弯曲BN纳米片的电子性质及其调制

BN纳米片是具有一定宽度、无限长度的一维蜂窝构型单层带状氮化硼材料,弯曲的BN纳米片因为P z轨道旋转,将表现出一定的独特的电子性质.通过第一性原理计算,利用MS(Material Studio)中的DMOL3(local density functional calculations on molecules)软件计算了Zigzag和Armchair型BN纳米片弯曲以后的能带结构.BN纳米带的带隙会随着弯曲角度的变化而改变,以Armchair型BN纳米带的变化较为明显;在弯曲的基础上再加入外电场,却是Zigzag型BN纳米带的带隙变化更显著.当电场加大到一定的值,纳米带就会从半导体变为金属,并且这一临界电场值的大小和纳米带的弯曲程度有关.电场对带隙的调制还和纳米带的尺寸有关系,电场对大尺度的纳米带的调控性更好,从半导体转变为金属所需要的电场值要更小.

Electronic properties and modulation of structurally bent BN nanoribbon

Boron nitride nanoribbon (BNNR) is a one-dimensional single layer nano-material with finite width and infinite length. Bent BNNR will show some unique electronic properties because of the rotation of Pz orbit. The software DMOL³ of Material Studio, based on the first principles, can be used to calculate the energy band, and the band gap will change with the bending angle; in the armchair BN nanoribbons the change is more obvious. Band gaps of zigzag BN nanoribbons may change more than those in armchair BN nanoribbons do if the external electric field is also added on the bent BN nanoribbons. When the electric field is increased to a certain value, nanoribbons will transit from semiconductor to metal, and it is important that the corresponding critical electric field value depends on the bending angle. The modulation of electric field on the band gap is also related with the size of nanoribbons; the wider the nanoribbon, the easier the modulation, and the smaller the critical electric field.