Visible photoluminescence of Si clusters embedded in silicon nitride films by plasma-enhanced chemical vapor deposition

Strong visible photoluminescence (PL) has been observed in the hydrogenated amorphous silicon nitride (a-SiNx:H) films prepared by plasma-enhanced chemical vapor deposition (PECVD). With various temperatures annealing, the evolution of the structure and of the PL properties has been studied to explain the PL origin. With the disappearance of PL peak with respect to triple bond; length of mdashSi0 (dangling bonds) at the higher annealing temperature, the intense PL peak shows an obvious blueshift. Accompanying with the blueshift, a new PL peak on the high-energy side, about 640 nm, has been observed in the spectra, and the appearance of the new PL peak has been discussed. In terms of the present results, the intense PL originates from the Si clusters embedded in the silicon nitride.