Published online by Cambridge University Press: 15 February 2011
Negative Cu ions of 60 keV have been applied to generate metal nanocrystals embedded in insulators. Crystalline (c-), amorphous (a-)SiO2 and a spinel oxide, MgO·2(Al2O3), were irradiated at various dose rates up to about 100 µA/cm2, at a total dose of 3.O×1016 ions/cm2. In a-Sio2, 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-Si0 2 (a-quartz) was qualitatively similar to that of a-SiO2, but the implanted region of c-SiO2 showed different irradiation responses. The c-SiO2 was susceptible to radiation-induced amorphization but the nanoparticle morphology was still different from a-SiO2, suggesting a stronger depth-oriented driving force. Unlike SiO2, the 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.