Relaxation of Photoexcited Electrons at a Nanostructured Si(111) Surface
Relaxation of Photoexcited Electrons at a Nanostructured Si(111) Surface
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DOI：
10.1021/jz100122f
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发表时间：
2010-03
影响因子：
5.7
通讯作者：
D. Kilin;D. Micha
中科院分区：
文献类型：
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作者：
D. Kilin;D. Micha
利用时间依赖的密度矩阵和从头算电子结构方法获得了纳米结构半导体表面光致电子重分布的弛豫路径，给出了电子能量和空间随时间的变化。将它们应用于Si（111）表面上的Ag团簇，最初由短脉冲光激发，结果表明Ag团簇增加了表面局域态，增强了电子转移。在价带和导带上，能级密度分布在能量和空间上的时间演化，探索了Si板的能带景观，在不同的弛豫途径中，Si板上有一个空穴，吸附的Ag簇中有一个电子。Si(111)/H的计算电子弛豫时间与类似半导体系统的实验值具有相同的数量级。
Relaxation pathways of photoinduced electronic redistribution at nanostructured semiconductor surfaces are obtained from time-dependent density matrix and ab initio electronic structure methods, giving electronic changes in energy and space over time. They are applied to a Ag cluster on a Si(111) surface, initially photoexcited by a short pulse, and show that the Ag cluster adds surface-localized states that enhance electron transfer. Results on the time evolution of population density distributions in energy and in space, for valence and conduction bands, explore the energy band landscape of a Si slab, with various relaxation pathways ending up in a charge-separated state, with a hole in the Si slab and an electron in the adsorbed Ag cluster. Calculated electronic relaxation times for Si(111)/H are of the same order as experimental values for similar semiconductor systems.