period of 70 nm (Co: 40 nm, C: 30 nm) and sharp and flat Co-C interfaces.
High magnetization (602 emu/cm3) and low coercivity (1.6 Oe) are obtained for such a film. However, increasing the substrate temperature to 250 °C was found
to be detrimental to the magnetic properties due to the formation of cobalt carbide at the Co-C interface.
Received: 11 July 2000 / Accepted: 13 July 2000 / Published online: 30 November 2000 相似文献
13.
Jong-Ho ParkChung-Sik Kim Jong-Seng BaeByung-Chun Choi Jung-Hyun JeongByung Kee Moon Hyo-Jin SeoIll Won Kim Jin-Soo Kim 《Solid State Communications》2003,126(11):635-638
Ferroelectrics SrBi2Ta2O9 (SBTO) thin films were grown on a highly oriented Pt/Ti/SiO2/Si substrates using the pulsed laser ablation. The ac impedance of SBTO thin films have been measured at room temperature both in the frequency range from 10−1 to 106 Hz and bias voltage range from −6 to 6 V. The ac impedance dispersion was observed at low frequency with increasing bias voltage, which was interpreted based on a blocked charge. We can explain that the blocking interface gives rise to constant phase element (CPE) response, and we give an impedance model function that can fit data along the low frequency range when such a CPE is found. The low frequency dispersion phenomena of SBTO thin film are related to a charge diffusion process at the surface of thin film. 相似文献
14.
Thin films of (111)-oriented spinel ferrite Al0.5Fe2.5O4 have been prepared by a pulsed-laser deposition (PLD) technique on α-Al2O3 (0001) substrates. The films exhibit cluster-glass behaviors with a spin-freezing temperature, Tg, near or above room temperature. The magnetization was found to increase following light irradiation below Tg, which indicates the photoinduced melting of cluster-glass states. An analysis comparing the dynamic behavior of magnetic response to light irradiation between zero-field-cooled (ZFC) states and field-cooled (FC) states at 10 K under various light intensities, I, revealed that the direct photoexcitation of spins occurs when I≤0.78 mW/mm2, while the thermal heating effect following the light absorption of the samples also contributes to the enhancement of magnetization when I≥1.22 mW/mm2. The magnetization of the films could be controlled by light irradiation even at room temperature. This suggests the possibility of utilizing these films in the development of novel magneto-optical memory devices. 相似文献
15.
H. Spillmann P.R. Willmott M. Morstein P.J. Uggowitzer 《Applied Physics A: Materials Science & Processing》2001,73(4):441-450
High-quality thin films of ZrN, ZrxAlyN and ZrxGayN have been grown by pulsed reactive crossed-beam laser ablation using Zr, Zr-Al and Zr-Ga ablation targets, respectively,
and a N2 gas pulse. The films were characterized for their chemical, crystallographic 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 room
temperature and 600 °C. High-quality epitaxial films could be grown on Si (001) at 400 °C, though the crystallinity was disrupted
at 525 °C by Si diffusion into the film bulk and the formation of ZrSi2 crystallites. Films grown on stainless steel were polycrystalline. The ratios of the metals in the alloy targets were in
general not equal to those in the films: the Al content in the ZrxAlyN films was lower than the target value, which we attribute to differential scattering in the ablation plume. The Ga content
in the ZrxGayN films fell with increasing substrate temperature, indicative of re-evaporation of Ga from the substrate surface. Those ZrxGayN films with the highest Ga content, grown at the lowest temperatures, were particularly nitrogen-deficient, which we attribute
to the low reactivity of Ga with N2. The ZrxAlyN films had an exceptionally low coefficient of friction (0.20) versus steel and the greatest nanohardness of 28 GPa.
Received: 9 November 2000 / Accepted: 14 November 2000 / Published online: 28 February 2001 相似文献
16.
SrBi2Ta2O9 (SBT) ferroelectric thin films with different preferred orientations were deposited by pulsed laser deposition (PLD). Several
methods have been developed to control the preferred orientation of SBT thin films. For SBT films deposited directly on Pt/TiO2/SiO2/Si substrates and in situ crystallized at the deposition temperature, the substrate temperature has a significant impact
on the orientation and the remnant polarization (Pr) of the films; a higher substrate temperature benefits the formation of
(115) texture and larger grain size. The films deposited on Pt/TiO2/SiO2/Si substrates at 830 °C are (115)-oriented and exhibit 2Pr of 6 μC/cm2. (115)- and (200)-predominant films can be formed by using a La0.85Sr0.15CoO3 (LSCO) buffer layer or by annealing amorphous SBT films deposited on Pt/TiO2/SiO2/Si substrates at 450 °C using rapid thermal annealing (RTA). These films exhibit good electric properties; 2Pr of the films
are up to 12 μC/cm2 and 17 μC/cm2, respectively. The much larger 2Pr of the films deposited on the LSCO buffer layer and of the films obtained by RTA than
2Pr of the films deposited on Pt/TiO2/SiO2/Si substrates at 830 °C is attributed to a stronger (200) texture.
Received: 30 January 2001 / Accepted: 30 May 2001 / Published online: 25 July 2001 相似文献
17.
Guo Yong Zhang Peng Xiang Zhang Hai Rong Zheng Xiang Yu Zhang Dang Li Gao Hui Zhang Li Pi Wing Kee Lee 《Optics & Laser Technology》2008,40(6):844-849
We have posed the design of a time-integral type laser energy meter based on anisotropic Seebeck effect for the first time. Anisotropic Seebeck effect is responsible for the laser-induced thermoelectric voltage effect in high temperature superconductor (HTSC) cuprates and colossal magnetoresistance (CMR) manganites thin films grown on tilted single crystal substrates. In this study, for an example, an epitaxial La2/3Ca1/3MnO3 thin film prepared on a tilted LaAlO3 substrate by standard pulsed-laser deposition (PLD) method is tested with a 1064-nm Q-switched Nd:YAG laser and its 2nd (532 nm), 3rd (355 nm), and 4th (266 nm) harmonics from room temperature to 16 K. The integral of the voltage signal with time shows a good linear relation with the laser energy per pulse in the measured wavelength and temperature range, which confirms the theoretical analysis given in this letter and can be used to design a time-integral type laser energy meter. The sensitivity increases as the film thickness increases or as the thermal diffusion constant decreases, which makes the time-integral type laser energy meter low cost as compared with the peak-voltage type. It operates with fast (nanosecond range) and broad-spectrum (from infrared to ultraviolet) response in wide temperature range (from room temperature to 10s K), and can be useful replacements for pyroelectric power/energy meters. 相似文献
18.
Hyun Kyoung Yang Byung Kee Moon Jung Hyun Jeong Soung Soo Yi Kwang Ho Kim 《Journal of luminescence》2009,129(5):492-5107
YVO4:Sm3+ films were deposited on Al2O3 (0 0 0 1) substrates at various oxygen pressures changing from 13.3 to 46.6 Pa by using the pulsed laser deposition method. The crystallinity and surface morphology of these films were investigated by means of X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The XRD pattern confirmed that YVO4:Sm3+ film has zircon structure and the AFM study revealed that the films consist of homogeneous grains ranging from 100 to 400 nm. The room temperature photoluminescence (PL) spectra showed that the emitted radiation was dominated by a reddish-orange emission peak at 602 nm radiating from the transition of (4G5/2→6H7/2). The crystallinity, surface morphology, and photoluminescence spectra of thin-film phosphors were highly dependent on the deposition conditions, in particular, the substrate temperature. The surface roughness and photoluminescence intensity of these films showed similar behavior as a function of oxygen pressure. 相似文献
19.
Synthesis of carbon nitride films by direct current plasma assisted pulsed laser deposition 总被引:1,自引:0,他引:1
Y.H. Cheng X.L. Qiao J.G. Chen Y.P. Wu C.S. Xie S.B. Muo Y.B. Sun B.K. Tay 《Applied Physics A: Materials Science & Processing》2002,74(2):225-231
Carbon nitride films were deposited by pulsed laser ablation of a graphite target under a nitrogen atmosphere at room temperature.
A direct current discharge apparatus was used to supply active nitrogen species during the deposition of carbon nitride films.
The composition and bonding structure of carbon nitride films were determined by Fourier-transform infrared (FTIR) spectroscopy
and X-ray photoelectron spectroscopy. The incorporation of nitrogen atoms in the films is greatly improved by the using of
a dc glow discharge. The ratio N/C can reach 0.34 at the discharge voltage of 400 V. Six peaks centered at 1025 cm-1, 1226 cm-1, 1381 cm-1, 1534 cm-1, 1629 cm-1, and 2200 cm-1 can be clearly distinguished from the FTIR spectra of the deposited films, which indicates the existence of C–N, C=N, and
C≡N bonds. The fraction of sp2 C, C≡N bonds, and C=N bonds in the deposited films increases with increasing discharge voltage. Deconvolution results of
C 1s and N 1s spectra also indicate that nitrogen atoms in the films are chemically bonded to sp1 C, sp2 C, and sp3 C atoms. Most of the nitrogen atoms are bonded to sp2 C atoms. Increasing the discharge voltage leads to a decrease of the fraction of nitrogen atoms bonded to sp2 C and the fraction of amorphous carbon; however, it leads to an increase of the fraction of nitrogen atoms bonded to sp3 C and the fraction of sp2 C and sp3 C atoms bonded to nitrogen atoms.
Received: 7 June 2000 / Accepted: 19 February 2001 / Published online: 27 June 2001 相似文献
20.
In2(Se1-xTex)3 polycrystalline films were prepared by a dual-source thermal evaporation technique. The depositions onto glass and SnO2-coated glass substrates were carried out in a vacuum chamber and followed by an annealing in neutral ambient (Ar or N2). The structural, morphological and compositional studies of the films were made by X-ray diffraction, energy-dispersive
X-ray analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, Raman scattering and optical transmission.
Optimum conditions are investigated for the formation of the ternary compound In2(Se1-xTex)3 in order to tune the band gap by changing the Te concentration. The film properties as a function of Te amount are discussed.
It is shown that single-phase, textured and homogeneous layers of In2(Se1-xTex)3 can be grown with x≤0.2 at optimal deposition and heat treatment conditions. For x≅0.17 these films showed an energy band
gap of about 1.45 eV and an electrical conductivity at room temperature six orders of magnitude higher than that of the binary
γ-In2Se3 thin films.
Received: 9 July 1999 / Accepted: 25 November 1999 / Published online: 13 July 2000 相似文献