It was recalled that previous studies had reported the existence of a 1.8eV photoluminescence band [full-width at half-maximum of 0.2 to 0.4eV, decay time of about 200ns, photoluminescence excitation peak of 2.1eV] in silica glass which was exposed to visible light. The O-deficiency associated defect centers [Si clusters or SiOx (x < 2) structure] were thought to be the cause of this photoluminescence band. The heat-treatment characteristics of the 1.8eV photoluminescence band in silica glass (excited by visible light) were described here. In the low-temperature region (~600C), a decrease in the intensity of this photoluminescence band was observed. On the other hand, the 2.1eV photoluminescence band (full-width at half-maximum of ~0.32eV, decay time unknown) was observed upon annealing at about 1050C. It was proposed that the high-probability SiOx (x < 2) structure, rather than the Si clusters, played a predominant role in the generation of the 1.8eV photoluminescence band, and that crystalline Si nanoparticles were probably the cause of the 2.1eV photoluminescence band.

Effect of Thermal Heat Treatment on Oxygen-Deficiency Associated Defect Centers - Relation to 1.8eV Photoluminescence Bands in Silica Glass. Y.Sakurai: Journal of Applied Physics, 2004, 95[2], 543-5