Factors responsible for the stability and the existence of a clean energy gap of a silicon nanocluster
Factors responsible for the stability and the existence of a clean energy gap of a silicon nanocluster
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硅纳米团簇稳定性和清洁能隙存在的因素
DOI：
10.1063/1.1402672
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发表时间：
2000
影响因子：
3.2
通讯作者：
S. Wu
中科院分区：
文献类型：
--
作者：
Lei Liu;C. Jayanthi;S. Wu
利用N[O(N)]阶非正交紧束缚分子动力学和电子结构局域分析，对硅纳米团簇的电子性质进行了重要的理论研究，特别是对称性、弛豫和氢钝化对体系的稳定性、能隙状态和能隙的影响。我们发现，对于原子占据正四面体网络的非弛豫团簇，无扭曲的局域成键组态的存在足以出现小的清洁能隙。然而，非弛豫团簇的能隙并不是从最高占据分子轨道(HOMO)开始的。事实上，在HOMO和能隙下缘之间，发现了局域悬挂键态。氢钝化后，局域悬挂键态被消除，从而产生更宽且清洁的能隙。氢钝化团簇的弛豫并不改变其结构和能隙。
We present a critical theoretical study of electronic properties of silicon nanoclusters, in particular the roles played by symmetry, relaxation, and hydrogen passivation on the stability, the gap states and the energy gap of the system using the order N [O(N)] nonorthogonal tight-binding molecular dynamics and the local analysis of electronic structure. We find that for an unrelaxed cluster with its atoms occupying the regular tetrahedral network, the presence of undistorted local bonding configuration is sufficient for the appearance of a small clean energy gap. However, the energy gap of the unrelaxed cluster does not start at the highest occupied molecular orbital (HOMO). In fact, between the HOMO and the lower edge of the energy gap, localized dangling bond states are found. With hydrogen passivation, the localized dangling bond states are eliminated, resulting in a wider and clean energy gap. Relaxation of these hydrogen passivated clusters does not alter either the structure or the energy gap appre...