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Theoretical study of electronic structure of silicon nanocrystals

Persson, Martin LU and Xu, Hongqi LU (2002) Proceedings of the 19th Nordic Semiconductor Meeting In Physica scripta T101. p.147-150
Abstract
We report on a theoretical study of the electronic structure of silicon nanocrystals with a shape of the regular rhombic dodecahedron, based on a tight-binding method. The energies of the lowest unoccupied state and the highest occupied state have been calculated. We have shown that the six-fold degenerate conduction band minima of the bulk silicon crystal are split into a non-degenerate A(1) state, a double-degenerate E state and a triple-degenerate T-2 state and that the ordering of the energies of these states depends on the size of the silicon nanocrystal. Thus the lowest unoccupied state of the silicon nanocrystal can have different symmetries at different nanocrystal sizes. However. as the size of the nanocrystal changes, the... (More)
We report on a theoretical study of the electronic structure of silicon nanocrystals with a shape of the regular rhombic dodecahedron, based on a tight-binding method. The energies of the lowest unoccupied state and the highest occupied state have been calculated. We have shown that the six-fold degenerate conduction band minima of the bulk silicon crystal are split into a non-degenerate A(1) state, a double-degenerate E state and a triple-degenerate T-2 state and that the ordering of the energies of these states depends on the size of the silicon nanocrystal. Thus the lowest unoccupied state of the silicon nanocrystal can have different symmetries at different nanocrystal sizes. However. as the size of the nanocrystal changes, the symmetry of the highest occupied state remains the same; it is T-2 symmetric. The wave functions of the lowest unoccupied and highest occupied states have also been calculated. It is shown that these states have very different localization properties. The wave function of the lowest unoccupied A(1) state is largely localized on the central atomic site and on its nearest neighbors. In contrast, the wave function of the lowest unoccupied E state has no contribution from the orbitals of the central atom. Furthermore, the wave functions of both the lowest unoccupied and the highest occupied T-2 states are distributed more evenly over a large portion of the silicon nanocrystals. (Less)
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author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
Wave functions
in
Physica scripta
volume
T101
pages
147 - 150
publisher
Royal Swedish Academy of Sciences
conference name
Proceedings of the 19th Nordic Semiconductor Meeting
external identifiers
  • wos:000179465600039
  • scopus:0036437376
ISSN
1402-4896
0031-8949
DOI
10.1238/Physica.Topical.101a00147
language
English
LU publication?
yes
id
fec74dd9-69fc-4e3d-af10-705c585e6757 (old id 322738)
date added to LUP
2007-11-28 13:49:43
date last changed
2017-01-01 05:11:46
@inproceedings{fec74dd9-69fc-4e3d-af10-705c585e6757,
  abstract     = {We report on a theoretical study of the electronic structure of silicon nanocrystals with a shape of the regular rhombic dodecahedron, based on a tight-binding method. The energies of the lowest unoccupied state and the highest occupied state have been calculated. We have shown that the six-fold degenerate conduction band minima of the bulk silicon crystal are split into a non-degenerate A(1) state, a double-degenerate E state and a triple-degenerate T-2 state and that the ordering of the energies of these states depends on the size of the silicon nanocrystal. Thus the lowest unoccupied state of the silicon nanocrystal can have different symmetries at different nanocrystal sizes. However. as the size of the nanocrystal changes, the symmetry of the highest occupied state remains the same; it is T-2 symmetric. The wave functions of the lowest unoccupied and highest occupied states have also been calculated. It is shown that these states have very different localization properties. The wave function of the lowest unoccupied A(1) state is largely localized on the central atomic site and on its nearest neighbors. In contrast, the wave function of the lowest unoccupied E state has no contribution from the orbitals of the central atom. Furthermore, the wave functions of both the lowest unoccupied and the highest occupied T-2 states are distributed more evenly over a large portion of the silicon nanocrystals.},
  author       = {Persson, Martin and Xu, Hongqi},
  booktitle    = {Physica scripta},
  issn         = {1402-4896},
  keyword      = {Wave functions},
  language     = {eng},
  pages        = {147--150},
  publisher    = {Royal Swedish Academy of Sciences},
  title        = {Theoretical study of electronic structure of silicon nanocrystals},
  url          = {http://dx.doi.org/10.1238/Physica.Topical.101a00147},
  volume       = {T101},
  year         = {2002},
}