碳纳米管超晶格结构能隙的第一性原理研究

本文采用基于密度泛函理论的CASTEP模块研究了B/N共掺(5,5)碳纳米管环超晶格的电子结构。形成能计算结果为负值表明，B/N原子对共掺碳纳米管环具有稳定存在的可能性。能带结构和态密度结果表明，B/N原子对的掺入使得(5,5)金属型碳纳米管能隙打开，导电性质向半导体转变。当管径在合理的变化范围内，纯碳纳米管的能隙宽度强烈敏感于管径的变化，而B/N共掺碳纳米管环结构的能隙值随管径的变化较小，这就降低了碳纳米管电子器件的制备要求。对新型结构施加变形作用，压缩变形使得B/N共掺碳纳米管环的能带宽度增大，这相当于提高了碳纳米管的掺杂体积浓度；拉伸变形作用下所得结论恰恰相反。实现控制碳纳米管超晶格结构的导电性能，对纳米管电子器件的应用具有重要意义。

First-principle study on energy gap of CNT superlattice structure

By using the CASTEP modules based on density functional theory, the electronic structures of B/N pair co-doping (5, 5) CNT rings superlattice have been investigated.The calculation results show that the formation energies of B/N pair co-doping CNT rings are negative, indicating that the new type construction will probably be stable.The band structure and state density of the new type construction show that the energy gap is opened by B/N co-doping in (5, 5) metallic CNT and the metallic CNT is changed into a semiconductor.The energy gap of pure CNT is strongly sensitive to the changes of CNT diameter but the energy gap of B/N co-doping CNT rings remains stable when the diameters are in a reasonable scope, which means that the requirements for the production of CNT have been reduced.The compressive deformation effects mean that the energy gaps are narrowed, which is equivalent to enhancing the doping volume concentration.However, the changes of the energy gap under the tensile deformation effect are opposite.Achieving control of the electrical conductivity of CNT has an important significance for electron devices.