含有碳链通道的石墨烯纳米带电子特性的第一性原理研究

First Principle Calculation on the Electronic Properties of Graphene Nanoribbons with Carbon Chains

采用第一性原理的密度泛函理论结合非平衡格林函数的计算方法,研究了含有多碳链通道的石墨烯纳米带的原子结构、电子能带结构与电子输运特性.结果表明,移除大量原子后含有双碳原子链的纳米带的能隙显著增大,这说明电子从占据态到未占据态的跃迁将更加困难;并且最高占据子能带与最低未占据子能带几乎与费米能级平行,说明边缘态几乎完全消失.电子输运特性的计算结果与电子能带结果是自洽的,碳链的引入导致纳米带电导隙的增大和费米能级位置电导的湮没.这说明通过电子束轰击的方式裁剪纳米带的原子结构来制备集成度更高、尺度更小的一维半导体纳米器件是可行的.

Using the first principle density functional theory combined with the non-equilibrium Green＇ s function technology, we investigate the atomic structure, electronic band structures and electron transport properties of graphene nanoribbons with carbon chains. The present results reveal that the band gap of the graphene nanoribbons （GNRs） with carbon chains is increased, indicating that it is unfavorable for the electronic transition between the occupied states and the unoccupied states in this uanostructure. Moreover, it is found that the highest occupied suhband and the lowest unoccupied subband become dispersionless and almost parallel to the Fermi level, suggesting the edge state observed in the pristine GNR is absent in the defective nanostructure. Electronic transport result shows a good consistency with the electronic band structures results, that is, the presence of the carbon chains leads to the increasing of GNR＇ s conductance gap and the absence of the striking conductance peak in the vicinity of the Fermi level. The present results suggest the possibility of new approaches to tailor the atomic nanostructure by energetic electron irradiation to make more integrated and smaller nanodeviee based on the one-dimensional nanostructures.