Quantum confinement and optical gaps in Si nanocrystals

被引:361
作者
Ogut, S
Chelikowsky, JR
Louie, SG
机构
[1] UNIV CALIF BERKELEY,DEPT PHYS,BERKELEY,CA 94720
[2] UNIV CALIF BERKELEY,LAWRENCE BERKELEY LAB,DIV MAT SCI,BERKELEY,CA 94720
关键词
D O I
10.1103/PhysRevLett.79.1770
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
Quasiparticle gaps, self-energy corrections, exciton Coulomb energies, and optical gaps in Si quantum dots are calculated from first principles using a real-space pseudopotential method. The calculations are performed on hydrogen-passivated spherical Si clusters with diameters up to 27.2 Angstrom (similar to 800 Si and H atoms). It is shown that (i) the self-energy correction in quantum dots is enhanced substantially compared to bulk, and is not size independent as implicitly assumed in all semiempirical calculations, and (ii) quantum confinement and reduced electronic screening result in appreciable excitonic Coulomb energies. Calculated optical gaps are in very good agreement with absorption data.
引用
收藏
页码:1770 / 1773
页数:4
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