Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 10: Quantum Dots and Wires: Preparation and Characterization II (mainly Arsenides)
HL 10.8: Vortrag
Montag, 26. März 2012, 13:00–13:15, EW 202
Relaxation of excited charge carriers in silicon nanocrystals embedded in silicon dioxide — •Andrey Moskalenko1, Jamal Berakdar1, Alexander Poddubny2, Alexei Prokofiev2, Irina Yassievich2, and Serguei Goupalov2,3 — 1Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, Germany — 2Ioffe Physical-Technical Institute of RAS, St. Petersburg, Russia — 3Department of Physics, Jackson State University, USA
We study different mechanisms of the charge carrier relaxation in silicon nanocrystals embedded in silicon dioxide. In our work we assume the spherical shape of the nanocrystals and use the single carrier states obtained in the framework of the multiband effective mass approximation [1]. We find that the relaxation is dominated by the phonon-induced transitions. For small nanocrystals, generally, several phonons needed to be emitted due to the relatively large interlevel energy spacings for both electrons and holes. The corresponding transition rates of the multiphonon transitions are calculated in dependence on the nanocrystal size and temperature. Typically, these rates vary in a broad range from nanoseconds to picoseconds for an ensemble of nanocrystals with a certain size distribution, leading to the multiexponential decay of the carrier populations that should be observed.
[1] A. S. Moskalenko, J. Berakdar,
A. A. Prokofiev, and I. N. Yassievich, Phys. Rev. B 76, 085427 (2007).