不同浓度Er掺杂Si纳米晶粒电子结构和光学性质的第一性原理研究

First principles study of electronic and optical properties of Er-doped silicon nanoparticles with different densities

利用基于密度泛函理论的第一性原理,对不同浓度Er掺杂Si纳米晶粒的结构稳定性、电子和光学性质进行了研究.结果表明:Si纳米晶粒中Er掺杂浓度越低,结构越稳定;Er掺杂后的Si纳米晶粒引入了杂质能级,导致禁带宽度变窄;掺杂后的Si纳米晶粒在低能区出现了一个较强的吸收峰,随着浓度的降低,吸收峰峰值逐渐减小,甚至消失.这为Si基发光材料的设计提供了理论依据.

The structural stability,the electronic and the optical properties of Er-doped silicon nanoparticles are investigated by first principles based on the density functional theory.The results show that the structure is more stable when the doping concentration of Er atoms is smaller in silicon nanoparticles.The doping of Er atom in silicon nanoparticle introduces the impurity levels which result in the narrowing of band gap.A strong absorption peak occurs in the low-energy region of Er-doped silicon nanoparticles,and the intensity of the absorption peak decreases gradually,even disappears with doping concentration decreasing.The study provides the theoretical basis for the design of silicon-based materials.