Effect of hydrogen passivation on the microstructure of silicon nanocrystals in SiO2

Si nanocrystals were formed by implantation of Si+ into SiO2 film on (1 0 0) Si, followed by high-temperature annealing. Transmission electron microscopy (TEM) was used to examine the effect of hydrogen passivation on the microstructure of the Si nanocrystals (nc) in SiO2 film. The size and spatial distribution of the Si nc in both non-passivated and passivated samples were investigated using dark-field imaging technique. It is shown that the size and spatial distribution of the Si nc are much similar for both samples. The concentration of Si nc in SiO2 film was determined from the dark field images taken under different diffraction conditions. Selected area electron diffraction pattern shows that there is no preferential orientation for the Si nc in the SiO2 film. For the passivated sample, the increase of photoluminescence intensity is attributed to the elimination of the optically inactive defects in SiO2 matrix and around the Si nc/SiO2 interface.