正三角锯齿型石墨烯的电子输运特性

利用密度泛函理论和非平衡格林函数方法, 系统研究了正三角锯齿型石墨烯的电子输运特性. 研究表明: 正三角石墨烯的电流-电压(I-V)特性及整流效应与几何尺寸、边缘吸附原子的类型密切相关, 在其边缘吸附H原子和S原子的情况下, 小的正三角石墨烯有大的电流, 但有小的整流比; 改变边缘吸附原子的类型(用O原子替换H原子), 电流增大, 但其整流效应明显变低. 分析表明, 这种整流是由于正三角石墨烯前线轨道的空间分布不对称以及在正、负偏压下分子能级的非对称移动所致. 我们的研究对于认识正三角石墨烯的基本物性(电子结构及器件应用)有重要意义.

Electronic Transport Properties for a Zigzag-Edged Triangular Graphene

Based on the density functional theory and the non-equilibrium Green s function method, the electronic transport properties of zigzag-edged triangular graphene were studied systematically. The results revealed that the current-voltage (I-V) characteristics and rectifying effects were closely related to the geometric size and the type of atoms terminated at the edges of triangular graphene. In the case of H- and S-terminated edges, a small triangular graphene had a large current but with a small rectifying ratio. Although the current increased, the rectifying behavior was lowered when H atoms at the edges of the structure were replaced by O atoms. Deeper analysis demonstrated that such a rectification was caused by the asymmetry in the spatial distribution of the frontier orbitals and an asymmetric movement on the molecular-level in triangular graphene under positive and negative biases. It is of great significance that our investigations develop a thorough understanding of the basic physical properties of a triangular graphene.