Photoluminescence properties of Ge-doped silica glass

Ge crystals doped in SiO2 glassy materials were formed by heating GeO2/SiO2 glass at 700 degrees C in the presence of hydrogen. The GeO2/SiO2 glass was prepared by the sol-gel technique. The Ge/SiO2 samples showed a special photoluminescence property to give off strong room temperature luminescence at 392 nm(3.12 eV), secondary strong luminescence at 600 nm(2.05 eV) and weak luminescence at 770 nm(1.60 eV), when excited by 246nm (5.01 eV) ultra-violet light. The structure of this new luminescence material was studied by XRD, XPS, and TEM techniques. The results show that the existences of nanometer-sized (around 10 nm) Ge and GeO crystals in the SiO2 may cause the three band photoluminescence property. As a comparison, there is only GeO2 in SiO2 glass before the heating plus reducing process, and the photoluminescence property is not found.