共查询到20条相似文献,搜索用时 15 毫秒
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The optical properties of a composite material consisting of a thin polymer film, which is activated by semiconductor CdSe/ZnS quantum dots (QDs) and silver nanoparticles, on a transparent dielectric substrate have been investigated. It is revealed that the presence of silver nanoparticles leads to an increase in the QD absorption (by a factor of 4) and in the fluorescence intensity (by a factor of 10), whereas the fluorescence time drops by a factor of about 10. Excitation of the composite medium by a pulsed laser is found to result in narrowing of the fluorescence band and a sublinear dependence of its intensity on the pulse energy. In the absence of silver nanoparticles, the fluorescence spectrum of QDs is independent of the excitation-pulse energy density, and the fluorescence intensity depends linearly on the pulse energy in the entire range of energy densities, up to 75 mJ/cm2. 相似文献
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基于复合纳米结构的局域表面等离子体光学传感器 总被引:1,自引:0,他引:1
局域表面等离子体光学传感器由于其体积小、灵敏度高、免标记等特点成为目前传感器研究热点之一。然而由于银纳米结构的生物兼容性以及氧化问题,成为该传感器发展的瓶颈。提出了利用金/银混合的金属纳米结构克服上述困难,并从有限时域差分数值计算方法入手,设计了银层50nm,金层5nm的六边形分布三角形复合传感结构,并利用纳米球自组装技术实现了该类型传感器。同时,与生物分子蛋白A的结合实验结果表明,该传感器在生物分子溶液浓度213.85nM的条件下仍然具有较高的灵敏度。 相似文献
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K. N. Astankova A. S. Kozhukhov I. A. Azarov E. B. Gorokhov D. V. Sheglov A. V. Latyshev 《Physics of the Solid State》2018,60(4):700-704
The process of local anodic oxidation of thin GeO films has been studied using an atomic force microscope. The electron-probe microanalysis showed that oxidized areas of a GeO film were germanium dioxide. The effect of the voltage pulse duration applied to the probe–substrate system and the atmospheric humidity on the height of the oxide structures has been studied. The kinetics of the local anodic oxidation (LAO) in a semi-contact mode obeys the Cabrera–Mott model for large times. The initial growth rate of the oxide (R0) significantly increases and the time of starting the oxidation (t0) decreases as the atmospheric humidity increases by 20%, which is related to an increase in the concentration of oxygen-containing ions at the surface of the oxidized GeO film. It was shown that nanostructures in thin GeO layers can be formed by the LAO method. 相似文献
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Magnetic properties and nanostructures of FePtCu:C thin films with FePt underlayers (ULs) are studied. The effect of FePt ULs on the orlentation and magnetic properties of the thin films are investigated by adjusting FePt UL thicknesses from 2nm to 14nm. X-ray diffraction (XRD) scans reveal that the orientation of the films is dependent on FePt UL thickness. For a 5-nm FePtCu:C nanocomposite thin film with a 2-nm FePt UL, the coercivity is 6.S KOe, the correlation length is 59 nm, the desired face-centred-tetragonal (fct) ordered structure [Llo phase] is formed and the c axis normal to the film plane [(001) texture] is obtained. These results indicate that the beffer orientation and magnetic properties of the films can be tuned by decreasing the thockness of the FePt UL. 相似文献
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Polycrystalline LaCrO_3(LCO) thin films are deposited on Pt/Ti/SiO_2/Si substrates by pulsed laser deposition and used as the switching material to construct resistive random access memory devices. The unipolar resistive switching(RS) behavior in the Au/LCO/Pt devices exhibits a high resistance ratio of ~104 between the high resistance state(HRS) and low resistance state(LRS) and exhibits excellent endurance/retention characteristics.The conduction mechanism of the HRS in the high voltage range is dominated by the Schottky emission, while the Ohmic conduction dictates the LRS and the low voltage range of HRS. The RS behavior in the Au/LCO/Pt devices can be understood by the formation and rupture of conducting filaments consisting of oxygen vacancies,which is validated by the temperature dependence of resistance and x-ray photoelectron spectroscopy results.Further analysis shows that the reset current I_R and reset power P_R in the reset processes exhibit a scaling law with the resistance in LRS(R_0), which indicates that the Joule heating effect plays an essential role in the RS behavior of the Au/LCO/Pt devices. 相似文献
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Le Wang Shengyan Wang Lin Mei Jie Sun Feng Shi Nan Zhang Ruibin Jiang 《Particle & Particle Systems Characterization》2021,38(4):2000321
As one kind of alternative to conventional metals, titanium nitride offers many advantages in the rapidly growing fields of plasmonics and metamaterials. However, the development of TiNx-based plasmonics is severally limited by the difficulty in the preparation. Herein, a facial approach is developed for the preparation of Au@TiNx core-shell nanostructures. The synthesis starts with colloidal Au nanospheres, followed by the growth of amorphous TiO2 shells. The obtained Au@a-TiO2 nanostructures convert into Au@TiNx through nitridation at high temperature in ammonia atmosphere. The prepared Au@TiNx nanostructures have strong plasmonic scatting in the visible region and strong field enhancement at the surface of nanostructures. Au@TiNx nanostructures also exhibit a relatively large enhancement for Raman scattering. The developed preparation method can produce TiNx nanostructures with relatively uniform size and thus will be very helpful to the development of TiNx-base plasmonics. 相似文献
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Denis Rodríguez‐Fernández Paula C. Angelomé Galo J. A. A. Soler‐Illia Luis M. Liz‐Marzán 《Particle & Particle Systems Characterization》2017,34(5)
A novel composite material based on metal nanoparticles (NP) and mesoporous thin films (MPTF), more specifically bilayers of MPTF with a submonolayer of NP deposited between them is introduced. By controlling the deposition conditions, it is possible to build a variety of multilayers including MPTF with different compositions (TiO2, SiO2) and pore sizes (templated with cetyltrimethylammonium bromide, F127, Brij 58) and NP of different characteristics and sizes (Au spheres, Au decorated SiO2). By means of 2D small angle X‐ray scattering, transmission electron microscopy, UV–vis spectroscopy, and ellipsometric porosimetry it is demonstrated that NP and MPTF retain their structure and properties within the new material. Importantly, the NP remain accessible for further reactions, a feature that is established by Au overgrowth. Interestingly, the extent of Au growth depends on the mesoporous size and the position of the MPTF with respect to the NP. This new architecture allows the NP to be in direct contact with two different chemical environments and, as a consequence, opens up the possibility to control identity and size of the molecules that can reach them. Thus, the obtained materials may be applied in the development of highly specific sensors and catalysts, in which spatial position plays a fundamental role. 相似文献
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Khmelevskaya D. Shcherbinin D. P. Konshina E. A. Abboud M. M. Dubavik A. Gladskikh I. A. 《Optics and Spectroscopy》2018,125(5):731-734
Optics and Spectroscopy - Local fields of metal nanoparticles can change quantum dots (QDs) absorption and luminescence. In this work, we have investigated the interaction of granulated Ag NPs... 相似文献
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Coplanar Phase Shifters Based on Ferroelectric Thin Films 总被引:2,自引:0,他引:2
Chunlin Fu Fusheng Pan Hongwei Chen Shucheng Feng Wei Cai Chuanren Yang 《International Journal of Infrared and Millimeter Waves》2007,28(3):229-235
Barium strontium titanate (Ba0.6Sr0.4TiO3, short for BST) thin films were prepared by RF-magnetron sputtering. The dielectric tunability, loss tangent, remanent polarization
(2Pr) and coercive electric field (Ec) of the BST films are respectively 29.5%, 0.013, 2.29 μC/cm2 and 22.27 kV/cm at 1 kHz and 20 V. The designed coplanar waveguide (CPW) phase shifter consists of 56 same sections. It is
shown that the fabricated lines of electrodes are smooth and the widths at the tip of bottom electrodes are about 5 μm. At
the central frequency of 28 GHz and a bias voltage of 20 V, the figure of merit is approximately 13°/dB. 相似文献
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Physics of the Solid State - The electrical conductivity of polycrystalline V(1 – x)FexO2 films has been investigated in a wide temperature range, which covers both the... 相似文献
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Physics of the Solid State - The electrical conductivity of thin polycrystalline V(1 – x)WxO2 has been studied in a wide temperature range, which covers the regions of both... 相似文献
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Physics of the Solid State - The resistive switching effect is studied in composite films based on organometallic perovskites CH3NH3PbBr3 and CH3NH3PbI3 with graphene oxide (GO) particles with... 相似文献
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用MOCVD方法在c面蓝宝石衬底上生长ZnO薄膜。生长前衬底表面进行预处理,观察不同表面预处理对ZnO薄膜质量的影响。测量氧化锌的XRD谱,观察表面预处理后对氧化锌薄膜结晶质量的影响。室温下用325nm的He-cd激光器作为激发源测量ZnO薄膜的紫外发光谱,观察表面处理后对ZnO薄膜发光特性的影响。用HL5500 Hall System分别对ZnO薄膜的电学特性进行了测试。得到了ZnO薄膜的电阻率和霍尔迁移率,并得到氧气气氛处理后电阻率变小,霍尔迁移率变大;氮气气氛射频处理后电阻率变大,霍尔迁移率变小的结果。 相似文献
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Bipolar Resistive Switching in Epitaxial Mn_3O_4 Thin Films on Nb-Doped SrTiO_3 Substrates
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《中国物理快报》2016,(6)
Spinel(001)-orientated Mn_3O_4 thin films on Nb-doped SrTiO_3(001) substrates are fabricated via the pulsed laser deposition method.X-ray diffraction and high-resolution transmission electron microscopy indicate that the as-prepared epitaxial film is well crystallized.In the film plane the orientation relationship between the film and the substrate is[100]Mn_3O_4\\[110]Nb-doped SrTiO_3.After an electroforming process,the film shows bipolar nonvolatile resistance switching behavior.The positive voltage bias drives the sample into a low resistance state,while the negative voltage switches it back to a high resistance state.The switching polarity is different from the previous studies.The complex impedance measurement suggests that the resistance switching behavior is of filament type.Due to the performance reproducibility and state stability,Mn_3O_4 might be a promising candidate for the resistive random access memory devices. 相似文献