Effect of surface reconstruction on the structural prototypes of ultrasmall ultrabright Si29 nanoparticles
Effect of surface reconstruction on the structural prototypes of ultrasmall ultrabright Si29 nanoparticles
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DOI：
10.1063/1.1356447
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发表时间：
2001-03-26
影响因子：
4
通讯作者：
Nayfeh, MH
中科院分区：
文献类型：
--
作者：
Mitas, L;Therrien, J;Nayfeh, MH
我们建议，使用密度泛函，组态相互作用，量子蒙特卡罗计算，结构原型的超小超亮粒子的分散体制备。我们构建了近球形结构（Td点群对称），包含29个Si原子，其中5个构成一个四面体的核心，其余24个构成氢终止重建Si表面。表面是一个高度褶皱或起皱的六边形和五边形系统（如在一个充满富勒烯）。我们计算了几种表面重构模型的原子坐标、吸收光谱、吸收边、极化率和电子衍射花样。Si 29 H24（六个重构的表面二聚体）给出0.9nm的尺寸、吸收光谱和带隙（3.5 +/-0.3eV），与测量相当一致。该结构产生830a.u的极化率。具有类似于6.0的有效“介电”常数。计算的单粒子的电子衍射显示大而不是小的散射角的残余晶体相干散射。(C)2001年美国物理学会。
We propose, using density functional, configuration interaction, and quantum Monte Carlo calculations, structural prototypes of ultrasmall ultrabright particles prepared by dispersion from bulk. We constructed near spherical structures (Td point group symmetry) that contain 29 Si atoms, five of which constitute a tetrahedral core and the remaining 24 constitute a hydrogen terminated reconstructed Si surface. The surface is a highly wrinkled or puckered system of hexagons and pentagons (as in a filled fullerene). We calculated, for several surface reconstruction models, the coordinates of atoms, the absorption spectrum, the absorption edge, polarizability, and the electron diffraction pattern. The Si29H24 (six reconstructed surface dimers) gives a size of 0.9 nm, an absorption spectrum and bandgap (3.5 +/-0.3 eV), in fair agreement with measurement. The structure yields a polarizability of 830 a.u. with an effective "dielectric" constant of similar to6.0. The calculated electron diffraction of single particles shows residual crystalline coherent scattering for large but not small scattering angles. (C) 2001 American Institute of Physics.