Zn Ion Post-Implantation-Driven Synthesis of CuZn Alloy Nanoparticles in Cu-Preimplanted Silica and Their Thermal Evolution

Cu nanoparticles (NPs) were fabricated in silica by 45 keV Cu ion implantation at a fluence of 1.0 x 10(17) cm(-2) and were then subjected to implantation of 50 keV Zn ions at fluences of 1.0 x 10(16), 5.0 x 10(16), and 10.0 X 10(16) cm(-2), respectively. Our results clearly show that post Zn ion implantation could significantly modify structures and components of the preformed Cu NPs and thus the corresponding surface plasmon resonance (SPR) absorption can be modulated in a wide range. In particular, CuZn alloy NPs with unique SPR absorption were synthesized in Cu-implanted silica followed by Zn ion implantation at a fluence of 5.0 X 10(16) cm(-2). During subsequent annealing, two distinguished processes concerning CuZn alloy NPs (i.e., realloying and dealloying) were found that directly result from thermally driven diffusion of Zn atoms. Moreover, owing to Zn diffusion, lots of core-shell nanostructures consisting of Zn-related compound shells around Cu cores were observed after annealing at 500 degrees C and higher. The underlying mechanism concerning the formation and decomposition of CuZn alloy NPs is discussed and presented.