Sun L, Zhang Z H, Wang H, Li M
School of Physics and Electronics, Central South University Changsha 410083 China.
School of Physics and Electronic Science, Changsha University of Science and Technology Changsha 410114 China.
RSC Adv. 2020 Jan 8;10(3):1400-1409. doi: 10.1039/c9ra06360a. eCollection 2020 Jan 7.
Using the first-principles method based on density-functional theory and nonequilibrium Green's function, electronic properties of zigzag phosphorene nanoribbons (ZPNRs) terminated with nonmetallic (NM) atoms such as H, C, F, N, O, S and Si, as well as a pristine case, are studied systematically. Three possible cases are considered, namely, ZPNRs with symmetrical edge terminations, asymmetrical edge terminations, and the half-bare edge case. It is shown that the pristine ZPNRs show metallic behavior. For ZPNRs terminated with C, O, S and Si atoms, they are always metals regardless of the termination cases. For ZPNR terminated with H, F, and N, the electronic structure is either a metal or a semiconductor, which depends on the termination cases. The results from the calculated edge formation energy show that the ribbons with C, F, N, O, S and Si atom edge modifications are more stable than the H-terminated ZPNR. Moreover, an applied external transverse electric field can effectively modulate the bandgaps of ZPNRs terminated with H, F and N, especially reducing the gap with the increase of the applied external transverse electric field strength. The ZPNRs terminated with N undergo a semiconductor-to-metal transition. We also investigate the electronic transport properties in nano devices consisting of the ZPNRs terminated respectively by O and S at both edges and with the fully bare edge. It is found that O and S terminated ZPNR devices have a good linear response on bias, and the current is bigger than the pristine case. The results indicate that the introduction of NM atoms at the edge(s) can effectively modulate the electronic and transport properties of ZPNRs. These novel electronic properties suggest that PNRs are a promising candidate for future nanoelectronic and optoelectronic applications.
采用基于密度泛函理论和非平衡格林函数的第一性原理方法，系统地研究了以H、C、F、N、O、S和Si等非金属（NM）原子终止的锯齿形磷烯纳米带（ZPNR）以及原始情况下的电子性质。考虑了三种可能的情况，即具有对称边缘终止、非对称边缘终止和半裸边缘情况的ZPNR。结果表明，原始的ZPNR表现出金属行为。对于以C、O、S和Si原子终止的ZPNR，无论终止情况如何，它们始终是金属。对于以H、F和N终止的ZPNR，其电子结构取决于终止情况，可能是金属或半导体。计算得到的边缘形成能结果表明，具有C、F、N、O、S和Si原子边缘修饰的纳米带比H终止的ZPNR更稳定。此外，施加的外部横向电场可以有效地调制以H、F和N终止的ZPNR的带隙，特别是随着施加的外部横向电场强度的增加而减小带隙。以N终止的ZPNR会发生半导体到金属的转变。我们还研究了由分别在两边以O和S终止以及完全裸边缘的ZPNR组成的纳米器件中的电子输运性质。发现以O和S终止的ZPNR器件对偏压具有良好的线性响应，并且电流比原始情况大。结果表明，在边缘引入NM原子可以有效地调制ZPNR的电子和输运性质。这些新颖的电子性质表明，PNR是未来纳米电子和光电子应用的有前途的候选材料。
