Optical transitions and nature of Stokes shift in spherical CdSquantum dots
We study the structure of the energy spectra along with the character of the states participating in optical transitions in colloidal CdS quantum dots (QDs) using the ab initio accuracy charge patching method combined with the folded spectrum calculations of electronic structure of thousand-atom nanostructures. In particular, attention is paid to the nature of the large resonant Stokes shift observed in CdS quantum dots. We find that the top of the valence band state is bright, in contrast with the results of numerous k {center_dot} p calculations, and determine the limits of applicability of the k {center_dot} p approach. The calculated electron-hole exchange splitting suggests the spin-forbidden valence state may explain the nature of the ''dark exciton'' in CdS quantum dots.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of AdvancedScientific Computing Research. Office of Basic Energy Research. MaterialsSciences and Engineering Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 891218
- Report Number(s):
- LBNL-59231; R&D Project: K11702; BnR: KC0203010; TRN: US0605322
- Journal Information:
- Physical Review B, Vol. 73, Issue 15; Related Information: Journal Publication Date: 04/2006
- Country of Publication:
- United States
- Language:
- English
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