硼掺杂拓扑绝缘体Bi2Se3单晶的电输运性质研究

本文首次报道了用自助溶剂法(self-flux)制备优良的硼(B)掺杂硒化铋(Bi2BxSe3-x)样品的探索。实验结果显示掺杂样品中大部分B是以替代Se位方式存在，少量B以插入Bi2Se3晶格或范德瓦尔斯间隙的形式存在。当B的含量逐渐增加时，Bi2Se3的晶格常数c先减小后增加，且样品具有清晰的层状结构。掺杂量x=0.05的样品局部区域出现纳米带结构，同时该样品在低温下出现了明显的金属-绝缘转变现象。Bi2Se3样品电阻率随掺杂含量的增加而增加，表明B掺杂提高了样品表面态对整体电导的贡献，同时纳米带结构也有助于增加表面态的贡献。

Studyof Transport Properties of Boron-doped Topological Insulator Bi2Se3

Boron-doped Bi2Se3 (Bi2BxSe3-x) crystals were synthesized by a self-flux method. The crystal structure of B-doped Bi2Se3 was investigated by X-ray diffractometry and Raman spectroscopy. The scanning electronic microscopy and physical property measurement system were used to measure the morphology and electrical transport properties. The results show that most of B atoms incorporated into the structure occupy Se sites while some other B atoms are inserted between the lattice sites or in the van der Waals gap. The lattice constant c of Bi2Se3 is first decreased and then increased by the increasing the dopant content. Nanoribbon structures appear in some regions of the sample with the doping content x=0.05. The resistivity of Bi2Se3 sample increases with the increase of doping content, indicating that B doping increases the contribution of surface conductance. The nanoribbon structure also helps increase the surface contribution.