共查询到20条相似文献,搜索用时 15 毫秒
1.
Tianhao Ji Maoyu Tang Lin Guo Xingyi Qi Qinglin Yang Huibin Xu 《Solid State Communications》2005,133(12):765-769
Scalable Sb(III)Sb(V)O4 nanorods from Sb2O5 powder were prepared using solvothermal route. XRD and HRTEM demonstrate that the nanorods are single-crystal orthorhombic-Sb2O4 phase with several micrometers long and 200-300 nm diameter size. XPS result further shows that the antimony cations in the nanorods are composed of three valence and five valence antimony ions. The emission of the nanorods appears around 450 nm wavelength. The formation mechanism of the Sb(III)Sb(V)O4 nanorods was discussed in detail. 相似文献
2.
J.X. Wang H.J. Yuan X.Q. Yan D.F. Liu Y. Gao Z.P. Zhou L. Song L.F. Liu X.W. Zhao X.Y. Dou W.Y. Zhou G. Wang 《Solid State Communications》2004,131(7):435-440
A large quantity of single-crystal Zn2SnO4 (ZTO) nanobelts is synthesized by using a thermal evaporation method. The lengths of the nanobelts are up to several hundreds of micrometers, and the average width and thickness are about 400 and 30 nm, respectively. Some ring-like nanobelts, called nanorings here, are also observed. The nanobelts are characterized in detail with scanning electron microscope, X-ray powder diffraction, transmission electron microscope, high-resolution transmission electron microscope and selected area electron diffraction. Possible growth mechanisms for the ZTO nanobelts and nanorings are proposed. In addition, the photoluminescence spectrum (PL) of the nanobelts at room temperature shows a stable broad blue-green emission around the 400-600 nm wavelengths with a maximum center at 490 nm. The strong PL emission of the nanobelts may find potential applications in nano-scale optoelectronic devices. 相似文献
3.
Growth and mechanism of titania nanowires 总被引:1,自引:0,他引:1
Anatase and rutile-phase titania nanowires have been prepared via an efficient molten salt-assisted and novel pyrolysis route, respectively. The growth of anatase nanowires is parallel to [010] direction. The anatase titanium oxide nanowires are obtained by exchange reaction between Na2TiO3 and HCl, whereas the formation of rutile titania nanowires is conventional vapor-liquid-solid growth mechanism. 相似文献
4.
Single-crystalline SnO2 nanowires with sizes of 4-14 nm in diameter and 100-500 nm in length were produced in a molten salt approach by using hydrothermal synthesized precursor. Structural characters of the nanowires were examined by X-ray diffraction and high-resolution electron transmission microscopy. Raman, photoluminescence and X-ray photoelectron spectra of the samples were examined under heat treatments. Three new Raman modes at 691, 514 and 358 cm−1 were recorded and assigned. The former two are attributed to activation of original Raman-forbidden A2uLO mode and the third is attributed to defects in small-sized nanowires. A strong photoluminescence is observed at about 600 nm, the temperature effects is examined and the origin of the PL process is discussed via X-ray photoelectron spectra. 相似文献
5.
Stannic oxide (SnO2) nanowires have been prepared by Chemical vapor deposition (CVD). The low-temperature transport properties of a single SnO2 nanowire have been studied. It is found that the transport of the electrons in the nanowires is dominated by the Efros-Shklovskii variable-range hopping (ES-VRH) process due to the enhanced Coulomb interaction in this semiconducting nanowire. The temperature dependence of the resistance follows the relation lnR∼T−1/2. On the I-V and dI/dV curves of the nanowire a Coulomb gap-like structure at low temperatures appears. 相似文献
6.
ZnS nanorods were fabricated by annealing precursor ZnS nanoparticles, which were prepared by one-step, solid-state reaction of ZnCl2 and Na2S through grinding by hand at ambient temperature, in NaCl flux. The as-prepared ZnS nanorods have diameters of 40-80 nm, and lengths up to several micrometers. The structural features and chemical composition of the nanorods were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), and Raman spectra. 相似文献
7.
The RuO2 nanorods array is grown selectively on the SiO2-patterned sapphire (SA) wafers using reactive sputtering. The area-selectivity is attributed to an early nucleation of RuO2 and its fast surface coverage on SA (1 0 0) and (0 1 2), in contrast to the sluggish nucleation on glassy SiO2 in the initial sputtering period. The growth domain is explored by investigating the temperature windows at sputtering power 40, 50, and 60 W. The low-temperature bound is limited by the mobility of precursors on SiO2 surface, which enables the precursors to depart before aggregating into a large size to smear the non-growth region. The high-temperature bound is set by the horizontal growth which enlarges the rod width and deteriorates its one-dimensional feature. The temperature window shrinks with increasing sputtering power. The X-ray photoelectron spectra indicate the as-sputtered rod surface is ruthenium rich. The X-ray diffraction analysis shows that RuO2 growth on SA (1 0 0) and (0 1 2) follows the epitaxial relations between RuO2 and SA crystals. 相似文献
8.
We report the visible light-induced hydrogen generation over a series of Keggin-structure heteropoly blue (HPB) anions (PW12O403−, phosphotungstic blue (PTB), GeW12O404− (GTB), SiW12O404− (STB), BW12O405− (BTB)) sensitized Pt/TiO2 photo-catalysts. The sensitization of TiO2 by HPB was certified using photo-electrochemical measurements and UV-vis absorption spectra. PTB showed the most pronounced sensitization effect for TiO2 in those HPB anions and Pt/TiO2-PTB showed the highest hydrogen generation activity. The sensitization of TiO2 was significantly dependent on the reduction potential of HPA, which was determined by the kind of central atom in HPA. 相似文献
9.
Growth of Ru- and RuO2-composite (ROC) nanodots on atomic-layer-deposited Al2O3 film has been studied for the first time using ion-beam sputtering followed by post-deposition annealing (PDA). X-ray photoelectron spectroscopy analyses reveal that RuO2 and Ru co-exist before annealing, and around 10% RuO2 is reduced to metallic Ru after PDA at 900 °C for 15 s. Scanning electron microscopy measurements show that well-defined spherical ROC nanodots are not formed till the PDA temperature is raised to 900 °C. The mean diameter of the nanodots enlarges with increasing PDA temperature whereas the nanodot density decreases, which is attributed to coalescence process between adjacent nanodots. It is further illustrated that the resulting nanodot size and density are weakly dependent on the annealing time, but are markedly influenced by the decomposition of RuO2. In this article, the ROC nanodots with a high density of 1.6 × 1011 cm−2, a mean diameter of 20 nm with a standard deviation of 3.0 nm have been achieved for the PDA at 900 °C for 15 s, which is promising for flash memory application. 相似文献
10.
Zn-Ni-Al2O3 nanocomposite coating, which was fabricated by eletrodeposition technique with the aid of ultrasound, was investigated by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and X-ray photoelectron spectroscopy (XPS). The results reveal that 7.2 wt.% nano-alumina particles uniformly dispersed in the matrix of the composite coating. The XPS analyses demonstrate that the outermost layer of Zn-Ni-Al2O3 coating was composed of nano-alumina and Zn(OH)2, while the transition layer between the outermost layer and the Zn-Ni matrix consisted of nano-alumina, metallic Zn, ZnO and metallic Ni. In order to investigate the influences of ultrasonic agitation and the incorporation of nano-alumina on the composition and surface structure of Zn-Ni matrix, the comparison studies of Zn-Ni-Al2O3 nanocomposite coating with Zn-Ni coatings fabricated with and without ultrasound were conducted. The results indicate that ultrasonic agitation resulted in a decrease of Ni content in the Zn-Ni matrix and an increase of the thickness of surface oxide layer; while the incorporation of nano-α-Al2O3 increased the Ni content in the Zn-Ni matrix. 相似文献
11.
T. WeiQ.G. Song Q.J. ZhouZ.P. Li X.L. QiW.P. Liu Y.R. GuoJ.-M. Liu 《Applied Surface Science》2011,258(1):599-603
We have synthesized a series of high quality EuTi1−xCrxO3 (x = 0.0, 0.02, and 0.04) nanoparticles by simple sol-gel technique. The averaged grain size of these obtained nanoparticles displays no obvious change with Cr-doping and is about 100 nm. The structural and magnetic properties of EuTi1−xCrxO3 (x = 0.0, 0.02, and 0.04) samples were detailedly investigated. It is found that the G-antiferromagnetic (G-AFM) ordering of pure EuTiO3 can be significantly modified with slight Cr-doping, and finally the ferromagnetic behavior is enhanced for EuTi1−xCrxO3 system with Cr-doping. 相似文献
12.
SnO2/In2O3 one-dimensional nano-core-shell structures have been synthesized at 1350 °C by thermal evaporation of the mixture of metal Sn, Fe(NO3)3 powders and In particles. The as-synthesized products have been characterized by energy-dispersive X-ray spectroscopy, selected-area electron diffraction and high-resolution transmission electron microscopy. Microstructure characterization indicates the orientation relationship between core and shell is , . The formation mechanism of this nano-core-shell structure can be attributed to the cover of In2O3 on the surface of SnO2 nanochains. The photoluminescence properties of the nano-core-shell structures have been measured. The PL spectrum shows some difference with the result from pure SnO2 and In2O3 nanostructure that be deemed to relate to interface defects in SnO2/In2O3 nano-core-shell structure. 相似文献
13.
Ki-Hong Lee Charles Lofton Won-Seon Seo Myung-Hyun Lee 《Solid State Communications》2004,131(11):687-692
Photoluminescence characteristics of amorphous silica nanowires (a-SiONWs) grown on TiN/Ni/Si and TiN/Ni/SiO2 substrates have been studied. A-SiONWs grown on TiN/Ni/Si substrates show a Si-rich composition compared to those grown from TiN/Ni/SiO2/Si. The emission characteristics of the nanowires were found to depend on the type of substrate. By annealing the a-SiONWs grown on TiN/Ni/Si in air, emission bands shift from blue to green bands. It is likely that silicon to oxygen ratio is an important factor in deciding the types of defects and emission bands of amorphous silica nanowires. 相似文献
14.
Size-controlled synthesis of pure rutile-phase TiO2 nanorods was carried out by a hydrothermal method using different organic acids as modifiers, and metatitanic acid and concentrated sulfuric acid as raw materials. The synthesized rutile TiO2 nanorods were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of organic acid modifiers on the sizes of rutile TiO2 nanorods were investigated. It was found that the steric effect occurred by the organic modifiers and non-polarity of organic acids were beneficial to the formation of small-sized rutile TiO2 nanorods. The strongly coordinative interaction between the carboxyl (or hydroxyl) group of the modifier and the surface of TiO2 nanoparticles effectively inhibited the crystal growth. 相似文献
15.
Low-temperature preparation of F-doped TiO2 film and its photocatalytic activity under solar light 总被引:2,自引:0,他引:2
A novel and simple method for preparing F-doped anatase TiO2 (defined as FTO) film with high photocatalytic activity was developed using titanium-n-butoxide and NH4F as TiO2 and fluorine precursors under mild condition, i.e. low temperature (lower than 373 K) and ambient pressure. The prepared samples were characterized by XRD, SEM, X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectrum (DRS), photoluminescence spectrum (PL) and TG-DSC analysis. The photocatalytic activity was evaluated by decomposing X-3B under artificial solar light. The results showed that the crystallinity of TiO2 was improved by F-doping. F− ions can prevent the grain growth, and the transformation of anatase to rutile phase was also inhibited. The doped fluorine atoms existed in two chemical forms, and the ones incorporated into TiO2 lattice might take a positive role in photocatalysis. Compared with surface fluorination samples, FTO film exhibited better photocatalytic activity. The high photocatalytic activity of FTO may due to extrinsic absorption through the creation of oxygen vacancies rather than the excitation of the intrinsic absorption band of bulk TiO2. Furthermore, the FTO can be recycled with little photocatalytic activity depression. Without any further treatment besides rinsing, after 6 recycle utilization, the photocatalytic activity of FTO film was still higher than 79%. 相似文献
16.
Yuan-Ron Ma Chai-Chang Tsai Shang Fan Lee Kai-Wen Cheng Yung Liou Yeong Der Yao 《Journal of magnetism and magnetic materials》2006
Large-area one-dimensional (1D) monoclinic WO2 and MoO2 nanorods in the space group P21/c were synthesized by reactive thermal evaporation. The as-synthesized 1D WO2 and MoO2 nanorods become soft magnetic materials at 10 K, implying that structural or magnetic transitions occur. There are large differences in saturation magnetization, the coercive field, and remanence between the 1D WO2 and MoO2 nanorods, although both 1D nanorods have a similar shape. 相似文献
17.
Single-phase layered nanocomposite containing 4Hb-TaS2 and poly(ethylene oxide) [PEO] has been first synthesized by using the exfoliation-adsorption technique. It has been characterized by powder X-ray diffraction (XRD) and electrical dc resistivity measurements. As the product exhibited lattice expansions along the stacking direction, PEO was intercalated into 4Hb-TaS2 galleries. 相似文献
18.
We have demonstrated the synthesis of one-dimensional (1D) structures of bismuth oxide (Bi2O3) by a reaction of a trimethylbismuth (TMBi) and oxygen (O2) mixture at 450 °C. Scanning electron microscopy showed that the product consisted of 1D materials with width or diameters less than 1 μm and lengths up to several tens of micrometers. The X-ray energy dispersive spectroscopy revealed that the materials contained elements of Bi and O. The results of X-ray diffraction and selected area electron diffraction pattern indicated that the obtained Bi2O3 were crystalline with monoclinic structure. 相似文献
19.
Hong-Qiang Song Yong Wang Shi-Shen Yan Liang-Mo Mei Ze Zhang 《Journal of magnetism and magnetic materials》2007
TiO2:Co thin films of high Co concentration were investigated by the high resolution transmission electron microscopy, physical property measurement system and energy dispersive X-ray. The as-deposited films are amorphous magnetic semiconductors and we did not find any Co metal particles in them. The electronic transport process in the low-temperature range below 80 K could be described by the spin-dependent variable-range-hopping process. However, after the samples were annealed at 300 °C, large amounts of Co metal particles were observed to connect each other and the films show a metallic behavior. The origin of ferromagnetism of the thin films is also discussed. 相似文献
20.
Adam Orendorz 《Applied Surface Science》2005,252(1):85-88
Nanocrystalline TiO2 (anatase) films were prepared using either colloidal suspensions or a sol-gel route. The electronic structure of these films was analyzed using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). Apart from pristine films, films containing defects introduced by annealing under ultra-high vacuum conditions or by ion bombardment were investigated. Generally, annealing in the temperature range up to 720 K results in no significant changes in the XPS and UPS spectra as compared to the pristine state, indicating that the amount of defect formation is too low to be observable by these techniques. On the other hand, ion irradiation causes the appearance of distinct defect states; these could be identified in agreement with previous data from photoemission studies on rutile and anatase single crystals. From UPS, a valence-band width of ∼4.6 eV was determined for the nanocrystalline anatase films. 相似文献