B/N掺杂类直三角石墨烯纳米带器件引起的整流效应

Rectifying behaviors induced by B/N-doping in similar right triangle graphene devices

基于密度泛函理论结合非平衡格林函数的方法,研究了硼(氮)非对称掺杂类直三角石墨烯纳米带器件的电子输运性能.计算结果表明:单个硼或氮原子取代类直三角石墨烯纳米带顶点的碳原子后,增强了体系的电导能力,并且出现了新颖的整流效应.分析表明:这是由于硼氮掺杂类直三角石墨烯纳米带器件在正负偏压下分子能级的移动方向和前线分子轨道空间分布的不对称而产生的.最重要的是,当左右类直三角石墨烯纳米带的顶端原子同时被硼和氮掺杂后,体系的整流效应显著增强,而且出现负微分电阻效应.

By using nonequilibrium Green’s functions in combination with the first principles density functional theory, for the similar right triangle graphene devices as the research object, we take the zigzag graphene as electrodes, to investigate the B（N） doping and B-N co-doping effect, i.e. mainly the influence of doping on the transport properties of similar right triangle graphene devices, as well as the asymmetric doping effect on the rectifying behaviors in similar right triangle graphene devices. Calculated results show that the system conductivity is increased when the vertex carbon atom of a similar right triangle graphene is substituted by a boron or nitrogen atom, and a novel rectifying effect appears. The rectification behavior can be observed because of an asymmetric movement on the molecular-level in B（N） doping in the similar right triangle graphene devices under positive and negative biases and the asymmetry in the spatial distribution of the frontier orbitals. Most importantly, when the vertex carbon atoms of the right and left similar right triangle graphenes are simultaneously doped with boron and nitrogen atoms, the rectifying effect of the system is significantly enhanced and appears also a negative differential resistance effect.