Gold/Tin Oxide Nanocomposite by Nanojoining

In this paper we report synthesis of Au-SnO2 nanocomposite by nano-joining. It involves synthesis of Au and SnO2 colloids separately followed by post irradiation of mixed Au-SnO2 colloids. We have used 532 nm and 1064 nm wavelengths of a pulsed Nd:YAG laser and different post irradiation time. The post irradiation by 532 nm laser light results in formation of Au-SnO2 nanocomposite by nanojoining. Distinct gold nanoparticles along with the SnO2 aggregates are observed in case of post irradiation by 1064 nm showing no nanojoining effect. Our results indicate that nanojoining is a wavelength selective process. The X-ray Photoelectron Spectroscopy (XPS) indicates negative binding energy shift of Au 4f peak whereas the position of Sn 3d peak remains unaffected after the post irradiation process. The invariance of Sn 3d peak after post irradiation indicates no change in the valence state of Sn. A red shift with respect to the plasmon resonance peak of gold colloids is observed in Au-SnO2 nanocomposite. PACS: 52.38.Mf; 61.46.-w; 81.07. –b.