Photoluminescence of SiO_x Thin Films After Annealingat Various Temperatures

We study photoluminescence (PL) of SiO_x (0< x <2) thin films after annealing at temperatures in the range of 700-1100°C. The SiO_x thin films were prepared by evaporation of SiO powder onto the substrate of Si(100). Two PL emission structures were observed in the measuring range of 580 -755 nm. The one centered around ～ 730 nm was confirmed to be due to Si nanocrystals. The origin for the other one spanning the range of 580-650 nm was investigated by using hydrogen and oxygen passivations, and by short time annealing at 1100°C followed by hydrogenation. Our results support the model of structural defects in SiO₂ matrix for the origin of the 580-650 nm PL peak.