Time-resolved photoluminescence study of hydrogenated amorphous silicon nitride

Time-resolved measurements of photoluminescence were carried out on a hydrogenated amorphous silicon nitride film prepared by low-pressure chemical vapor deposition. When excited with 5.0-eV photons, photoluminescence occurs over a broad spectrum ranging from 1.8 to 3.6 eV. The peak energy of this photoluminescence varies with time from several nanoseconds to nearly 1 ms. These results are explained by a combination of an excitonlike recombination process and a radiative tunneling recombination process of photogenerated carriers within the band-tail states, which are affected by the contributions of thermalization, the Coulombic interaction, and the extent of localization.