Optical Extinction Spectra
of Silicon Nanocrystals: Size Dependence upon the Lowest Direct Transition
Ryan Gresback
Yoichi Murakami
Yi Ding
Riku Yamada
Ken Okazaki
Tomohiro Nozaki
10.1021/la3042082.s001
https://acs.figshare.com/articles/journal_contribution/Optical_Extinction_Spectra_of_Silicon_Nanocrystals_Size_Dependence_upon_the_Lowest_Direct_Transition/2445040
We investigate the size-dependent optical extinction
properties of colloidal silicon nanocrystals (Si NCs) from the near
infrared (NIR) to the ultraviolet (UV). Experimental results are compared
to the Mie solution to Maxwell’s equations using the same refractive
index as bulk Si to evaluate the deviation from bulk properties. We
find that the energy for the lowest direct transition (<i>E</i><sub>1</sub>) continuously blueshifts from near bulk-like at ∼3.4
eV in large NCs (16 nm) to ∼3.6 eV for small NCs (3.9 nm),
contrary to the Mie solution. The extinction cross-section of NCs
on a per atom basis was found to be independent of the NC size, within
our experimental resolution. The results suggest that quantum confinement
effects strongly influence excitons associated with the <i>E</i><sub>1</sub> transition.
2013-02-12 00:00:00
Optical Extinction Spectra
extinction
Mie solution
nm
NC
eV
Si
bulk
UV
quantum confinement effects
NIR
E 1 transition