论文标题:基于碳纳米管的金属纳米线生长机理的分子模拟研究
Molecular Simulation of Metal Nanowires Growing Based on Carbon Nanotubes
论文作者
论文导师 王积森,论文学位 硕士,论文专业 流体机械及工程
论文单位 山东科技大学,点击次数 72,论文页数 80页File Size5983K
2007-05-01论文网 http://www.lw23.com/lunwen_115733402/
carbon nanotubes;; sodium atom;; nanowire;; molecular dynamics;; simulation
纳米技术是21世纪的优先发展领域，纳米材料与纳米器件的发展将会对信息、医学、能源、环境等领域带来革命性的变化。碳纳米管以其独特的优点、广泛的应用价值和良好的发展前景在各个领域中中引起科学家的普遍关注。纳米线具有优越的物理性能，是构造纳米尺度元器件如激光器、传感器、场效应晶体管、发光二极管、逻辑电路、自旋电子器件以及量子计算机等的结构单元。利用在碳纳米管中填充金属原子生成纳米线的方法，可以使纳米线稳定、均匀的生长，从而提高金属纳米线的质量和性能。 本文选用经典分子动力学方法模拟在不同直径的碳纳米管中填充金属Na原子的过程。利用最速下降法对填充进碳纳米管中的Na原子进行能量优化；对碳纳米管沿轴线方向使用周期性边界条件；Na原子的速度按Velocity Verlet Algorithm方法来确定；选用Lennard-Jones 12-6势做为分子间作用力的势函数：系综取等温等压系综：压力为一个大气压。 通过分别在armchair型碳纳米管(4，4)和(6，6)中填充Na原子，发现在两种碳纳米管中均可得到Na纳米线。且碳纳米管的直径对纳米线的直径及结构有明显的影响，碳纳米管(4，4)中得到的纳米线为单原子排列的直线结构，而碳纳米管(6，6)中得到的纳米线则为直径较大的、带有一定螺旋性的线性结构。
At the prior place of science technique, the development of nano material and nano device will bring revolutionary change to the information, medicine, energy and environment. With the unique characters, widely use and good expectation, carbon nanotubes attract great deal of scientists interesting of many fields. Having superior physical characters, nanowires are the structure part of manufacting nanometer device, such as LASER, sensor, field-effect transistor, emitting LED, logical circuit, spinning electronic device and quantum computers. Using the method of filling metal atoms into carbon nanotubes, we can get the metal nanowire growing equably, which can improve the quality of metal nanowires. In this article, we choose molecular dynamics simulation to study the process of filling sodium atoms into carbon nanotubes. We apply Steepest Descent method to optimize the energy of sodium atoms; Periodic boundary condition is employed along the wire axis of carbon nanotubes. The velocities of sodium atoms are confirmed according to Velocity Verlet Algorithm; The potential energy between atoms is described using Lennard-Jones 12-6 function. We choose Isothermal-Isobaric (NPT), and the pressure is 1 Arm. By filling Na atoms into armchair carbon nanotubes (4,4) and (6, 6), respectively, we can get the conclusion that nanowire is growing in the carbon nanotubes. Also, we can find that the diameter of carbon nanotubes affects the structure of Na nanowire obviously. In the carbon nanotube (4,4), the Na nanowire is monatomic linear strcture, while it is of helicity and larger diameter.
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