Excited-state relaxations and Franck-Condon shift in Si quantum dots

被引：67

作者：

Franceschetti, A ^{[1
]}

Pantelides, ST

机构：

[1] Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA

[2] Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA

来源：

PHYSICAL REVIEW B | 2003年 / 68卷 / 03期

关键词：

D O I：

10.1103/PhysRevB.68.033313

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Excited-state relaxations in molecules are responsible for a redshift of the absorption peak with respect to the emission peak (Franck-Condon shift). The magnitude of this shift in semiconductor quantum dots is still unknown. Here we report first-principle calculations of excited-state relaxations in small (diameter less than or equal to2.2 nm) Si nanocrystals, showing that the Franck-Condon shift is surprisingly large (similar to60 meV for a 2.2-nm-diameter nanocrystal). The physical mechanism responsible for the Stokes shift changes abruptly around similar to1 nanometer in size, providing a clear demarcation between "molecules" and "nanocrystals."

引用

页码：333131 / 333134

页数：4

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