At room temperature

samples of single crystal a --SiO2 were implanted with Ag+at 200kV potential to 6.7×1016 ions/cm2. The structure and optical absorption of the implanted SiO2 layer were investigated by means of Raman

XPS

RBS

TEM and optical absorption spectroscopy. The Raman spectya prove that SiO2 amorphous layer is formed in the surface of single crystal SiO2 implanted with 6.7 × 1016 Ag+/cm2. The XPS result indicates that silver exists in a metallic state in the implanted layer. And the RBS analysis illustrates that the depth distribution of the implanted Ag is bimodal in shape. The bright--field TEM adage shows that the nano--sized spherical particles of Ag are formed in the implanted layer

with two kinds of maan sizes

i.e.about 25nm and 5nm respectively. The size distribution for the larger particles is considerably narrow. The optical absorption spectya demonstrate that three absorption bands exist around 404nm

210nm and 620nm respectively. The absorption around 404nm results from the surface plasmon resonance of silver particles

and the others are attributed to the defects caused by implantation.