Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
J Phys Condens Matter. 2013 Feb 27;25(8):085506. doi: 10.1088/0953-8984/25/8/085506. Epub 2013 Jan 30.
Unlike graphene, a hexagonal InP sheet (HInPS) cannot be obtained by mechanical exfoliation from the native bulk InP, which crystallizes in the zinc blende structure under ambient conditions. However, by ab initio density functional theory calculations we found that a slightly buckled HInPS is stable both in pristine form and when doped with Zn atoms; the same occurred for hydrogen-passivated zigzag InP nanoribbons (ZInPNRs), quasi-one-dimensional versions of the quasi-two-dimensional material. We investigated the electronic properties of both nanostructures, in the latter case also in the presence of an external transverse electric field, and the results are compared with those of hypothetical planar HInPS and ZInPNRs. The band gaps of planar ZInPNRs were found to be tunable by the choice of strength of this field, and to show an asymmetric behavior under weak electric fields, by which the gap can either be increased or decreased depending on their direction; however, this effect is absent from slightly buckled ZInPNRs. The binding energies of the acceptor impurity states of Zn-doped HInPS and ZInPNRs were found to be similar and much larger than that of Zn-doped bulk InP. These latter findings show that the reduction of the dimensionality of these materials limits the presence of free carriers.
与石墨烯不同，六方磷化铟（HInPS）不能通过机械剥离从本征块状磷化铟中获得，因为磷化铟在环境条件下结晶为闪锌矿结构。然而，通过从头算密度泛函理论计算，我们发现原始形式和掺杂锌原子的 HInPS 都稳定存在；同样的情况也发生在氢化锯齿形磷化铟纳米带（ZInPNRs）上，这是准二维材料的准一维版本。我们研究了这两种纳米结构的电子性质，在后一种情况下，还研究了存在横向外电场时的情况，并将结果与假设的平面 HInPS 和 ZInPNRs 进行了比较。我们发现，选择电场的强度可以调节平面 ZInPNRs 的带隙，并且在外电场较弱的情况下表现出不对称行为，通过这种行为，根据其方向，间隙可以增加或减小；然而，这种效应在稍微弯曲的 ZInPNRs 中不存在。我们发现，掺杂锌的 HInPS 和 ZInPNRs 的受主杂质态的结合能相似，且远大于掺杂锌的块状磷化铟的结合能。这些发现表明，这些材料的维度降低限制了自由载流子的存在。
