Si(111)面上氮原子薄膜的电子态密度第一性原理计算及分析

由于氮原子在Si(1 1 1)表面成键的失配度最小,因此考虑Si(1 1 1)取向上用不同百分比的氮原子钝化硅表面悬挂键.由第一性原理计算结果显示,当Si(1 1 1)表面层中的氮原子含量为75%—100%时,带隙展宽并且有局域陷阱态产生. 我们提出相应的局域电子态模型,从而解释了Si基氮膜光致荧光(PL)发光增强实验的物理机理.关键词：第一性原理计算氮化Si薄膜PL发光增强局域陷阱态

The first-principle calculations and analysis on density of states of silion plane (111) formed by nitrogen film

Nitrogen and silicon atoms have the smallest mismatch of bonding in the Si surface (111), and different percentages of nitrogen atoms are adopted to passivate silicon surface dangling bonds in the Si (111) orientation. The first-principle calculations showed that the band gap is broadened and the localized trap states are generated when the nitrogen atom content is 75%—100% in the Si surface (111). Then the corresponding local electronic-state model is proposed, and the physical mechanism of the previous experimental results of the visible PL emission on SiN films is clarified.