共查询到20条相似文献,搜索用时 31 毫秒
1.
Yanfeng Zhang Teng Gao Shubao Xie Boya Dai Lei Fu Yabo Gao Yubin Chen Mengxi Liu Zhongfan Liu 《Nano Research》2012,5(6):402-411
Graphene growth on the same metal substrate with different crystal morphologies, such as single crystalline and polycrystalline,
may involve different mechanisms. We deal with this issue by preparing graphene on single crystal Ni(111) and on ∼300 nm thick
Ni films on SiO2 using an ambient pressure chemical vapor deposition (APCVD) method, and analyze the different growth behaviors for different
growth parameters by atomically-resolved scanning tunneling microscopy (STM) and complementary macroscopic analysis methods.
Interestingly, we obtained monolayer graphene on Ni(111), and multilayer graphene on Ni films under the same growth conditions.
Based on the experimental results, it is proposed that the graphene growth on Ni(111) is strongly templated by the Ni(111)
lattice due to the strong Ni-C interactions, leading to monolayer graphene growth. Multilayer graphene flakes formed on polycrystalline
Ni films are usually stacked with deviations from the Bernal stacking type and show small rotations among the carbon layers.
Considering the different substrate features, the inevitable grain boundaries on polycrystalline Ni films are considered to
serve as the growth fronts for bilayer and even multilayer graphene.
相似文献
2.
Two simple methods have been demonstrated to obtain large area, single crystalline lamellae of copper-7,7,8,8-tetracyanoquinodimethane
(CuTCNQ). The formation of the lamellae was a result of fine tuning of the processes during the synthesis processes of CuTCNQ
phase II. This facile synthesis of large area single crystalline lamellae suggests bright prospects for the study and understanding
of the electrical switching of CuTCNQ by using single crystals of its phase II, and future applications of the material in
memory and switching devices.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
3.
Synthesis of high magnetic moment CoFe nanoparticles via interfacial diffusion in core/shell structured Co/Fe nanoparticles 总被引:1,自引:0,他引:1
We report the synthesis of high magnetic moment CoFe nanoparticles via the diffusion of Co and Fe in core/shell structured
Co/Fe nanoparticles. In an organic solution, Co nanoparticles were coated with a layer of Fe to form a Co/Fe core/shell structure.
Further raising the solution temperature led to inter-diffusion of Co and Fe and formation of CoFe alloy nanoparticles. These
nanoparticles have high saturation magnetization of up to 192 emu/g CoFe and can be further stabilized by thermal annealing
at 600 °C.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
These two authors made an equal contribution to the work. 相似文献
4.
Bingzhi Liu Huihui Wang Wei Gu Le Zhou Zhaolong Chen Yufeng Nie Congwei Tan Haina Ci Nan Wei Lingzhi Cui Xuan Gao Jingyu Sun Yanfeng Zhang Zhongfan Liu 《Nano Research》2021,14(1):260-267
Growing high quality graphene films directly on glass by chemical vapor deposition(CVD)meets a growing demand for constructing high-performance electronic and optoelectronic devices.However,the graphene synthesized by prevailing methodologies is normally of polycrystalline nature with high nucleation density and limited domain size,which significantly handicaps its overall properties and device performances.Herein,we report an oxygen-assisted CVD strategy to allow the direct synthesis of 6-inch-scale graphene glass harvesting markedly increased graphene domain size(from 0.2 to 1.8μm).Significantly,as-produced graphene glass attains record high electrical conductivity(realizing a sheet resistance of 900Ω·sq-1at a visible-light transmittance of 92%)amongst the state-of-the-art counterparts,readily serving as transparent electrodes for fabricating high-performance optical filter devices.This work might open a new avenue for the scalable production and application of emerging graphene glass materials with high quality and low cost. 相似文献
5.
Wen Qian Rui Hao Yanglong Hou Yuan Tian Chengmin Shen Hongjun Gao Xuelei Liang 《Nano Research》2009,2(9):706-712
Monolayer and bilayer graphene sheets have been produced by a solvothermal-assisted exfoliation process in a highly polar
organic solvent, acetonitrile, using expanded graphite (EG) as the starting material. It is proposed that the dipole-induced
dipole interactions between graphene and acetonitrile facilitate the exfoliation and dispersion of graphene. The facile and
effective solvothermal-assisted exfoliation process raises the low yield of graphene reported in previous syntheses to 10
wt%–12 wt%. By means of centrifugation at 2000 rpm for 90 min, monolayer and bilayer graphene were separated effectively without
the need to add a stabilizer or modifier. Electron diffraction and Raman spectroscopy indicate that the resulting graphene
sheets are high quality products without any significant structural defects.
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6.
An individual suspended graphene sheet was connected to a scanning tunneling microscopy probe inside a transmission electron
microscope, and Joule heated to high temperatures. At high temperatures and under electron beam irradiation, the few-layer
graphene sheets were removed layer-by-layer in the viewing area until a monolayer graphene was formed. The layer-by-layer
peeling was initiated at vacancies in individual graphene layers. The vacancies expanded to form nanometer-sized holes, which
then grew along the perimeter and propagated to both the top and bottom layers of a bilayer graphene joined by a bilayer edge.
The layer-by-layer peeling was induced by atom sublimation caused by Joule heating and facilitated by atom displacement caused
by high-energy electron irradiation, and may be harnessed to control the layer thickness of graphene for device applications.
相似文献
7.
Various materials have been found to “catalyze” carbon nanotube growth in chemical vapor deposition (CVD) when they become
nano-sized particles. These involve not only metals, such as Pd, Pt, Au, Ag, and Cu, but also semiconductors, such as Si,
Ge, and SiC. Alumina and diamond nanoparticles also produce carbon nanotubes. These “catalysts”, which are better called “seeds”,
can be categorized into two types: one type forms a eutectic liquid or highly-mobile alloy with carbon, and carbon atoms precipitate
from the eutectic alloy; the other type remains as a solid phase and form a carbon surface layer during CVD growth. In this
paper, we review recent studies of SWCNT growth with these non-iron-group materials and highlight the mechanisms involved.
相似文献
8.
Christine H. Moran Sean M. Wainerdi Tonya K. Cherukuri Carter Kittrell Benjamin J. Wiley Nolan W. Nicholas Steven A. Curley John S. Kanzius Paul Cherukuri 《Nano Research》2009,2(5):400-405
Capacitively coupled shortwave radiofrequency fields (13.56 MHz) resistively heat low concentrations (∼1 ppm) of gold nanoparticles
with a thermal power dissipation of ∼380 kW/g of gold. Smaller diameter gold nanoparticles (< 50 nm) heat at nearly twice
the rate of larger diameter gold nanoparticles (≥50 nm), which is attributed to the higher resistivity of smaller gold nanostructures.
A Joule heating model has been developed to explain this phenomenon and provides critical insights into the rational design
and engineering of nanoscale materials for noninvasive thermal therapy of cancer.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
These two authors made an equal contribution to the work. 相似文献
9.
Tristan Rawling Christine E. Austin Dominic Hare Philip A. Doble Hadi M. Zareie Andrew M. McDonagh 《Nano Research》2009,2(9):678-687
Four new ruthenium phthalocyanine complexes bearing axial ligands with thioacetate groups that facilitate thin film formation
on gold surfaces are presented. Scanning tunnelling microscopy (STM) images and surface coverage data obtained by solution
inductively coupled plasma mass spectrometry (ICP-MS) experiments show that peripheral and axial ligand substituents on the
complexes have a significant effect on their surface coverage. A laser ablation ICP-MS technique that provides information
about thin films across macro-sized areas is described here for the first time. Using the technique, the maximum surface coverage
of a ruthenium phthalocyanine complex was found to occur within one minute of gold substrate immersion in the complex-containing
solution.
相似文献
10.
Using magnetic nanoparticles to enhance gene transfection, a recently developed technique termed magnetofection, has been
shown to be a powerful technology in gene delivery. The most widely used magnetic nanoparticles in this area are those coated
with polyethyleneimine, which is a well known nonviral transfection agent. In this article, we report methods to control the
aggregate size of polyethyleneimine-coated magnetite particles. These particles were then used to enhance transfection of
green fluorescent protein (GFP) into NIH 3T3 cells in vitro. We find that the aggregate size of the particles has a great effect on their performance in magnetofection, with less aggregated
magnetic particles being more effective in enhancing the gene transfection.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
11.
Current methods of synthesizing single-walled carbon nanotubes (SWNTs) result in racemic mixtures that have impeded the study
of left- and right-handed SWNTs. Here we present a method of isolating different SWNT enantiomers using density gradient ultracentrifugation.
Enantiomer separation is enabled by the chiral surfactant sodium cholate, which discriminates between left- and right-handed
SWNTs and thus induces subtle differences in their buoyant densities. This sorting strategy can be employed for simultaneous
enrichment by handedness and roll-up vector of SWNTs having diameters ranging from 0.7 to 1.5 nm. In addition, circular dichroism
of enantiomer refined samples enables identification of high-energy optical transitions in SWNTs.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
12.
Metallic nanostructures with hollow interiors or tailored porosity represent a special class of attractive materials with
intriguing chemicophysical properties. This paper presents the fabrication of a new type of metallic nanoporous nanotube structure
based on a facile and effective combination of nanocrystal growth and surface modification. By controlling the individual
steps involved in this process, such as nanowire growth, surface modification, thermal diffusion, and dealloying, one-dimensional
(1-D) metallic nanostructures can be prepared with tailored structural features and pre-designed functionalities. These tubular
and porous nanostructures show distinct optical properties, such as tunable absorption in the near-infrared region, and enhanced
capability for electrochemiluminescence signal amplification, which make them particularly desirable as novel 1-D nanocarriers
for biomedical, drug delivery and sensing applications.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
13.
We report synthesis windows for growth of millimeter-long ZnTe nanoribbons and ZnSe nanowires using vapor transport. By tuning
the local conditions at the growth substrate, high aspect ratio nanostructures can be synthesized. A Cu-ion immersion doping
method was applied, producing strongly p-type conduction in ZnTe and ionic conduction in ZnSe. These extreme aspect ratio
wide-bandgap semiconductors have great potential for high density nanostructured optoelectronic circuits.
相似文献
14.
Franziska Schäffel Jamie H. Warner Alicja Bachmatiuk Bernd Rellinghaus Bernd Büchner Ludwig Schultz Mark H. Rümmeli 《Nano Research》2009,2(9):695-705
The controlled etching of graphite and graphene by catalytic hydrogenation is potentially a key engineering route for the
fabrication of graphene nanoribbons with atomic precision. The hydrogenation mechanism, though, remains poorly understood.
In this study we exploit the benefits of aberration-corrected high-resolution transmission electron microscopy to gain insight
to the hydrogenation reaction. The etch tracks are found to be commensurate with the graphite lattice. Catalyst particles
at the head of an etch channel are shown to be faceted and the angles between facets are multiples of 30°. Thus, the angles
between facets are also commensurate with the graphite lattice. In addition, the results of a post-annealing step suggest
that all catalyst particles—even if they are not involved in etching—are actively forming methane during the hydrogenation
reaction. Furthermore, the data point against carbon dissolution being a key mechanism during the hydrogenation process.
相似文献
15.
Yunzhou Xue Bin Wu Yunlong Guo Liping Huang Lang Jiang Jianyi Chen Dechao Geng Yunqi Liu Wenping Hu Gui Yu 《Nano Research》2011,4(12):1208-1214
We demonstrate a simple and controllable way to synthesize large-area, few-layer graphene on iron substrates by an optimized
chemical vapor deposition (CVD) method using a mixture of methane and hydrogen. Based on an analysis of the Fe-C phase diagram,
a suitable procedure for the successful synthesis of graphene on Fe surfaces was designed. An appropriate temperature and
cooling process were found to be very important in the synthesis of highly crystalline few-layer graphene. Graphene-based
field-effect transistor (FET) devices were fabricated using the resulting few-layer graphene, and showed good quality with
extracted mobilities of 300–1150 cm2/(V·s).
相似文献
16.
A novel process is demonstrated whereby dense arrays of single-walled carbon nanotubes (SWNT) are grown directly at the interface
of a carbon material or carbon fiber. This growth process combines the concepts of SWNT tip growth and alumina-supported SWNT
base growth to yield what we refer to as “odako” growth. In odako growth, an alumina flake detaches from the carbon surface
and supports catalytic growth of dense SWNT arrays at the tip, leaving a direct interface between the carbon surface and the
dense SWNT arrays. In addition to being a new and novel form of SWNT array growth, this technique provides a route toward
future development of many important applications for dense aligned SWNT arrays.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
This article is published with open access at Springerlink.com 相似文献
17.
Zhongwei Niu Saswat Kabisatpathy Jinbo He L. Andrew Lee Jianhua Rong Lin Yang Godfrey Sikha Branko N. Popov Todd S. Emrick Thomas P. Russell Qian Wang 《Nano Research》2009,2(6):474-483
A sol-gel process has been developed to incorporate bionanoparticles, such as turnip yellow mosaic virus, cowpea mosaic virus,
tobacco mosaic virus, and ferritin into silica, while maintaining the integrity and morphology of the particles. The structures
of the resulting materials were characterized by transmission electron microscopy, small angle X-ray scattering, and N2 adsorption-desorption analysis. The results show that the shape and surface morphology of the bionanoparticles are largely
preserved after being embedded into silica. After removal of the bionanoparticles by calcination, mesoporous silica with monodisperse
pores, having the shape and surface morphology of the bionanoparticles replicated inside the silica, was produced,. This study
is expected to lead to both functional composite materials and mesoporous silica with structurally well-defined large pores.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
18.
We show by molecular dynamics simulations that configuration-sensitive molecular spectroscopy can be realized on optimally
doped graphene sheets vibrated by an oscillatory electric field. High selectivity of the spectroscopy is achieved by maximizing
Coulombic binding between the detected molecule and a specific nest, formed for this molecule on the graphene sheet by substituting
selected carbon atoms with boron and nitrogen dopants. One can detect binding of different isomers to the nest from the frequency
shifts of selected vibrational modes of the combined system. As an illustrative example, we simulate detection of hexanitrostilbene
enantiomers in chiral nests formed on graphene.
相似文献
19.
A two-dimensional (2D) Si film can form between a graphene overlayer and a Ru(0001) substrate through an intercalation process. At the graphene/2D-Si/Ru(0001) surface, the topmost graphene layer is decoupled from the Ru substrate and becomes quasi-freestanding. The interfacial Si layers show high stability due to the protection from the graphene cover. Surface science measurements indicate that the surface Si atoms can penetrate through the graphene lattice, and density functional theory calculations suggest a Si-C exchange mechanism facilitates the penetration of Si at mild temperatures. The new mechanism may be involved for other elements on graphene, if they can bond strongly with carbon. This finding opens a new route to form 2D interfacial layers between graphene and substrates. 相似文献
20.
The strong hydrogen bonding ability of 2-pyridones were exploited to build nanotrains on surfaces. Carborane wheels on axles
difunctionalized with 2-pyridone hydrogen bonding units were synthesized and displayed spontaneous formation of linear nanotrains
by self-assembly on SiO2 or mica surfaces. Imaging using atomic force microscopy confirmed linear formations with lengths up to 5 μm and heights within
the range of the molecular height of the carborance-tipped axles.
Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.
This article is published with open access at Springerlink.com 相似文献