Si-P掺杂石墨烯的稳定性和能带结构的理论研究

Theoretical Study on the Stability and Energy Band Structure of Si-P Doped Graphene

采用基于紧束缚密度泛函的计算方法,研究比较了Si掺杂、P掺杂、Si-P掺杂石墨烯的稳定性和能带结构。在Si和P掺杂的石墨烯体系中,发现在掺杂元素方面,Si掺杂石墨烯比P掺杂石墨烯稳定;在掺杂方式方面,高对称性的对位掺杂石墨烯结构的形成能较低,比较稳定。Si掺杂石墨烯的能带结构在G点产生了约0.1 eV的带隙,从良导体过渡到了半导体。在P或Si-P掺杂石墨烯体系中,费米能级上升而穿过价带,使掺杂系统保持金属性。态密度计算表明,P或Si-P掺杂石墨烯体系中费米能级附近主要由P原子的3p态电子和C原子的2p态电子占据,主要的电子性质与P的3p轨道和C的2p轨道相互作用有关。

Based on the calculation method of tight - binding density functional, the stability and energy band structure are studied on Si , P and Si - P doped graphene. In Si and P doped graphene system, Si doped graphene is more stable than P doped graphene as far as the doped elements are concerned, and doped graphene with structure of para - positioned high symmetry become more stable for the low forma-tion .The band structure of Si doped graphene at G point has a gap of 0.1 eV, which indicates that it transforms from good conductor to a semiconductor. In P or Si - P doped graphene system, fermi level rises over the valence band and keeps the doped system metallic. The density of state calculation shows that the 3p level of P and 2p level of C occupy a certain place nearby fermi level in the P or Si - P doped graphene system, which indicates that the major electronic properties are related to the 3p level of P and 2p level of C.