Dose dependence of room temperature photoluminescence from Si implanted SiO²

Photoluminescence from Si implanted silica is studied as a function of Si fluence and Si concentration profile in order to assess the effect of particle size and size distribution on emission spectra. Peaked (skewed Gaussian) concentration profiles were produced by implanting with 400 keV Si ions and uniform Si profiles were produced by a multi-energy implant sequences. Both as-implanted and annealed samples are shown to exhibit a distinct maximum in the emission intensity as a function of ion fluence, with the intensity increasing with fluence up to the maximum and then decreasing at higher fluences. Samples with a uniform Si profile are also shown to produce emission which is significantly red-shifted relative to that of samples with a peaked Si profile. This is consistent with the fact that such samples are expected to have a narrower particle size distribution (i.e. a greater fraction of larger particles).