Ion irradiation induced hollow and sandwiched nanoparticles

We report on the fabrication of hollow and sandwiched nanoparticles by ion irradiation. Ag nanoparticles embedded in silica were irradiated by $N+$⁠, $Si+$⁠, $Ar+$⁠, and $Cu+$ ions at $300keV$ to a fluence of $5×1016ions∕cm2$⁠, by $Cu+$ ions at varying energies from $110to500keV$ to a fluence of $5×1016ions∕cm2$⁠, and by $Cu+$ ions at $400keV$ to fluences varied from $1×1016to1×1017ions∕cm2$⁠. The size of the irradiation-induced nanovoids increases with increasing ion mass and energy. The formation of nanovoids depends on the electronic and nuclear energy loss of the irradiation ions. The formation of irradiation-induced sandwiched nanoparticles is because of the capture of knocked-out Ag atoms from nanoshells by nanovoids. The size of the inner nanoparticles within the sandwiched structure increases with increasing fluence.