Disorder and cluster formation during ion irradiation of Au nanoparticles in SiO2

作     者：P. Kluth B. Johannessen G. J. Foran D. J. Cookson S. M. Kluth M. C. Ridgway 

作者机构：Department of Electronic Materials Engineering Australian National University Canberra ACT 0200 Australia Australian Nuclear Science and Technology Organization Menai Australia Australian Synchrotron Research Program Building 434 9700 South Cass Avenue Argonne Illinois 60439 USA 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2006年第74卷第1期

页      面：014202-014202页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：Au nanoparticles (NPs) have been formed by ion beam synthesis in 600nm thin SiO2. Subsequently the NPs were irradiated with 2.3MeV Sn ions at liquid nitrogen temperature. Samples were analyzed using extended x-ray absorption fine structure (EXAFS) spectroscopy and small angle x-ray scattering (SAXS) as a function of Sn irradiation dose. Transmission electron microscopy shows that the NPs largely retain their spherical shape upon irradiation. However, we observe a reduction in average NP size and a concomitant significant narrowing of the size distribution with increasing irradiation dose as consistent with inverse Ostwald ripening. At lower irradiation doses, significant structural disorder is apparent with an effective bond length expansion as consistent with amorphous material. At higher irradiation doses, EXAFS measurements indicate dissolution of a significant fraction of Au from the NPs into the SiO2 matrix (as monomers) and the formation of small Au clusters (dimers, trimers, etc.). We estimate the volume fraction of such monomers/clusters. Ion irradiation thus yields disordering then dissolution of Au NPs.