88 research outputs found
Large-scale fabrication of ordered arrays of microcontainers and the restraint effect on growth of CuO nanowires
Technique has been developed to fabricate ordered arrays of microcontainers. We report that ordered microcontainer arrays of Cu can be fabricated on glass substrate by thin film deposition and self-assembly technology. In addition, CuO nanowires are found to grow only in the inner sides of microcontainers, which verifies the stress growth mechanism of CuO nanowires. High-resolution transmission electron microscopy study reveals that CuO nanowires grow along the [110] direction. Such structure may have potential application in micro-electron sources, which have the self-focused function
Screening effects on field emission from arrays of (5,5) carbon nanotubes: Quantum-mechanical simulation
The simulation of field electron emission from arrays of micrometer-long
open-ended (5, 5) carbon nanotubes is performed in the framework of quantum
theory of many electrons. It is found that the applied external field is
strongly screened when the spacing distance is shorter than the length of the
carbon nanotubes. The optimal spacing distance is two to three times of the
nanotube length, slightly depending on the applied external fields. The
electric screening can be described by a factor that is a exponential function
of the ratio of the spacing distance to the length of the carbon nanotubes. For
a given length, the field enhancement factor decreases sharply as the screening
factor larger than 0.05. The simulation implies that the thickness of the array
should be larger than a value but it does not help the emission much by
increasing the thickness a great deal
Atomic decoration for improving the efficiency of field electron emission of carbon nanotubes
The field electron emission from the single-walled carbon nanotubes with
their open ends terminated by -BH, -NH, and -O has been simulated. The
apex-vacuum barrier and the emission current have been calculated. It has been
found that -BH and -NH suppress the apex-vacuum barrier significantly and lead
to higher emission current in contrast to the -O terminated structure in the
same applied field. The calculated binding energy implies that the carbon
nanotubes terminated with -BH and -NH are more stable than those saturated by
oxygen atoms or by hydrogen atoms.Comment: 8 pages, 9 figures, LaTeX; content changed, typos corrected,
references adde
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