Photoluminescence of Si Microcrystals Embedded in SiO2 Glass Films

Abstract

Si microcrystals were doped into SiO₂ glass film by the rf magnetron sputtering technique. The average diameter of Si microcrystals was estimated by transmission electron microscopy observation. The dependence of photoluminescence of Si microcrystals on the average diameter is discussed in detail. The absorption of Si microcrystals and the photoluminescence for the larger diameter (≥ 3 nm) seem to be determined by the bulk property of a quantum dot. For the smaller diameter (≤ 3 nm), surface effects of a quantum dot seem to play a role in the photoluminescence. The experimental line shape of the PL spectrum was explained theoretically by the inhomogeneous broadening of the size distribution function of a quantum dot for the larger diameter (> 3 nm).