采用基于密度泛函理论的第一性原理计算，研究了 C/Ge 掺杂对单壁扶手型硅纳米管电子结构和光电性质的影响。结果表明，本征态和C/Ge掺杂的硅纳米管均属于直接带隙半导体，其价带顶主要由Si-3p态电子构成，而导带底则主要由Si-3p态电子决定。通过C掺杂，可使硅纳米管的禁带宽度减小，静态介电常数增大，吸收光谱产生红移；而通过Ge掺杂，可使硅纳米管的禁带宽度增大，静态介电常数减小，吸收光谱产生蓝移。研究结果为硅纳米管在光电器件方面的应用提供了理论基础。
The electronic structures and optoelectronic properties of C/Ge-doped single-walled armchair silicon nanotubes were determined by using first-principles calculations in the framework of density-functional theory. In par-ticular, the calculated results indicate that both pure and C/Ge-doped silicon nanotubes display a direct band gap. The band gap is decreased firstly and then increased for the silicon nanotubes doped with C and Ge, respectively. Moreover, the upper of valence band is mainly contributed by the Si-3p states and the lower of conduction band is primarily oc-cupied by the Si-3p states. The state dielectric constant is improved and the optical absorption shows a red-shifted for the C-doped silicon nanotubes, whereas the state dielectric constant is reduced and the optical absorption shows a blue-shifted for the Ge-doped silicon nanotubes. The results provide an useful theoretical guidance for the applications of single-walled armchair silicon nanotubes in optical detectors.
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