Nanocrystal growth crystalline insulators irradiated with high-current Cu ions

摘要

Negative Cu ions of 60 keV have been applied to generate metal nanocrystals embedded in insulators.Crystalline (c-),amorphous (a-)SiO_2 and a spinel oxide,MgO 2(Al_2O_3),were irradiated at various dose rates up to about 100 um A/cm~2 ,at a total dose of 3.0x10~16 ions/cm~2.In a-SiO_2,morphology of nanoparticles and the resultant optical property changed with dose rate and,at a critical condition,showed in-plane arrangement of nanocrystals.The optical property of c-SiO_2 ( alpha -quartz) was qualitatively similar to that of a-SiO_2 but the implanted region of c-SiO_2 showed different irradiation responses.The c-SiO_2 was suseptible to radiation-induced amorphization but the nanoparticle morphology was still different from a-SiO_2,suggesting a stronger depth-oriented driving force.Unlike SiO_2 ,kthe spinel oxide showed good structural stability against the implantation and no tendency of the long-range atomic rearrangement.The results indicate that the crystallinity and the relevant interactions may play an important role in the nanoparticle growth during the implantation.