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 ${\mathrm{N}}^{+}$ , ${\mathrm{Si}}^{+}$ , ${\mathrm{Ar}}^{+}$ , and ${\mathrm{Cu}}^{+}$ ions at $300\mathrm{keV}$ to a fluence of $5\times {10}^{16}\text{ions}∕{\mathrm{cm}}^2$ , by ${\mathrm{Cu}}^{+}$ ions at varying energies from $110\text{to}500\mathrm{keV}$ to a fluence of $5\times {10}^{16}\text{ions}∕{\mathrm{cm}}^2$ , and by ${\mathrm{Cu}}^{+}$ ions at $400\mathrm{keV}$ to fluences varied from $1\times {10}^{16}\text{to}1\times {10}^{17}\text{ions}∕{\mathrm{cm}}^2$ . 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.