Effect of ion-irradiation induced defects on the nanocluster Si/Er~(3+) coupling in Er-doped silicon-rich silicon oxide

摘要

The effect of ion-irradiation induced defects on the nanocluster Si/Er~(3+) coupling in Er-doped silicon-rich silicon oxide (SRSO) thin film is investigated. Er-doped SRSO, which consists of silicon nanoclusters (nc-Si) in a SiO_2 matrix, was fabricated using electron-cyclotron resonance plasma enhanced chemical vapor deposition using SiH_4 and O_2 with concurrent sputtering of Er followed by a high temperature annealing. Defects were introduced into the film via irradiation with 3 MeV Si ions and subsequently removed by high temperature annealings. The authors find that ion irradiation reduces Er~(3+) luminescence from SRSO films, even when the excitation cross section and luminescence efficiency of Er~(3+) ions are completely restored. On the other hand, ion irradiation increases the intrinsic nc-Si luminescence and has little effect on the Er~(3+) luminescence from a similarly prepared, Er-doped SiO_2 film, indicating that the presence of irradiation induced defects in the initial amorphous film can reduce the number of Er~(3+) ions available for nc-Si mediated luminescence by as much as a factor of 3.