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1.
采用两步法在FTO导电玻璃衬底上制备ZnO纳米棒,首先利用浸渍-提拉法在FTO导电玻璃衬底上制备ZnO晶种层,然后把有ZnO晶种层的FTO衬底放入盛有生长溶液的反应釜中利用水热法制备ZnO纳米棒.研究了生长溶液的浓度、生长温度和生长时间对所制备的对ZnO纳米棒阵列的微结构和光致发光性能的影响,利用X射线衍射(XRD)、扫描电子显微镜(SEM)和光致发光谱(PL)研究了ZnO样品的结构、形貌和光学性质.实验结果表明:所制备的ZnO纳米棒呈现六方纤锌矿结构,沿(002)晶面择优取向生长,纳米棒的平均直径约为100 nm,长度约为2.5 μm.所制备的ZnO纳米棒在390 nm附近具有很强的紫外发光峰和在550 nm附近有较弱的宽绿光发光峰. 相似文献
2.
H. Wang Z. P. Zhang X. N. Wang Q. Mo Y. Wang J. H. Zhu H. B. Wang F. J. Yang Y. Jiang 《Nanoscale research letters》2008,3(9):309-314
By thermal evaporation of pure ZnO powders, high-density vertical-aligned ZnO nanorod arrays with diameter ranged in 80–250 nm
were successfully synthesized on Si substrates covered with ZnO seed layers. It was revealed that the morphology, orientation,
crystal, and optical quality of the ZnO nanorod arrays highly depend on the crystal quality of ZnO seed layers, which was
confirmed by the characterizations of field-emission scanning electron microscopy, X-ray diffraction, transmission electron
microscopy, and photoluminescence measurements. For ZnO seed layer with wurtzite structure, the ZnO nanorods grew exactly
normal to the substrate with perfect wurtzite structure, strong near-band-edge emission, and neglectable deep-level emission.
The nanorods synthesized on the polycrystalline ZnO seed layer presented random orientation, wide diameter, and weak deep-level
emission. This article provides a C-free and Au-free method for large-scale synthesis of vertical-aligned ZnO nanorod arrays
by controlling the crystal quality of the seed layer. 相似文献
3.
In this work, ZnO nanorod arrays were grown on glass substrate by the wet chemical method, and the effect of synthesis temperature on the properties was investigated. The grown nanorods were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Raman and Photoluminescence (PL) measurements. XRD pattern showed that nanorod prepared at 80 °C and 90 °C has high crystallinity with wurtzite structure and orientated along the c-axis. However, nanorods were not formed at 60 °C and 70 °C due to less energy supply for the growth of the ZnO. FE-SEM results showed that the morphology and the size of ZnO can be effectively controlled. In particular, as the temperature increased, diameter of the nanorod was increased while length decreased. Raman scattering spectra of ZnO nanorod arrays revealed the characteristic E2high mode that is related to the vibration of oxygen atoms in the wurtzite ZnO. Room-temperature PL spectra of the ZnO nanorods revealed a near-band-edge (NBE) emission peak. The NBE (UV light emission) band at ~383 nm might be attributed to the recombination of free exciton. The narrow full-width at half-maximum (FWHM) of the UV emission indicated that ZnO nanorods had high crystallinity. 相似文献
4.
Qian Li Kui Cheng Wenjian Weng Chenlu Song Piyi Du Ge Shen Gaorong Han 《Nanoscale research letters》2011,6(1):477
In this study, controllable ZnO nanorod arrays were successfully synthesized on Si substrate at room temperature (approx. 25°C). The formation of controllable ZnO nanorod arrays has been investigated using growth media with different concentrations and molar ratios of Zn(NO3)2 to NaOH. Under such a nonequilibrium growth condition, the density and dimension of ZnO nanorod arrays were successfully adjusted through controlling the supersaturation degree, i.e., volume of growth medium. It was found that the wettability and electrowetting behaviors of ZnO nanorod arrays could be tuned through variations of nanorods density and length. Moreover, its field emission property was also optimized by changing the nanorods density and dimension. 相似文献
5.
SnO(2) nanorod arrays have been deposited on 4 inch SiO(2)/Si and Si wafers and stainless steel substrates by plasma-enhanced chemical vapor deposition without any high temperature treatment or additional catalysis. The SnO(2) nanorods grow up from seed nanocrystals along the [110] preferential direction by a self-catalyzed vapor-solid growth mechanism. The surface of the SnO(2) nanorods was modified by ZnO, Pt and Ni nanocrystals. After surface modification, the field emission properties of the SnO(2) nanorod arrays are improved. The Ni nanocrystal with sharp tips and edges act as additional field emission sites to SnO(2) nanorods and thus the Ni/SnO(2)/SiO(2)/Si outperforms other samples due to the synergistic effects of good conductivity and hierarchical sharp apexes. The field enhancement factor of the Ni/SnO(2)/SiO(2)/Si increased around 3 times while the turn-on field of 8.0 V μm(-1) is about one third of the SnO(2)/SiO(2)/Si device. 相似文献
6.
In this study, we have fabricated and characterized the silicon [Si] wire solar cells with conformal ZnO nanorod antireflection
coating [ARC] grown on a Al-doped ZnO [AZO] seed layer. Vertically aligned Si wire arrays were fabricated by electrochemical
etching and, the p-n junction was prepared by spin-on dopant diffusion method. Hydrothermal growth of the ZnO nanorods was
followed by AZO film deposition on high aspect ratio Si microwire arrays by atomic layer deposition [ALD]. The introduction
of an ALD-deposited AZO film on Si wire arrays not only helps to create the ZnO nanorod arrays, but also has a strong impact
on the reduction of surface recombination. The reflectance spectra show that ZnO nanorods were used as an efficient ARC to
enhance light absorption by multiple scattering. Also, from the current-voltage results, we found that the combination of
the AZO film and ZnO nanorods on Si wire solar cells leads to an increased power conversion efficiency by more than 27% compared
to the cells without it. 相似文献
7.
High density ZnO nanorod arrays were grown on Si substrates coated with ZnO seed layers via aqueous solution route. The ZnO seed layers were deposited on the substrate using DC reactive sputtering and RF magnetron sputtering. It was found that ZnO seed layer with (1 0 3) preferred orientation, prepared using DC reactive sputtering, did not facilitate the formation of ZnO nanorods in the solution grown process. Prior seeding of the surface by ZnO layer with (0 0 2) preferred orientation, deposited using RF magnetron sputtering, leads to nucleation sites on which ZnO nanorod arrays can grow in a highly aligned fashion. ZnO nanorods with well-defined hexagonal facets (0 0 2) were grown almost vertically over the entire substrate. The uniformity and alignment of the nanorod arrays are strongly related to the properties of underneath ZnO seed layers. 相似文献
8.
Juan Zhao Zheng-Guo Jin Tao Li Xiao-Xin Liu Zhi-Feng Liu 《Journal of the American Ceramic Society》2006,89(8):2654-2659
Zinc oxide (ZnO) nanorod arrays on the ZnO-coated seed substrates were prepared by the solution chemical method from Zn(NO3 )2 /NaOH under an assisted electrical field. The influence of the electrical field on ZnO nanorod growth was primarily explored, and the positive effects of the electrical field were demonstrated by adding polyethylene glycol in growth solution. It has been proved that the electrical field enhances ion adsorption to the substrate and lowers the nucleation energy barrier by increasing charge intensity; meanwhile, it produces H+ through oxidation of OH− and increases properly the degree of solution supersaturation near the substrate surface. XRD results show that the nanorods grown under the electrical field primarily have a zincite structure. With increasing precursor concentration, the average diameter and length of ZnO nanorods increase. The maximum rod growth rate at a given concentration of Zn2+ ion occurs at a specific temperature. 相似文献
9.
Francisco Solís-Pomar Eduardo Martínez Manuel F Meléndrez Eduardo Pérez-Tijerina 《Nanoscale research letters》2011,6(1):524
A hydrothermal method to grow vertical-aligned ZnO nanorod arrays on ZnO films obtained by atomic layer deposition (ALD) is presented. The growth of ZnO nanorods is studied as function of the crystallographic orientation of the ZnO films deposited on silicon (100) substrates. Different thicknesses of ZnO films around 40 to 180 nm were obtained and characterized before carrying out the growth process by hydrothermal methods. A textured ZnO layer with preferential direction in the normal c-axes is formed on substrates by the decomposition of diethylzinc to provide nucleation sites for vertical nanorod growth. Crystallographic orientation of the ZnO nanorods and ZnO-ALD films was determined by X-ray diffraction analysis. Composition, morphologies, length, size, and diameter of the nanorods were studied using a scanning electron microscope and energy dispersed x-ray spectroscopy analyses. In this work, it is demonstrated that crystallinity of the ZnO-ALD films plays an important role in the vertical-aligned ZnO nanorod growth. The nanorod arrays synthesized in solution had a diameter, length, density, and orientation desirable for a potential application as photosensitive materials in the manufacture of semiconductor-polymer solar cells.
PACS
61.46.Hk, Nanocrystals; 61.46.Km, Structure of nanowires and nanorods; 81.07.Gf, Nanowires; 81.15.Gh, Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.) 相似文献10.
CY Kung SL Young HZ Chen MC Kao L Horng YT Shih CC Lin TT Lin CJ Ou 《Nanoscale research letters》2012,7(1):372
ABSTRACT: One-dimensional pure zinc oxide (ZnO) and Y-doped ZnO nanorod arrays have been successfully fabricated on the silicon substrate for comparison by a simple hydrothermal process at the low temperature of 90°C. The Y-doped nanorods exhibit the same c-axis-oriented wurtzite hexagonal structure as pure ZnO nanorods. Based on the results of photoluminescence, an enhancement of defect-induced green-yellow visible emission is observed for the Y-doped ZnO nanorods. The decrease of E2(H) mode intensity and increase of E1(LO) mode intensity examined by the Raman spectrum also indicate the increase of defects for the Y-doped ZnO nanorods. As compared to pure ZnO nanorods, Y-doped ZnO nanorods show a remarked increase of saturation magnetization. The combination of visible photoluminescence and ferromagnetism measurement results indicates the increase of oxygen defects due to the Y doping which plays a crucial role in the optical and magnetic performances of the ZnO nanorods. 相似文献
11.
Dye-sensitized solar cells based on electrodeposited ZnO nanorod arrays were fabricated and tested. Field-emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) were used to identify the characters of ZnO nanorod arrays. The effects of dye etching on the morphology and performance of ZnO nanorod dye-sensitized solar cells were studied. It was found that the surfaces of ZnO nanorods were both etched by dye solutions, no matter N3 or N719. Compared with N3, N719 had a larger damage to the structure of ZnO nanorod photoanode, and the photoelectric conversion efficiency of cells decreased quickly with the sensitizing time increasing. In a certain range, the increasing length of ZnO nanorods can clearly improve the photoelectric conversion efficiency of cells. 相似文献
12.
A hybrid technique for the selective growth of ZnO nanorod arrays on wanted areas of thin cover glass substrates was developed
without the use of seed layer of ZnO. This method utilizes electron-beam lithography for pattern transfer on seedless substrate,
followed by solution method for the bottom-up growth of ZnO nanorod arrays on the patterned substrates. The arrays of highly
crystalline ZnO nanorods having diameter of 60 ± 10 nm and length of 750 ± 50 nm were selectively grown on different shape
patterns and exhibited a remarkable uniformity in terms of diameter, length, and density. The room temperature cathodluminescence
measurements showed a strong ultraviolet emission at 381 nm and broad visible emission at 585–610 nm were observed in the
spectrum. 相似文献
13.
Large-scale and highly oriented ZnO nanotube arrays are synthesized on transparent conductive glass substrates by a two-step route. First, ZnO nanorod arrays were prepared by electrochemical deposition from an aqueous solution of zinc nitrate. Then, hollow ZnO nanotubes were obtained by the selective dissolution of the electrodeposited ZnO nanorods in potassium hydroxide solution. Field emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) have been used to characterize the morphology and structure of the derived products. The effect of the concentration of alkali, dissolution time, and temperature on the formation process and morphologies of ZnO nanotube arrays has been discussed. 相似文献
14.
Jian-Hong Lee Min-Hsiung Hon Yi-Wen Chung Ing-Chi Leu 《Journal of the American Ceramic Society》2009,92(10):2192-2196
This paper describes a simple method for preparing well-aligned ZnO nanorod arrays in a more tunable fashion, which enables the synthesis of nanorods directly in various patterns and the easy control of the array density. This method is based on a combination of the microcontact printing process for patterning and a solution approach for depositing ZnO nanorods. The growth behavior between the contact and noncontact areas is investigated. Different formation mechanisms are proposed, and it is found that the key difference between nanorod and microrod forms was the ZnO seed layer and the van der Waals force at specific conditions. The role of self-assembled monolayers of octadecyl-trichloro-silane in the reaction solution is also discussed. Wettability of the surfaces is assessed by measuring the water contact angle, and the results show significant variation with surface morphology, from 17.6° to 123.6°. The lowest turn-on applied field strength is 4.65 V/μm at the current density of 10 μA/cm2 , which is achieved by the lowest array density of nanorods. The field-emission characteristics of the nanorods are found to be highly reproducible. The results could be valuable for the application of field-emission-based devices using ZnO nanorod arrays as cathode materials. 相似文献
15.
16.
We reported the enhancement of the structural and optical properties of electrochemically synthesized zinc oxide [ZnO] nanorod
arrays [NRAs] using the multi-walled carbon nanotube [MWCNT]-composed seed layers, which were formed by spin-coating the aqueous
seed solution containing MWCNTs on the indium tin oxide-coated glass substrate. The MWCNT-composed seed layer served as the
efficient nucleation surface as well as the film with better electrical conductivity, thus leading to a more uniform high-density
ZnO NRAs with an improved crystal quality during the electrochemical deposition process. For ZnO NRAs grown on the seed layer
containing MWCNTs (2 wt.%), the photoluminescence peak intensity of the near-band-edge emission at a wavelength of approximately
375 nm was enhanced by 2.8 times compared with that of the ZnO nanorods grown without the seed layer due to the high crystallinity
of ZnO NRAs and the surface plasmon-meditated emission enhancement by MWCNTs. The effect of the MWCNT-composed seed layer
on the surface wettability was also investigated. 相似文献
17.
In this study, a simple thick‐film humidity sensor was fabricated by coating wet‐synthesized ZnO nanorods on screen‐printing interdigitated electrodes. We investigated the influence of the coating procedure on the microstructure of ZnO nanorod films and thereby on humidity sensing. The experimental results revealed that the specific surface area (SSA) decreased and the average pore size (APS) increased with increasing the sintering time and the number of coating layer. The humidity response depended significantly on the pore properties of the ZnO nanorod films. By virtue of the incipient wetness analysis, it was found that the adsorption of water molecules on the ZnO surface led to the decrease in electrical resistance even though the ZnO was rod like, n‐type semiconductor. While tuning the pore structure of the ZnO nanorod film, the thick‐film humidity sensor might display near‐linear response in the full range of 0%–100% relative humidity (RH). 相似文献
18.
Zinc oxide (ZnO) nanorods were vertically grown on the surface of graphene sheets by chemical vapor deposition, and their use in a field emission device was demonstrated. In comparison with pristine graphene, the graphene/ZnO nanorod hybrid structure exhibited efficient field emission with low turn-on field, low threshold field, high emission spot density, high field enhancement factor and excellent emitting stability. It is proposed that the introduction of mid-density ZnO nanorods on the surface of graphene sheets can increase the number of emitters, enhance tunneling probability, and lead to optimized field emission for the hybrid emitters. The results showed that the field emission properties of graphene can be tailored by growing various ZnO nanostructures on its surface. 相似文献
19.
ZnO nanorod arrays are prepared on a silicon wafer through a multi-step hydrothermal process. The aspect ratios and densities
of the ZnO nanorod arrays are controlled by adjusting the reaction times and concentrations of solution. The investigation
of field emission properties of ZnO nanorod arrays revealed a strong dependency on the aspect ratio and their density. The
aspect ratio and spacing of ZnO nanorod arrays are 39 and 167 nm (sample C), respectively, to exhibit the best field emission
properties. The turn-on field and threshold field of the nanorod arrays are 3.83 V/μm and 5.65 V/μm, respectively. Importantly,
the sample C shows a highest enhancement of factor β, which is 2612. The result shows that an optimum density and aspect ratio of ZnO nanorod arrays have high efficiency of field
emission. 相似文献
20.
J. Volk T. Nagata R. Erdélyi I. Bársony A. L. Tóth I. E. Lukács Zs. Czigány H. Tomimoto Y. Shingaya T. Chikyow 《Nanoscale research letters》2009,4(7):699-704
Highly uniform and c-axis-aligned ZnO nanorod arrays were fabricated in predefined patterns by a low temperature homoepitaxial
aqueous chemical method. The nucleation seed patterns were realized in polymer and in metal thin films, resulting in, all-ZnO
and bottom-contacted structures, respectively. Both of them show excellent geometrical uniformity: the cross-sectional uniformity
according to the scanning electron micrographs across the array is lower than 2%. The diameter of the hexagonal prism-shaped
nanorods can be set in the range of 90–170 nm while their typical length achievable is 0.5–2.3 μm. The effect of the surface
polarity was also examined, however, no significant difference was found between the arrays grown on Zn-terminated and on
O-terminated face of the ZnO single crystal. The transmission electron microscopy observation revealed the single crystalline
nature of the nanorods. The current–voltage characteristics taken on an individual nanorod contacted by a Au-coated atomic
force microscope tip reflected Schottky-type behavior. The geometrical uniformity, the designable pattern, and the electrical
properties make the presented nanorod arrays ideal candidates to be used in ZnO-based DC nanogenerator and in next-generation
integrated piezoelectric nano-electromechanical systems (NEMS). 相似文献