Abstract
This Ph.D. thesis is focused on the study of relaxation and recombination processes in silicon nanocrystals embedded in dielectric (SiO2, SiC and Si3N4) matrices that were fabricated within the EU 7th Framework Programme Silicon Nanodots for Solar Cell Tandem (NASCEnT). Dierent host materials, in which silicon nanocrystals are incorporated, not only provide dierent transport properties, but also dierently aect the nanocrystal surfaces.
A large part of the thesis is devoted to research of SiO2{embedded silicon nanocrystals having various sizes (in the order of nanometers) and various inter-nanocrystal separation, that dier also in the manner of an additional annealing. Experimental techniques of optical spectroscopy are used to monitor the photoexcited charge carrier dynamics on a wide time scale from picoseconds to milliseconds.
The initial (picosecond) dynamics is characterized very well using a relevant rate equation. We propose a theoretical description of how the multiparticle recombination rate depends on the inter-nanocrystal separation.
Furthermore, we show that P{type doping with boron and remote plasma hydrogen passivation have a dramatic eect on the recombination of photoexcited charge carriers in SiC{embedded silicon nanocrystals. In the case of silicon nanocrystals embedded in Si3N4 matrix, the origin of visible photoluminescence is studied and discussed in detail.