Publication at Faculty of Mathematics and Physics |
2013
Abstract
We studied the nonlinear transient absorption dynamics in silicon nanocrystals/SiO2 superlattices. A different dependence of the measured dynamics on excitation intensity was observed depending on the relative position of the probe photon energy and the absorption edge of nanocrystals.
At low photon energies, the dynamics changed with excitation fluence and the signal was ascribed to excited state absorption. However, at photon energies above the absorption edge, the phonon enhancement of indirect absorption prevails over excited state absorption what is reflected in excitation fluence independent dynamics of transient absorption. (c) 2013 AIP Publishing LLC.