共查询到19条相似文献,搜索用时 250 毫秒
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ZnO纳米线的气相沉积制备及场发射特性 总被引:3,自引:0,他引:3
运用气相沉积方法分别在硅片表面和钨针尖上制备了非取向生长的ZnO纳米线,并通过场发射显微镜研究了纳米线样品的平面场发射特性和针尖场发射特性.结果显示,非取向生长的ZnO纳米线薄膜场发射的开启电压和阈值电压所对应的场强分别为4.7和7.6V/μm,场增强因子达103量级,具有较阵列生长的ZnO纳米线更为优异的场发射能力.非取向生长ZnO纳米线薄膜场发射能力的增强归因于其所具有的稀疏结构避免了强场作用下屏蔽效应的产生,有效地提高了薄膜场发射的电流密度.将ZnO纳米线组装在钨针尖上能够明显地改善针尖的场发射性能,在超高分辨显微探针领域具有良好应用前景. 相似文献
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运用气相沉积方法分别在硅片表面和钨针尖上制备了非取向生长的ZnO纳米线,并通过场发射显微镜研究了纳米线样品的平面场发射特性和针尖场发射特性.结果显示,非取向生长的ZnO纳米线薄膜场发射的开启电压和阈值电压所对应的场强分别为4.7和7.6V/μm,场增强因子达103量级,具有较阵列生长的ZnO纳米线更为优异的场发射能力.非取向生长ZnO纳米线薄膜场发射能力的增强归因于其所具有的稀疏结构避免了强场作用下屏蔽效应的产生,有效地提高了薄膜场发射的电流密度.将ZnO纳米线组装在钨针尖上能够明显地改善针尖的场发射性能,在超高分辨显微探针领域具有良好应用前景. 相似文献
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采用水合肼还原硝酸铜的方法制备了高长径比铜纳米线,在此基础上,通过导电双面胶带将铜纳米线转移至阴极表面,基于二板场发射器件结构研究了铜纳米线的场发射特性.结果表明:铜纳米线是一种优良的场发射冷阴极材料,其开启场强为2.18 V/μm,阈值场强为3.69 V/μm,经过2h老练后具有良好的发射稳定性. 相似文献
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采用水合肼还原硝酸铜的方法制备了高长径比铜纳米线,在此基础上,通过导电双面胶带将铜纳米线转移至阴极表面,基于二极场发射器件结构研究了铜纳米线的场发射特性。结果表明:铜纳米线是一种优良的场发射冷阴极材料,其开启场强为2.18 V/μm,阈值场强为3.69 V/μm,经过2 h老练后具有良好的发射稳定性。 相似文献
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通过简单的热蒸发在ITO电极上合成图形化氧化锌纳米线,利用SEM,XRD,EDX和PL光谱分析氧化锌纳米线的表面形貌、微观结构和光学特性,并测试其场发射性能。SEM表明,ZnO纳米线的直径约为100-200nm,长度大于5um,且均匀长在ITO电极表面。场发射测试表明,图形化ZnO纳米线的开启电场和阈值电场分别为1.6 V/m和4.92 V/m,在电场强度为5.38 V/m时发射电流高达 2.26 mA/cm2,经4.5h场发射测试后发射电流的浮动低于5%。低的开启电场、高的发射电流和好的稳定性表明图形化氧化锌纳米线是一种应用前景广阔的场发射材料。 相似文献
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通过改变溅射功率以磁控溅射法制备了Cu/Cr合金催化剂,研究了化学气相沉积法制备的碳纳米管(CNTs)作为大电流密度场发射阴极的场发射性能。采用扫描电镜和场发射测试仪分别对不同功率催化剂制备的CNTs进行了形貌及性能分析。结果表明,根据溅射功率与催化剂颗粒的关系,可以通过调节溅射功率改变CNTs的长径比及密度,在250WCu/Cr催化剂制备的CNTs薄膜具备了良好的场发射性能,阴极电子发射的开启电场仅为1.47V/μm,当电场为3.23V/μm,发射电流密度可高达3259μA/cm2。 相似文献
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为了减小场发射的屏蔽效应,采用图形化技术对氧化锌(ZnO)纳米枝阵列进行调控,并研究图形化ZnO枝阵列的性能。首先采用光刻法在ITO导电玻璃上制备图形化ZnO种子层,再用电沉积法在图形化种子层上生长ZnO纳米枝阵列。利用扫描电子显微镜(SEM)、X射线衍射(XRD)研究所制备的图形化ZnO阵列形貌、结构等,并测试其场发射性能。研究结果表明,制备的图形化ZnO纳米枝是圆阵列,直径为330μm左右,纳米ZnO主干平均直径为400~500nm,发现主干上有一些精细的类似锥状的纳米量级微细枝结构,并且具有良好的场发射性能,开启场强为2.15V/μm,场增强因子为16 109。该图形化生长ZnO阵列阴极的方法是一种能较好改善材料场发射性能的方法,在场发射应用领域表现出较好的前景。 相似文献
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基于HCl辅助热蒸发GaN粉末的方法制备了纯净的一维GaN纳米线垂直阵列,重点研究了不同生长时间对应不同形貌的GaN纳米结构的电子场发射性能,以及氨气氛围下热退火对GaN纳米线阵列场发射性能的影响,并分析了其影响机理.通过对生长时间分别为20 min,60 min(未退火处理)与60 min(退火处理)的三组样品进行对比,结果显示:生长时间为60 min(未退火处理)的样品,电流密度达到1μA/cm2时的开启电场的值为2.1 V/μm,且获得1 mA/cm2的阈值电流密度也只需要4.5 V/μm的电场. 相似文献
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为寻找替代硬质氧化铟锡的新型柔性透明导电薄膜,采用液相还原法制备了大长径比的铜纳米线,并利用喷涂法实现铜纳米线柔性透明导电薄膜的制备。采用透射电子显微镜、扫描电子显微镜、X射线衍射仪对形貌和相结构进行了分析,并用紫外可见分光光度计和四探针测试仪分别对铜纳米线柔性透明导电薄膜的电学性能和光学性能进行了表征测试。结果表明,铜纳米线直径约为40 nm,长度为10~20μm,具有高长径比、分散性好、形貌规整的特点。同时,铜纳米线薄膜的电学和光学性能优异,方阻约为100Ω/,在550 nm处的光透射率为82%左右。该薄膜还具有较好的温度稳定性,耐温可达110℃,且其方阻在不同弯折程度下变化不大,具有良好的抗弯折性,可用于柔性可穿戴电子产品。 相似文献
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Enling Li Sha Song Deming Ma Nannan Fu Yulong Zhang 《Journal of Electronic Materials》2014,43(5):1379-1383
Helical gallium nitride nanowires were synthesized by chemical vapor deposition using a Pt catalyst. The prepared helical GaN nanowires with a single-crystalline hexagonal wurtzite structure have a coil diameter of 150–280 nm and lengths of up to tens of micrometers. The helical GaN nanowires have six equivalent 〈0 $ \bar{1} $ 11〉 growth directions along the [0001] axis. Field emission measurements show that helical GaN nanowire sheets possess excellent field emission properties, with a low turn-on field of ~4.5 V/μm and a high field enhancement factor of ~2,751. It is believed that this material’s excellent electron emission behavior can be attributed to its unique three-dimensional spiral structure. The growth mechanism of helical GaN nanowires has also been analyzed. 相似文献
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B. Varghese C. H. Teo Y. Zhu M. V. Reddy B. V. R. Chowdari A. T. S. Wee V. B. C. Tan C. T. Lim C.‐H. Sow 《Advanced functional materials》2007,17(12):1932-1939
We report an efficient method to synthesize vertically aligned Co3O4 nanostructures on the surface of cobalt foils. This synthesis is accomplished by simply heating the cobalt foils in the presence of oxygen gas. The resultant morphologies of the nanostructures can be tailored to be either one‐dimensional nanowires or two‐dimensional nanowalls by controlling the reactivity and the diffusion rate of the oxygen species during the growth process. A possible growth mechanism governing the formation of such nanostructures is discussed. The field‐emission properties of the as‐synthesized nanostructures are investigated in detail. The turn‐on field was determined to be 6.4 and 7.7 V μm–1 for nanowires and nanowalls, respectively. The nanowire samples show superior field‐emission characteristics with a lower turn‐on field and higher current density because of their sharp tip geometry and high aspect ratio. 相似文献
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Y.‐K. Tseng C.‐J. Huang H.‐M. Cheng I.‐N. Lin K.‐S. Liu I.‐C. Chen 《Advanced functional materials》2003,13(10):811-814
Needle‐like ZnO nanowires with high density are grown uniformly and vertically over an entire Ga‐doped conductive ZnO film at 550 °C. The nanowires are grown preferentially in the c‐axis direction. The X‐ray diffraction (XRD) θ‐scan curve shows a full width at half maximum (FWHM) value of 2°. This indicates that the c‐axes of the nanorods are along the normal direction of the substrate surface. The investigation using high‐resolution transmission electron microscopy (HRTEM) confirmed that each nanowire is a single crystal. A room‐temperature photoluminescence (PL) spectrum of the wires consists of a strong and sharp UV emission band at 380 nm and a weak and broad green–yellow band. It reveals a low concentration of oxygen vacancies in the ZnO nanowires and their high optical quality. Field electron emission from the wires was also investigated. The turn‐on field for the ZnO nanowires was found to be about 18 V μm–1 at a current density of 0.01 μA cm–2. The emission current density from the ZnO nanowires reached 0.1 mA cm–2 at a bias field of 24 V μm–1. 相似文献
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Mohammed Riaz Jinhui Song Omer Nur Zhong Lin Wang Magnus Willander 《Advanced functional materials》2011,21(4):628-633
The piezoelectric power generation from ZnO nanowire arrays grown on different substrates using different methods is investigated. ZnO nanowires were grown on n‐SiC and n‐Si substrates using both the high‐temperature vapor liquid solid (VLS) and the low‐temperature aqueous chemical growth (ACG) methods. A conductive atomic force microscope (AFM) is used in contact mode to deflect the ZnO nanowire arrays. No substrate effect was observed but the growth method, crystal quality, density, length, and diameter (aspect ratio) of the nanowires are found to affect the piezoelectric behavior. During the AFM scanning in contact mode without biasing voltage, the ZnO nanowire arrays grown by the VLS method produced higher and larger output voltage signal of 35 mV compared to those grown by the ACG method, which produce smaller output voltage signal of only 5 mV. The finite element (FE) method was used to investigate the output voltage for different aspect ratio of the ZnO nanowires. From the FE results it was found that the output voltage increases as the aspect ratio increases and starts to decreases above an aspect ratio of 80 for ZnO nanowires. 相似文献
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We present low cost hydrothermally deposited uniform zinc oxide (ZnO) nanorods with high haze ratios for the a-Si thin film solar cells. The problem of low transmittance and conductivity of hydrothermally deposited ZnO nanorods was overcome by using RF magnetron sputtered aluminum doped zinc oxide (ZnO:Al ~300 nm) films as a seed layer. The length and diameters of the ZnO nanorods were controlled by varying growth times from 1 to 4 h. The length of the ZnO nanorods was varied from 1 to 1.5 µm, while the diameter was kept larger than 300 nm to obtain various aspect ratios. The uniform ZnO nanorods showed higher transmittance (~89.07%) and haze ratio in the visible wavelength region. We also observed that the large diameters (>300 nm) and average aspect ratio (3–4) of ZnO nanorods favored the light scattering in the longer wavelength region. Therefore, we proposed uniformly deposited ZnO nanorods with high haze ratio for the future low cost and large area amorphous silicon thin film solar cells. 相似文献
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Jung-Hyeon Park Hyung-Il Lee Heung-Sik Tae Jeung-Soo Huh Jung-Hee Lee 《Electron Devices, IEEE Transactions on》1997,44(6):1018-1021
Lateral field emission diodes were fabricated by using separation by implantation of oxygen (SIMOX) wafer and their current-voltage characteristics (I-V) were analyzed. Applying conventional photolithography and local oxidation of silicon (LOGOS) process, we fabricated single-crystalline lateral silicon field emitters with very sharp cathode and anode tips and very short cathode to anode spacing ranging from 0.3 to 0.8 μm as well. Two different types of tips, tapered and wedge-shaped emitters, were typically formed according to oxidation time. The turn-on voltages for both types of diodes were as low as 22~25 V and the emission currents were as high as 6 μA/tip at voltages of 35~38 V. From the Fowler-Nordheim (FN) equation, field emitting area (A) and field enhancement factor (β) for both types of diodes were estimated to explain the low turn-on voltages and the high emission currents 相似文献
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Nanostructural ZnO is a good candidate for field emission (FE) because of its high aspect ratio, controllable electrical conductivity,
and good thermal and chemical stability. In order to improve the FE performance, ZnO nanopins, gallium-doped nanofibers, periodic
nanorod arrays, and aligned nanotubes were designed and fabricated by a vapor-phase transport method using ZnO + C and ZnO + C + Ga2O3 powder mixtures, electrochemical deposition, and hydrothermal decomposition, respectively. The FE behaviors including threshold
of electric field, emission current density, field enhancement factor, and stability are reviewed in this paper based on our
previous works. Some strategies to improve the performance of the nanostructural ZnO field emitters are demonstrated. 相似文献