A study of structure and optical absorption of α-SiO2 layer implanted with Ag+

At room temperature, samples of single crystal α-SiO2 were implanted with Ag+ at 200 kV potential to 6.7 x 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 spectra prove that SiO2 amorphous layer is formed in the surface of single crystal SiO2 implanted with 6.7 x 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 image shows that the nano-sized spherical particles of Ag are formed in the implanted layer, with two kinds of mean sizes, i.e. about 25 nm and 5 nm respectively. The size distribution for the larger particles is considerably narrow. The optical absorption spectra demonstrate that three absorption bands exists around 404 nm, 210 nm and 620 nm respectively. The absorption around 404 nm results from the surface plasmon resonance of silver particles, and the others are attributed to the defects caused by implantation