On the formation of silicon nanoclusters ncl-Si in a hydrogenated amorphous silicon suboxide matrix a-SiOx:H (0 < x < 2) with time-modulated dc magnetron plasma

Resumo

Activation of the process of amorphous-silicon-nanocluster formation in a hydrogenated amorphous- silicon suboxide matrix with time-modulated dc discharge plasma is investigated. The plasma is modulated by repeatedly switching on and off a dc magnetron magnetic coil. It is demonstrated that the resulting self-induction effect leads eventually to an increase in the probability of collisions between discharge electrons and gaseous components. The infrared (IR) spectra of the films showed that plasma modulation enhances predominantly the content of bridging oxygen in the a-SiO_x:H matrix by strengthening the oxygenionization process. It is assumed that this also increases the concentration of silicon nanoclusters ncl-Si with an oxidized outer surface in the plasma and, thus, enhances the ncl-Si flux toward the electrodes of the dc magnetron. The photoluminescence spectra include two broad overlapping bands characteristic of amorphous ncl-Si with maxima in the range of 600–1000 nm.