Ion beam synthesis of Au and Cu nanoclusters in MgO

Abstract Implantation of 2 MeV ions of Au or Cu into single crystals of MgO (1 0 0) at room temperature results in the spontaneous formation of metallic nanoclusters for implantation fluences above a threshold value. The formation and growth of these clusters may be induced by post implantation bombardment with silicon ions which stop beyond the implantation layer, as well as by thermal annealing. We have compared spontaneous nanocluster formation, ion bombardment induced cluster formation and post thermal annealing. The size and number of nanoclusters were studied by optical absorption spectroscopy and using the Mie and Doyle theories which relate the optical absorption bands to the formation of nanoclusters. The post bombardment of the gold implanted samples was made with 1.2, 2.0 and 5.0 MeV silicon ions. The depth and distribution of the gold and silicon were observed using RBS.