铂掺杂扶手椅型石墨烯纳米带的电学特性研究

本文采用基于密度泛函理论(DFT)的第一性原理计算了铂原子填充扶手椅型石墨烯纳米带(AGNR)中双空位结构的电学性能.计算结果表明: 通过控制铂原子的掺杂位置, 可以实现纳米带循环经历小带隙半导体—金属—大带隙半导体的相变过程; 纳米带边缘位置是铂原子掺杂的最稳定位置, 边缘掺杂纳米带的带隙值随宽度的变化与本征AGNR一样可用三簇曲线表示, 但在较大宽度时简并成两条曲线, 一定程度上抑制了带隙值的振荡; 并且铂原子边缘掺杂导致宽度系数N_a = 3p和3p + 1(p是一个整数)的几个较窄纳米带的带隙中出现杂质能级, 有效地降低了其过大的带隙值. 此外, 铂掺杂AGNR的能带结构对掺杂浓度不是很敏感, 从而降低了对实验精度的挑战. 本文的计算有利于推动石墨烯纳米带在纳米电子学方面的应用.

Electrical properties of platinum doped armchair graphene nanoribbons

The platinum-doped graphene has been achieved in our previous experiments. To further study the effects of metal doping on the band structures of graphene, and provide theoretical guidance for the next step of the experiment, we analyze the electronic properties of armchair graphene nanoribbons (AGNRs) with platinum atoms doping in the divacancy positions using first principle calculation based on density functional theory. The results show that the band structures of AGNRs can be effectively tailored by controlling the doping position on ribbons. Edge position is the most stable position for platinum atom. The band gaps of edge doped AGNRs can be shown in three curves like that of pristine AGNRs. However, they degenerate into two curves at large width, inhibiting the vibration of band gaps to some extent. In addition, several narrow platinum-doped AGNRs with width index N_a = 3p and 3p + 1 have impurity level(s) in the band gap, reducing the large band gap effectively. Furthermore, band characteristics of platinum doped AGNRs are not sensitive to doping concentration, thus reducing the challenge of experimental precision. Our results will promote the application of graphene nanoribbons in the field of nano-electronics.