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1.
Large‐scale In2O3 nanorods, nanocubes and nanowires have been successfully synthesized by chemical vapor deposition route under atmospheric pressure. The structures and morphologies were characterized by x‐ray diffraction (XRD), scanning election microscopy (SEM) and high‐resolution transmission electron microscopy (HRTEM). The growth mechanisms of these In2O3 nanostructures were analyzed in detail based on the experimental results. Field‐emission measurements of these nanostructures demonstrated that nanorods with rectangular cross‐section possessed good performance with a turn‐on field of 2.47 Vμm–1 and a field enhancement factor of 4597. The room‐temperature photoluminescence (PL) spectrum of the In2O3 nanostructure showed UV emission centered at about 396 nm and visible emissions located at 541 and 623 nm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
2.
Various TiO2 nanostructures, such as nanorings, nanorods were synthesized via potentiostatic anodization of titanium powder under different conditions. The morphology of the obtained TiO2 nanostructures can be easily tuned by varying applied voltage. The crystal structure, compositional information and morphological structures were characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectra (XPS) and field emission scanning electronic microscopy (FESEM). XRD and XPS analysis confirmed the anodization products were TiO2. A possible formation mechanism was suggested on the basis of the shape evolution of TiO2 nanostructures observed by FESEM. The results revealed that the applied voltage played an important role in the formation of various nanostructures. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
3.
We synthesized In2O3/ZnO/Al‐doped ZnO (AZO) core‐double shell nanowires, in which the inner shell (ZnO) and the outer shell (AZO) have been subsequently deposited on the core In2O3 nanowires. With their one‐dimensional morphology being preserved, the X‐ray diffraction (XRD), lattice‐resolved transmission electron microscopy (TEM) image, selected area electron diffraction, and Raman spectrum coincidentally revealed that the shell was comprised of hexagonal ZnO phase. In addition, TEM‐EDX investigation revealed the presence of Al elements in the shell region. The thermal annealing at 700 °C did not significantly change the nanowire morphology, however, the XRD spectrum indicated that the ZnO phase was crystallized by the annealing. PL spectrum of the 700 °C‐annealed In2O3/ZnO/AZO core‐double shell nanowires was comprised of three Gaussian bands at approximately 2.1 eV, 2.4 eV, and 3.0 eV, respectively. The integrated intensities of 2.1 eV‐, 2.4 eV‐, and 3.0 eV‐bands were decreased by the thermal annealing. This study will pave the road to the preparation and applicaition of double‐shelled nanowires. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
4.
Different morphologies of single‐crystalline orthorhombic phase bismuth sulfide (Bi2S3) nanostructures, including sub‐microtubes, nanoflowers and nanorods were synthesized by a urea‐assisted hydrothermal method at a low temperature below 120 °C for 12 h. The as‐synthesized powders were characterized by X‐ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM) and UV‐vis spectrophotometry. The experimental results showed that the sulfur sources had a great effect on the morphology and size of the resulting powders. The formation mechanism of the Bi2S3 nanostructures with different morphologies was discussed. All Bi2S3 nanostructures showed an appearance of blue shift relative to the bulk orthorhombic Bi2S3, which might be ascribed to the quantum size effect of the final products. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
5.
Zhenyuan Ji Jiquan Sun Xiaoping Shen Guoxing Zhu 《Crystal Research and Technology》2013,48(11):1022-1026
A simple and general microwave route is developed to synthesize nanostructured ZnO using Zn(acac)2·H2O (acac = acetylacetonate) as a single source precursor. The reaction time has a great influence on the morphology of the ZnO nanostructures and an interesting spindle‐like nanostructure is obtained. The microstructure and morphology of the synthesized materials are investigated by X‐ray diffraction (XRD), scanning electron microscopy (SEM), field‐emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high‐resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). It is found that all of them with hexagonal wurtzite phase are of single crystalline structure in nature. Ultraviolet–visible (UV‐vis) absorption spectra of these ZnO nanostructures are investigated and a possible formation mechanism for the spindle‐like ZnO nanostructures is also proposed. 相似文献
6.
SnO2 nanowalls were synthesized on silicon substrate by the thermal chemical vapor transport method at a low temperature of around 650 °C under atmospheric pressure. The microstructure and morphology of the SnO2 nanowalls were evaluated by using scanning electron microscopies and X‐ray diffraction. Room temperature photoluminescence spectra of the nanowalls showed a broad emission band centering at about 530 nm. Field emission measurements demonstrated that the nanowalls possessed good performance with a turn‐on field of ∼3.5 V/μm and a threshold field of ∼6.1 V/μm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
7.
Xiaobin Yin Youjin Zhang Zhiyong Fang Zhenyu Xu Wei Zhu Hongmei He 《Crystal Research and Technology》2010,45(9):961-964
Cross‐like Pr2(C2O4)3·10H2O micro‐particles were synthesized through a simple precipitation method at room temperature. The products were characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), field‐emission scanning electron microscopy (FESEM), thermogravimetry–differential thermal analysis (TG‐DTA) and photoluminescence (PL). The possible formation mechanism of the cross‐like Pr2(C2O4)3·10H2O micro‐particles was discussed, and Pr6O11 with similar morphology was obtained by calcining the oxalate precursor. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
Yongkui Cui Fengping Wang M. Zubair Iqbal Yan Li Arbab Mohammad Toufiq Ziya Wang Zhiyuan Wang Shujaat Ali 《Crystal Research and Technology》2015,50(3):210-214
Self‐assembling nanoflakes‐based crossed architectures of stannous oxide (SnO) were successfully synthesized via template‐free hydrothermal growth method by using SnCl2·2H2O and KOH as precursors. Crystal structures, morphology, chemical composition and optical properties were examined by X‐ray diffraction (XRD), field‐emission scanning electron microscopy (FESEM), energy dispersive X‐ray analysis, and Raman spectroscopy, respectively. The results indicate that the as‐synthesized product belongs to tetragonal phase SnO with crossed morphology self‐assembled by nanoflakes. Furthermore, UV‐vis spectrophotometry was used to determine optical band gap of the SnO nanostructures and the direct band gap of 2.90 eV was obtained. The photocatalysis of the product has been evaluated with methyl orange and the high degradation ratio of 87% is obtained in 240 minutes under the measuring condition which is attributed to the wide band gap and large specific surface area of the nanoflakes‐based crossed SnO architectures. A possible growth mechanism is proposed in the end. 相似文献
9.
Y. Huang B. J. Zhao S. F. Zhu W. L. Zhu C. F. Xu S. Q. Wan Z. Y. He 《Crystal Research and Technology》2007,42(3):227-230
High‐pure and single‐phase AgGa1‐xInxSe2 (x=0.2) polycrystalline was synthesized by the mechanical and temperature oscillation method. Adopting the modified Bridgman method an integral AgGa1‐xInxSe2 single crystal with diameter of 14 mm and length of 35 mm has been obtained at the rate of 6 mm/day. It was found that there is a new cleavage face which was (101), and observed the four order X‐ray spectrum of the {101} faces. By the method of DSC analysis the melting and freezing points of the AgGa1‐xInxSe2 (x=0.2) single crystal were about 828°C and 790°C. The transmission spectra of the AgGa1‐xInxSe2 (x=0.2) sample of 5×6×2 mm3 were obtained by means of UV and IR spectrophotometer. The limiting frequency was 774.316nm and the band gap was 1.6eV. It can be found in the infrared spectrum that the infrared transmission was above 60% from 4000cm‐1 to 600cm‐1. The value of α in 5.3µm and 10.6µm were 0.022cm‐1 and 0.1cm‐1 respectively. All results showed that the crystal was of good quality. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
Changhyun Jin Jungkeun Lee Kyungjoon Baek Chongmu Lee 《Crystal Research and Technology》2010,45(10):1069-1074
It is essential to passivate one‐dimensional (1D) nanostructures with insulating materials to avoid crosstalking as well as to protect them from contamination and oxidation. The structure and influence of thermal annealing on the photoluminescence properties of ZnS‐core/SiO2‐shell nanowires synthesized by the thermal evaporation of ZnS powders followed by the sputter deposition of SiO2 were investigated. Transmission electron microscopy and X‐ray diffraction analyses revealed that the cores and shells of the core‐shell nanowires were single crystal zinc blende‐type ZnO and amorphous SiO2, respectively. Photoluminescence (PL) measurement showed that the core‐shell nanowires had a green emission band centered at around 525 nm with a shoulder at around 385 nm. The PL emission of the core‐shell nanowires was enhanced in intensity by annealing in an oxidative atmosphere and further enhanced by subsequently annealing in a reducing atmosphere. Also the origin of the enhancement of the green emission by annealing is discussed based on the energy‐dispersive X‐ray spectroscopy analysis results. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
11.
F. P. Yu D. R. Yuan X. Zhao X. L. Duan S. Y. Guo X. F. Cheng X. Q. Wang 《Crystal Research and Technology》2009,44(3):253-257
Dysprosium (Dy) doped La3Ga5.5Nb0.5O14 single crystals were grown by the traditional Czochralski method along z‐axis. The structure of the crystal has been studied by X‐ray powder diffraction method, and the unit‐cell parameters are calculated to be a=8.22070 Å, c=5.12533 Å and V=299.965 Å3. The segregation coefficient of Dy3+ in La3Ga5.5Nb0.5O14 crystal was measured by X‐ray fluorescence analysis. For 1 mol% doping level in the melt, the distribution coefficient of Dy3+ was determined to be 0.341 wt%. Specific heat, thermal expansion and transmission spectrum of Dy: La3Ga5.5Nb0.5O14 single crystals have been measured. The fluorescence spectra of Dy3+: La3Ga5.5Nb0.5O14 crystals were measured at room temperature, and there were four emission transitions occurring at 479, 576, 662 and 754 nm, respectively. The fluorescent lifetimes measurement results show 1.0% Dy: La3Ga5.5Nb0.5O14 possesses shorter fluorescence decay time (303.4 μs) than does 1.0%Dy:LGS (436.12 μs). (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
12.
Dapeng Xu Hang Yang Liang Li Qiang Zhou Hongming Yuan Tian Cui 《Crystal Research and Technology》2014,49(7):502-506
By using an optical floating zone technology, orthorhombic columbit ZnNb2O6 single crystals are fabricated successfully. The as‐prepared sample are blue and transparent rods of Φ 4 to 6 mm ×L 48 mm and the biggest domain of Φ 4 mm× L 25 mm. After annealing, the sample fades to colorless. X‐ray diffractions indicates that the as‐perpared samples are ZnNb2O6 with orthorhombic columbite structure and grows along the a‐axis. The micropolariscopy in cross transmission arrangements analyzing give that the crystals are of low‐angle crystal boundary‐free and bubble‐free. Besides, the crystals have also been tested by Raman spectra, optical absorption and photoluminescence spectra before and after being annealed. The luminescence pattern has an emission peak located at 450 nm blue‐region. 相似文献
13.
Millimetric straw‐like rutile monocrystals were grown by the flux growth technique. A suitable mixture of flux (MoO3, V2O5, Li2CO3) and amorphous TiO2 gel was slowly cooled down to 750°C from 1250°C or 1350°C. The best yields of straw‐like rutile were obtained with a nutrient/flux ratio and a cooling rate in the range 0.015‐0.006 and 1.8‐1.9 K h‐1, respectively. The hollowed crystals were characterized by powder and single‐crystal X‐ray diffraction, scanning electron microscopy, microthermometry, and µ‐Raman spectroscopy. As for skeletal crystal, the formation of axial canals in rutile is attributed to a lack of nutrient due to the viscosity of the melt and the high growth rate along [001]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
Peng‐Yan Xiao Tie‐Zhen Ren Zhi‐Qiang Wang K. E. Christensen 《Crystal Research and Technology》2010,45(6):589-592
A Si modified Ge10 cluster with structure Na4(Ge,Si)9O20 (denoted as HUT‐1) was synthesized by hydrothermal synthesis at 160 °C with a sodium silicate source. The compound was characterized by single crystal, powder X‐ray diffraction and TGA‐DSC analysis. HUT‐1 crystallizes in space group I41 (80) with calculated unit cell (a=14.966(5) Å, c=7.343(2) Å, V=1644.8(9) Å3), which has the same structure as Na4Ge9O20. HUT‐1 has a high Si/Ge ratio with an approximate formula of Na4Ge7.68Si1.32O20. Single crystal X‐ray structure refinements together with results from X‐ray powder diffraction (XRPD) confirm the occupancy of Si at two tetrahedral sites. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
15.
Xu Hongyan Diwu Jiangtao Hai Zhenyin Gao Libo Zhang Qiang Tang Jun Zhang Binzhen Xue Chenyang 《Crystal Research and Technology》2016,51(2):123-128
Pure Co3O4 microcrystals were prepared by a hydrothermal method from Co(NO3)2·6H2O and urea solution, and the effect of thermal treatment time on the growth of Co3O4 microcrystals was studied by X‐ray diffraction (XRD), scanning electron microscopy (SEM), Raman and UV‐Vis absorption spectra. The results show that with the thermal treatment time increases from 2 h to 12 h, the shape of as‐prepared Co3O4 microcrystals changes from the hedgehog sphere‐like to the as‐cubic one that were stacked by lots of lamella, and finally cubes, and then longer time treatment will only lead to the size growth and agglomeration of particles. In conclusion, the cubic Co3O4 microcrystals of uniform size (∼6 μm) are synthesized via a 12‐h thermal treatment. Moreover, the synthesis mechanism has been studied. 相似文献
16.
Shuangquan Fang Zhaoxiang Han Yingjie Qiao Yingying Liu Qi Jia 《Crystal Research and Technology》2009,44(11):1211-1214
With K2O as flux, near‐stoichiometric In:LiNbO3 (In:SLN) crystals with different indium contents were grown by the top seed solution growth (TSSG) method. Defect structure characteristics and the replacement principle of extrinsic ions were derived from X‐ray powder diffraction, differential thermal analysis (DTA), ultraviolet‐visible (UV) absorption and infrared (IR) spectrum measurement. Further analysis indicated that the threshold concentration of In2O3 in near‐stoichiometric LiNbO3 crystals were about 1.1 mol%. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
17.
A. Novoselov A. Yoshikawa N. Solovieva M. Nikl 《Crystal Research and Technology》2007,42(12):1320-1323
Using the micro‐pulling‐down method, (Ce,Sr)‐doped PrAlO3 square‐shaped single crystals (4×4×12 mm) were grown. Structural parameters studied by X‐ray powder diffraction were consistent with R3m space group. Compositional homogeneity was checked with electron probe micro‐analysis and found quite uniform. Absorption spectra and luminescence characteristics under UV and X‐ray excitations were measured at room temperature with no Ce‐related emission appeared. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
18.
K. Kolodziejak W. Wierzchowski K. Wieteska M. Malinowski W. Graeff T. Lukasiewicz 《Crystal Research and Technology》2008,43(4):369-373
The undoped Yb3Al5O12 (YbAG) single crystals and doped with 1.5, 10 and 30 at% erbium were grown by the Czochralski method. The YbAG crystals offer efficient emission of laser beam of 2.94 µm and 1.55 µm important for practical applications in communication and medicine. The crystals were investigated by various synchrotron X‐ray diffraction methods including white beam topographic methods, monochromatic beam topography and recording of the rocking curves. The experiments were performed at E2 and F1 experimental stations in HASYLAB. The investigations proved a good crystallographic perfection of the crystals, in most cases revealing only segregation fringes and growth facets. The crystallographic identification of the facets was performed together with direct evaluation of growth front radius from the transmission section topographs. Relative lattice parameter changes connected with erbium segregation were found to be less than 2 × 10‐5 inside the segregation fringes and 8 × 10‐5 in the facets. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
19.
A. A. Dakhel 《Crystal Research and Technology》2003,38(11):968-973
Thin Eu2O3 films were prepared on Si (P) substrates to form MOS devices. The oxide crystal structure was determined by X‐ray diffraction (XRD). The electrical transport properties of the devices with amorphous and crystalline Eu oxide were investigated. The current‐voltage and current‐temperature characteristics suggest a Poole‐Frenkel (PF) type mechanism of carrier transport through the device when the applied field is more than 105 V/cm. A deviation from PF leakage current course was found and attributed to the current carrier trapping. We have also observed that, the dielectric spectra of MOS structure are different when the insulator is an amorphous or crystalline thin film. From which we calculate the relaxation time (τ) of the interface (insulator/semiconductor) dipoles. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
20.
Jiang Diao Bing Xie Chengqing Ji Xu Guo Yonghong Wang Xiaojun Li 《Crystal Research and Technology》2009,44(7):707-712
Morphology of vanadium slags were investigated by scanning electron microscopy (SEM). The mineralogical phases were characterized by energy disperse X‐ray spectrometry (EDS) and powder X‐ray diffraction (XRD). The obtained results show that spinels and silicates are the major phases in the vanadium slag, and V is concentrated in FexV3‐xO4 and Mgx(V, Ti)3‐xO4. Both the spinel grain size and volume fraction in the slag with higher V2O3 content are much larger than that with lower V2O3 content. (Fe, Mn)2SiO4 and (Fe, Mn)SiO3 have a higher proportion in the slag with lower V2O3 and higher SiO2 content. The relation among cooling conditions and grain size and volume fraction of spinels is also discussed. It is found that low cooling rate and long holding time benefit spinel crystal growth, especially for the interval of 1200‐1250 °C. Both mean diameter and volume fraction of spinels could achieve or exceed the industry vanadium slag when holding more than 45 min. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献