QUANTUM CONFINEMENT IN SI NANOCRYSTALS
QUANTUM CONFINEMENT IN SI NANOCRYSTALS
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DOI：
10.1103/physrevb.47.1397
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发表时间：
1993-01-15
影响因子：
3.7
通讯作者：
STEIGMEIER, EF
中科院分区：
文献类型：
--
作者：
DELLEY, B;STEIGMEIER, EF
采用有限结构密度泛函方法计算了可见光致发光纳米晶Si的电子结构。除了几何学之外，这与半导体和其他固体的第一性原理能带结构的理论是相同的。我们的研究结果表明，集群范围高达706 Si原子的带隙线性尺度与L-1，其中L是集群直径。对于这样的集群，它被发现，偶极跃迁跨越差距是对称允许的。因此，有限结构显示出直接带隙，其显著大于体硅的带隙。对于较大的集群，我们发现一个强烈的振子强度的下降，与批量限制的间接间隙的发生一致。
The electronic structure of nanocrystalline Si which shows visible photoluminescence is calculated using the density-functional approach for finite structures. Except for geometry this is the same theory as for first-principles band structures of semiconductors and other solids. Our results for clusters ranging up to 706 Si atoms suggest that the band gap scales linearly with L-1, where L is the cluster diameter. For such clusters it is found that dipole transitions across the gap are symmetry allowed. The finite structures thus show a direct band gap which is considerably larger than the one of bulk silicon. For larger clusters we find a strong decrease of oscillator strength, consistent with the occurrence of the indirect gap in the bulk limit.