Effect of scattering and contacts on current and electrostatics in carbon nanotubes
Effect of scattering and contacts on current and electrostatics in carbon nanotubes
复制标题
碳纳米管中散射和接触对电流和静电的影响
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Anantram
中科院分区：
文献类型：
--
作者：
A. Svizhenko;M. Anantram
我们计算研究了碳纳米管的静电势分布和载流能力随长度和直径的变化。我们的研究是基于自洽地求解非平衡格林函数和泊松方程，包括电子-声子散射的影响。随着外加偏压的增加，电子输运的弹道区向扩散区的转变表现为纳米管中的电势分布、微分电导和电场发生了质的变化。在低偏压弹道极限下，大部分外加电压降发生在触点附近。此外，管子中心的电场随着管径的增大而成比例地增大。相反，在高偏压下，大部分外加电压下降到纳米管的两端，并且管中心的电场随着直径的增加而减小。我们发现，由于纳米管的长度、直径和接触的品质因数的相互作用，差动电导可以随着偏置而增加或减少。从应用的角度来看，我们发现纳米管的载流能力随着管径的增加而增加。最后，我们研究了内管在影响多壁纳米管最外层的载流中的作用。
We computationally study the electrostatic potential profile and current carrying capacity of carbon nanotubes as a function of length and diameter. Our study is based on solving the nonequilibrium Green’s function and Poisson equations self-consistently, including the effect of electron-phonon scattering. A transition from the ballistic to diffusive regime of electron transport with an increase of applied bias is manifested by qualitative changes in the potential profiles, differential conductance, and electric field in a nanotube. In the low-bias ballistic limit, most of the applied voltage drop occurs near the contacts. In addition, the electric field at the tube center increases proportionally with diameter. In contrast, at high biases, most of the applied voltage drops across the nanotube, and the electric field at the tube center decreases with an increase in diameter. We find that the differential conductance can increase or decrease with bias as a result of an interplay of nanotube length, diameter, and a quality factor of the contacts. From an application viewpoint, we find that the current carrying capacity of nanotubes increases with an increase in diameter. Finally, we investigate the role of inner tubes in affecting the current carried by the outermost tube of a multiwalled nanotube.