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1.
用多靶磁控溅射技术制备了Au/SiO2纳米多层薄膜.利用透射电子显微镜以及吸 收光谱对Au/SiO2复合薄膜的微观结构、表面形貌及光学性能进行了表征和测试 .研究结果表明:单层Au/SiO2薄膜中Au沉积时间小于10s时,分散在SiO2< /sub>中的Au颗粒随Au的沉积时间的延长而增大;当沉积时间超过10s后,Au颗粒的尺寸几乎 不随沉积时间变化,但Au颗粒的形状由网络状结构变为薄膜状结构.[Au(t1
关键词:
尺寸效应
纳米复合薄膜
吸收光谱
有效媒质理论 相似文献
2.
C. Gravalidis N. Hatziaras A. Laskarakis I. Tsiaoussis N. Frangis 《Applied Surface Science》2006,253(1):385-388
Silicon nanocrystals (nc-Si) have gained great interest due to their excellent optical and electronic properties and their applications in optoelectronics. The aim of this work is the study of growth mechanism of nc-Si into a-SiO2 matrix from SiO/SiO2 multilayer annealing, using non-destructive and destructive techniques. The multilayer were grown by e-beam evaporation from SiO and SiO2 materials and annealing at temperatures up to 1100 °C in N2 atmosphere. X-rays reflectivity (XRR) and high resolution transmission electron microscopy (HRTEM) were used for the structural characterization and spectroscopic ellipsometry in IR (FTIRSE) energy region for the study of the bonding structure. The ellipsometric results gave a clear evidence of the formation of an a-SiO2 matrix after the annealing process. The XRR data showed that the density is being increased in the range from 25 to 1100 °C. Finally, the HRTEM characterization proved the formation of nc-Si. Using the above results, we describe the growth mechanism of nc-Si into SiO2 matrix under N2 atmosphere. 相似文献
3.
Massimo Tallarida Rakesh Sohal Dieter Schmeisser 《Superlattices and Microstructures》2006,40(4-6):393
Silicon is by far the most important material used in microelectronics, partly due to the excellent electronic properties of its native oxide (SiO2), but substitute semiconductors are constantly the matter of research. SiC is one of the most promising candidates, also because of the formation of SiO2 as native oxide. However, the SiO2/SiC interface has very poor electrical properties due to a very high density of interface states which reduce its functionality in MIS devices. We have studied the electronic properties of defects in the SiO2/Si and SiO2/SiC interfaces by means of XAS, XPS and resonant photoemission at the O 1s and the Si 2p edges, using silicon dioxide thermally grown with thicknesses below 10 nm. Our XAS data are in perfect agreement with literature; in addition, resonant photoemission reveals the resonant contributions of the individual valence states. For the main peaks in the valence band we find accordance between the resonant behaviour and the absorption spectra, except for the peaks at −15 eV binding energy, whose resonant photoemission spectra have extra features. One of them is present in both interfaces and is due to similar defects, while another one at lower photon energy is present only for the SiO2/SiC interface. This is related to a defect state which is not present at the SiO2/Si interface. 相似文献
4.
利用多靶磁控溅射技术制备了Au/SiO2纳米颗粒分散氧化物多层复合薄膜.研究了在保持Au单层颗粒膜沉积时间一定时薄膜厚度一定、变化SiO2的沉积时间及SiO2的沉积时间一定而改变薄膜厚度时,多层薄膜在薄膜厚度方向的微观结构对吸收光谱的影响.研究结果表明:具有纳米层状结构的Au/SiO2多层薄膜在560 nm波长附近有明显的表面等离子共振吸收峰,吸收峰的强度随Au颗粒的浓度增加而增强,在Au颗粒浓度相同的情况下,复合薄膜
关键词:
2纳米复合薄膜')" href="#">Au/SiO2纳米复合薄膜
多靶磁控溅射
吸收光谱
有效介质理论 相似文献
5.
Nano metal-particle dispersed glasses are the attractive candidates for nonlinear optical material applications.Au/SiO 2 nano-composite thin films with 3 vol% to 65 vol% Au are prepared by inductively coupled plasma sputtering.Au particles as perfect spheres with diameters between 10 nm and 30 nm are uniformly dispersed in the SiO 2 matrix.Optical absorption peaks due to the surface plasmon resonance of Au particles are observed.The absorption property is enhanced with the increase of Au content,showing a maximum value in the films with 37 vol% Au.The absorption curves of the Au/SiO 2 thin films with 3 vol% to 37 vol% Au accord well with the theoretical optical absorption spectra obtained from Mie resonance theory.Increasing Au content over 37 vol% results in the partial connection of Au particles,whereby the intensity of the absorption peak is weakened and ultimately replaced by the optical absorption of the bulk.The band gap decreases with Au content increasing from 3 vol% to 37 vol % but increases as Au content further increases. 相似文献
6.
Nanocrystalline GaSb embedded in SiO2 films was grown by radio-frequency magnetron co-sputtering. X-ray diffraction pattern and transmission electron microscopy
(TEM) confirm the existence of GaSb nanocrystals in the SiO2 matrix. The average size of GaSb nanoparticles is in the range of 3 to 11 nm. Diffuse reflectance spectra were used to characterize
the small change of the band gap of the semiconductor. The diffuse reflectance spectra shows that the absorption peaks have
a large blueshift of about 4.0 eV of the absorption relative to that of bulk GaSb. It has been explained by quantum confinement
effects. Room temperature optical transmission spectra show that the absorption edge exhibits a very large blueshift of about
2.1 eV with respect to that of bulk GaSb in agreement with quantum confinement.
Received: 28 July 1999 / Accepted: 27 October 1999 / Published online: 1 March 2000 相似文献
7.
Core/shell nanoparticles consisting of a magnetic core of zinc-substituted manganese ferrite (Mn0.4Zn0.6Fe2O4) and a shell of silica (SiO2) are prepared by a sol-gel method using tetraethyl orthosilicate (TEOS) as a precursor material for silica and salts of iron, manganese and zinc as the precursor of the ferrite. Three weight percentages of the shell materials of SiO2 are used to prepare the coated nanoparticles. The X-ray diffractograms (XRD) of the coated and uncoated magnetic nanoparticles confirmed that the magnetic nanoparticles are in their mixed spinel phase in an amorphous matrix of silica. Particles sizes of the samples annealed at different temperatures are estimated from the width of the (3 1 1) line of the XRD pattern using the Debye-Sherrer equation. The information regarding the crystallographic structure together with the particles sizes extracted from the high-resolution transmission electron microscopy (HRTEM) of a few selected samples are in agreement with those obtained from the XRD. HRTEM observations revealed that particles are coated with silica. The calculated thickness is in agreement with that obtained from the HRTEM pictures. Hysteresis loops observed in the temperature range 300 down to 5 K and Mössbauer spectra at room temperature indicate superparamagnetic relaxation of the nanoparticles. 相似文献
8.
(Ge:SiO2)/SiO2 multilayers were fabricated for exploring the influence of the stress on the structure of Ge nanocrystals. When annealed at 800 °C, the multilayers show a clear splitting (fine structure) of the Ge (220) X-ray diffraction peak and have a preferred orientation. Similar effects cannot take place in the multilayers annealed at higher or lower temperature. Analyses of Raman scattering, X-ray diffraction spectroscopy, and transmission electron microscope observations suggest that the observed phenomena arise from compressive stress exerted on Ge nanocrystals, which is induced by the confinement of both the SiO2 matrix in the cosputtered layer and neighboring SiO2 layers. The stress may cause an orthorhombic distortion of the diamond structure of bulk Ge. This will lead to the disappearance of the (111) and (311) diffraction peaks and the splitting of the (220) peak. This kind of (Ge:SiO2)/SiO2 multilayers enables us to control the sizes of the Ge crystallites and enhance the stress, and is thus promising in forming new nanocrystal structures. 相似文献
9.
Lei Yuan Yuanan Zhao Congjuan Wang Hongbo He Zhengxiu Fan Jianda Shao 《Applied Surface Science》2007,253(7):3450-3454
Two kinds of HfO2/SiO2 800 nm high-reflective (HR) coatings, with and without SiO2 protective layer were deposited by electron beam evaporation. Laser-induced damage thresholds (LIDT) were measured for all samples with femtosecond laser pulses. The surface morphologies and the depth information of all samples were observed by Leica optical microscopy and WYKO surface profiler, respectively. It is found that SiO2 protective layer had no positive effect on improving the LIDT of HR coating. A simple model including the conduction band electron production via multiphoton ionization and impact ionization is used to explain this phenomenon. Theoretical calculations show that the damage occurs first in the SiO2 protective layer for HfO2/SiO2 HR coating with SiO2 protective layer. The relation of LIDT for two kinds of HfO2/SiO2 HR coatings in calculation agrees with the experiment result. 相似文献
10.
Valence electron states of α-quartz SiO2 are calculated self-consistently using the pseudopotential method. Excellent agreement is found with photoemission and UV-absorption data. X-ray emission spectra are calculated in an OPW scheme and compared to experiments. While the Si- and O - K spectra agree well with experiment, the Si L2,3 spectrum shows substantial differences. An explanation is offered base on the formation of amorphous Si in SiO2 during electron irradiation. 相似文献
11.
Prashant K. Sharma Ranu K. Dutta Prashant K. Singh Avinash C. Pandey 《Journal of luminescence》2009,129(6):605-950
Surface effects significantly influence the functionality of semiconductor nanocrystals. In the current work we present synthesis of ZnO quantum dots (QD) vis-a-vis symmetrically dispersed ZnO quantum dots embedded in SiO2 matrix and discussed their optical properties to understand the role of the surface effects. These nanomaterials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared (FTIR), absorption (UV-visible) and photoluminescence (PL) spectroscopy. TEM studies confirm the formation of ZnO nanophosphors inside the SiO2 matrix in highly symmetrical manner. These symmetrically dispersed ZnO@SiO2 nanophosphors exhibited enhanced stable emission over uncoated sample and would permit the conjugation of the nanocrystals to biological entities after functionalization. Furthermore, the mechanism behind the formation of symmetrically dispersed ZnO quantum dots embedded in SiO2 matrix was discussed in detail. 相似文献
12.
Kyung-Han Jung Jong-Won Yoon Naoto Koshizaki Young-Soo Kwon 《Current Applied Physics》2008,8(6):761-765
Au/SiO2 nanocomposite films were prepared on Si wafers by cosputtering of SiO2 and gold wires. Au/Si atomic ratios in Au/SiO2 nanocomposite films were varied from 0.53 to 0.92 by controlling the length of gold wire to study the evolution of the crystallization of gold, the size of Au/SiO2 nanocomposite particles, and the optical properties of as-deposited Au/SiO2 nanocomposite films. An X-ray photoelectron spectroscopy reveals that Au exists as a metallic phase in the bulk of SiO2 matrix. Dome-shaped Au/SiO2 nanocomposite particles and both Au (1 1 1) and (2 0 0) planes were observed in a field-emission scanning electron microscopy and X-ray diffraction studies respectively. With an ultraviolet-visible, absorption peaks of Au/SiO2 nanocomposite films were observed at 525 nm. 相似文献
13.
Valence electron states of α-quartz SiO2 are calculated self-consistently using the pseudopotential method. Excellent agreement is found with photoemission and u.v.-absorption data. X-ray emission spectra are calculated in an OPW scheme and compared to experiments. While the Si- and O-K spectra agree well with experiment, the Si L2, 3 spectrum shows substantial differences. An explanation is offered based on the formation of amorphous Si in SiO2 during electron irradiation. 相似文献
14.
Organic-inorganic composite SiO2-Al2O3 films have been prepared by sol-gel using methacryloxypropyl trimethoxysilane and aluminum sec-butoxide as the precursors. By introduction of organic groups into the inorganic backbone, the smooth and crack-free films could be readily achieved by a one-step dip-coating process, with the thickness up to 4.6 μm after being post-baked at 200 °C for 2 h. The films presented in an amorphous phase with an acceptable chemical homogeneity. Owing to the formation of chelate rings, the gel films showed a strong photosensitivity to ultraviolet light at 325 nm. The uniform fine patterns of SiO2-Al2O3 thick films could be well defined by ultraviolet light imprinting simply using a mask. These performances of SiO2-Al2O3 films indicate the potential for integrated optical systems. 相似文献
15.
The structure of SiOx (x = 1.94) films has been investigated using both X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The SiOx films were deposited by vacuum evaporation. XPS spectra show that SiO1.94 films are composed of silicon suboxides and the SiO2 matrix. Silicon clusters appeared only negligibly in the films in the XPS spectra. Si3O+ ion species were found in the TOF-SIMS spectra with strong intensity. These results reveal the structure of the films to be silicon monoxide embedded in SiO2, and this structure most likely exists as a predominant form of Si3O4. The existence of Si-Si structures in the SiO2 matrix will give rise to dense parts in loose glass networks. 相似文献
16.
Oleg A. Yeshchenko Igor. M. Dmitruk Andriy M. Dmytruk 《Journal of Physics and Chemistry of Solids》2008,69(7):1615-1622
Nickel nanoparticles were grown in silica glass by annealing of the sol-gel prepared silicate matrices doped with nickel nitrate. TEM characterization of Ni/SiO2 glass proves the formation of isolated spherical nickel nanoparticles with mean sizes 6.7 and 20 nm depending on annealing conditions. The absorption and photoluminescence spectra of Ni/SiO2 glasses were measured. In the absorption spectra, we observed the band related to the surface plasmon resonance (SPR) in Ni nanoparticles. The broadening of SPR was observed with decrease of Ni nanoparticle size. The width of the surface plasmon band decreases 1.5 times at the lowering of temperature from 293 to 2 K because of strong electron-phonon interaction. The spectra proved the creation of nickel oxide NiO clusters and Ni2+ ions in silica glass as well. 相似文献
17.
A pulsed KrF excimer laser of irradiance of about 108 W/cm2 was utilized to synthesize Si nanocrystals on SiO2/Si substrates. The results were compared with that ones obtained by applying low bias voltage to Si(1 0 0) target in order to control the kinetic energy of plasma ions. Glancing incidence X-ray diffraction spectra indicate the presence of silicon crystalline phases, i.e. (1 1 1) and (2 2 0), on SiO2/Si substrates. The average Si nanocrystal size was estimated to be about 45 nm by using the Debye-Scherrer formula. Scanning electron microscopy and atomic force microscopy images showed the presence of nanoparticles of different size and shape. Their distribution exhibits a maximum concentration at 49 nm and a fraction of 14% at 15 nm. 相似文献
18.
应用射频磁控共溅射方法在石英玻璃和抛光硅片上制备了InP/SiO2复合薄膜,并在几种条件下对这些薄膜进行退火.X射线光电子能谱和卢瑟福背散射实验结果表明,复合薄膜中InP和SiO2的化学组分都大体上符合化学计量配比.X射线衍射和激光喇曼谱实验结果都证实了复合薄膜中形成了InP纳米晶粒.磷气氛保护下的高温(520℃)退火可以消除复合薄膜中残存的In和In2O3并得到了纯InP/SiO2纳米复合薄膜.实验观察到了室温下纳米复合薄膜的明显的光学吸收边蓝移现象和光学非线性的极大增强
关键词:
InP
纳米晶粒
微观结构
光学性质 相似文献
19.
We have measured the photoemission of monolayers as well as thick films of H2 molecules condensed onto Cu and Au. The adsorbed monolayer exhibits a relaxation energy of 1.75 eV whereas we see a bandlike 1s state for thick layers having a bandwidth of 1.2 eV. We also observe energy loss features which are in agreement with previous electron energy loss and optical absorption studies. 相似文献
20.
Yanjie LiangJun Ouyang Hongyou WangWeili Wang Pengfei ChuiKangning Sun 《Applied Surface Science》2012,258(8):3689-3694
In this paper, the core-shell structured SiO2@YVO4:Yb3+,Er3+ microspheres have been successfully prepared via a facile sol-gel process followed by a heat treatment. X-ray diffraction, field emission scanning electron microscopy, energy disperse X-ray spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and photoluminescence spectra were used to characterize the samples. The results reveal that the SiO2 spheres have been successfully coated by YVO4:Yb3+,Er3+ phosphors to form core-shell structures and the size of obtained microspheres has a uniform distribution. Additionally, the samples exhibit bright green luminescence under the excitation of a 980 nm laser diode. The photoluminescence intensity increases with the number of coatings. These core-shell structured SiO2@YVO4:Yb3+,Er3+ microspheres may have great potential in the fields of infrared detection and display devices. 相似文献