Structural properties of hydrogenated silicon nanocrystals and nanoclusters
Structural properties of hydrogenated silicon nanocrystals and nanoclusters
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DOI：
10.1063/1.1513878
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发表时间：
2002-11
影响因子：
3.2
通讯作者：
D. K. Yu;Ruiqin Q. Zhang;Shui-Tong Lee
中科院分区：
文献类型：
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作者：
D. K. Yu;Ruiqin Q. Zhang;Shui-Tong Lee
采用基于经验紧束缚方法的几何优化和分子动力学模拟研究了完全氢化和部分氢化硅纳米晶和纳米团簇的结构。结果表明，氢饱和硅纳米晶的结构性质几乎没有尺寸效应，相反，它们的电子性质。在完全氢饱和的Si纳米晶体中，表面弛豫是相当小的，在最外面的两层或三层中具有0.01至0.02 A的晶格收缩。在氢化硅纳米晶体内部，只有非常小的应变（晶格膨胀），数量级为10 - 4至10 - 3，与x射线衍射测量一致。与部分氢化的纳米晶相比，完全氢化的纳米晶是最稳定的结构。对于较小的SimHx（m = 151）纳米晶体，去除高达50%的表面终止H原子只会导致晶体结构的扭曲，基本的四面体结构特征仍然存在。
The structures of fully and partially hydrogenated Si nanocrystals and nanoclusters are studied by geometric optimizations and molecular dynamics simulations based on an empirical tight-binding approach. It is shown that the structural properties of the hydrogen saturated Si nanocrystals have little size effect, contrary to their electronic properties. The surface relaxation is quite small in the fully hydrogen saturated Si nanocrystals, with a lattice contraction of 0.01 to 0.02 A residing in the outermost two or three layers. Inside the hydrogenated Si nanocrystals, there is only very small strain (lattice expansion) of the order 10−4 to 10−3, in agreement with the x-ray diffraction measurement. The fully hydrogenated Si nanocrystals are the most stable structures compared to those partially hydrogenated. For the smaller SimHx (m⩽151) nanocrystals, removing up to 50% of the surface terminating H atoms only causes distortions to the crystal structure, with the basic tetrahedral structural features still ...