Effect of Thermal Annealing on the Photoluminescence of Dense Si Nanodots Embedded in Amorphous Silicon Nitride Films

Luminescent amorphous silicon nitride-containing dense Si nanodots were prepared by using very-high-frequency plasma-enhanced chemical vapor deposition at 250 degrees C. The influence of thermal annealing on photoluminescence (PL) was studied. Compared with the pristine film, thermal annealing at 1000 degrees C gave rise to a significant enhancement by more than twofold in terms of PL intensity. The PL featured a nanosecond recombination dynamic. The PL peak position was independent of the excitation wavelength and measured temperatures. By combining the Raman spectra and infrared absorption spectra analyses, the enhanced PL was suggested to be from the increased density of radiative centers related to the Si dangling bonds (K0) and N-4(+) or N-2(0) as a result of bonding configuration reconstruction.

Automated summary

Luminescent amorphous silicon nitride-containing dense Si nanodots were prepared using very-high-frequency plasma-enhanced chemical vapor deposition at 250 degrees C, and the influence of thermal annealing on photoluminescence was studied. Thermal annealing at 1000 degrees C significantly enhanced the photoluminescence intensity, showing nanosecond recombination dynamics, and the peak position was independent of the excitation wavelength and temperatures. The enhanced photoluminescence was suggested to be from the increased density of radiative centers related to Si dangling bonds and nitrogen bonding configuration reconstruction.