基于第一性原理对硅取代、掺杂锯齿形石墨烯纳米带的电子结构及输运性质的研究

First-principles Study on the Electronic Structure and Transport Properties of Silicon Substituted and Doped Zigzag Graphene Nanoribbons

本文基于第一性原理对硅取代、掺杂石墨烯纳米带不同位置的电子能带结构、态密度及电子器件的电子输运性质进行了分析与研究。结果表明,锯齿形石墨烯纳米带(ZGNRs)在硅原子取代及掺杂后由原来的半导体态转变为金属态。在各种模型中,对于体系态密度有贡献的一般为原子指数为1、在p轨道的硅原子(Si1p);原子指数为2、在p轨道的硅原子(Si2p)和碳原子(C2p);少量的原子指数为1、在s轨道的氢原子(H1s)和碳原子(C1s)。经分析,在各取代位置中两端硅原子取代的锯齿形石墨烯纳米带的体系能量最小,表明其为最有可能发生的取代位置。在掺杂位置中,体系能量计算结果显示填隙硅原子的能量更低,最有可能发生此种掺杂。电子输运性质的研究中,在所有的取代位置中单边硅原子取代组成的电子器件电子输运性质最好。在所有电子器件模型中电子输运性质最好的是填隙硅原子掺杂模型。

Based on the first-principles,the electronic band structure,density of the states and the electronic transport properties of electronic devices of the different positions of the silicon substituted and doped in graphene nanoribbons systems were calculated and studied. The results show that,zigzag graphene nanoribbons（ ZGNRs） change the semiconductor original state into a metallic state after silicon atoms substituted and doped. In various models,the density of states is generally contributed by the silicon atom with atom indices 1 and the orbital p（ Si1p）,the silicon atom and the carbon atom with atom indices 2 and the orbital p（ Si2p） and（ C2p）,and the few hydrogen atom and the carbon atom with atom indices 1 and the orbital s（ H1s） and（ C1s）. After analyzing,the system energy of both-edge doped the zigzag graphene nanoribbons is a minimum of energy in all the position of the substituted,showing that is the most likely position of substituted position. Doping position,the system energy calculations show that gap-doped silicon atoms have the lower energy. Such doping is most likely to occur. In the study ofelectronic transport properties,the electronic device composed of the one-side silicon substituted has the best transport properties in all the substituted positions. The best electronic transport properties of all the electronic devices model is the gap-silicon atoms doped model.