共查询到20条相似文献,搜索用时 15 毫秒
1.
Babichev A. V. Dudelev V. V. Gladyshev A. G. Mikhailov D. A. Kurochkin A. S. Kolodeznyi E. S. Bougrov V. E. Nevedomskiy V. N. Karachinsky L. Ya. Novikov I. I. Denisov D. V. Ionov A. S. Slipchenko S. O. Lutetskiy A. V. Pikhtin N. A. Sokolovskii G. S. Egorov A. Yu. 《Technical Physics Letters》2019,45(7):735-738
Technical Physics Letters - Molecular beam epitaxy techniques were used to grow a quantum-cascade laser (QCL) heterostructure based on an In0.53Ga0.47As/Al0.48In0.52As heteropair lattice-matched... 相似文献
2.
《Science and Technology of Advanced Materials》2001,2(1):209-212
The morphological evolution near the absolute stability limit during directional solidification has been studied systematically on dilute Al–Mn alloys. It is found that the interfacial morphology of Al–0.52wt%Mn and Al–1.2wt%Mn alloys changes from coarse cellular structure to fine cells, and then again to be coarsened with the increase of velocity to near the absolute stability limit. This indicates that there exists a minimum cell spacing corresponding to the maximum effective constitutional supercooling. As the growth rate approximates to or exceeds the critical velocity of absolute stability by calculation according to M–S theory, the interfacial morphology of Al–0.52wt%Mn alloy may still retain a cellular structure. For Al–1.2wt%Mn alloy, when the growth velocity is near the absolute stability limit, the fine cells may change to a band or grain-like structure which in some cases takes an oscillating manner, which possibly implies the existence of a non-linear effect during high growth rate. 相似文献
3.
采用溶胶-凝胶法,研究了两种在Au/Cr/SiO2/Si基底上沉积PZT(Pb(Zr0.52Ti0.48)O3)厚膜的方法.把与PZT澄清溶胶成分相同的PZT纳米粉混入澄清PZT溶胶,然后超声混合形成PZT浆料,PZT纳米粉的粒径为50~100nm.XRD分析表明两种方法得到的PZT厚膜都获得了单相钙钛矿结构.SEM结果显示两种厚膜厚度大约4μm,第一种旋涂方法制得的PZT厚膜表面粗糙,第二种旋涂方法制得的厚膜表面致密,无裂纹.在1 kHz的测试频率下,第一种和第二种厚膜的矫顽场分别为30 kV/cm和50 kV/cm,饱和极化分别为45 μC/cm2和54 μC/cm2,剩余极化分别为25μC/cm2 and 30μC/cm2.第二种厚膜有较高的直流耐压性能,在300 kV/cm的电场下,仍然保持较好的铁电性能.因而,第二种旋涂方法能够改善PZT厚膜的表面形貌和铁电性能. 相似文献
4.
Xingguo Geng 《Science and Technology of Advanced Materials》2013,14(1):209-212
The morphological evolution near the absolute stability limit during directional solidification has been studied systematically on dilute Al–Mn alloys. It is found that the interfacial morphology of Al–0.52wt%Mn and Al–1.2wt%Mn alloys changes from coarse cellular structure to fine cells, and then again to be coarsened with the increase of velocity to near the absolute stability limit. This indicates that there exists a minimum cell spacing corresponding to the maximum effective constitutional supercooling. As the growth rate approximates to or exceeds the critical velocity of absolute stability by calculation according to M–S theory, the interfacial morphology of Al–0.52wt%Mn alloy may still retain a cellular structure. For Al–1.2wt%Mn alloy, when the growth velocity is near the absolute stability limit, the fine cells may change to a band or grain-like structure which in some cases takes an oscillating manner, which possibly implies the existence of a non-linear effect during high growth rate. 相似文献
5.
Huang W Zeng HZ Zhu J Hao JH Dai JY 《Journal of nanoscience and nanotechnology》2011,11(12):11227-11230
In this paper, the "sandwich" structured magnetoelectric composite films of Pb(Zr0.52Ti0.48)O3/ NiFe2O4/Pb(Zr0.52Ti0.48)O3 and Pb(Zr0.52Ti0.48)O3/CoFe2O4/Pb(Zr0.52Ti0.48)O3 are epitaxially grown on SrRuO3/SrTiO3 substrates by pulsed-laser deposition. The crystalline quality and microstructures of these heterostructures are investigated by X-ray diffraction technique. The effects of strain on the ferroelectric, magnetic and magnetoelectric coupling properties of these thin films are systematically studied. The results show that the strain effect induced by lattice mismatch between the ferroelectric/ferromagnetic layers plays an important role in the ferroelectric and magnetic properties of these composite films. Compared to the strained Pb(Zr0.52Ti0.48)O3/ CoFe2O4/Pb(Zr0.52Ti0.48)O3 heterostructure, improved ferroelectric properties with an out-of-plane polarization (2P(r)) of 34.2 microC/cm2 and electric coercivity field of 158 kV/cm are obtained in the strain-free Pb(Zr0.52Ti0.48)O3/NiFe2O4/Pb(Zr0.52Ti0.48)O3 heterostructure. The ME measurement results not only show that the strain induced by lattice mismatch has great influence on the ME behavior, but also provide an understanding of the multilayers with full control over the interface structure at the atomic-scale. 相似文献
6.
Shlomit Kraus‐Ophir Yuval Ben‐Shahar Uri Banin Daniel Mandler 《Advanced Materials Interfaces》2014,1(1)
Anisotropic CdS nanorods tipped by Au nanoparticles on one edge (Au‐CdS‐NRs) are perpendicularly oriented at the air/water interface, whereby all the Au tips are located in the subphase, using the Langmuir–Blodgett technique. Since these nano‐objects reveal light‐induced charge separation at the semiconductor/metal interface, it is of high interest to control their organization. The orientation of these assemblies is studied in situ while compressing the Langmuir–Blodgett trough using the π‐A isotherm, Brewster angle microscopy, and horizontal touch voltammetry. All these analyses clearly confirm the induced organization of the amphiphilic Au‐CdS‐NRs by compression of the Langmuir layer. The compressed layers are successfully transferred by the Langmuir–Schaefer method onto transmission electron microscopy grids while maintaining the preferential orientation as analyzed by transmission, scanning and scanning trasmission electron microscopy, and X‐ray photoelectron spectroscopy. As far as can be determined, the Langmuir–Blodgett technique has not been used so far for perpendicularly orienting anisotropic nano‐objects. Moreover, these findings clearly demonstrate that anisotropic amphiphilic nano‐objects can be treated with some similarity to the traditional amphiphilic molecular building blocks. 相似文献
7.
Jianxia Gao Lirong Zheng Xinzhong Duo Jipo Huang Lixin Yang Chenglu Lin Rongliang Yan 《Thin solid films》1999,340(1-2):132-136
PbZr0.52Ti0.48O3/YBa2Cu3O7−δ (PZT/YBCO) thin films have been fabricated on Y2O3 stabilized zirconate (YSZ) substrates by a pulsed excimer laser deposition (PLD) method. In order to investigate total dose radiation effects on the Au/PZT/YBCO ferroelectric capacitor, the capacitance–voltage (C–V) curves and the retained polarization property of the capacitor have been measured before and after γ-ray irradiation. The results showed that, with an increased total dose, the retained polarization and the dielectric constant decreased, but the coercive field drifted towards positive voltage direction. This is caused by charges trapped by defects in the PZT capacitor during irradiation. 相似文献
8.
Kim KJ Kim YH Jeong WJ Jeong SW Park JC Ahn HG 《Journal of nanoscience and nanotechnology》2007,7(11):4073-4076
The alloy catalyst has been widely used because it will be able to improve the activity and selectivity of the single metal catalyst in a given chemical reaction. In this study, the preparation and characteristics of nanosized Pt and Au particles on alumina and their catalytic activity were described. Nanosized Pt-Au catalysts were prepared by impregnation (IMP) method and deposition (DP) method using alumina or ZnO/Al2O3 as support. The size of Pt and Au particles were observed by transmission electron microscopy (TEM), energy dispersive spectroscope (EDS), and X-ray diffraction (XRD). Catalytic activity for oxidation of methanol was measured using a flow reactor. It could be seen that the Pt particle size and dispersion in the alloy catalysts was rarely influenced by preparation methods and Au particles coated by deposition method were well dispersed. TEM images showed that Au particles were well dispersed in the Pt/Au/ZnO/Al2O3 catalyst of which Au particles was supported by deposition method. The catalytic activity for methanol are given in the order of Pt-Au[IMP]/ZnO/Al2O3 > Pt[IMP]/Au[DP]/ZnO/Al2O3 > Au[DP]/Pt[IMP]/ZnO/Al2O3 > Pt-Au[DP]/ZnO/Al2O3. Therefore, Au particle size was doing not play an important role in increasing the oxidation activity, but the Au particles may promote the methanol oxidation. 相似文献
9.
D. A. Vinokurov S. A. Zorina V. A. Kapitonov D. N. Nikolaev A. L. Stankevich V. V. Shamakhov I. S. Tarasov 《Technical Physics Letters》2006,32(4):299-301
Heterostructures comprising highly strained GaAs quantum wells in Al0.48In0.52As and Ga0.47In0.53As layers have been grown by the metalorganic chemical vapor deposition method on InP(100) substrates. The photoluminescence spectra of these structures have been studied, and it is established that GaAs quantum wells form type-I heterojunctions with Al0.48In0.52As layers and type-II heterojunctions with Ga0.47In0.53As layers. 相似文献
10.
Xiaoqiang Chen Xi Yang Weifei Fu Mingsheng Xu Hongzheng Chen 《Materials Science and Engineering: B》2013,178(1):53-59
We reported the enhanced performance of polymer solar cells with the blend of poly (2-methoxy-5(2′-ethylhexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as active layer by incorporation of an assembled gold nanoparticle (Au NP) monolayer. The dense Au NP monolayer has been fabricated by Langmuir–Blodgett (LB) assembly and positioned between the transparent electrode ITO and the anode-modification PEDOT:PSS [poly (3,4-ethylenedioxythiophene):poly(styrene sulfonate)] layer, resulting in the device architecture of ITO/Au/PEDOT:PSS/MEH-PPV:PCBM/Al. We attribute the performance improvement to the localized surface plasmon resonance (LSPR) effect of Au NP films, which could lead to the increased absorption of the active layer. The parameters (nanoparticle size and interparticle distance) that govern this SPR effect have been optimized by selecting various sizes of Au NPs and controlling the LB assembly conditions. We observed ~10–20% enhancement in power conversion efficiency for all the devices with the Au NP monolayer. 相似文献
11.
《Thin solid films》2006,515(2):543-546
We have grown ErP on Ga0.52In0.48P (001) lattice-matched to GaAs and on InP (001) by low-pressure organometallic vapor phase epitaxy and investigated the surface morphology of ErP layers. Lattice-mismatch in ErP/Ga0.52In0.48P/GaAs heterostructures (Δa / a = − 0.8%) is much less than that of ErP/InP heterostructures (− 4.5%). Extended X-ray absorption fine structure measurement revealed that Er exists in the form of ErP rock-salt structure in both samples. The estimated growth rate of ErP on Ga0.52In0.48P is 1.8 ML/h. Our results demonstrate that ErP on Ga0.52In0.48P has smaller surface roughness than ErP on InP. Moreover, an ErP layer exists underneath the surface about 2 ML and the surface roughness does not depend on the ErP thickness in the range of our experiments (2.2–13.7 ML). 相似文献
12.
Kenichi Watanabe Kenichiro Kobayashi Cheong Chee Wong Yi-Ming Xiong Tadashi Saitoh Fumiaki Hyuga 《Thin solid films》1995,270(1-2):97-102
Spectroscopic ellipsometry (SE), a non-destructive optical method, was used for the characterization of In0.48Ga0.52P-based thin-layer structures. Two types of sample structures were investigated. One was an In0.48Ga0.52P-based single-layer structure and the other was an In0.48Ga0.52P-based multi-layer structure. Our objective was to determine the optical properties of In0.48Ga0.52P for the single-layer samples and to characterize the structures of the multi-layer samples, such as layer thicknesses. For each sample investigated, the measured spectra were analyzed with an appropriate fitting model, which was constructed based on the sample's nominal structure. In the determination of the optical properties of In0.48Ga0.52P, two methods were employed, namely, the harmonic oscillator approximation and the wavelength-by-wavelength fitting method, which is routinely used in SE analysis. The advantages and disadvantages of these two methods are discussed with the results from the chosen samples. In the structural characterization, the thickness results obtained by SE were compared with the corresponding ones determined by cross-sectional transmission electron microscopy. It is shown that, for each sample under study, very good agreement was found between the results obtained by the two methods. This in turn demonstrates that SE is reliable for thickness characterization of the multi-layer samples. 相似文献
13.
《Composites Part A》2002,33(10):1417-1420
Bimetallic automotive components consisting of an Al–Si light alloy reinforced with a cast iron insert have been manufactured by gravity die moulding. Special precautions have been taken to ensure a uniform wetting of the insert by the liquid light alloy. Under these conditions, three intermetallic compounds are formed at the insert/alloy interface: η (Al5Fe2), τ5 (Al7.4Fe2Si) and τ6 (Al4.5FeSi). Upon subsequent heat-treatment, τ2 (Al5Fe2Si2) and τ10 (Al12Fe5Si3) also appear. Growth of these compounds is discussed in terms of thermodynamics, kinetics and reaction mechanism in the Al–Fe and Al–Fe–Si systems. The effect of these chemical changes on the mechanical properties of the insert/alloy joint will be examined. 相似文献
14.
MIM electroreflectance data obtained with the symmetrical structures Al/Al2O3/Al, Au/Al2O3/Au and Au/ZnS/Au afford information about the metal-insulator interfaces. Al/Al2O3/Al gives no electroreflectance signal. Interpretation in terms of a change in the surface conductivity of gold when the electric field is applied is in good agreement with experimental data for Au/Al2O3/Au but the agreement is only qualitative for Au/ZnS/Au. 相似文献
15.
K.M. Varier M.P. Unnikrishnan 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1989,280(2-3):428-432
Cross sections for the elastic scattering of 59.54 keV gamma rays through 141° by Al, Cu, Mo, Yb, Ta, Au and Pb have been accurately determined using a Si(Li) detector. The values of the cross sections have been obtained by a normalization technique based on a comparison with the Compton scattering from the essentially free electrons from an Al scatterer. For the lower-Z elements Al, Cu and Mo the experimental cross sections are more or less in agreement with the form-factor predictions as well as the S-matrix calculations. For the heavier elements Ta, Au and Pb the experimental results deviate strongly from the form-factor values but agree favourably with the S-matrix values. As a by-product, incoherent scattering functions have been evaluated for Cu, Mo and Yb. Also, a clear indication has been obtained for resonant Raman scattering in the case of Yb. 相似文献
16.
D.M. Goldie 《Thin solid films》2010,519(4):1391-1396
The current injection properties of gold contacts fitted to hydrazone doped polyesters (HDPs) have been investigated using a series of thin-film Au/HDP/Al diode structures. Current-voltage characteristics of the HDP diodes recorded over a range of temperatures suggest that the measured injection is controlled by interface states which assist in the transfer of hole charge between the Au electrode and highest occupied molecular orbital (HOMO) of the hydrazone. Injection assistance occurs due to the energetic location of the interface states which are estimated to lie between the Fermi energy of the Au and the HOMO of the hydrazone. The density of the interface states is found to be independent of the hydrazone doping concentration used in the diodes and is calculated to be about 3 × 1016 cm-3. The available density of interface states which participate in the injection process may be progressively reduced through exposure of the Au electrode to increasing amounts of ultraviolet radiation. The diminished current injection following ultraviolet exposure is fully restored after a sufficiently long recovery period of several hundred days at room temperature. A charge transfer model that involves depopulation of the interface states to nearby hydrazone sites is proposed to explain the ultraviolet phenomena. 相似文献
17.
Liu Yang De-Yi Zheng Kai-Xin Guo Wan-Nan Zhao Ze-Hui Peng Gui-Gui Peng Tao Zhou 《Journal of Materials Science: Materials in Electronics》2018,29(21):18011-18019
Ferroelectric PbZr0.52Ti0.48O3 film and its partial substitutions by rare earth ions La3+ and Nd3+ Pb0.9(La/Nd)0.1Zr0.52Ti0.48O3, grown on Pt(111)/Ti/SiO2/Si(100) substrates, were prepared via sol–gel and rapid thermal processes. Structural characterization by X-ray diffraction and scanning electron microscopy showed that Pb(Zr0.52Ti0.48)O3 and Pb0.9La0.1(Zr0.52Ti0.48)O3 films are of (111) preferred orientation but Pb0.9Nd0.1(Zr0.52Ti0.48)O3 is more inclined to (100) reflection though both are of tetragonal perovskite structure. The results indicate that the piezoelectric properties of PZT thin films can be improved by doping La3+ and Nd3+ substituted A-site. The d33 can be dramatically improved by doping La3+. Moreover, Pr of Pb(Zr0.52Ti0.48)O3 films reaches up to 120.53 µC/cm2, while the doping samples present relatively inferior ferroelectric hysteresis loops (PrLa?=?64.32, PrNd?=?53.17 µC/cm2), greater dielectric constants, higher dielectric loss and lower leakage current than the undoped Pb(Zr0.52Ti0.48)O3 sample. And meanwhile, the samples showed a typical non-Debye dielectric spectroscopy of multiple quantum relaxation time distribution observing from the Cole–Cole plot at room temperature. 相似文献
18.
为制备高性能的ZnO基器件如UV光发射器,探测器、场效应晶体管,在ZnO上形成优良的金属电极是十分必要的。回顾了近年来ZnO上制备欧姆接触的新进展,对在n型ZnO上制备欧姆接触的Al,A1/Pt,A1/Au,Ti/Al,Ti,AU,Ti/A1/Pt/Au,Re/Ti/Au等金属化方案的性能与特点,以及影响欧姆接触电阻率和热稳定性的因素,如表面处理和退火等进行了分析与归纳。同时,对P型ZnO上难以获得低接触电阻的原因进行了讨论。文章还简要说明了ZnO上透明欧姆接触的研究现状,指出获得低阻、高导电、高透光和高热稳定性的接触是未来ZnO基光电器件的发展方向。 相似文献
19.
C. H. Ahn L. Antognazza T. Tybell K. Char M. Decroux R. H. Hammond T. H. Geballe M. R. Beasley Ø. Fischer J. -M. Triscone 《Journal of Low Temperature Physics》1996,105(5-6):1517-1522
We report on ferroelectric field effect experiments on Pb(Zr0.52Ti0.48)O3/SrCuO2 and Pb(Zr0.52Ti0.48)O3/SrRuO3 epitaxial heterostructures with an emphasis on the material characterization. Upon reversing the polarization of the Pb(Zr0.52Ti0.48)O3 ferroelectric layer, we measured a nonvolatile change in the resistivity of ultrathin layers of SrCuO2 and SrRuO3. In thin SrRuO3 films (30 Å) up to a 9% resistivity change has been observed at room temperature. 相似文献
20.
Ashery Adel Gaballah A. E. H. 《Journal of Materials Science: Materials in Electronics》2022,33(14):11194-11211
Journal of Materials Science: Materials in Electronics - This work presents a novel structure of Au/PPy-MWCNTs/TiO2/Al2O3/n-Si/Al which hasn't been explored before. This structure is applied in... 相似文献