中文摘要：

采用基于密度泛函理论的平面波超软赝势方法和广义梯度近似，计算了掺杂Ge前后单晶Si中Si-Ge键的布居值、键长以及能带结构和态密度。计算结果表明，Ge掺杂后体系晶格常数发生变化，Ge-Si键变长，布居值及带隙宽度减小。还进一步研究了掺杂Ge后的光学性质，掺杂后静态介电常数值与纯Si相比有所增大，且吸收带宽变窄、吸收带边明显红移，并对这些掺杂诱导的材料物性变化进行了解释。

英文摘要：

Using the plane-wave ultrasofe pseudo potential method based on the density functional theory, the electronic structures and optical properties variation in monocrystal silicon before and after Ge doping are studied it. The calculated data are supported by atomic population, band length, band structure and density of states of Si-Ge band in materials. And the results indicate that the band length and atomic population decrease, the crystal lattice constant changes. Furthermore, Ge doping causes the gap to decrease, and meanwhile, it makes static dielectric constant higher and results in red-shift and narrower part of absorption wavelength.