自偏压作用下纳米碳管的定向生长

以玻璃为基板材料, 在550 ℃的低温条件下利用微波等离子体化学气相沉积法合成了定向纳米碳管.结果表明, 在利用微波等离子体化学气相沉积法合成纳米碳管时, 因等离子体作用存在于基板表面的自偏压对纳米碳管的定向生长起着非常重要的作用.自偏压的作用总是使纳米碳管的生长垂直于基板表面.

Self-bias Induced Aligned Growth of Carbon Nanotubes

In this paper, under the catalytic effect of nickel particles supported on glass, self-aligned carbon nanotubes were synthesized by microwave plasma chemical vapor deposition under a mixture of methane and hydrogen gases at about 550 ℃.During the process of nanotubes growth, the total pressure in the chamber was kept at 3 kPa, the microwave plasma input power was 300 W, and the flow rates of H2 and CH4 were 50 and 1 standard cubic centimeter (sccm) per minute, respectively. It was found that the carbon nanotubes grew always perpendicular to the substrate surface under the effect of plasma. When the substrate was not contacted with plasma, only entangled carbon nanotubes grew on glass randomly. From the research results, we can demonstrate that the electrical self-bias imposed on the substrate is the primary mechanism responsible for the alignment of carbon nanotubes, and we can envision that this simple method can be of great importance for the fabrication of devices in the future.