Electronic Structure and Luminescence of 1.1- and 1.4-nm Silicon Nanocrystals: Oxide Shell versus Hydrogen Passivation
Electronic Structure and Luminescence of 1.1- and 1.4-nm Silicon Nanocrystals: Oxide Shell versus Hydrogen Passivation
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DOI：
10.1021/nl025890q
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发表时间：
2003-01
期刊：
影响因子：
10.8
通讯作者：
Zhiyong Zhou;L. Brus;R. Friesner
中科院分区：
文献类型：
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作者：
Zhiyong Zhou;L. Brus;R. Friesner
氧化物和氢钝化的小硅纳米晶体之间的差异进行了探索，通过全电子，混合功能的DFT计算与无限制的几何优化。氧化物钝化使Si35芯的带隙降低约2.4eV，使Si66芯的带隙降低约1.5eV。氧化物钝化的纳米晶体具有光学禁止的间接间隙型跃迁，而氢钝化的纳米晶体具有光学允许的直接间隙型跃迁。HOMO和LUMO在两种物种中都是离域的。这一结果解释了实验观察到的氢钝化的硅纳米晶体在蓝色发光，而氧化物钝化的硅纳米晶体在黄红色发光。
The difference between oxide and hydrogen passivation of small Si nanocrystals is explored by all-electron, hybrid functional DFT calculations with unrestricted geometry optimization. Oxide passivation lowers the band gap by about 2.4 eV for Si35 cores and by about 1.5 eV for Si66 cores. The oxide-passivated nanocrystals have optically forbidden, indirect-gap-type transitions whereas the hydrogen-passivated nanocrystals have optically allowed, direct-gap-type transitions. The HOMO and LUMO are delocalized in both species. This result explains the experimental observation that hydrogen-passivated Si nanocrystals luminesce in the blue whereas oxide-passivated Si nanocrystals luminesce in the yellow-red.