共查询到20条相似文献,搜索用时 31 毫秒
1.
P. Zhang H. Qi X. Zhang Q. Zhao Y. Tian D. Yu 《Applied Physics A: Materials Science & Processing》2006,84(1-2):165-169
Novel lotiform ZnO nanostructures were synthesized on silicon substrate via simple thermal evaporation. The average diameter of the ZnO nanostructures is ∼1.5 μm. The lotiform-like ZnO structures were formed by nanorods arrays with the average diameter of 70 nm. The as-grown lotiform ZnO nanostructures have excellent field-emission properties such as the low turn-on field of 3.4 V/μm, and very high emission current density of 12.4 mA/cm2 at the field of 9.6 V/μm. These features make the lotiform-like ZnO nanostructures competitive candidates for field-emission-based displays. PACS 61.46.-w; 61.82.Rx; 78.67.-n; 73.63.Bd; 74.78.Na 相似文献
2.
W. Bai K. Yu Q. Zhang Y. Huang Q. Wang Z. Zhu N. Dai Y. Sun 《Applied Physics A: Materials Science & Processing》2007,87(4):755-759
ZnO nanorods with 30 nm-diameter ultra-thin pinheads and ultra-thin nanobelts were successfully synthesized using a thiourea
solution to etch nanorods and nancombs, which were obtained by a conventional thermal evaporation method. The materials obtained
were investigated by field emission scanning electron microscopy and energy-dispersive X-ray fluorescence. The data shows
that hydrogen ions play an important role in synthesizing ZnO nanorods with ultra-thin pinheads and ultra-thin nanobelts.
Field emission plots indicated that the turn-on field was reduced from 2.10 V/μm to 1.55 V/μm after thiourea solution treatment
at a current density of 0.1 μA/cm2. Room-temperature photoluminescence spectra from ZnO nanostructures showed the PL spectrum peaks shifted towards short wavelengths
with a large enhancement of UV bands compared with those of ZnO nanorods and nanocombs.
PACS 75.55.Gs; 61.46.-w; 81.40.Wx; 78.55.-m; 78.60.Fi 相似文献
3.
X. Lu Q. Yang C. Xiao A. Hirose 《Applied Physics A: Materials Science & Processing》2006,82(2):293-296
Diamond nanocone, graphitic nanocone, and mixed diamond and graphitic nanocone films have been synthesized through plasma
enhanced hot filament chemical vapor deposition (HFCVD). The field emission properties of these films have been experimentally
investigated. The studies have revealed that all three kinds of nanocone films have excellent field electron emission (FEE)
properties including low turn-on electric field and large emission current at low electric field. Compared with the diamond
nanocone films (emission current of 86 μA at 26 V/μm with the turn-on field of 10 V/μm), the graphitic nanocone films exhibit
higher FEE current of 1.8×102 μA at 13 V/μm and a lower turn-on filed of 4 V/μm. The mixed diamond and graphitic nanocone films have been found to posses
FEE properties similar to graphitic nanocone films (emission current of 1.7×102 μA at 20 V/μm with the turn-on field of 5 V/μm), but have much better FEE stability than the graphitic nanocone films.
PACS 81.07.Bc; 81.05.Uw; 79.70.+q 相似文献
4.
D. K. T. Ng M. H. Hong L. S. Tan Y. W. Zhu C. H. Sow 《Applied Physics A: Materials Science & Processing》2008,93(3):685-689
Patterned gallium nitride nanowires and nanodots have been grown on n-Si (100) substrates by pulsed laser deposition. The
nanostructures are patterned using a physical mask, resulting in regions of nanowire growth of different densities. The field
emission (FE) characteristics of the patterned gallium nitride nanowires show a turn-on field of 9.06 V/μm to achieve a current
density of 0.01 mA/cm2 and an enhanced field emission current density as high as 0.156 mA/cm2 at an applied field of 11 V/μm. Comparing the peak FE current densities of both the nanowires and nanodots, the peak FE current
density of nanowires is around 700 times higher than that of the peak FE current density of nanodots since nanodots have a
lower aspect ratio compared to nanowires. The field emission results indicate that, besides density difference, crystalline
quality as well as the low electron affinity of gallium nitride, high aspect ratio of gallium nitride nanostructures will
greatly enhance their field emission properties. 相似文献
5.
Field-electron emission from polyimide-ablated films 总被引:1,自引:0,他引:1
H. Ma L. Zhang N. Yao Z. Bi B. Zhang H. Hu 《Applied Physics A: Materials Science & Processing》2000,71(3):281-284
Polyimide-ablated film was deposited by using pulsed laser ablation of a polyimide target, and field-electron emission from
the film was observed for the first time. The turn-on field of the polyimide-ablated film is 12 V/μm. The current density
is 0.725 mA/cm2, and the emission sites density is on the order of 106/cm2 at the applied field of 24 V/μm. The field-electron emission measurements indicate that this kind of film could be a new
cold cathode material. It is suggested that the graphite-like clusters contained in the film play an important role in the
field-electron emission.
Received: 2 February 2000 / Accepted: 13 March 2000 / Published online: 9 August 2000 相似文献
6.
Jong-Hyun Lee Parlindungan Yonathan Hyun-Tae Kim Dang-Hyok Yoon Jaemyung Kim 《Applied Physics A: Materials Science & Processing》2008,93(2):511-516
The field emission properties of multi-walled carbon nanotubes were examined using a screen-printed thick film with a diode-type
configuration in a vacuum. The effects of various concentrations of two different ceramic fillers, indium tin oxide (ITO)
powder and a glass frit, on the emission current density and turn-on field were evaluated. The emission properties of both
pastes were dependent on the amount of filler. Considerably enhanced emission properties were obtained with the paste containing
5–10 wt.% of either ITO or the glass frit compared with those without a filler. The paste containing the ceramic filler showed
enhanced emission properties compared with that containing the 5 wt.% Ag conventionally used, which confirmed the importance
of the filler. The paste containing 10 wt.% ITO represented an emission current density of 176.4 μA/cm2 at 5 V/μA, a turn-on field of 1.87 V/μA for an emission current density of 1 μA/cm2 and a field enhancement factor of 7580. The paste formulation was also found to be suitable for fine patterning using UV-lithography
techniques. A long-term stability test for 110 h of a paste containing 10 wt.% ITO revealed a half-life of approximately 30000 h,
which is appropriate for commercial applications. 相似文献
7.
Dattatray J. Late Ranjit V. Kashid Chandra Sekhar?Rout Mahendra A. More Dilip S. Joag 《Applied Physics A: Materials Science & Processing》2010,98(4):751-756
Field emission studies of WO2.72 nanowires synthesized by a solvothermal method have been performed in the planar diode configuration under ultra high vacuum
conditions. Fowler–Nordheim plots obtained from the current-voltage characteristics follow the quantum mechanical tunneling
process and a current density of ∼8.3×106 μA/cm2 can be drawn at an applied electric field of 2 V/μm. The field enhancement factor is 33025, while the turn-on field is only
1.4 V/μm. The emission current-time plot recorded at the pre-set value of emission current of 1 μA over a period of more than
3 h exhibits an initial increase and a subsequent stabilization of the emission current. The results reveal that the WO2.72 nanowire emitters synthesized by the solvothermal method are promising cathode materials for practical applications. 相似文献
8.
ZnO nanorods with different morphologies were grown by changing the temperature of the process using the thermal vapor deposition method without a catalyst. The X-ray diffraction pattern of these nanorods showed a single-crystalline wurtzite structure and a c-axis orientation. The turn-on fields of the pencil-like and normal ZnO nanorods were 1.7 V/μm and 2.2 V/μm at a current density of 0.1 μA/cm2, and the emission current density from the ZnO nanorods reached 1 mA/cm2 at bias fields of 5.1 V/μm and 7.5 V/μm, respectively. The results indicated that ZnO nanorods could give sufficient brightness as a field emitter in a flat panel display. 相似文献
9.
Field emission from single-walled carbon nanotubes (SWNTs) aligned on a patterned gold surface is reported. The SWNT emitters
were prepared at room temperature by a self-assembly monolayer technique. SWNTs were cut into sub-micron lengths by sonication
in an acidic solution. Cut SWNTs were attached to the gold surface by the reaction between the thiol groups and the gold surface.
The field-emission measurements showed that the turn-on field was 4.8 V/μm at an emission current density of 10 μA/cm2. The current density was 0.5 mA/cm2 at 6.6 V/μm. This approach provides a novel route for fabricating CNT-based field-emission displays.
Received: 3 May 2002 / Accepted: 6 May 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +82-54/279-8298, E-mail: ce20047@postech.ac.kr 相似文献
10.
Single-crystalline, pyramidal zinc oxide nanorods have been synthesized in a large quantity on p-Si substrate via catalyst-free thermal chemical vapor deposition at low temperature. SEM investigations showed that the nanorods were vertically aligned on the substrate, with diameters ranging from 60 to 80 nm and lengths about 1.5 μm. A self-catalysis VLS growth mechanism was proposed for the formation of the ZnO nanorods. The field emission properties of the ZnO nanopyramid arrays were investigated. A turn-on field about 3.8 V/μm was obtained at a current density of 10 μA/cm2, and the field emission data was analyzed by applying the Fowler-Nordheim theory. The stability of emission current density under a high voltage was also tested, indicating that the ZnO nanostructures are promising for an application such as field emission sources. 相似文献
11.
Vertically aligned ZnO nanorod arrays with different aspect ratios were synthesized by hybrid wet chemical route. Modulation of the field emission properties (FE) with aspect ratio of ZnO nanorods was examined. With the increase in the aspect ratio, the emission current density increases from 0.02 to 8 μA/cm2 at 7.0 V/μm. Turn-on voltage was seen to decrease from 9.6 to 7 V/μm at a current density of 10 μA/cm2 with the increase in aspect ratio in the ZnO films. The interrelation between the FE characteristics (emission thresholds, current density, surface uniformity, etc.) and microstructure of the ZnO nanostructure obtained from scanning electron microscopy (SEM) and atomic force microscopy (AFM) was discussed. Quality of the ZnO nanorods was also examined by using Raman spectroscopy and Fourier transformed infrared spectroscopy (FTIR). It was found that the observed enhancements of FE characteristics could mainly be attributed to the increase in aspect ratio and associated number density of ZnO nanorods. 相似文献
12.
Jing Xiao Yue Wu Wei Zhang Xin Bai Ligang Yu Shiqi Li Gengmin Zhang 《Applied Surface Science》2008,254(17):5426-5430
Zinc oxide nanopencil arrays were synthesized on pyramidal Si(1 0 0) substrates via a simple thermal evaporation method. Their field emission properties have been investigated: the turn-on electric field (at the current density of 10 μA/cm2) was about 3.8 V/μm, and the threshold electric field (at the current density of 1 mA/cm2) was 5.8 V/μm. Compared with similar structures grown on flat Si substrates, which were made as references, the pyramidal Si-based ZnO nanopencil arrays appeared to be superior in field emission performance, thus the importance of the non-flat substrates has been accentuated. The pyramidal Si substrates could not only suppress the field screening effect but also improve the field enhancement effect during the field emission process. These findings indicated that using non-flat substrates is an efficient strategy to improve the field emission properties. 相似文献
13.
Pradip Ghosh T. Soga M. Tanemura M. Zamri T. Jimbo R. Katoh K. Sumiyama 《Applied Physics A: Materials Science & Processing》2009,94(1):51-56
Vertically aligned carbon nanotubes have been synthesized from botanical hydrocarbons: Turpentine oil and Eucalyptus oil on
Si(100) substrate using Fe catalyst by simple spray pyrolysis method at 700°C and at atmospheric pressure. The as-grown carbon
nanotubes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution
TEM (HRTEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Raman spectroscopy. It was observed
that nanotubes grown from turpentine oil have better degree of graphitization and field emission performance than eucalyptus
oil grown carbon nanotubes. The turpentine oil and eucalyptus oil grown carbon nanotubes indicated that the turn-on field
of about 1.7 and 1.93 V/μm, respectively, at 10 μA/cm2. The threshold field was observed to be about 2.13 and 2.9 V/μm at 1 mA/cm2 of nanotubes grown from turpentine oil and eucalyptus oil respectively. Moreover, turpentine oil grown carbon nanotubes show
higher current density in relative to eucalyptus oil grown carbon nanotubes. The maximum current density of 15.3 mA/cm2 was obtained for ∼3 V/μm corresponding to the nanotubes grown from turpentine oil. The improved field emission performance
was attributed to the enhanced crystallinity, fewer defects, and greater length of turpentine oil grown carbon nanotubes. 相似文献
14.
R. B. Rakhi X. Lim X. Gao Y. Wang A. T. S. Wee K. Sethupathi S. Ramaprabhu C. H. Sow 《Applied Physics A: Materials Science & Processing》2010,98(1):195-202
The present work describes the field emission characteristics of nanoscale magnetic nanomaterial encapsulated multi-walled
carbon nanotubes (MWNTs) fabricated over flexible graphitized carbon cloth. Ni/MWNTs, NiFe/MWNTs and NiFeCo/MWNTs have been
synthesized by catalytic chemical vapor decomposition of methane over Mischmetal (Mm)-based AB3 (MmNi3, MmFe1.5Ni1.5 and MmFeCoNi) alloy hydride catalysts. Metal-encapsulated MWNTs exhibited superior field emission performance than pure MWNT-based
field emitters over the same substrate. The results indicate that a Ni-filled MWNT field emitter is a promising material for
practical field emission application with a lowest turn-on field of 0.6 V/μm and a high emission current density of 0.3 mA/cm2 at 0.9 V/μm. 相似文献
15.
Enhanced field emission from pulsed laser deposited nanocrystalline ZnO thin films on Re and W 总被引:1,自引:0,他引:1
Dattatray J. Late Pankaj Misra B. N. Singh Lalit M. Kukreja Dilip S. Joag Mahendra A. More 《Applied Physics A: Materials Science & Processing》2009,95(2):613-620
Nanocrystalline ZnO thin films have been deposited on rhenium and tungsten pointed and flat substrates by pulsed laser deposition
method. An emission current of 1 nA with an onset voltage of 120 V was observed repeatedly and maximum current density ∼1.3 A/cm2 and 9.3 mA/cm2 has been drawn from ZnO/Re and ZnO/W pointed emitters at an applied voltage of 12.8 and 14 kV, respectively. In case of planar
emitters (ZnO deposited on flat substrates), the onset field required to draw 1 nA emission current is observed to be 0.87
and 1.2 V/μm for ZnO/Re and ZnO/W planar emitters, respectively. The Fowler–Nordheim plots of both the emitters show nonlinear
behaviour, typical for a semiconducting field emitter. The field enhancement factor β is estimated to be ∼2.15×105 cm−1 and 2.16×105 cm−1 for pointed and 3.2×104 and 1.74×104 for planar ZnO/Re and ZnO/W emitters, respectively. The high value of β factor suggests that the emission is from the nanometric features of the emitter surface. The emission current–time plots
exhibit good stability of emission current over a period of more than three hours. The post field emission surface morphology
studies show no significant deterioration of the emitter surface indicating that the ZnO thin film has a very strong adherence
to both the substrates and exhibits a remarkable structural stability against high-field-induced mechanical stresses and ion
bombardment. The results reveal that PLD offers unprecedented advantages in fabricating the ZnO field emitters for practical
applications in field-emission-based electron sources. 相似文献
16.
D. Golberg P.S. Dorozhkin Y. Bando Z.-C. Dong C.C. Tang Y. Uemura N. Grobert M. Reyes-Reyes H. Terrones M. Terrones 《Applied Physics A: Materials Science & Processing》2003,76(4):499-507
Transport and field-emission properties of as-synthesized CNx and BNCx (x<0.1) multi-walled nanotubes were compared in detail. Individual ropes made of these nanotubes and macrofilms of those
were tested. Before measurements, the nanotubes were thoroughly characterized using high-resolution and energy-filtered electron
microscopy, electron diffraction and electron-energy-loss spectroscopy. Individual ropes composed of dozens of CNx nanotubes displayed well-defined metallic behavior and low resistivities of ∼10–100 kΩ or less at room temperature, whereas
those made of BNCx nanotubes exhibited semiconducting properties and high resistivities of ∼50–300 MΩ. Both types of ropes revealed good field-emission
properties with emitting currents per rope reaching ∼4 μA(CNx) and ∼2 μA (BNCx), albeit the latter ropes se- verely deteriorated during the field emission. Macrofilms made of randomly oriented CNx or BNCx nanotubes displayed low and similar turn-on fields of ∼2–3 V/μm. 3 mA/cm2 (BNCx) and 5.5 mA/cm2 (CNx) current densities were reached at 5.5 V/μm macroscopic fields. At a current density of 0.2–0.4 mA/cm2 both types of compound nanotubes exhibited equally good emission stability over tens of minutes; by contrast, on increasing
the current density to 0.2–0.4 A/cm2, only CNx films continued to emit steadily, while the field emission from BNCx nanotube films was prone to fast degradation within several tens of seconds, likely due to arcing and/or resistive heating.
Received: 29 October 2002 / Accepted: 1 November 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +81-298/51-6280, E-mail: golberg.dmitri@nims.go.jp 相似文献
17.
Electrochemical synthesis of Cu/ZnO nanocomposite films and their efficient field emission behaviour
The Cu/ZnO nanocomposite films have been synthesized by cathodic electrodeposition and characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL) and field emission microscope (FEM). The XRD pattern shows a set of well defined diffraction peaks, which could be indexed to the wurtzite hexagonal phase of ZnO. In addition, characteristic diffraction peaks corresponding to Cu and Zn are also observed. The SEM image shows formation of two-dimensional (2D) hexagonal sheets randomly distributed and aligned almost normal to the substrate. Uniformly distributed small clusters of Cu nanoparticles possessing average diameter of ∼25 nm, as revealed from the TEM image, are seen to be present on these 2D ZnO sheets. The selected area electron diffraction (SAED) image confirms the nanocrystalline nature of the Cu particles. From the field emission studies, carried out at the base pressure of ∼1 × 10−8 mbar, the turn-on field required for an emission current density of 0.1 μA/cm2 is found to be 1.56 V/μm and emission current density of ∼100 μA/cm2 has been drawn at an applied field of 3.12 V/μm. The Cu/ZnO nanocomposite film exhibits good emission current stability at the pre-set value of ∼10 μA over a duration of 5 h. The simplicity of the synthesis route coupled with the better emission properties propose the electrochemically synthesized Cu/ZnO nanocomposite film emitter as a promising electron source for high current density applications. 相似文献
18.
Liang Xu Shuankui Li Zhiguo Wu Huajun Li De Yan Chunyu Zhang Pengju Zhang Pengxun Yan Xudong Li 《Applied Physics A: Materials Science & Processing》2011,103(1):59-65
Nanotip arrays of amorphous carbon with embedded hexagonal diamond nanoparticles were prepared at room temperature for use
as excellent field emitters by a unique combination of anodic aluminum oxide (AAO) template and filtered cathodic arc plasma
(FCAP) technology. In order to avoid nanopore array formation on the AAO surface, an effective multi-step treatment employing
anodization and pore-widening processes alternately was adopted. The nanotips were about 100 nm in width at the bottom and
150 nm in height with density up to 1010 cm−2. Transmission electron microscopy investigation indicates that many nanoparticles with diameters of about 10 nm were embedded
in the amorphous carbon matrix, which was proved to be hexagonal diamond phase by Raman spectrum and selected-area electron
diffraction. There is no previous literature report on the field emission properties of hexagonal diamond and its preparation
at room temperature under high-vacuum condition. The nanotip arrays with hexagonal diamond phase exhibit a low turn-on field
of 0.5 V/μm and a threshold field of 3.5 V/μm at 10 mA/cm2. It is believed that the existence of hexagonal diamond phase has improved the field emission properties. 相似文献
19.
Field emission in diamond and graphite-like polycrystalline films is investigated experimentally. It is shown that the emission
efficiency increases as the nondiamond carbon phase increases; for graphite-like films the threshold electric field is less
than 1.5 V/μm, and at 4 V/μm the emission current reaches 1 mA/cm2, while the density of emission centers exceeds 106 cm−2. A general mechanism explaining the phenomenon of electron field emission from materials containing graphite-like carbon
is proposed.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 56–60 (10 July 1998) 相似文献
20.
利用水热法制备了垂直于衬底的定向生长的ZnO纳米棒,利用扫描电子显微镜及光致发光的方法对其形貌及光学特性进行了表征,利用场发射性能测试装置对ZnO纳米棒的场发射性能进行了测试.结果表明:利用水热法在较低的温度(95 ℃) 下生长了具有较好形貌和结构的ZnO纳米棒,并表现出了较好的场发射特性,当电流密度为1 μA/cm2时,开启电场是2.8 V/μm,当电场为6.4 V/μm时,电流密度可以达到0.67 mA/cm2,场增强因子为3360.稳定性测试表明,在5 h内,4.5 V/μm的电场下,其波动不超过25%.将制备的ZnO纳米棒应用到有机/无机电致发光中,其中ZnO纳米棒为电子传输层,m-MTDATA(4,4',4″-tris{N,(3-methylphenyl)-N-phenylamino}-triphenylamine) 为空穴传输层,得到了ZnO的342 nm的紫外电致发光,此发光较ZnO纳米棒光致发光的紫外发射有约40 nm的蓝移.
关键词:
ZnO纳米棒
场发射
水热法
有机/无机复合电致发光 相似文献